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Seite ci erie Ft ee tn ae rs) = Gran: oe east sae cae cane a ae it aye iS mee > Ss = mien CR se Sees pets meen Sets a el ¥ pot ona on, 44 , we Jy Saree tosis CEMA, rr Reha Sie ae *) > oan maa oe ‘ 7 +} a ee - seed A As eis " eu as eee Nora Fertitta as hate he ma aFa FoF ‘ are tthe ahaa ieee WeT pment Byatt aay ¥ oe #7; Peete AisGran Lat abs, eZ 4 Bee ie, it 4 3 ¢ oy ae i ees ee 23 Bs ea Sw TA eae CANGS 4) = ey vie aa ‘ ht a > +e, * or is a eit ee 5 at eek in Pasion) ie Ent ae. ee cm . eee BAS ms oe a) “ars Gs tet Ay ZL ete Aes, ve \ os an Pore Ne Oe ate ote corn se ined * ahde ie in eee ed Get ; Rama baeys ay Mites Alii State ht + cannes irate RiiG Psp toy 249%) Ese RHE Oe ‘i he Batis EER EM he vei H Rai Bae i“ A" oa baie ss = = Wet ty MSE gtsta a Ltathtetaepeiae Shs ete Bs NS S ie i 4 eae or Sosor te x Oa Sse Meet ~~ Me —— ; oh) NS pas cand Se A & tee) ECL ns i oe 5 ey RAs Te eee =e oa Soe Fee eee ee en a Sp se mae ats ba Sate c, aa) as etek ase Pe t yA path St ee © Se ee Sel Bulletin of the British Museum (Natural History’ | The lichen genus Usnea subgenus Neuropogon F. Joy Walker Botany series Vol 13 No 1 28 March 1985 The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. Papers in the Bulletin are primarily the results of research carried out on the unique and ever-growing collections of the Museum, both by the scientific staff of the Museum and by specialists from elsewhere who make use of the Museum’s resources. Many of the papers are works of reference that will remain indispensable for years to come. Parts are published at irregular intervals as they become ready, each is complete in itself, available separately, and individually priced. Volumes contain about 300 pages and several volumes may appear within a calendar year. Subscriptions may be placed for one or more of the series on either an Annual or Per Volume basis. Prices vary according to the contents of the individual parts. Orders and enquiries should be sent to: Publications Sales, British Museum (Natural History), Cromwell Road, London SW7 5BD, England. — World List abbreviation: Bull. Br. Mus. nat. Hist. (Bot.) © Trustees of the British Museum (Natural History), 1985 The Botany series is edited in the Museum’s Department of Botany Keeper of Botany: Mr J. F. M. Cannon Editor of Bulletin: Mr J. R. Laundon Assistant Editor: Dr A. J. Harrington ISBN 0 565 08004 0 ISSN 0068-2292 Botany series Vol 13 No 1 pp 1-130 British Museum (Natural History) Cromwell Road London SW7 SBD Issued 28 March 1985 The lichen genus Usnea subgenus Neuropogon Mey Ee] F. Joy Walker Department of Botany, British Museum (Natural History), eta Road, London SW7 5BD et Contents = MMs cess ne coy pees A yen slr douse va pucean ven SEC Leela asaT aoe itaniee ne cue 1 ME OC NUCN chest 5 is haan psec osnubey enn shoes das eed desde ad ae ona cade Vanden ee iteors demons Previouscollectionsand research... 5,-2.0. ce<-.cccescocseccecseesevaresscuvserstesieccene ..BRITISH MUSEUM See eee Tg, DCSE Ey PAU At le ER PLEO NSO ENR MOV Saat ae A eC LAA AERATOR TRANG, orate {NATL URAL HISTORY) Dee GIR AIMIN TOO oy sa. on crs vocndsc ses ecevengaestcaey cy teksto se eic over comide eae ees MER iss Fares Gesine SPN eet tev oe waa nd PEN CASE E TEETER ooh va CRED CemEeCLaS oes oe Lg BAR i you DUNS ARN Se ec as val Sey acs adak s oistaw Nc eke sera e Lao Gem FRl Ade CORTES ELIA CRONE oie yalsoe Mikes RP NAR EN edict cicn yer ta Catook ve ee ee ids ee Eee ene Re P PASENTE D ET TSE EE AER St oeet PEPE GORE Sie RES SAG AT ie TER .GENERAL LIBRARY OE ER RE SS POORC CODER PRC PURE ERE RRA NETS UOMO REN DREEE T UoE See BPO RNS Net EE IEE 24 BNW MIS 2s ouih cee sole one ah Ske Puc Valls stead og ek ag awk CaM RSet cA Reta ad oa Zr MOM ORIME RUINS ic dec oas a rs PuGhg Ae as ee aan eee ata Cae Ue ey FE 31 MMMM 520 5755 os aA Sos seb eas ee cate ea bide siesile Pads luo Ts Cone IRONS PEIN 36 Rape AURIPRCHINEOIT On SINE BDECION 25055 5 og oe sae onsen rug a ueyuuabiatadsestucarstesaleccacisccoes nice 36 Genercconcept and infrageneric classification ............0.cccesvecsecsesenecsececsevvsserecees 41 PEC IMD TNCUTIOROM? 555.550.5505 3c dx2555 Sha og scaneecn esuaigoies Soueeed ateeens fomebsatawdornies odes 43 Ree RUN ANN ENCS ict Zatch ox ox scsi Faasan io Vacdaniry chur sein cc seen oes pane Coe uae een ea rereleeca cos 44 MERI rs ie sate ow oany heey 7k mC ah eee spre cess ONG ea Tanee omnes TOs ance ee ins case ot eee 47 REAR Me PEN rcta re sincee ic cy access cerstha rene car aadiess ou oabaskuves cube ore wear 47 FoR: MIU Boe css eco osi Seer e re ee cA oR OO ERTERET EINE RESCRRTG ELEN ETE RE ARE Ge 48 SB 5 A INLET CRD ios ds cascity ee tepe agen Sel I Ge Cth enn CGN Pda To Tee toad ng outs OLE EAS TS 55 oe CPS MD TABCONI Goh 55 rc ue thes waa eee Tene ae eiien ee odes theo Nene NMEA aio ee 62 RR OU cic es Siig Tee Sonnale cones etc ve nade none Snes Be tenATR Oa tau OEE dG ee aera ss 74 A Me elon eae as teehee eka Tee Kee dieses WWE RUS ee he ae 78 Let, VETO DOR OMNES Ss cece cue agen tarde decane say aazet on oie tepoa a tadek suey isoow es 80 Tes RMR O COR ast Tit Seaton co Ranke gets ad dian i toneay Peau Tas dome Ice h oaertyeys uTIE 82 ADEE TU Ey Ree SEEN AA oe OnE ERERE SPP LI UnS te ROTA AGA AN TLIMNOAAY Cl Sree ye 85 UES OU SEE) 111 | ane 2 AA SRO ae PAR et Wea evant CIR Eyer a Pe 89 RE Wy BPACCIOIG sos, fa era bcs oe ane Na eda one cee ten suetee edule Mem nedeeees tg eeieenieh ea nee 92 Bis os Ree ENNIO oh Sic f sia s asi ah ec at eRe en FUT ae Wee te oe dan ew cals WORE Peeves eeTeeES 99 Mes 0d, MEM MAOTABIUD occ 5.t5.25 pa shang dias 3s bc SE SSN SS He eS BUMS mam MD heyy a exes canine oe cade eS Se 104 BANS Rt MOUND so 25 ch cahitons coew nts cdgsces atc aeee. teaseken ta cer ses se etosbees ahaa ehece ones ceaeaecyeaie ras 108 Een MECCA A ao 5525 (auxin aceelagacsx so eb cus cates seirecs sTRE Sos 50 vi eeeeetea ewes senant tae ts 110 Pe ie PATIO COR cassc cach sanotacn a eraae en Ka een ees MRE ins 115 PUM BE. RGU (AEA 555 os cations Sor cunk sas oaaunea sane sarees eecas seamen dan cantestavoue nuns 120 PN NINETIES 5 oo bd iets Ada b ertce Sancta Papaek be vated antes aia stues eu ey een fucks 122 eM I ee iio 2 cn iss gant bah hs OY Sec bs Sev ne eaaN Dane Gis eC RSa eT TAR SRT PEN ses FES 122 EE URSA Sided Re ace heel Bey ARCO Ere RNP RE OY ECT PREP CERT TS eee ean eee 129 Synopsis A world-wide taxonomic revision is presented for the lichen genus Usnea subgenus Neuropogon. In summary, this subgenus is here circumscribed to include polar-alpine species with a yellow to yellow-green thallus with varying black or violaceous black pigmentation; a black, or rarely brown, matt apothecial disc, often with excipular rays; and almost always a saxicolous habitat. Fifteen species are recognised, of which three are new: Usnea patagonica, U. pseudocapillaris, and U. subantarctica. Two described species, U. durietzii and U. neuropogonoides, are included in the subgenus for the first time; one name change, U. Bull. Br. Mus. nat. Hist. (Bot.) 13 (1): 1-130 Issued 28 March 1985 2 F. J. WALKER sulphurea to U. sphacelata, has had to be made resulting from nomenclatural considerations; three new combinations are made: U. acanthella (Lamb) F. J. Walker, U. perpusilla (Lamb) F. J. Walker, and U. subcapillaris (D. Galloway) F. J. Walker. Several taxa are reduced to synonymy, including U. melaxantha with U. aurantiaco-atra and U. rohmederi with U. perpusilla. The taxonomic section is preceeded by an outline of previous research and accounts are given of morphology, chemistry, distribution, ecology, phytosociology, and biogeography. Reasons for accepting subgeneric status are given. In delimiting species much consideration has been given to the polymorphic nature of Usnea species and hence a wide range of infraspecific variation is often tolerated. A detailed account is provided for each species with particular emphasis attached to variation, chemistry, and species concepts. Three allied species belonging to Usnea subgenus Usnea which may be pigmented are included in the key to the species and are discussed in Appendix I. Introduction Previous collections and research Species of Usnea subgenus Neuropogon form one of the most conspicuous groups of bipolar- alpine lichens, often being the dominant fruticose lichens found in such inhospitable localities. Apart from a distinctive variegated black and yellow-green colouration (yellow to ochraceous in herbaria) and comparatively large size, members of the group are more easily collected than other associated saxicolous lichens which are frequently crustose. Consequently the group has often formed the major part of collections made by botanists and non-botanists alike on expeditions to the antarctic and arctic from the late eighteenth century to the present day. Despite their prominence there are still certain areas, in particular the northern Andes and even Central and North America, where the subgenus is extremely rare and difficult to interpret. Frequently the only known collections from these areas have been made by explorers and mountaineers, for example Whymper; further field work is needed to fill in the gaps that still exist in distributional patterns and to provide the essential ecological information which is particularly needed for the study of this group. The first arctic Neuropogon specimens to be brought back to Europe by explorers and described as new taxa by contemporary lichenologists were collected during the late eighteenth and early nineteenth centuries. Early literature was restricted to the description of individual species and the first group of these, Lichen sulphureus (K6nig, 1772) and L. pallidus (Retzius, 1779), were based on material collected in Iceland, whilst Usnea sphacelata (Brown, 1823) was described from arctic North America. During the same era expeditions to southernmost areas of South America also brought back Neuropogon material. The earliest southern hemisphere species to be described, Lichen aurantiaco-ater (Jacquin, 1781), i.e. Usnea aurantiaco-atra, was based on collections made by Commerson in 1767 from the Magellan Straits area. Other notable collectors of new taxa during the early nineteenth century include Cavanilles (Acharius, 1803) and Gaudichaud (Persoon, 1828), who both collected on the Falkland Islands, as well as Poeppig (Nees & Flotow, 1835) from southern Chile. Material was also collected by Darwin from Tierra del Fuego in 1833 and in his journal (Darwin, 1979) he likens the abundance of the extensive swards of Neuropogon around Cape Horn to a variety of grass when viewed from a distance. By the early nineteenth century explorers were beginning to survey the antarctic continent. The first Neuropogon species, Usnea fasciata (= U. aurantiaco-atra), to be described as new from Antarctica was brought back to America from the South Shetland Islands (Torrey, 1823), probably by a whaling party. Hooker’s account of the botany of the voyage of the ships ‘Erebus’ and ‘Terror’ (Hooker, 184447) and ‘Lichenes antarctici’ (Hooker & Taylor, 1844) provided the earliest accounts of antarctic lichens as a group and also recorded the presence of Neuropogon species on Iles Kerguelen, one of the isolated subantarctic islands in the southern Indian Ocean. These islands were revisited by other expeditions during the latter part of the nineteenth century, with Neuropogon taxa being described from collections made by the ‘Venus Transit’ Expedition (Crombie, 1876a) and the ‘Challenger’ Expedition (Stirton, 1881). This was not long after the description (Nylander, 1866) of the first Australasian taxon, Neuropogon melaxanthus var. ciliatus (= Usnea ciliata). USNEA SUBGENUS NEUROPOGON 3 Major expeditions to Antarctica on which notable lichen collections were made have been adequately listed by Dodge (1948) for the period 1839-1935 and Lamb (1964) for 1901-1958, together with details of relevant publications and herbaria. Arctic collections have mainly been the province of Scandinavian expeditions and relevant historical collections have been ade- quately cited by Lynge in various publications (for example: Lynge, 1932, 1941). Late nineteenth and early twentieth century lichenologists who contributed to the knowledge of the group included Miiller (1888, 1895), Du Rietz (1926), Rasanen (1932), and Zahlbruckner (1903, 1917), although many of the taxa described by them were subsequently reduced to synonymy. Howe (1915) produced a useful compilation of type data of South American taxa, whilst Du Rietz (1926) provided the first comparative account of the southern hemisphere species although he excluded relevant chemical information. The three twentieth century lichenologists that feature most prominently in the study of Neuropogon are Motyka, Lamb, and Dodge. These authors produced detailed taxonomic studies that were mainly based on collections made by contemporary antarctic expeditions and surveys. Important collections included those made by members of the British Antarctic Survey, formerly ‘Operation Tabarin’ prior to 1946, and the Falkland Islands Dependencies Survey (F.I.D.S.) 1946-1961.* Others include the British, Australasian, New Zealand Antarctic Research Expedition 1929-31 (B.A.N.Z.A.R.E.), and the United States Antarctic Service Expedition 1940-41 (U.S.A.S.). Lamb (1948) also studied some of the rich collections made in Patagonia by Santesson from 1939-41 (S, UPS) which have also been invaluable to the present author during this reappraisal of the group. Motyka (1936-38) included 12 species in the subgenus Neuropogon and also described an additional two species in the subgenus Euusnea nom. illeg. (Article 21.3), i.e. Usnea, that are accepted here as belonging to the group. Motyka was the first author to include any indication of medullary chemistry in his account, which was limited to spot tests with potassium hydroxide solution (K). The most detailed monographic account was produced by Lamb (1939a) who revised Motyka’s work and recognised 13 species and their varieties and forms. Lamb was the first author to make a detailed study of medullary chemistry of the group, using thallus spot tests and microchemical crystal tests, and to use this information on a taxonomic basis. Lamb later (1964) had access to some thin-layer chromatographic (TLC) data provided by Hale. This was a major step forward, although sometimes too much weight was attached to minor chemical differences which would today be regarded as individual races, rather than distinct taxa, by most taxonom- ists. Lamb subsequently (1948a, 1964) emended and added to his earlier account, eventually recognising a total of 15 species of Usnea subgenus Neuropogon. He also realised that many of his individual forms were simply chemical ‘phases’ of a particular species that were only significant at a distributional and ecological level. There have been few reports of medullary chemistry of Neuropogon besides those of Lamb. These include Hawksworth & Moore (1969), Golubkova & Schapiro (1970), Kashiwadani (1970), Filson (1974), and Ghogomu & Bodo (1982), which frequently report the lack, rather than the presence, of depsidones. Lamb’s work provided a sound basis for the identification of Neuropogon species world-wide with particular emphasis on antarctic and some South American taxa. Meanwhile Dodge and associates (Dodge & Baker, 1938; Dodge, 1948, 19655, 1973) had much narrower species concepts and described a series of additional species. Many existing infraspecific taxa were raised to specific rank, often without the study of extant type specimens. Dodge’s work was confined to Antarctica and the subantarctic islands of the Indian Ocean in which he recognised 21 species (Dodge, 1973) and six species (Dodge, 1948, 19655) respectively, accepting a grand total of 30 species in Neuropogon, including one arctic and two Australasian taxa. Some of the taxa described by Dodge have been examined by Lamb (1964) and tentatively reduced to synonymy. Lamb’s interpretations of Dodge’s material have, for the most part, been followed * The collections made by ‘Operation Tabarin’ were referred to by Lamb as F.1.D.S. both on herbarium labels and in subsequent publications (Lamb, 1964); both names are used here following label details. + F. J. WALKER here, particularly where type specimens have not been made available for study; many of the species distinguished by Dodge were separated on minute morphological differences with little or no reference to chemical data. More recent work has primarily concentrated on ecological observations and several plant associations have been described based on Neuropogon-containing communities with other lichens and bryophytes. Examples include Smith & Corner (1973), Follmann (1965a, 1967), Lamb (1970), and Gimingham & Smith (1970). Taxonomic work has been limited to the preparation of local antarctic and subantarctic floras following Lamb’s treatment and includes floras of South Georgia (Lindsay, 1975), the South Orkney Islands (Smith, 1973), the South Sandwich Islands (Longton & Holdgate, 1979), Marion Island (Lindsay, 1977b), Macquarie Island (Filson, 1981), Mac. Robertson Land (Filson, 1966, 1975), Wilkes Land (Filson, 1974), and Bouvet@y (Jgrgensen, pers. comm.). These floras have been produced in conjunction with recent expeditions or the work of permanent scientific bases (for example, the British Antarctic Survey) that have been established around the antarctic continent by various nations. The aim of this present study is to give a comprehensive account of the species belonging to Usnea subgenus Neuropogon. Special emphasis has been placed on the circumscription of the species in the light of the wide range of infraspecific variation, new chemical data, and relationships with closely allied taxa. There has been no critical work on the subgenus since that of Lamb (1939a, 1948a, 1964). Taxonomic review Neuropogon was published as a genus by Nees & Flotow (1835) within the Usneaceae (= Parmeliaceae, Henssen & Jahns, 1973) and was based on two species N. poeppigii and N. antennarius. N. poeppigii was subsequently transferred from the genus by later authors, details of which are given by Lamb (1939a, 1964), commencing with the transfer to Chlorea by Nylander (1860) and, more recently, to the subgenus (Motyka, 1936-38) or genus Protousnea (Krog, 1976). Nylander (1860) is consequently considered to have emended the original concept of the genus since the original description of Nees & Flotow circumscribed both Protousnea and Neuropogon, based on common features of thallus colour, anatomy, apothecial shape, and disc colour. However the citation ‘Neuropogon (Nees & Flotow) Nyl.’ by Lamb (1939a) is erroneous as no new combination was actually made by Nylander. Nylander (1860: 272) is also considered to have, in effect, selected N. antennarius as the lectotype of Neuropogon, consequently Motyka’s (1936-38) citation of N. melaxanthus as the type species is superfluous. The genus Neuropogon was relegated to the rank of section or subsection of the genus Usnea Hill ex Browne (Laundon, 1984) by Montagne, in Gay (1852), and to a subgenus by Jatta (1900), although he (Jatta, 1909) later accepted Neuropogon as a distinct genus. Jatta’s combination (Jatta, 1900) Usnea subgenus Neuropogon (Nees & Flotow) Jatta was based on two species, Usnea arboricola and U. soleirolii, that were not subsequently regarded as belonging to the subgenus and were finally included in Lethariella subgenus Lethariella (Krog, 1976). For this reason Jatta’s combination was wrongly regarded as invalid by Motyka (1936-38) and omitted by Lamb (1964). However, in accordance with the Code (Article 63.2) the combination must be accepted, as the type of Neuropogon is, by implication, included in the combination. Conse- quently the full citation at subgeneric level is Usnea subgenus Neuropogon (Nees & Flotow, emend. Nyl.) Jatta, and the citation ‘Usnea subgenus Neuropogon (Nees & Flotow) Motyka’ (Motyka, 1936) is incorrect (Culberson, 1966). Materials and methods The following account is based primarily on collections in institutional herbaria. I have also had access to material collected in recent years by the following botanists: James (Patagonia, New Zealand), Henssen & Vobis (Patagonia), Follmann (South America), Santesson (Patagonia), Hertel (Marion and Prince Edward Islands), Engelskjgn (Bouvetgy), Galloway (New Zea- land), Bratt (Tasmania), S@mme, Angard (Dronning Maud Land), Seppelt (Knox Coast, McDonald and Macquarie Islands), Halls (Bolivia), and, in addition, extensive collections made USNEA SUBGENUS NEUROPOGON 5 by various members of the British Antarctic Survey (Antarctic peninsula and islands). The material referred to in this study has been subjected to thin-layer chromatography (TLC) by means of standard methods (Culberson, 1972; Culberson & Johnson, 1976; Culberson et al., 1981; Walker & James, 1980). Type specimens have been examined and tested by TLC unless otherwise stated. In the text + denotes sporadic or low concentration of a given substance. Details of morphology and anatomy were also studied using the scanning electron microscope (SEM) (Cambridge Stereoscan ISI 60A). Species descriptions are based on either type material or characteristic specimens in rare instances where the type is very atypical. Details of variation, species concept, chemistry and distribution are given for each species, together with notes on typification and nomenclature when applicable. Allied taxa, not considered to belong to Usnea subgenus Neuropogon, are given in Appendix I, and excluded taxa in Appendix II. Only selected records are cited for the commoner and more widespread species according to chemical race. Full lists are only given in instances where new records or critical or new taxa are involved. Author abbreviations follow guidelines laid down by Laundon (1979). Results Morphology For convenience various morphological features are discussed under subheadings. Emphasis is placed on those features that were found to be of value for species delimitation within the subgenus. Species may be divided initially into two groups, namely those which produce apothecia and lack vegetative propagules, and those which produce soredia, pseudoisidia, or isidia and only rarely produce apothecia. Habit and mode of branching, surface ornamentation, and branch anatomy are important diagnostic characters, whilst others, including pigmentation and faveolation were found to be less reliable. The relative importance of these characters is discussed below. It is important to emphasise that within any given species specimens may exhibit considerable variation due to modification by ecological factors (Filson, 1982; Hawks- worth, 1973) and consequently certain features may then be atypical of the species. Scanning electron microscopy was used in certain instances to clarify interpretation of some features, for example vegetative propagules, and to show similarities to Usnea subgenus Usnea. Habit and mode of branching: Most species within the subgenus can be distinguished by their saxicolous habitat with erect, cartilagineous main branches arising from either a delimited or proliferating holdfast. In some species the form and blackening of the holdfast, together with the initial branching pattern, are characteristic, whilst in other species this is a much more variable feature. For example, Usnea ciliata arises monopodially from a proliferating, often blackened, holdfast; U. durietzii branches a short distance above a solitary holdfast to give a tree-like habit; whilst in U. acromelana and U. sphacelata the form is much more variable, ranging from a delimited holdfast to a spreading colonial form. Occasionally thalli are subpendulous or subdecumbent. This is a feature of Usnea subcapillaris and, to a lesser extent, U. pseudocapillaris. Many antarctic species may atypically become subdecumbent when growing in very exposed habitats. Similarly, thalli, for example in U. aurantiaco-atra, may rarely become detached and develop a scrambling habit resembling that of U. neuropogonoides. The extent of branching in any given species is often very variable although the overall form is often characteristic. Some species remain virtually monopodial or more or less subdichotomous towards the apices, for example Usnea ciliata and U. taylorii. Others, for example U. antarctica and U. aurantiaco-atra, may be richly branched from a delimited holdfast. An angular, divergent, branching pattern is characteristic of U. subcapillaris and U. pseudocapillaris which both branch repeatedly from a confined holdfast to form a loosely interwoven network of fine branches. These two species are further characterised by the very friable nature of the secondary branches, the brittleness is accentuated in herbarium material. 6 F. J. WALKER Pigmentation: The extent of black or violaceous black pigmentation of the thallus is very variable within the subgenus and frequently appears to reflect particular ecological parameters (see p. 25). Pigmentation may be extensive or confined to apices or papillae. Pigmentation of the thallus base near the holdfast was rarely of value, owing to the lack of correlation with other features, although it was occasionally used. Although pigmentation is one of the main features of the subgenus it is not unique within Usnea s. lat. and its relative importance is discussed elsewhere under ‘Generic concept’ (p. 42). Black pigmentation of the apothecial disc is characteristic of most species, although there are two exceptions, Usnea trachycarpa and the rarely fertile U. subantarctica, which have a brown to rufous brown disc. Pigmentation may also be a feature of vegetative propagules and is only found when soredia or other structures, such as isidia and pseudoisidia, are partially corticate. Some specimens of the norstictic-salazinic race of Usnea aurantiaco-atra assume a pinkish colouration of the medulla in the herbarium. This has no taxonomic value and is not compatible with the pigment found in some Usnea species, as for example in U. roseola, as reported by Swinscow & Krog (1979). Surface ornamentation: Surface features may either be uniform or rather variable within the individual species. A smooth, waxy, rarely subfaveolate, thallus with blackened annulations is a constant feature of all four species belonging to the Usnea ciliata complex (U. acromelana, U. ciliata, U. pseudocapillaris and U. subcapillaris). Such annulations may sometimes occur in other species, for example, U. patagonica, or may atypically, be the result of weathering effects or necrosis in species where they are usually absent. A smooth, waxy surface is also characteris- tic of U. taylorii which, in addition, sometimes has scattered, slightly raised, pale maculae, formed by protrusion of the axis towards the surface through the cortex. In some species, for example U. perpusilla and U. sphacelata, the surface is more variable, and may either be smooth and waxy or become more or less scabrid to subpapillate with minute, frequently pigmented, papillae. On occasions this variation may be observed in different parts of the same specimen. In those species which have a very lax medulla, the primary branches may become notably inflated and attenuated at the point of attachment. This is a particular feature of Usnea durietzii and abnormal forms of U. sphacelata. In contrast to Usneas. str., pseudocyphellae, as described by Swinscow & Krog (1979), do not occur in the subgenus, although they may be recognised when associated with certain forms of asexual propagule formation (see below); the use of the term ‘soralium’ in the broad sense is preferred in this context. Gaps in the cortex left on the branch after the breaking away of fibrils or erosion of pseudoisidia may sometimes resemble pseudocyphellae. Papillae: These are recognised as small hemispherical or conical protuberances composed mainly of cortex (Swinscow & Krog, 1979). Prominent papillae are a feature of several species, in particular Usnea antarctica and U. aurantiaco-atra and, to a lesser extent, U. subantarctica and U. trachycarpa. In these species the thallus usually lacks the waxy lustre that is a characteristic feature of epapillate species. The relative size and presence of pigmentation of papillae may sometimes be used as an additional distinguishing feature. For example, papillae are small and normally pigmented in U. sphacelata and usually coarser and generally lack pigment in U. antarctica and U. aurantiaco-atra. U. aurantiaco-atra has a very varied range of morphology which varies from almost smooth or faveolate to papillate or verrucose-rugose; variation of this diversity may rarely be observed in a single thallus of this species. Fibrils: Fibrils are regarded (Swinscow & Krog, 1979) as laterally developed appendages containing an axis as well as a medulla. Numerous stout, elongate fibrils on the main branches, derived from papillae, are a feature of Usnea trachycarpa imparting a bottle brush-type of appearance; in some individuals the surface in this species may, less typically, be more or less papillate or faveolate. Short, capillaceous, spreading fibrils are often a feature of U. subantarc- tica, whilst in U. patagonica the fibrils are usually replaced by extended, thin, rarely branching, lateral branches that bear soralia. USNEA SUBGENUS NEUROPOGON 7 Internal structure: Relative widths of cortex, medulla, and axis are important taxonomic features and are frequently expressed as a ratio. However, a wide range of variation may be exhibited in individual species and, in some instances (Swinscow & Krog, 1979), may be of little taxonomic significance. It is essential to examine well-developed main branches since the medulla may not be fully expanded in finer, secondary branches. Within Neuropogon the basic delimitation of the cortex, medulla, and central axis is uniform in all species except Usnea taylorii, where a broad axis is deeply invaded by strands of medullary tissue containing algal cells, often resulting in the unique formation of several separate axial strands in this species. In some species the presence of a lax, arachnoid medulla accompanied by a thin axis, often occupying less than half the diameter in main branches, is diagnostic and occurs in, for example, Usnea acanthella, U. durietzii, U. perpusilla, and U. sphacelata. In the latter two species there is considerable variation, and the medulla may only be slightly lax and the axis consequently occupying a greater portion of the main branch diameter. By contrast, a compact medulla with a broad axis is a characteristic feature of U. antarctica and U. aurantiaco-atra. In other species, for example U. trachycarpa, although the medulla may sometimes be relatively broad, it is often sublax, and even species which normally have a compact medulla, for example in the U. ciliata complex, there may occasionally be some degree of laxness, especially towards the axis. Examples of various transverse sections are given in Fig. 1. SEM work has revealed that some species with a lax medulla, for example Usnea acanthella, U. perpusilla, and U. trachycarpa, have medullary hyphae ornamented with small nodular outgrowths. This was not found to be of taxonomic value and has previously been reported in Usnea s. str. (L6pez-Figueras & Palacios-Prii, 1981) and also within the Parmeliaceae in Alectoria s. lat. (Brodo & Hawksworth, 1977). Apothecia: Within the subgenus six species: Usnea aurantiaco-atra, U. ciliata, U. perpusilla, U. subcapillaris, U. taylorii, and U. trachycarpa, produce abundant apothecia and lack vegetative propagules and, to date, four asexual species: U. acromelana, U. antarctica, U. pseudocapillaris, and U. subantarctica are occasionally fertile. Apothecia have not been observed in the remaining five species: U. acanthella, U. durietzii, U. neuropogonoides, U. patagonica, and U. sphacelata. The position as well as the form of the apothecium may be a useful diagnostic feature in some instances. For example, in Usnea subcapillaris apothecia are lateral, whilst in U. taylorii, U. trachycarpa, U. aurantiaco-atra, and U. ciliata they are almost invariably subterminal, some- times with a short, geniculate appendage; in U. perpusilla they are often produced laterally in series along a branch, each with a broad area of attachment (Fig. 2). Exceptions to this arrangement frequently occur in all these species. Excipular rays always occur in Usnea trachycarpa, U. ciliata, and U. subcapillaris but are only rarely present in U. perpusilla and U. aurantiaco-atra; they are absent in U. taylorii. The undersurface ornamentation of the excipulum may be diagnostic and usually reflects that of the subtending branch. However, in U. perpusilla and, occasionally, in U. ciliata, the surface may become individually faveolate. The dark disc colour is also a characteristic of the subgenus, although sometimes pigmentation may not be fully developed in abnormal or immature apothecia in those species which normally have a black disc resulting in a greenish grey colouration. U. trachycarpa and U. subantarctica are unique in the subgenus in having a rufous brown disc. The spores are similar to those in Usnea s. str. and are simple, ellipsoid, hyaline and usually fall within the range 7-10(-12) x 5—7(-8) wm. Variation in size has not been studied statistically, but there appears to be little variation between species and no taxonomic importance has consequently been attached to them here. The structure of the ascus apex is identical to that of the subgenus Usnea and corresponds to the ‘Lecanora-type’ described by Honegger (1978). Vegetative propagules: Three types of vegetative propagules are found within the subgenus: soredia, pseudoisidia, and isidia. Soredia are defined as clusters of fungal hyphae and algal cells without cortex, whilst pseudoisidia, which originate in the same way, are outgrowths from F. J. WALKER ? Fig. 1 Examples of transverse sections of main branches. A & B — U. taylorii, C - U. ciliata, D - U. antarctica, E & F — U. aurantiaco-atra, G — U. sphacelata, H — U. patagonica, I — U. perpusilla. USNEA SUBGENUS NEUROPOGON 9 Fig. 2 Disposition of apothecia. A — U. ciliata (Bartlett 25962, BM) x2, B — U. perpusilla (Lamb 6046, CANL) x4, C- U. aurantiaco-atra (Lamb 1085, CANL) x2. soredia or soralia-like areas that become partially secondarily corticate in contrast to true isidia, which are corticate from conception. A detailed study of propagules and their formation has been provided by Beltman (1978) using the SEM; similarities with her findings occur in Neuropogon species. However, in some instances the clear distinction between soredia, pseudoisidia, and true isidia may be rather difficult to resolve since intergradation and regeneration often occurs. Such intergradation may occur within a species or an individual thallus and is the result of breakdown of the primary propagule, for example pseudoisidia, with the subsequent formation of the second, for example soredia. However, the primary type of propagule formed is specific for the species and consequently used as the diagnostic character. Examination of a range of structures using the SEM has shown that soredia are not corticate, whilst pseudoisidia often have a thin, incomplete, secondarily developed outer cortex, and true isidia have a primary, structured cortex. Differ- ences between vegetative propagules in selected species are given in Fig. 3. (a) Soredia: Shape and formation of soralia in Usnea, together with the type of soredia produced, can be diagnostic, although considerable variation may occur within a given species. According to previous investigations (Krog et al., 1980; Swinscow & Krog, 1975, 1979) soralia formation .in Usnea is either primary or secondary. Primary soralia in, for example, U. glabratula, develop directly from the cortex by local breakdown and are usually plane or concave initially, sometimes becoming protuberant on development. Secondary soralia arise from pseudocyphellae subsequent to the breakdown of isidia, for example in U. subfloridana, and are often protuberant. However, in this species it is apparent that such soralia may become 10 F. J. WALKER Fig.3 Vegetative propagules. A isidia—U. acanthella (holotype, BM), B soredia— U. antarctica (F.1.D.S. B1119, BM), C pseudoisidia — U. patagonica (Henssen & Vobis 244991, MB), D pseudoisidia — U. durietzii (Gibby & Barrett, July 1979, BM). Based on SEM studies; blackened areas represent cortex. Scales A = 1mm, B-D = 50 um. corticate, thus producing pseudoisidia. This is in contrast to true isidia that are produced directly from the cortex. According to the above definition, soralia initiation in the majority of asexual species of Neuropogon may be classified as primary, although this distinction is often difficult to interpret in species that produce pseudoisidia. In most species such primary soralia arise directly from the thallus, for example in Usnea acromelana, U. pseudocapillaris, U. sphacelata, and U. subantarc- tica, and are initially concave, though they may become convex to globose. Soredia may become secondarily corticate, often very irregularly or thinly so, thus forming minute, more or less spherical pseudoisidia. This is a feature of species which appear to have pigmented soredia; for example in certain forms of U. acromelana and U. sphacelata, where the pigment corresponds to overlying fragments of cortex. Such structures can be distinguished by size from the cylindrical, more or less elongate pseudoisidia that are a feature of U. durietzii and U. patagonica. Soralia initiation in Usnea antarctica is unusual and may be classified as secondary in a different sense since they are produced on papillae and, unlike species in which soralia develop USNEA SUBGENUS NEUROPOGON Le from the cortex, are not confined to apices or secondary branches. These soralia often have a distinct crateriform margin and rarely also produce small, dark, pigmented pseudoisidia. Soredia development in Usnea patagonica and U. durietzii may also be regarded as secondary since they are produced from the breakdown of pseudoisidia. This process appears to be cyclic since both structures may occur in an individual ‘soralium’. In U. patagonica such soralia often arise from small papillae but do not have a distinct margin characteristic of U. antarctica. (b) Pseudoisidia: Pseudoisidia were defined by Dahl & Krog (1972) as isidia-like structures lacking a true original cortex, such as occur in Evernia prunastri. Beltman (1978) found the delimitation impractical in that species, although she observed intermediate structures amongst soralia and lobules that presumably corresponded to pseudoisidia. Other terms have been used to describe similar structures: ‘soredial isidia’ was used by Du Reitz (1924) and Maas Geester- anus (1947) to describe isidia-like structures formed in soralia to distinguish them from ‘isidial soralia’ or ‘sorediose isidia’ (Beltman, 1978) which are produced by breakdown of apices of isidia, as in Parmelia subaurifera. Similar small, corticate structures resembling isidia, particu- larly in Alectoria, have been referred to as ‘soredialasten’ (Henssen & Jahns, 1973); ‘isidioid spinules’ (Brodo & Hawksworth, 1977) and ‘isidial soralia’ (Jahns, 1980; Krog et al., 1980). All these terms appear to correspond to a structure that is characteristic of two species of Neuropogon, namely Usnea durietzii and U. patagonica. The term pseudoisidia is here preferred to describe the small, partially secondarily corticate, pigmented structures that are produced in soralia-like clusters and have the same origin as soralia. The cortex is often ill-defined unlike that found in true isidia. Pseudoisidia are either produced in delimited, soralia-like structures, or may be of secondary origin, formed by regeneration after the breakdown of true isidia as, for example, in U. torulosa and U. amblyoclada (see Appendix I) where they may also erode to produce soralia. (c) Isidia: True isidia only occur in one species, Usnea acanthella, where they may be up to 1 mm in length. They arise as small clusters from tubercules on the surface of the thallus. Such isidia lack a central axis but have a true primary cortex, often with a minute fracture at the constricted base assumed to assist in dispersal, and fracture leaving a scar (Beltman, 1978; Du Rietz, 1924; Maas Geesteranus, 1947). Sometimes fibrillae are also produced in this and other species and may be distinguished by the presence of a central axis; they correspond to structures occasionally observed in Protousnea dusenii (Krog, 1976). Pycnidia: Pycnidia are immersed in the cortex and form irregular, hemispherical swellings, ranging from 100-200 wm in diameter, towards the apices of ultimate branches in pigmented or unpigmented areas. Individual loculi are separated by thallus tissue although often superficially appearing to be compound with several ostioles. Lindsay (1859) provided a detailed account of the pycnidia of Usnea taylorii and U. aurantiaco-atra (as Neuropogon melaxanthus). Lamb (1939a) also observed pycnidia in U. aurantiaco-atra, and described the conidia as ‘staff-shaped, sometimes with a slight eccentric swelling’, and subsequently (Lamb, 1948a) described those of U. perpusilla (as U. rohmederi) as ‘broadly fusiform’. Pycnidia are rare and difficult to observe, but have been examined in the following fertile species: Usnea aurantiaco-atra, U. perpusilla, U. taylorii, and U. trachycarpa. Examination of the type of U. trachycarpa f. elatior revealed the pycnidial wall to be hyaline whilst in U. aurantiaco-atra this was found to be pigmented throughout. More specimens should be examined before any conclusions may be reached, although this might indicate an additional taxonomic difference between species with rufous brown and black apothecial discs. Conidia were found to be of a similar size in all species, in the range 9-11(-14) x 1-1-7(-2) wm. Their shape conforms to sublageniform as described by Krog (1982) or are more or less narrowly fusiform but are slightly swollen at the proximal end. However, insufficient specimens have been examined to indicate the full range of infraspecific variation. There is apparently no conidial difference between the two races of Usnea aurantiaco-atra, at least from examination of the lectotypes of Neuropogon antennarius and Lichen aurantiaco-ater, both from subantarctic South America. Krog & Swinscow (1981) described conidial formation in the Parmeliaceae as endobasidial on 12 F. J. WALKER conidiophores of the bayonet type. The terms ‘endobasidial’ and ‘exobasidial’ of Steiner (1901) have often been misinterpreted or confused by previous authors (Lamb, 1939a, 1948a; Rogers, 1981) when applied to the subgenus Neuropogon. These terms have since been rejected by mycologists (Henssen & Jahns, 1973; Vobis & Hawksworth, 1981) and replaced by ‘terminal’ and ‘lateral’ as defined by Vobis (1980), each comprising a range of types of conidiophores. The conidiophores appear to correspond to type VI of Vobis & Hawksworth (1981) in which conidiogenous cells arise in branched chains with the conidia arising laterally. However, intermixed with these, some more or less conidiogenous cells are seen to arise directly from the wall tissue (type II); such cells are occasionally seen with one or two percurrent proliferations. In addition, a few conidiophores approximating to type V have been observed in which conidia are produced terminally. Chemistry Usnic acid is present in varying concentrations in the cortex of all species. A limited range of B-orcinol depsidones (connorstictic, fumarprotocetraric, norstictic, protocetraric, psoromic, 2'-O-demethylpsoromic, and salazinic acids), rarely B-orcinol depsides (squamatic and hypothamnolic acids), or fatty acids (murolic acid complex) occur in the subgenus. As in Usnea subgenus Usnea, frequently a particular species may exhibit more than one chemical race with either different, but often biosynthetically related, substances present. Many species also have an acid-deficient phase which may be dominant, for example, in U. taylorii and U. sphacelata; one species, U. acanthella, has no demonstrable chemistry. The substances, with the species in which they occur, are given in Table 1. Only those of a diagnostic value are given, whilst substances which may occur in conjunction with one of the main compounds, such as connorstictic acid, cph-1 (yellow accessory with fumarprotocetraric acid, Culberson et al., 1981) and unknown accessory substances, are omitted from the table. In some species the overall distribution and abundance of certain chemical races may vary but in areas where there is an overlap of two races thalli are encountered which have a composite chemical complement. This phenomenon is known to occur, for example, in Usnea aurantiaco- atra and U. subcapillaris and often produces evidence against accepting species based solely on chemical differences. Such mixed strains are omitted from Table 1 and are discussed further under ‘Circumscription of the species’ (p. 39) and U. aurantiaco-atra (p. 71). 1. B-orcinol depsides: Squamatic and hypothamnolic acids are the only two f-orcinol depsides known within the subgenus Neuropogon, occurring with, or rarely replacing, B-orcinol depsi- dones in a single species, Usnea subcapillaris. This is in contrast to the subgenus Usnea where a wide range of depsides is found. Consequently, in specific instances, the detection of f-orcinol depsides can be a useful factor in separating certain species of the subgenus from closely allied taxa. For example, in the Usnea ciliata complex, squamatic acid is only known in arare race of U. subcapillaris whilst it is frequently found in U. torulosa; a species belonging to the subgenus Usnea which is superficially similar to some ecotypes of U. acromelana. Conversely barbatic acid is sometimes found in U. torulosa but has not yet been found in any Neuropogon species. Further, in South American collections, the presence of the orcinol depside divaricatic acid in species of Protousnea is an additional character useful for separating members of that genus from Usnea neuropogonoides or decumbent forms of U. aurantiaco-atra. 2. B-orcinol depsidones: The range of f-orcinol depsidones found in the subgenus Neuropogon and related taxa were identified by TLC using solvent systems HEF and TDA following the method of Walker & James (1980). Solvent system G (toluene/ethylacetate/formic acid) of Culberson et al. (1981) was used to confirm the presence of salazinic acid and connorstictic acid in norstictic-salazinic acid chemotypes, using Parmelia sulcata and P. perforata as controls. The presence of connorstictic acid was only demonstrated when the concentration of norstictic acid was high. Stictic acid has not been found in the subgenus. An additional unknown yellow spot, Rf class TDA 1, HEF 2-3, accessory to norstictic acid, was sometimes found in Usnea trachycarpa. USNEA SUBGENUS NEUROPOGON 13 Table 1 Chemical properties of Usnea subgenus Neuropogon. nor sal pe fpc pso sqm _ hth fat frequency U. acanthella U. acromelana : x x + ; i U. acromelana 2 x R U. acromelana 3 i U. antarctica 1 = x< C U. antarctica 2 x x R U. antarctica 3 Gc U. aurantiaco-atra 1 ‘ 7 x Cc U. aurantiaco-atra 2 x x a3 L U. aurantiaco-atra 3 c U. ciliata = U. durietzii 1 x Gc U. durietzii 2 R U. neuropogonoides 1 x a Cc U. neuropogonoides 2 = € U. patagonica + U. perpusilla 1 x R U. perpusilla Z C U. pseudocapillaris x D4 NE U. sphacelata | x R U. sphacelata 2 ec U. subantarctica 1 4 na G U. subantarctica Z G U. subcapillaris 1 x x si ; Cc U. subcapillaris 2 < at R U. subcapillaris 3 x R U. taylorii 1 = R U. taylorii Z G U. trachycarpa 1 x x a5 , : : ; + Cc U. trachycarpa 2 x : ; ae R U. trachycarpa 3 + = Only substances of diagnostic importance are included. nor = norstictic acid, sal = salazinic acid, pe = protocetraric acid, fpc = fumarprotocetraric acid, pso = psoromic acid (including 2'-O-demethylpsoromic acid), sqm = squamatic acid, hth = hypothamnolic acid, fat = fatty acids. Symbols: x = constant; + usually present as an accessory substance or occurring in low concentrations; + = present in most specimens. C = Common, widespread throughout range. R = Rare throughout range or from a single locality. L = Locally abundant, restricted distribution within range. Solvent system G was also particularly useful for identification of substances belonging to the fumarprotocetraric acid complex in Usnea aurantiaco-atra and U. antarctica. The substance cph-1 (Culberson et al., 1981) was frequently found as an accessory substance to fumarpro- tocetraric acid, producing a yellow spot on developed chromatograms. Its presence was confirmed using Cetraria straminea as a control and further by two-dimensional chromatography employing first solvent system G and then HEF, with suitable controls and following fig. 2 of Culberson et al. (1981). This method was also used to confirm the occasional presence of traces of salazinic acid and distinguish it from cph-2 (Culberson et al., 1981), in specimens containing 14 F. J. WALKER the fumarprotocetraric acid complex. For example, traces of salazinic acid were confirmed in a collection of Usnea antarctica from South Georgia (Lindsay 4327, AAS) and in U. aurantiaco- atra from Tierra del Fuego (Henssen & Vobis 24417a, MB), both containing fumarprotocetraric acid as the primary constituent. In the subgenus Usnea Swinscow & Krog (1979) found that although protocetraric acid nearly always excluded the production of salazinic acid it neverthe- less occurred in some thalli that contained both substances. In Neuropogon protocetraric and salazinic acid may occur together when norstictic acid is present, as for example in the Usnea ciliata complex. The same method of two-dimensional chromatography was used to check the identity of depsidones in a chemically mixed specimen of the two depsidone-containing races of Usnea aurantiaco-atra from the Falkland Islands (R. I. L. Smith 2572, AAS). It was also used to establish the identity of salazinic acid and protocetraric acid in Race 2 of the same species from Isla de Los Estudos (Staten Island) which lack norstictic acid. With two-dimensional chromato- grams it was sometimes found useful to run an additional control plate containing a mixed extract of the test specimen with known substances as an alternative, or in addition to, running one-way controls in each solvent on the same plate. The distribution of psoromic acid cannot reliably be used as a diagnostic feature since it occurs randomly throughout the subgenus as it tends to do in quite a few taxa of Usnea subgenus Usnea. Its presence is apparently of a spasmodic nature and it is frequently only known from a handful of collections in a single species with a different chemistry. It is also of interest to note that in two instances, in Usnea perpusilla and U. sphacelata, psoromic acid occurs in species which otherwise characteristically lack diagnostic medullary substances. A previous report of psor- omic acid in antarctic material of, for example, U. antarctica (Golubkova & Schapiro, 1970) is incorrect and refers to an unknown substance (see p. 15). 3. Fatty acids: A series of fatty acids which may be of diagnostic importance are found primarily in Usnea trachycarpa. These are related to lichesterinic acid and are here referred to as the murolic acid complex. Their chemical structure has already been elucidated by previous authors (Bodo & Molho, 1980; Ghogomu & Bodo, 1982) who found that two of the acids isolated corresponded to murolic and muronic acids, previously known from Lecanora muralis (Huneck et al., 1979). Ghogomu & Bodo (1982), using material from Iles Kerguelen, identified the remaining four acids as 13-acetoxyprotolichesterinic acid, 13-acetoxylichesterinic acid, isomur- onic acid, and neuropogolic acid. The six acids were found to have Rf values ranging from 0-30 to 0-46 in TA. The murolic acid complex has here been demonstrated in all three chemical races of Usnea trachycarpa throughout its range. These were found to correspond to Rf classes 3 to 5 in TA, using norstictic, psoromic, and stictic acids as markers. Improved separation was obtained when plates were run twice over a distance of 11 cm. Additional acetone extracts were also run in solvent system G (Culberson et al., 1981), designed to separate depsidones with low Rf values. This system also gave improved separation of spots lying approximately between norstictic and stictic acids. Traces of additional substances were sometimes found which made it difficult to identify individual fatty acids. This may indicate that the complex also contains traces of other unknown fatty acids. A series of fatty acids, apparently belonging to the same complex, has also been found in Usnea patagonica. Frequently only two to four fatty acids were detected with the remaining acids absent or only present in trace amounts. The number of fatty acids detected in a single specimen on the TLC plate from this species varied according to the solvent system used or the number of times the plate was run. This may be due to variation in the concentration of the extract spotted on each plate, or, since U. trachycarpa uniformly resolved into six spots, may indicate that some different acids are involved which do not separate so readily in the solvent systems used. At least one fatty acid found in U. trachycarpa belonging to Rf class 5 in TA did not occur in U. patagonica. At least two fatty acids belonging to Rf classes 2-3 in TA occur in Usnea neuropogonoides and USNEA SUBGENUS NEUROPOGON 15 are present in both chemical races. These appear to be identical to those of lower Rf classes found in U. patagonica. Very rarely traces of similar, unidentified fatty acids occur in other species in the subgenus, for example Usnea acanthella, U. antarctica*, and U. subantarctica, but their presence is not constant enough to warrant taxonomic significance. 4. Accessory substances: Throughout the subgenus three undetermined substances were found which produced characteristic coloured fluorescence under long-wave UV light (see Table 2) on chromatograms before charring. On developed plates the spots are either colourless or have slight pinkish or yellow-grey colouration. These substances are here referred to as ‘UV + unknowns’ and appear at random in most species in the subgenus, with or without medullary substances, and are consequently of no taxonomic value. They are probably unstable or locally concentrated as it was often not possible to repeat the original results from the same thallus. In most species UV + unknowns are only present in trace amounts but in Usnea perpusilla they often occur in high concentrations. \S Table 2 TLC properties of UV + unknown substances in Usnea subgenus Neuropogon. Rf classes UV fluorescence colour of spot Substance TDA HEF _ TA before charring after charring (+) A 3 5 3 pale violet quench or purple pale pink B 2 5 2 pale yellow greenish grey pale yellow-grey Cc 2 3 1 pale violet quench or purple pale pink D 1-2 3 1 white quench or purple colourless + The TLC properties of the UV + unknowns A, B, and C are given in Table 2 along with an additional unknown, D, which fluoresces white under long wave UV light and sometimes occurs in trace amounts with unknown C. Substances C and D may, in trace amounts, be mistaken for fumarprotocetraric or protocetraric acids which have similar Rf classes; however, the character- istic fluorescence of the unknown substances should be a distinguishing feature. Rf classes obtained for unknowns A, B, and C agree with those found by Jgrgensen (pers. comm.), working on material from Bouvet@y, in Usnea antarctica and U. aurantiaco-atra. The occurrence of these unknown substances in antarctic Neuropogon specimens has previously been published by Golubkova & Schapiro (1970). One substance was incorrectly identified by them as psoromic acid and probably corresponds to unknown A. These substances have occasionally been detected in Usneas. str. Distribution Figs 4-8 The subgenus Neuropogon has a bipolar distribution and largely replaces the subgenus Usnea in arctic, antarctic, and subantarctic regions. Only one species, Usnea sphacelata, is bipolar, witha circumpolar distribution in the northern boreal regions as well as in Antarctica, and with outliers in the subantarctic and North, Central, and South America. One species, U. acanthella, is apparently confined to the northern Andes, whilst the remaining species have antarctic or subantarctic-alpine distributions. Further details are to be found under each species. The distributions discussed here are arranged according to various geographical areas as a back- ground to biogeographical considerations and to substantiate, or comment upon, some records to be found in the literature. Areas where difficulties may arise in identification of species, due to variation or overlap of distributions, are also indicated. 1. Northern Andean chain At present three species, Usnea acanthella, U. durietzii, and U. sphacelata, are known to occur in * Identified as murolic and neodihydromurolic acids by Huneck et al. in J. Hattori bot. lab. 56: 461—480 (1984). 16 F. J. WALKER 1% / ! SS / \ t | a | \ ! \ ! \ - \ | N 1 "qn | m Leee OF Eas Oe or +0 \ is © \ mee \ \ a = r 4 rh 4 \ U. antarctica U. aurantiaco-atra Wis taylorii Fig.4 Antarctic and subantarctic distribution patterns. USNEA SUBGENUS NEUROPOGON ‘i see a -): % Seo — 0, VE io a ee _ S 4 es See en ee NO Od Baek & U. neuropogonoides —meaomeo oa: U. patagonica Fig. 8 South American distribution patterns. USNEA SUBGENUS NEUROPOGON 21 this area. The possible occurrence of a fourth species, U. acromelana, remains uncertain or doubtful, whilst U. patagonica reaches its northern limit in Bolivia. The few collections examined have been referred, where possible, to one of these species, sometimes as atypical forms. Frequently specimens are depauperate, moribund, eroded, or extensively pigmented, and in such instances it is not possible to identify material conclusively. 2. Subantarctic South America This area includes Patagonia, Tierra del Fuego, and the Falkland Islands. The greatest concentration of species occurs in this region with three fertile, one sterile, and six asexually reproducing species known. All three fertile species Usnea aurantiaco-atra, U. perpusilla, and U. trachycarpa are known as far north as about 40°S. Two other fertile species, U. ciliata and U. taylorii, have been incorrectly reported from this area, for example by Lamb (1948a) and Rasanen (1932), and misidentifications refer to either atypical, smooth forms of U. aurantiaco- atra, or weathered forms of U. perpusilla. The sterile U. neuropogonoides is only known from a small area on the Chilean—Argentinian border. U. aurantiaco-atra and U. trachycarpa also occur on the Falkland Islands. The six asexual species found in this area are Usnea acromelana, U. antarctica, U. durietzii, U. patagonica, U. sphacelata, and U. subantarctica. Some of these species are reaching the limits of their distribution and consequently atypical morphotypes may occur which may lead to misidentification. For example, U. antarctica and U. durietzii here reach their northern and southern limits respectively. Atypical forms of these two species might be mistaken for U. patagonica but fortunately medullary chemistry can be used as an additional guideline since, unlike U. patagonica, the two species are usually represented by the depsidone-containing race. Morphological differences between all three species are summarized in Table 3. U. antarctica is the only asexual species known from the Falkland Islands and is represented there by a single specimen. Table3 Differences between U. durietzii, U. patagonica, and U. antarctica. U. durietzii U. patagonica U. antarctica Habit/branching irregular to tufted regular with regular with with short laterals extended laterals extended laterals Pigmentation apices, base, apices, base, apices, + soralia, pseudoisidia pseudoisidia, + cortex + cortex Medulla very lax + lax or sublax compact Papillae rare + common common Soralia often becoming remaining + delimited with + confluent delimited, ulcerose crateriform margin Pseudoisidia large, c. 100 um Small, c. 50 wm + absent Chemistry norstictic/salazinic deficient/fatty + fumarprotocetraric acids acids acid 3. Australasia (a) Australia: Two species Usnea acromelana and U. subcapillaris or possibly three (U. ciliata) occur in Australia. The subgenus is uncommon in Tasmania and is extremely rare at very high altitudes in the mountains of Victoria (see below). The majority of specimens examined so far from the mainland are referable to either Usnea torulosa or U. inermis of the subgenus Usnea. Rogers (1981) reported five species (unlisted) from Australia based on catalogues produced by Wetmore (1963) and Weber & Wetmore (1972). These were U. acromelana, U. antarctica, U. ciliata, U. aurantiaco-atra (as U. melaxantha), and U. sphacelata. The epithet ‘melaxanthus’ has frequently been misapplied to sorediate material resulting from Nylander’s (1855) misconcep- 22 F. J. WALKER tion of the species. Examples include Darbishire (1912), Crombie (1879b), and Wilson (1888, 1890, 1893) and again specimens are referable to Usnea subgenus Usnea or rarely, when in Tasmania, to U. acromelana. The record of U. sphacelata from Tasmania (Lawrence, 1834) may also refer to U. acromelana. U. antarctica does not occur in Australia (cf. Filson, 1982). (i) Victoria: Weber & Wetmore (1972) reiterated reports by Wilson (1888, 1890) based on material from Mt. Macedon (37°27'S: 144°34’E) and Mt. Hotham (36°58’S: 147°11’E). Unfortu- nately Wilson’s main herbarium was lost in transit (Filson, 1976). Some duplicate material of Mt. Macedon collections has been traced (NSW!) and specimens belong to the barbatic acid race of U. torulosa. To date the only collections of Usnea acromelana examined are from the Bogong High Plains (36°45’S: 147°21’E) (MEL 18755!, MEL 1018193!). (ii) Tasmania: Usnea acromelana and U. subcapillaris are known from several alpine localities in Tasmania and were previously reported by Lamb (1939a) and Bratt & Cashin (1976) respec- tively. Some specimens of U. acromelana examined have close affinities with U. pseudocapillaris but are somewhat coarser and are retained in the former species for the present, since a wider range of variation is found than amongst New Zealand populations of U. pseudocapillaris. U. ciliata may also occur in Tasmania, but unfortunately, I have not seen any definitive, fertile, material. The few examples seen are damaged and lack apothecia and soralia (for example MEL 1029344! and CHR 342744!), and could be either U. acromelana or U. ciliata. Dodge (1948) cited a specimen, possibly of U. ciliata, in herb. Stirton (GLAM) from Mt. Wellington, but this has not been traced. U. antarctica was reported from Tasmania by Du Rietz (1929). This was a misidentification of U. acromelana, a species which he does not include in his taxonomic treatment (Du Rietz, 1926) since he referred all northern hemisphere material to U. sulphurea and all southern hemisphere to U. antarctica (Du Rietz, 1929). Wilson’s (1893) report of U. melaxantha from Table Mountain was based on Robert Brown’s collections which mainly consist of U. acromelana. | (b) New Zealand and subantarctic islands Five species have recently been recorded from the South Island of New Zealand (Galloway, 1985): Usnea acromelana, U. antarctica, U. ciliata, U. sphacelata, and U. subcapillaris; a further species, U. pseudocapillaris, is described here. Previous reports of U. aurantiaco-atra and U. trachycarpa (Mark & Bliss, 1970; Martin & Child, 1972) are erroneous and probably refer to U. ciliata. The subgenus is commonly represented in alpine areas east of the Main Divide, particularly in central Otago but is rare elsewhere, with U. antarctica and U. sphacelata confined to a few exposed, predominately high altitude localities. U. acromelana and U. ciliata are both known from Stewart Island although the subgenus is rare there and is confined to Mt. Anglem (CHR 343356! and CHR 342749! respectively). The subgenus is very rare in the North Island and, apart from a few recent collections, records are often based on historical data. U. acromelana, U. ciliata, and U. subcapillaris are all known to occur. One collection from Mt. Ruahine (Colenso 1164, WELT!), previously determined as U. ciliata, is Alectoria nigricans, although another specimen (Colenso C1776, BM!, WELT!) from the same locality ‘prope Napier’ (Miller, 1896) is U. acromelana. Both U. acromelana and U. ciliata are known from Tongariro National Park and the subgenus has recently been refound by Bartlett as far north as Gisbourne, from Mt. Hikurangi in the Raukumara Range (Bartlett 25965, BM!) and from the Kaweka Range in Hawkes Bay (Bartlett 25961, BM! 25962, BM!), thus verifying the record in Martin & Child (1972). Only one collection is known from Chatham Island, that collected by Travers (BM!), which is an unusual, decumbent form of Usnea acromelana, growing at a much lower altitude than elsewhere in New Zealand. The subgenus does not occur on the Auckland Islands or on Campbell Island, where it is probably replaced by U. xanthopoga. U. antarctica is the only species examined from Macquarie Island where it is confined to a few localities at the north of the island. Sometimes specimens are somewhat subdecumbent and this has led to misidentifica- tions as that of U. /axissima (= U. sphacelata) reported by Filson (1981). USNEA SUBGENUS NEUROPOGON 23 4, Subantarctic islands of the Indian Ocean Three species are known, two fertile and one asexual. Of the two fertile species, Usnea taylorii and U. trachycarpa, the former i is only known from [les Kerguelen and Crozet. U. antarctica is known from both island groups as well as from Marion Island in the Prince Edward Island group, thus completing the subantarctic circumpolar distribution of this species eastwards from Bouvetgy. Many sorediate taxa have been described from these islands and all are here regarded as synonymous with U. antarctica; the species is represented by a range of rather robust, depsidone-containing variants in this area. Specimens of U. aurantiaco-atra, said to have been collected from {les Kerguelen by Hooker (M!) are unique, and presumably originated from Cabo de Hornos (Patagonia) having been subsequently mislabelled. 5. Antarctica For the purposes of this study Antarctica is here divided into two areas based on geological, climatic, and ecological considerations. The Antarctic peninsula and the antarctic continent as far west as the Ross Ice Shelf are included with the subantarctic islands of the South Orkneys, South Shetlands, South Sandwich islands, and South Georgia and Bouvet@y, and is considered separately from eastern Antarctica, which lies from Dronning Maud Land eastwards to Victoria Land. These approximately correspond to maritime and continental antarctic zones as defined by ecologists, for example Lindsay (1977a), although the maritime antarctic usually only includes the west coast of the Antarctic peninsula as far south as Marguerite Bay (Holdgate, 1970). (See ‘Phytosociology’, p. 28.) (i) Antarctic peninsula and islands: The three most common asexual species are Usnea antarctica, U. sphacelata, and U. subantarctica. U. antarctica replaces U. sphacelata and U. subantarctica in the island groups and is often the only species of the subgenus to be found in some localities, for example, the South Sandwich Islands. U. acromelana is also found in this area, but is rare or overlooked, and is confined to the northern part of the peninsula and some of the islands. Occasionally all four species may be found in a given locality and may exhibit a bewildering range of variation, besides, with the exception of U. sphacelata, sometimes producing apothecia. Usnea aurantiaco-atra is found on the west side of the Antarctic peninsula, the South Orkneys, the South Shetlands, and on South Georgia. U. antarctica and U. aurantiaco-atra both occur on Bouvetgy but are rare (Holdgate et al, 1968). The occurrence of U. trachycarpa is doubtful, based on a single sterile specimen (R. J. L. Smith 3453, AAS!) from the Antarctic peninsula; if supported by further fertile records this would represent a significant extension of its subantarc- tic distribution. (ii) Eastern Antarctica: Only two species, Usnea antarctica and U. sphacelata, have been identified from material from eastern Antarctica. Both species are circumpolar, although U. sphacelata is the commoner, usually occupying more exposed habitats (pp. 26-27). Where both species do rarely occur together one of them is often depauperate, abnormal, or even somewhat intermediate, and particular thalli may be difficult to identify. Unusual, weathered forms of U. sphacelata with a less lax medulla have led some authors (Dalenius & Wilson, 1958; Filson, 1974, 1975; Golubkova & Schapiro, 1970) to confuse this species with U. acromelana, a species that is confined to subantarctic regions and only extends its range as far south as the tip of the Antarctic peninsula. The occurrence of unusual forms has also resulted in the descrip- tion of a spectrum of microspecies which are here reduced to synonymy. Further specimens need to be examined before antarctic distributions can be assessed in detail. A report of U. aurantiaco-atra from Dronning Maud Land (Dalenius & Wilson, 1958) is a misidentification of U. sphacelata (UPS!). Further problems encountered in this area are discussed under “Bio- geography’ (p. 33). 24 F. J. WALKER 6. South Africa Two collections comprising saxicolous Usnea species collected at 1830 m from Cedarberg (Schelpe 1961 BOL!, 1966 p.p. BOL!) have been examined and have proved to be very interesting. Schelpe 1966 is a mixed gathering of an Alectoria species with an unknown, possibly undescribed, Usnea species. Thalli have scattered, pigmented, true isidia that are reminiscent of the type found in Usnea inermis and, like that species, contain psoromic acid. Part of the second collection (Schelpe 1961) was examined by Lamb (1948a) and identified as possibly Neuropogon acromelanus (CANL 16944!) and Neuropogon sp. (CANL 17284!). Material identified by Lamb as Neuropogon acromelanus and part of the original collection (Schelpe 1961!) very closely conforms to Usnea patagonica and is tentatively referred to that species; for differences between the two see p. 84. Other thalli in this collection and the specimen referred to Neuropogon sp. by Lamb do not resemble Usnea patagonica quite so closely and remain unidentified. Further material is required, along with detailed study of South African montane species of Usnea, including types, before the taxonomic position of the Cedarberg specimens can be finally resolved. Taxa related to Usnea pulvinata aggregate, for example U. capensis, may also have to be considered. Since some specimens are tentatively included in Usnea patagonica it is remotely possible that the subgenus Neuropogon s. lat. is extremely rare at high altitudes in South Africa. Another species with a similar pattern of distribution is Pseudocyphellaria gilva which was described from South Africa and is also known from South America. According to Schelpe (pers. comm.) the Cedarberg locality is one of the coldest in the south-west Cape Mountains and is the richest locality for Umbilicariaceae in southern Africa, and consequently is the most likely refugia for any Neuropogon species. Ecology There has only been a brief opportunity for a first-hand study of the ecological requirements of Neuropogon species during the preparation of this account. Consequently much of the informa- tion presented here has been drawn from available literature and discussion with lichenologists who have made detailed field observations. As a result many gaps still exist, in particular for South America, and for species which have a restricted distribution or are only known from a few collections. One of the earliest ecological observations was made by Dumont d’Urville (1826) in his Flore des Malouines who noted that (translation) ‘Usnea melaxantha (U. aurantiaco-atra) grew by preference on bare rocks exposed to the south-west winds, forming an unusual type of sward on smooth rock faces. These rocks were always arranged in fairly regular strata inclined at an angle of 40 to 50 degrees and running from east to west’. This observation reflects the general ecological requirements of the subgenus. These are a more or less acidic, saxicolous substrate and an exposed, predominately arctic-alpine environ- ment which is unfavourable to, and usually excludes, the subgenus Usnea. Species are able to flourish in harsh microclimates where temperature variation, radiation, and drought from freezing or high winds, are all major controlling factors. Such conditions are often termed ecological cold-deserts (Lindsay, 1977a), since water availability is often the most important factor, and are not necessarily confined to polar regions. Consequently a remarkable altitudinal amplitude is exhibited by the subgenus, ranging from sea-level upwards in polar regions, to c. 5000 m in the Andes of tropical America. In areas where the climate is warmer and the rainfall higher, the subgenus is rapidly replaced by the subgenus Usnea. Here Neuropogon is confined to exposed, drier, upland areas, as for example, on Macquarie Island and the New Zealand shelf islands. Neuropogon species are rarely able to compete with the subgenus Usnea; an exception is Usnea acromelana which occupies similar habitats to U. torulosa. Species of Neuropogon are adapted ecologically, morphologically and physiologically (Ahmadjian, 1970) to these cold-desert conditions which impose stresses that are rarely encountered elsewhere (Lindsay, 1977a). The presence of a thick cortex is probably an USNEA SUBGENUS NEUROPOGON 25 adaptation against water loss and, conversely, water uptake (Ahmadjian, 1970), although the latter can still occur via the soralia. In addition much mechanical strength, as found in the tough axial strand, is required to withstand wind-blast. It has often been observed that pigmented lichens are more frequent in Antarctica, and Lindsay (1977a) noted that thalli of Usnea sphacelata are more heavily pigmented in continental than in maritime Antarctica. This pigmentation may provide protection for the underlying algal cells against UV radiation (Ahmadjian, 1970), but more importantly absorbs heat which may assist in melting snow (Lindsay, 1977a) and increase carbon assimilation (Kershaw, 1983). Neuropogon species have to withstand a great range of temperatures (Lindsay, 1977a) and their metabolism shows a remarkably effective physiological adaptation to low temperatures, particularly when dry, and hence may be described as facultatively or obligatively psychrophilic (Lamb, 1970). Field and laboratory measurements of respiration and photosynthetic rates (Ahmadjian, 1970) have shown that thalli of Usnea sphacelata are able to maintain a positive metabolic balance of temperatures as low as —18-5°C, whilst a negative balance occurs above +20°C. Consequently an extended period of high temperatures would be damaging. Distribution of the subgenus is controlled by climatic, edaphic, and biotic factors (i.e. bird rookeries) (Lamb, 1970). Consequently there are few habitats in the polar regions where species of Neuropogon do not occur. Despite being able to withstand severe physiological drought, it is evident that some moisture is essential, either as mist or melt-water, although this requirement varies considerably according to the species. For example, in New Zealand species of the Usnea ciliata complex are absent from areas where there is prolonged snow cover, including the bases of exposed tors on mountain plateaux and in fellfields (Mark & Bliss, 1970). Such intolerance towards prolonged snow cover is similar to that exhibited by Parmelia olivacea in Scandinavia (Ahti, 1966). This is in contrast to some other macrolichens, for example Umbilicaria cylindrica (Mark & Bliss, 1970) and Cladonia bellidiflora (Lynge, 1937), which appear to require prolonged winter snow protection against wind-blast. Similarly in New Zealand, the Usnea ciliata complex is rarely found in the nival zone above the permanent snow-line, or in areas of permanent glaciation. In contrast U. sphacelata, a species that has its main distribution in the polar regions, is best adapted to withstand much harsher climatic conditions and, for this reason, mainly occurs in New Zealand (and Patagonia), in very exposed, snow-free, alpine areas and nunataks at higher altitudes. The distribution of Neuropogon species on the Antarctic continent, excluding the Antarctic peninsula, appears to be very local, thus reflecting the availability of suitable habitats which are limited to ice-free coastal areas and exposed nunataks (Ahmadjian, 1970). For example, the subgenus was not found on Mawson Rock, Mac. Robertson Land (Seppelt & Ashton, 1978) although species of Alectoria, Umbilicaria, and Xanthoria occurred, but has been recorded from many other localities to the west (Filson, 1966, 1975). There are also many localities where, asa result of under-collection, the subgenus has not been previously reported, for example at Hallett Station, Victoria Land (Rudolph, 1963, 1967). On the antarctic continent inland areas often receive more sunshine than coastal areas (Lamb, 1970) and consequently melt-water streams sometimes flow from inland nunataks to coastal outcrops allowing subsequent colonisation (Filson, 1982). The subgenus appears to have a southern distributional limit, since it is often absent from localities that might be considered favourable that support Umbilicaria species (Lindsay & Brook, 1971), although duration of snow-cover may again be a critical factor. Microlichens extend further south than macrolichens (Lamb, 1970; Siple, 1938). This may be due to the narrowing of the boundary layer of warmer air through which fruticose lichens extend (Kershaw, 1983), coupled with an increase in the effect of ice-blast, the relative harshness of which increases with decrease in temperature (Lindsay, 1977a). This is enhanced by the constant katabatic winds (Lamb, 1970; Greene & Longton, 1970) which, combined with the freeze-thaw action may modify thallus morphology (Filson, 1982). Edaphic factors are important since most species are obligate saxicoles, although a few may rarely secondarily occupy more diverse substrates. For example, Usnea antarctica may occa- 26 F. J. WALKER sionally grow on bryophytes, discarded timber, eroded peat, or soil (Lindsay, 1973, 1978; Smith & Corner, 1973), although the range of habitats it is able to colonise decreases towards its southern limit of distribution. Similarly, the South American species, U. acanthella and U. neuropogonoides, may become detached or fragmented and assume a terricolous habitat. The subgenus almost always occurs on acidic rocks and is regarded as calciphobous; it is only able to colonise stable ground (Smith, 1973). For example, in New Zealand, the species of the Usnea ciliata complex are virtually confined to chlorite schists and, to a lesser extent, greywacke or, rarely, rocks of volcanic origin. In contrast, in the subantarctic regions, U. antarctica is often found on volcanic rocks and lavas, for example on Macquarie Island (Huntley, 1971) and on Marion and Prince Edward Islands (Lindsay, 1977b), although the species is unable to grow in the vicinity of active fumaroles that occur, for example, on the South Sandwich Islands (Longton & Holdgate, 1979). Similarly, in Patagonia, Neuropogon species are found on a wide range of substrates from lavas to basaltic rocks and sandstones. Observations in continental Antarctica (Siple, 1938) have shown that whilst Usnea antarctica and U. sphacelata both occurred on granitic and metamorphic sediments, such as schists and sandstones, U. antarctica was more widely distributed on the former. This species is also calciphobous since studies of schist-marble boundaries (Gimingham & Smith, 1970; Smith, 1973) show an abrupt demarkation at the interface. Similarly in the arctic, Lynge (1941) observed that U. sphacelata was common on basaltic or siliceous deposits and did not occur on purely calcareous rocks, although recent collections indicate that this species may rarely occur on slightly calcareous rocks (E. Hansen, pers. comm.) and sandstones. It may be possible that the hardness of the rock in addition to its composition may also influence colonisation. For example, on the Kar Plateau, South Victoria Land, Usnea antarctica was found to occur on dolerite boulders covered with a wind-blown deposit of sandstone grit (Schofield, 1972), thus providing a more suitable substrate. Similarly, in New Zealand, strongly foliated schists are easily colonised (Mark & Bliss, 1970). In addition to substrate composition aspect is also important in relation to microclimate. Despite being able to tolerate very exposed conditions, it is often noticeable that some degree of shelter is necessary against wind or, in maritime environments, against salt-spray. Field observations in New Zealand have shown that the growth of species of the Usnea ciliata complex is more luxuriant on the underhangs of sheltered vertical sides of tors and exposed ridges than on horizontal faces. U. subcapillaris, and presumably U. pseudocapillaris, tend to favour more sheltered habitats and crevices. Similarly in Antarctica, Usnea antarctica occurs in more sheltered habitats than U. sphacelata and consequently the species is usually found at lower altitudes, often growing more luxuriantly some distance inland than at sea-level (Lamb, 1964) due to mist-formation caused by coastal temperature inversions (Lindsay, 1977a). Where both species occur together in continental Antarctica, U. antarctica is generally rare (Dodge, 1962; Ovstedal, 1978) and poorly developed, as it is just surviving at the southern limit of its distribution. Thalli are often small, atypical, and as such may be difficult to identify conclusively. Consequently communities dominated by U. antarctica, that are frequent in the subantarctic regions and on the Antarctic peninsula, are rare in continental Antarctica, being restricted to sheltered habitats (Longton, 1973). In contrast, U. antarctica cannot tolerate excessive moisture. For example on the South Shetland Islands, this species is found in a community with bryophytes and. Umbilicaria antarctica where melt-water collects, but is only prominent on dry surfaces and south-facing aspects (Lindsay, 1971a). Within the subgenus species exhibit varying ecological requirements and tolerances, with asexual species often having wider distributions and occupying a wider range of habitats than their fertile counterparts. The absence of any sexually reproducing species from continental Antarctica may primarily be controlled by environmental conditions rather than distributional factors. Hawksworth (1973), in discussing ecological differences between primary and secon- dary species, observed that greater soralia production occurs in humid situations and that sorediate species are more able to utilise atmospheric moisture. For example, Usnea antarctica has much broader requirements than U. aurantiaco-atra, being able to colonise more varied habitats and occupy a wider range of altitudes (Lamb, 1964; USNEA SUBGENUS NEUROPOGON 27 Lindsay, 1971a). U. aurantiaco-atra is regarded as a montane, maritime species (Lindsay, 1971a; 1977a) which tends to favour slightly more sheltered aspects (Smith & Corner, 1973) and is less tolerant of strong winds (Smith, 1973). This species is unable to produce mature spores towards the southern limit of its distribution (Lindsay, 1971a). U. antarctica, in contrast to U. aurantiaco- atra, is slightly tolerant of nutrient-enriched melt-water (Lindsay, 1969, 1971a). This species is usually regarded as indifferent rather than nitrophilous (Lamb, 1964, 1970), since it may sometimes grow in nitrogenous habitats around bird rookeries with, for example Caloplaca regalis, Xanthoria elegans, and Lecanora aspidophora (Lindsay, 1971a). Both species of Usnea are regarded as halophobous (Lindsay, 1971a), being replaced in coastal communities by Ramalina terebrata (Follmann, 1965b), although U. antarctica may be able to tolerate some salt spray. From general observations on the distribution and ecology of Usnea antarctica and U. sphacelata throughout their respective ranges, it is apparent that the latter is characteristically a species of exposed habitats, usually not in close proximity to the sea, and is consequently the more common species is continental Antarctica. Consequently in the arctic, this species is only found where the climate is sufficiently continental (Bliss, 1981; Greene & Longton, 1970; K. Hansen, 1962; Lindsay, 1977a, 1978). The somewhat restricted distribution in the arctic may therefore be due to climatic as well as biogeographical factors, although its absence from large continental areas may be due to under-collecting rather than ecological reasons (E. Hansen, 1982). Lamb (1964), from studies in the Antarctic peninsula, indicated that although the distribu- tions of the two species overlap, U. sphacelata is often found at higher altitudes than U. antarctica and has a somewhat southerly and easterly distribution in that area. On the Antarctic peninsula U. sphacelata is often replaced by U. subantarctica at low altitudes, a species that appears to have ecological requirements that are intermediate between the other two species. In the subantarctic regions species occur that have different ecological requirements from the antarctic—arctic species. The requirements of the Usnea ciliata complex have already been discussed and these species from an alpine—-southern temperate element which, in Patagonia, is represented by U. perpusilla and U. acromelana. In addition in this area a specialised group of species is prominent which may be referred to as a transitional arid-montane element. This comprises U. durietzii, U. neuropogonoides, U. patagonica, and U. trachycarpa, which are characteristic of areas of low rainfall between the main high Andean Cordillera and the Patagonian plains, although often extending into both areas. Such species occupy a variety of habitats and, although often occurring with arctic-alpine or alpine southern—-temperate species, are primarily adapted to open, exposed, dry but misty, rather than necessarily polar—alpine, habitats. Phytosociology Antarctica and the surrounding subantarctic regions have been divided into various ecological zones, primarily based on phanerogamic communities, by numerous workers (see Holdgate, 1970), and those defined by Longton (1966) have been most widely accepted. Three main zones are recognised: the southern cold-temperate, the subantarctic, and the antarctic, based on the position of the subtropical and Antarctic Convergences (Holdgate, 1970; Skottsberg, 1960). The subantarctic regions have been variously defined (Bliss, 1979; Godley, 1960; Greene, 1964a; Skottsberg, 1960; van Zinderen Bakker, 1971; Wace, 1960) and various islands are included that lie in the vicinity of the Antarctic Convergence, either side of which marked climatic, and hence vegetational differences occur. For example, although South Georgia and Isla de Los Estados (Staten Island) lie on approximately the same latitude, the snow-line on the former is lower than the tree-line on the latter (Deacon, 1960). Consequently South Georgia has been included in the subantarctic zone for floristic and climatic affinities (Greene, 1964a, 19645; Lindsay, 1975), although possessing affinities with both the antarctic and subantarctic regions (Bliss, 1979). Similarly various classifications of arctic vegetation have been proposed, which have been 28 F. J. WALKER summarised by Bliss (1981). Bliss (1979, 1981) has also recently described a new classification for the vegetation of polar and alpine regions based on integrated ecological information. Broadly, various biomes (arctic, subarctic; alpine, subalpine; antarctic, subantarctic) were defined and each divided into low and high zones according to altitude or latitude. Within this regime each high zone may be further subdivided into desert and semi-desert units, thus reflecting the concept of ecological cold-deserts of Lindsay (1977a). This classification is much more flexible than earlier proposals since it is not based primarily on strict geographical or climatic boundaries. Subdivisions of each biome are based on the distribution of key genera which, in the polar desert subdivisions includes bryophytes and lichens. Consequently a particular island or region may support different vegetation zones and be placed in the relevant divisions, thus supporting evidence that gradients exist between zones (Longton, 1967). The divisions maritime (or oceanic) and continental antarctic (Holdgate, 1970) are retained here for convenience, since they reflect the distribution and ecology of particular Neuropogon species, although both are included in the polar desert subdivisions of the high antarctic biome by Bliss (1979). The maritime antarctic includes Bouvetéy, the South Sandwich Islands, the South Orkneys, South Shetlands, the Palmer Archipelago, and the western coast of the Antarctic peninsula as far south as Marguerite Bay. Continental Antarctica has been further subdivided into three zones (Holdgate, 1970; Schofield, 1972), but these are not discussed here. As a result of climatic differences, lichen communities in the maritime antarctic are more diverse, having some affinities with those of the boreal-arctic zones, than those found in continental Antarctica which are local, less diverse, and show affinities with the high arctic (Lindsay, 1978). Antarctic A range of lichen and bryophyte phytosociological communities have been described from the antarctic and subantarctic regions which reflect the general ecological differences that occur between Neuropogon species. In contrast, little ecological work has been undertaken in continental Antarctica and frequently communities described do not contain Neuropogon species. The most detailed research has been undertaken in the maritime antarctic (Allison & Smith, 1973; Gimingham & Smith, 1970; Lindsay, 1969, 1971a; Longton & Holdgate, 1979; Redon, 1969, 1973; Smith, 1973; Smith & Corner, 1973) of which three groups are relevant: those in which Neuropogon species either form a major component, or are less important, or are absent. Fruticose and foliose lichens predominate (Lindsay, 1977a) and three major community types dominated by Neuropogon may be recognised. The Usnea antarctica sociation is characteristic of windswept, gravel-covered cols, and windgaps; whilst that of U. aurantiaco-atra (as U. fasciata) is found on boulder-fields; and that of U. sphacelata (as U. sulphurea) is more characteristic of the east coast of the Antarctic peninsula and continental Antarctica. The first two community- types only are discussed in more detail below. Habitats on the west coast of the peninsula become drier with increasing latitude (Longton, 1967) and consequently vegetation is much sparser and communities less complex, when, for example, those of the Argentine Islands are compared with the South Orkneys (Smith & Corner, 1973). Usnea antarctica is the most widespread Neuropogon species in the maritime antarctic, and many communities have been based on this species, for example the alliance Neuropogonion antarcticum (Follmann, 1967). U. antarctica is the dominant species in the Andreaea-Usnea sociation on the South Orkneys (Smith, 1973) and forming the Usnea antarctica sociation on the South Shetlands (Smith, 1973, 1984) and South Orkneys (Allison & Smith, 1973), which is rare in continental Antarctica (Longton, 1973). The species is also found in the Lecideetum sciatraphae (Follmann, 1967). It is often a primary coloniser (Lindsay, 1978) of boulders in moraines and there is often a succession of U. antarctica followed by crustose species, including Buellia anisomera and B. russa (Lamb, 1970), although the reverse has been observed (Lindsay, 1978). Moss banks may be colonised by a range of lichen species (Smith, 1973) including USNEA SUBGENUS NEUROPOGON 29 Ochrolechia frigida, Cladonia rangiferina, Sphaerophorus globosus, and U. antarctica, when the growing tips of the mosses are not covered by snow. U. antarctica is the major component of the Sphaerophoretum teneri (Redon, 1969) and is occasionally found in more halophobous com- munities with Himantormia lugubris and Andreaea species (Allison & Smith, 1973). In contrast Usnea aurantiaco-atra occurs in much more halophobous and nitrophobous communities than U. antarctica. For example, on the South Orkneys this species forms a distinct community on raised beaches with Himantormia lugubris over a range of a latitude with species of Andreaea, Rhizocarpon, and Lecidea. U. aurantiaco-atra is also found in communities with halophobous species, including Sphaerophorous and Stereocaulon. Lindsay (1971a) has de- scribed a series of communities along a gradient away from a slightly nitrophilic habitat dominated by U. antarctica that is finally replaced by the U. aurantiaco-atra—H. lugubris- Andreaea sociation. Occasionally communities may contain both Usnea antarctica and U. aurantiaco-atra (Smith, 1973). U. antarctica is characteristic of dry deposits of fine gravel and sandy soil and is often replaced on exposed, windswept ridges by U. aurantiaco-atra and Himantormia lugubris. However, U. aurantiaco-atra is also found in an Usnea—Umbilicaria-H. lugubris sociation on dry, exposed rock faces at higher altitudes, which are dominated by U. antarctica and species of Buellia, Lecidea and Rhizocarpon. Similarly, in the Andreaea—Grimmia—Usnea—Umbilicaria sociation (Smith & Corner, 1973) U. antarctica is the most prominent species on windswept outcrops whilst U. aurantiaco-atra is only locally abundant in slightly more sheltered situations. Subantarctic The subantarctic islands are all characterised by an extremely cool, oceanic or maritime climate with little annual or diurnal temperature variation (Du Rietz, 1960), high rainfall, constant high humidity, and strong westerly winds (Eaton, 1879; Greene, 1964a; Wace, 1960). Lichen communities are not so prominent, being confined to very exposed rocky situations on, for example, Marion Island (Lindsay, 1977b) and Macquarie Island (Filson, 1981). Consequently most ecological and floristic work has been concentrated on phanerogamic communities (Greene, 1964a, 1964b; Hooker, 1879a, 1879b; Taylor, 1955; Wace, 1960). Two species, Usnea antarctica and U. aurantiaco-atra, that are characteristic of the maritime antarctic, occur in this region, with the latter being replaced by U. taylorii beyond the eastern limit of its distribution in similar habitats (Dodge & Rudolph, 1955). U. trachycarpa also occurs on Iles Kerguelen but is characteristic of exposed, dry, windswept, rather than alpine, habitats. Consequently the species of Neuropogon occurring in the subantarctic are a mixture of antarctic and cold- temperate elements, bearing strongest affinities with the maritime antarctic. The lichen flora of South Georgia has affinities with the other subantarctic islands, Tierra del Fuego, the Falkland Islands, and the Scotia Arc. Communities dominated by fruticose and crustose lichens (Lindsay, 1975) were found to be similar to those of the South Orkneys. For example, an Usnea aurantiaco-atra (as U. fasciata)-crustose lichen community was widespread on moderately exposed, dry, boulders and cliff faces in which U. aurantiaco-atra often gave 80% cover with an understorey of mosses, Lecidea, Lecanora, Pertusaria, and Rhizocarpon species. In contrast at lower altitudes an U. antarctica-crustose lichen community, tolerant of slightly nitrogenous melt-water, had less cover of Neuropogon and a greater variation of crustose lichen understorey. U. aurantiaco-atra also occurs in a markedly nitrophibous community, which has a restricted distribution in very dry situations at high altitudes, in which Pseudephebe pubescens and Alectoria miniuscula were often co-dominant, forming an understorey which virtually excluded crustose lichens and mosses. Lichen communities on Marion and Prince Edward Islands have been briefly outlined by Lindsay (1977b). Communities on Marion Island were found to be local on exposed ridges and dominated by Usnea, Alectoria, Himantormia, and Umbilicaria species. U. antarctica (as U. insularis) was an associated species in a community dominated by Lecidea species on moderately exposed boulders and rock-faces. Little revision has been made of the lichen flora of iles Kerguelen since that made by Crombie (1876a, 1877, 1879a) of Hooker’s work (Hooker & 30 F. J. WALKER Taylor, 1844; Hooker, 1847) apart from Dodge’s contributions (Dodge, 1948, 1966). Crombie (1879a) reported U. taylorii from high altitudes on Iles Kerguelen and his other records refer to U. antarctica and U. trachycarpa which may sometimes occupy the same habitats. Southern cold temperate The southern cold-temperate zone has been variously defined (Darlington, 1965; Godley, 1960; Holdgate, 1970; Skottsberg, 1960) and very broadly encompasses regions of southern South America (including the Falkland Islands), New Zealand and the associated shelf islands, and even the south-eastern corner of Australia with Tasmania. In these regions most Neuropogon species reach their northern distributional limit and are primarily represented by a group of species that may be termed alpine-southern temperate, rarely with isolated occurrences of antarctic or subantarctic species. In Australasia this element is well-represented by the Usnea ciliata aggregate. Little ecological work has been undertaken in this region apart from studies in Central Otago, New Zealand by Mark & Bliss (1970). Similarly, little is known of the alpine lichen flora of Tasmania, where Neuropogon species are rare and confined to relatively few high altitude localities (c. 850-1250 m). The dominant alpine phanerogamic vegetation is different from that of New Zealand (Kirkpatrick, 1980) which indicates that climatic and vegetational differences exist at corres- ponding latitudes which exclude Neuropogon. Recent observations on the Rock and Pillar Range, Otago, have shown that a characteristic community, dominated by Neuropogon species, occurs on exposed, isolated rock tors in Celmisia-Poa herbfield at the boundary (c. 1200 m) of the low and high alpine zones (Mark & Bliss, 1970) or biomes (Bliss, 1981). Such communities were dominated by Usnea acromelana and U. ciliata with occasional small thalli of U. subcapillaris. Associated species included Alectoria nigricans, Coccocarpia palmicola, Hypogymnia lugubris, Lecanora polytropa aggr., Lecidea spp., Menegazzia aeneofusca, M. castanea, M. lucens, M. nothofagi, Parmelia pet- riseda, Pertusaria dactylina, P. superba, Umbilicaria spp., and Usnea torulosa. At lower altitudes Usnea ciliata is much rarer, for example on Mt. Maungatua, Otago (c. 880 m) and only U. acromelana was found growing with U. torulosa on scattered tors in tussock grassland. At even lower altitudes, c. 370 m, on an exposed plateau at the foot of the Rock and Pillar Range, only U. acromelana was found. This species was only represented by a few deformed thalli on schist boulders in a community dominated by Parmelia and Xanthoparmelia species, including P. mougeotina, P. petriseda, P. pseudosorediosa, P. reticulata, P. signifera, P. subrudecta, P. sulcata, X. mexicana, and X. tasmanica. Associated species included Buellia macularis, Lecanora blanda, Lecidea irrubens, Rhizocarpon geographicum aggr., and Siphula coriacea. The climate of southern South America is more oceanic than at corresponding latitudes in the northern hemisphere and, in some respects, is more like the montane climate of the equatorial Andes (Troll, 1960). The mountainous Magellanic archipelago provides few habitats that are sufficiently dry (Holdgate, 1960) for Neuropogon species. A southerly decrease in the level of the permanent snow-line and a sharp climatic gradient from west to east (Auer, 1960) provides a wide range of habitats and hence communities. The mountainous region of the Argentine—Chile border is subject to almost constant winds and frequent storms (Shipton, 1959) which impose rigorous conditions. There is an abrupt change to the east from Nothofagus forest on the slopes of the higher mountains to the grasslands of the lower hills and undulating plateaux (Shipton, 1959) which extend eastwards to form the dry, semi-desert plains (mesetas) of Patagonia (Darlington, 1965). Ecological studies have previously primarily been directed towards the classiciation of phanerogamic vegetation (Godley, 1960; Holdgate, 1960; H. Weber, 1969). Previous lichenolo- gical investigations have mainly been taxonomic, adding to distributional records (Crombie, 1876b; Grassi, 1952; Lamb, 1948a, 1955; Rasanen, 1932, 1939; Redon, 1972; Santesson, 1942) with little ecological investigation (Lamb, 1959; Mattick, 1951). Lamb (1959) made brief reference to a saxicolous alpine community composed of species of Neuropogon associated with USNEA SUBGENUS NEUROPQGON 31 Lecidea species, Pseudephebe pubescens, Rhizocarpon adarense, and Umbilicaria decussata, which was found to be a mixture of antarctic and subantarctic elements and was similar to those described from central Chile (Follmann, 1965a; Redon, 1973) probably based on U. patagonica (as U. acromelana). Redon (1972, 1974) described various alpine communities from Chile and found them to be similar to those occurring on the Argentinian side of the Cordillera. U. aurantiaco-atra was found in a community with Rhizocarpon geographicum, R. crystalligenum, Umbilicaria cylindrica, and U. nylanderiana. Altogether ten species of Neuropogon are found in southern South America which may be grouped into various floristic elements that form distinct communities or intergrade. Usnea sphacelata represents a continental antarctic element that is confined to high alpine areas, particularly those associated with areas of glaciation. U. antarctica, U. aurantiaco-atra, and U. subantarctica represent the northern limit of a maritime antarctic element. Alpine southern- temperate species are represented by U. acromelana, which is restricted to glacial valleys and moraines, and the endemic U. perpusilla which tends to replace U. aurantiaco-atra towards northern Patagonia. Perhaps the most interesting group of species are those which form a transitional arid-montane element, represented by U. durietzii, U. neuropogonoides, U. patagonica, and U. trachycarpa, which occur within a wide range of altitudes and are capable of extending into the mesetas as well as the lower alpine slopes of the Cordillera. Consequently many unusual communities occur which contain several of these floristic elements. For example, on the lower mountains of Tierra del Fuego, at c. 800 m, collec- tions have been examined consisting of U. antarctica and U. cf. subantarctica, together with un- usually fibrillate forms of U. aurantiaco-atra, U. perpusilla, and U. trachycarpa. The lichen flora is less diverse on the Falkland Islands since low altitude, maritime communi- ties containing Usnea antarctica are absent, possibly due to univestigated ecological factors or extinction due to changes in land-use. Only remnants of a unique lichenicolous heath commun- ity (Standring, 1983) now remain which support Protousnea species (Krog, 1976), and which is probably closely related to the Magellanic moorlands of Chile. On these islands strong winds, rather than low temperatures, favour the growth of U. trachycarpa whilst the maritime antarctic element is represented solely by U. aurantiaco-atra. Tropical-alpine The climate and the flora of the tropical high mountain zone of Central and South America have been compared to that of the subantarctic (Darlington, 1965; Troll, 1960; Wace, 1960) as for example, seen by a comparison of tussock grassland and the paramos. By contrast, these vegetation types are very different from those of the cold-temperate zone of the northern hemisphere. For example, in Ecuador, at Quito (2850 m) there is great diurnal but little annual temperature range (Troll, 1960) whilst at higher altitudes, close to the permanent snow-line (e.g. Mt. Chimborazo, c. 4750 m) there is little annual or diurnal temperature variation. Usnea durietzii is found at the lower altitudes (c. 3000-4000 m) and is characteristic of dry, exposed, rocky paramos in communities associated with U. acanthella, U. bogotensis, and Stereocaulon species, whilst U. sphacelata is confined to higher, alpine habitats. Biogeography Many authors (Ahmadjian, 1970; Dodge, 1965a; Filson, 1982; Jorgensen, pers. comm.; Lamb, 1970) regard the antarctic lichen flora as a mixture of relict endemic elements, which survived Pleistocene glaciations, as well as immigrant elements that recolonised the continent from adjacent areas, for example Fuegia. Lindsay (1977a) considered the nunatak cryptogamic flora of Antarctica was, in contrast to the arctic, somewhat impoverished as a result of polar isolation, more drastic climatic changes during the late Cenozoic, and slower rate of recolonisation. However, despite physiographical, climatic, and vegetational differences between the polar regions, taken in its entirety, the present-day lichen flora of Antarctica is as rich as that of the arctic, thus indicating a varied origin and opportunities for speciation. AZ F. J. WALKER The present day distribution of the subgenus Neuropogon has often been used as an example by biogeographers when discussing origins of bipolar disjunctions. Together with other genera which have a predominately southern hemisphere distribution, for example Menegazzia, Placopsis, and Pseudocyphellaria, it has been generally accepted (Du Rietz, 1929, 1940; Galloway, 1979; Henssen & Jahns, 1973; James, 1960; Lindsay, 1977a; Lynge, 1938, 1941) that the subgenus Neuropogon possibly had a monophyletic southern origin. However, many features are shared with the subgenus Usnea, for example pigmentation of pseudoisidia, and this could indicate either common ancestry or subsequent parallel development. This contrasts with other genera, for example Bryoria and Evernia, which are thought to have evolved in the northern hemisphere, since they are today poorly represented or absent in the southern hemisphere (Galloway, 1979). Jgrgensen (1983) postulates that the present-day tricentric antarctic distribution of fertile species, as exemplified by Usnea aurantiaco-atra in southern South America—Antarctic Peninsu- la, U. ciliata in New Zealand, and U. taylorii in the subantarctic Indian Ocean, indicates ancient antarctic origins. This is despite difficulties in associating a cold-tolerant group with Gondwana- land when glaciation only occurred comparatively recently. A possible centre for subsequent speciation may have been in South America—west Antarctica, but Jorgensen proposes that some elements must have been present in Gondwanaland to account for present-day distributions. Krog (1982) considered that disjunct distributions of several genera in the Parmeliaceae could indicate origins in the Cretaceous or Late Jurassic. Present-day distributions of fertile Neuropo- gon species indicate that the subgenus may have been established in Gondwanaland prior to the opening up of the south Atlantic at the start of the Cretaceous (Raven & Axelrod, 1974). The asexual species Usnea patagonica, which occurs in Patagonia and possibly South Africa, may represent the remnants of a once much richer flora in South Africa that was subsequently wiped out. However, distributions based on asexual species are likely to be speculative in view of the likelihood of subsequent long-distance dispersal. Krog (1982) also suggested that the distribution of Neuropogon is an indication that the subgenus is more primitive than the more widespread and diverse subgenus Usnea. Today Usnea s. Str. is mainly a tropical genus with only a few, all asexual, species sharing the same habitats with Neuropogon. This distribution indicates that Usnea may be a much younger group and any connection between the two subgenera must be very ancient. Certainly some of the South American species included in the subgenus, for example, Usnea durietzii and U. patagonica, have close affinities with the subgenus Usnea which are discussed under ‘Generic concept’. (p. 42). These species might either suggest evolution from Neuropogon to Usnea or convergent evolution, or represent remnants of an ancestral group from which Neuropogon s. str. adapted to tolerate polar environments and Usnea spread to occupy a wider range of habitats and less severe ecological conditions. Similarly, one species, U. neuropogonoides, has some affinities with Protousnea although the two groups differ in other respects, including chemistry. Protous- nea appears to be a further modification of the basic Usnea-type, and may be regarded (Krog, 1976) as a rather primitive group with possible affinities with hypothetical predecessors. The unique thallus anatomy of Usnea taylorii might be interpreted as an indication of a primitive species, but is more likely to have been secondarily derived from a species with a thick axis, for example U. aurantiaco-atra. This species is confined to the fles Kerguelen, Heard Island, and {les Crozet. There is geological evidence (Brundin, 1970; Harrington, 1965) that these islands are partly ancient and partly of recent volcanic origin; thus indicating a Gondwana- land connection with an ancient endemic flora (Dodge, 1948). Biogeographically these islands, with Marion and Prince Edward Islands, form the Kerguelen Province (van Zinderen Bakker, 1971). There is evidence that the so-called ‘Grande Terre’ of the [les Kerguelen, which straddles the Antarctic Convergence, had an aberrant type of glaciation with certain sheltered areas probably serving as refugia for flora and fauna during the glaciations (van Zinderen Bakker, 1970). A parallel may be drawn from studies on an endemic genus of chironimid midges found on Iles Crozet (Brundin, 1970) which are thought to be the survivor of a group whose ancestors existed during the Jurassic—Cretaceous transition. This would indicate that such islands must have been USNEA SUBGENUS NEUROPOGON 33 isolated before the separation of Antarctica, New Zealand, and Australia, and like [les Kerguelen and Heard Island are thought to be of continental origin (Shields, 1976). The bicentric distribution of Usnea trachycarpa in Patagonia with the Falkland Islands and iles Kerguelen suggests that this could be a very old species with origins in Gondwanaland, since it is unlikely to have subsequently spread by long distance dispersal. The Falkland Islands are thought to have Precambrian origins (Shields, 1976). Even as early as 1879 Hooker (Hooker, 1879a) recognised affinities between the vascular and cryptogamic floras of [les Kerguelen and South America. This is in contrast to the much younger subantarctic islands that were of recent volcanic origin, for example Marion and Prince Edward Islands, which were also subsequently glaciated (van Zinderen Bakker, 1970; Verwoerd, 1971). Despite the previous acceptance of an endemic sorediate species of Neuropogon, Usnea insularis (= U. antarctica) (Dodge, 1948; Lamb, 1939a; Lindsay, 1977b) it is consequently unlikely that such a species could have had sufficient time to evolve. It is more plausible that U. antarctica recolonised these islands post-glacially by long distance dispersal via the Scotia Arc, which is probably of continental origin, or with islands dating from Precambrian to Cretaceous times (Shields, 1976). Lindsay (19775) indicates that the lichen flora of the Prince Edward Island group has affinities with that of the Iles Kerguelen, as exemplified by Orceolina kerguelensis, which has recently been found on {les Crozet (Tilman, BM). However, these islands floras also share a common bipolar element. Bouvet@y and the other islands of the Scotia Arc, which extends eastwards from Tierra del Fuego through South Georgia to the South Sandwich Islands then westwards through the South Orkneys towards the Antarctic peninsula (Greene, 1964), were similarily glaciated and con- sequently have a low incidence of endemism. Two main species, Usnea antarctica and U. aurantiaco-atra have recolonised these islands from Fuegia, and Bouvetgy represents the easterly limit of the latter species. Some ice-free nunataks may have existed along the Scotia Arc, although there is, as yet, no geological evidence, where U. antarctica and U. aurantiaco- atra may have survived glaciations (Lindsay, 1975). The South Sandwich Islands are of recent origin, formed from a crust c. 8 million years old, and have no exposed rocks older than c. 3 million years and are still actively volcanic. Consequently the flora must have arrived by transoceanic migration (Longton & Holdgate, 1979). Biogeographers attach considerable importance to the extent of endemism, particularly at species level, in a given area. Results are often conflicting and may, in some instances, be more relevant for phanerogams. With lichens it is essential for the flora of a particular region to be well documented and compared to that of adjacent areas. The flora of the antarctic regions is a test case where failure to do this can lead to recording of spurious endemism, as, for example, in the case of the taxa described by Dodge (1965a, 1970). Many groups still require critical systematic revision, which may show that many endemic taxa are superfluous, merely representing environmental modifications rather than genetic differences (Filson, 1982). Geological evidence (Harrington, 1965) indicates that east and west Antarctica had different origins, with the western, younger part having close affinities with South America. The islands of the northern Antarctic peninsula are thought to have Middle Paleozoic origins (Shields, 1976). Dodge (1948, 1965b, 1973) recognised endemic species of Neuropogon in east Antarctica derived from Usnea antarctica. Although this area is older, with Gondwanaland origins, such elements are now regarded as ecotypes (Ahmadjian, 1970). Their precursors may have survived Pleistocene glaciations on inland nunataks or ice-free refugia (Lamb, 1970) and subsequently spread along melt-water channels to colonise coastal areas (Filson, 1982). However there would not have been sufficient time for speciation to occur, since the rate of evolution in lichens is thought to be very slow (Lindsay, 1977a; Jorgensen, '1983) and then growth is even slower in polar regions (Lamb, 1970). This is in contrast to the proposed relict indigenous elements which may have survived at high altitudes above the tree-line during more temperate eras and form the truly endemic portion of the flora. The Antarctic peninsula is considered (Dodge, 1973; Lindsay, 1977a) to have a high incidence of specific, but low generic, endemism. This is exemplified by the occurrence of lichen groups which have developed unusual characteristics such as the possibly more highly evolved stipate 34 F. J. WALKER forms of many crustose genera (Lamb, 1970). Many of these species also occur in southernmost South America, having a distribution pattern similar to that of Usnea aurantiaco-atra and U. subantarctica. Such species probably evolved during the rapid phase of speciation that occurred in Patagonia after the initial break up of Gondwanaland, and spread postglacially into the Antarctic peninsula via the Scotia Arc. Limited dispersal of fertile species must have occurred by this route although the Arc was formed after the separation of the Antarctic peninsula and South America. The timing of the separation of the Antarctic peninsula is uncertain but an estimate of 29-3 million years B.P. is preferred by Crook (1981). Dodge (1973) recognised a greater number of Neuropogon species in the Antarctic peninsula than are accepted here. At present five, or possibly six, species are known, of which none are endemic. In contrast ten species occur in Fuegia, of which one fertile species, U. perpusilla, is endemic, and one, U. aurantiaco-atra, is common to the Antarctic peninsula and islands. It is clear from present-day distributions that there has at some stage been explosive speciation of Neuropogon in southernmost South America and subsequent spread, possibly as a response to drastic climatic changes (van Zinderen Bakker, 1970) and opening up of ecological possibili- ties. This does not necessarily prove that the area coincides with a centre of origin and could conversely be regarded as an area where many species occur as the result of continual replacement or accumulation of relicts (Darlington, 1965). There is evidence that the greater part of Tierra del Fuego was glaciated although refugia may still have existed for old species, such as U. trachycarpa. Other species, such as U. antarctica, may have evolved from a fertile primary species, i.e. U. aurantiaco-atra, and subsequently spread postglacially by long distance dispersal. South America has long been of biogeographical interest as a centre of speciation and a migration route to and from the northern hemisphere. With respect to Neuropogon, .it is apparent that at some stage taxa were isolated in the northern Andes. Such proximity to the tropics and varied climates has led to the evolution of a series of closely related, asexual species, such as Usnea acanthella and U. durietzii, which together with U. sphacelata are often difficult to identify and may indicate either a centre of great diversification or parallel evolution. Only one of these asexual, South American taxa managed to spread into North America. Usnea sphacelata probably had its origins in Patagonia since it may be the sorediate counterpart of U. perpusilla. Various theories as to how and when this migration occurred have been proposed or discussed by previous authors (Du Rietz, 1929, 1940; Lynge, 1941). It seems probable that migration north may have occurred prior to the recent joining of North and South America; possibly along a series of volcanic islands during the Late Cretaceous (Raven & Axelrod, 1974; Jorgensen, pers. comm.). The absence of a possible fertile counterpart in the northern hemisphere and the uniformity of the population in contrast to the greater variation found amongst southern hemisphere populations indicate recent migration to the northern hemisphere. A similar situation is seen in Placopsis and Menegazzia. However, it might be argued that less variation is found because climatic conditions have been more stable than in Antarctica during the late Cenozoic glaciations and the arctic was not isolated geographically (Lindsay, 1977a). Spread in the northern hemisphere was apparently eastward towards Green- land, following the prevailing winds, rather than across the Bering Straits. The distribution of U. sphacelata is not truly circumpolar and is mainly in the Canadian eastern arctic, being rare between Novaya Zemlya and western arctic Canada, with a single record from the New Siberian Islands (Lynge, 1941). Thomson (1972) considered that the present day disjunct distributions of many arctic lichens may reflect the availability of suitable habitats rather than the spread from a centre of origin. Since U. sphacelata is more or less confined to island groups in the northern hemisphere rather than the continents, this might be a relevant proposition. Post-Pleistocene colonisation was probably rapid from North America by means of wind-blown propagules and thallus fragments. Biogeographic treatments of New Zealand have been the subject of much debate and were recently summarised by Craw (1978). Galloway (1979) comments that the cryptogamic and phanerogamic floras of New Zealand and southern South America have many common genera but few shared species. For example, in Usnea subgenus Usnea closely related species occupy USNEA SUBGENUS NEUROPOGON 35 similar habitats. U. xanthopoga and U. contexta are replaced by U. nobilis and U. pallida in South America (Galloway, 1979) and also U. torulosa and U. inermis by U. igniaria and U. _nidulifera. Similarly different fertile species of Neuropogon also occur. This is also true for Menegazzia where few species are common to South America and New Zealand (P. W. James, pers. comm.). In the New Zealand alpine flora there is a considerable extent of endemism in phanerogams but this is not as high in the lichen flora. New Zealand was separated from Gondwanaland, and hence from Australia and Tasmania, approximately 80 million years B.P. (Raven & Axelrod, 1974), whilst separation of Australia and Antarctica did not occur until 60-53 million years B.P. (Crook, 1981). The subgenus Neuropogon is restricted to schists east of the main divide in the South Island and is rare in the North Island. This substrate specificity could indicate that a norstictic acid-containing precursor of the Usnea ciliata aggregate or even U. ciliata itself, was isolated at that time and subsequently underwent speciation with the resulting four taxa. This isolation occurred well before the more or less direct migration route between South America and Australia via Antarctica was broken, and hence explains why one would not expect U. ciliata to occur in South America, despite erroneous reports (Lamb, 1948a). In South America U. ciliata is replaced by U. aurantiaco-atra and U. perpusilla. The lichen flora of Australia has diverse origins (Rogers & Stevens, 1981) but how and when Neuropogon reached Tasmania and Victoria remains conjectural. As far as vascular plant dispersal is concerned there have been conflicting views as to whether migration was possible from east to west (Wardle, 1978) as well as from Tasmania to New Zealand with the prevailing winds (Raven, 1973). The former migration would had to have occurred if Neuropogon spread to Tasmania after separation of New Zealand. Evidence that this direction of migration has occurred in some groups of organisms is also given by Fleming (1976). An alternative explanation is that ancestors of Usnea ciliata were much more widespread in Gondwanaland and consequently already present in Tasmania and New Zealand prior to continental movements; this certainly seems to be true for species of Menegazzia (P. W. James, pers. comm.). Additional evidence for spread from New Zealand comes from the fact that U. ciliata has not reliably been recorded from Tasmania and the two species present, U. acromelana and U. subcapillaris could spread by soredia or thallus fragmentation. Slight differences between New Zealand and some Australian populations may either be due to ecological conditions or conversely indicative of a longer isolation. Long distance dispersal may have also been by other agents, including birds (Bailey & James, 1979). There is evidence (Burton, 1968) that gulls and skuas use lichens to line their nests. In addition, Wardle (1978) suggested that dispersal of sorediate taxa may have still occurred from Antarctica to New Zealand prior to glaciation. This may account for the presence of an antarctic element, Usnea antarctica and U. sphacelata, in the flora. It seems more probable that U. sphacelata, from its restricted distribution on very old outcrops, is a relict species. Further evidence also comes from the recent discovery of this species in north-west Nelson (herb. Bartlett 25810!, 25811!), together with other bipolar species including Solorina spongiosa (Galloway, pers. comm.). In contrast U. antarctica may have spread more recently from Fuegia or Antarctica. The sorediate Usnea acromelana is common in Australasia and infrequent in southernmost South America and the Antarctic peninsula area. It may be argued that this species subsequently spread from Australasia, where its fertile counterpart, U. ciliata, occurs, to Patagonia via Antarctica before the continents finally separated. However, this present-day distribution does not necessarily reflect earlier patterns and migration might have occurred in the opposite direction, although U. ciliata is today confined to Australasia. U. acromelana is absent from east Antarctica and associated subantarctic islands which may be a result of ecological factors, with habitats more suited to U. antarctica and U. sphacelata. It is also worth emphasising that some populations from the Antarctic peninsula and Patagonia are only tentatively included in U. acromelana and may eventually prove to be examples of parallel evolution. Ecological factors may also explain the limited distribution of U. subantarctica. Fleming (1976) considered that most of the outlying subantarctic islands of New Zealand were not connected to the mainland during the Tertiary, being partly formed during that era by 36 F. J. WALKER volcanism although with older, continental elements (Shields, 1976). He suggested that they were subsequently glaciated or had very cold climates with the result that many inhabitants are more recent colonists. However, Wardle (1978) drew attention to the high level of endemism in the vascular plant flora on the Antipodes, Stewart, Campbell, and Auckland Islands, which suggests they survived glaciations; on the other hand there is evidence that the Macquarie Island flora was to some extent impoverished by glaciations (van Zinderen Bakker, 1970). Dodge (1973) believed that there was no relationship between the antarctic lichen flora and that of Iles Kerguelen and the subantarctic islands of New Zealand. However, it has now been shown that the New Zealand flora has a substantial austral element (Galloway, 1979) which has affinities with those of its subantarctic islands (Dodge, 1970) and even with Iles Kerguelen, as illustrated by the distribution of the genus Steinera (Henssen & James, 1982) which is probably a relict of a once more widely dispersed flora lost from New Zealand and South America during glaciations (Galloway, 1979). The oceanic climate of Auckland and Campbell Islands is not suitable for Neuropogon species. It is probable that Usnea acromelana spread to Chatham Island from New Zealand, and U. antarctica to Macquarie Island, by later, long distance dispersal. The distribution and evolution of chemical races in Neuropogon has not been considered from a biogeographical standpoint. However, it does seem likely that the precursor of the subgenus might have contained norstictic acid, since this substance is the most widely distributed, with subsequent development of other races. Alternatively, many species, including U. taylorii, often lack medullary substances; a state that is the commoner phase of many antarctic species. Discussion Circumscription of the species The genus Usnea s. lat. is notorious when it comes to delimiting species since there is inherent a great plasticity of form. The subgenus Neuropogon is no exception. Complexes exist within which it may be difficult to delimit individual species because rare linking intermediates are encountered. Such groups of individuals are regarded as noda along an axis of variation and may either be considered as distinct species, if sufficient criteria exist, or else as variants of a single species. Often there are indications that convergent evolution has occurred and this may lead to misidentifications. Immature, damaged, or thalli from sites of ecological stress may prove anomalous or even impossible to identify. In his world monograph Lamb (1939a) attached importance to both morphological and chemical characters when delimiting taxa. The morphological features found to be useful criteria are cortical features, relative widths of axis and medulla and corresponding laxness, and colour of the apothecial disc, and presence of rays. In asexual species the type and formation of propagules is important and may sometimes be species specific. For example, soralia may be plane, crateriform, ulcerose, or globose, and soredia may or may not be pigmented. In some instances the habit and branching of the thallus as well as the form of blackening of the holdfast may also be of value besides distributional and ecological considerations. Frequently, during this study, it has been found that a combination of characters must be taken into account when identifying a particular species. This accounts for the wide range of infraspecific variation and any anomalies that may consequently occur. Microscopical characters, for example spores and conidia, have not been studied in depth and hence no great taxonomic value is attached to them in this instance, although they have belatedly been found to be significant in other instances within the Parmeliaceae (Krog, 1982). Lamb (1939a) suggested that the structure or formation of conidia may provide useful evidence for separating genera. This theory has been proved by recent authors (Culberson & Culberson, 1980; Krog, 1982; Hawksworth, 1981) who have found them useful in separating genera or species. Krog (1976) used pycnidial morphology to separate Neuropogon from Protousnea based on absence of pigment in the ostiole rather than details of conidia structure or formation. Pycnidia are rather rare in Neuropogon, although further work on conidial shape and formation may provide useful information in confirming conspecificity of taxa such as Usnea aurantiaco- atra and U. melaxantha (see ‘Morphology’ p. 11). USNEA SUBGENUS NEUROPOGON 37 As mentioned earlier (p. 3) virtually all Lamb’s taxonomic work on Neuropogon was carried out before the advent of TLC, relying on thallus spot tests and microchemical crystal tests. Consequently too much weight was sometimes placed on slight differences in concentra- tion of medullary substances. The use of TLC in delimiting species is discussed below. In contrast Dodge (1948, 1973) virtually ignored chemical data and attached considerable weight to small differences in morphology and thallus anatomy. His very narrow species concepts led to the description of a large number of taxa which cannot be accepted today. Reasons for reducing many of these taxa to synonymy are also discussed under the relevant species. From studying a wide range of material some indication has been obtained of the morpholo- gical variation of each species. Concepts may have to vary according to the species concerned, and a wider or narrower range of variation of a particular character accepted. Frequently a broader view must be taken of species which have a wider distribution. These are species which usually only spread by means of vegetative propagules. Such species may occupy a wider range of habitats or have a greater ecological tolerance and hence exhibit more variation than species with a limited range (Krog & Swinscow, 1981). Swinscow & Krog (1978) proposed the concept that widespread and variable Usnea species may be represented by different morphotypes or chemical races towards their distributional limits. At extremes such thalli may look very different and have often been interpreted as distinct species. Consequently several Neuropogon taxa accepted by previous authors are here reduced to synonymy (Table 5). An example is Usnea sphacelata where there are some differences between certain antarctic and arctic propulations, although this variation is not considered to be sufficient to warrant the acceptance of distinct taxa. In addition there may be considerable variation within populations resulting from ecological factors (Filson, 1982, Hawksworth, 1973) which may be misinterpreted. It is possible that the diverse forms met with whilst evaluating the variation of Usnea sphacelata, particularly in South American and antarctic populations, are the result of the response to differing ecological conditions which some authors would recognise as distinct subspecies. Hawksworth (1972) discussed the effect of ecological factors on species delimitation in lichens. He concluded that variations may be caused by phenotypic plasticity but in addition these may have a genetic origin and require taxonomic recognition. Hence, ideally, the need for careful field analysis before new taxa are recognised. It is very likely that montane and arctic-alpine conditions influence variation in thallus morphology of fruticose lichens. Previous authors have come to different conclusions. For example, Kristinsson (1969) studied Cetraria islandica and C. ericetorum in Iceland and found no consistent correlation between morphotypes and chemotypes, finding a range of forms intermediate between the two taxa. More recent world-wide studies by Karnefelt (1979) have revealed that the two Cetraria species may be further subdivided with geographical subspecies, using taxonomic and ecological criteria. Both species have a bipolar disjunction coinciding with racial differentiation and the recognition of a southern hemisphere subspecies for each. However, there are many examples where species, which have their main distribution in the northern hemisphere, and also occur in the southern hemisphere, do not develop a southern race, for example Cladonia mitis and Alectoria nigricans (Karnefelt, 1979). Usnea sphacelata could be regarded in a similar fashion as a series of subspecies. However, in many instances, as with U. acromelana, it seems more plausible that environmental factors are the primary cause of variation. Altitude may be important since thalli from high-altitude ‘nunatak’ situations are usually distinct, although these intergrade with lower altitude forms. Similarly, although the majority of southern hemisphere material of U. sphacelata examined is slightly different from that of the northern hemisphere, occasionally thalli ‘true to type’ do occur in populations of varied morphology. Depsidone-containing specimens belong to U. subantarc- tica. Thalli in shaded conditions are greener than those in exposed situations due to lower concentrations of usnic acid. Parallels exist in the pigmentation of antarctic Teloschistaceae (Filson, 1969). In more exposed habitats thalli are often smaller, may be more richly branched, or become subdecumbent, or may be more extensively pigmented. The development of a 38 F. J. WALKER violaceous black pigment in the outer layers of the cortex is thought to be a shielding mechanism against UV radiation. Lindsay (1977a) observed that in the continental antarctic, thalli of Usnea sphacelata are heavily or even almost entirely pigmented, whilst in the maritime antarctic (Antarctic peninsula) thalli are only lightly variegated at branch apices. Ecological factors may also effect the development of the lax medulla in some species, for example U. perpusilla and U. sphacelata. Such environmentally induced variation may account for some abnormalities that are occasionally encountered. These include the rare occurrence of minute papillae in species which usually have a smooth surface, for example, U. acromelana and U. taylorii, or the uncharacteristic presence or absence of excipular rays in fertile species. Variation and development of atypical features in eastern antarctic populations of U. antarctica and U. sphacelata has led to the description and acceptance of many distinct taxa from this area by Dodge and his associates, who applied very narrow species concepts and recognised pockets and endemism around the eastern antarctic (Dodge, 1948, 1965b, 1973). Some of Dodge’s taxa are difficult to assign to either U. antarctica or U. sphacelata, particularly where they are based on poorly developed thalli or when holotype material is not available for study. In addition named material examined of a single species often included both U. antarctica and U. sphacelata. For example, U. subfoveolata and U. subpapillata were both described from the same locality in Queen Mary Land. Type specimens were examined by Lamb (1964) and photographed (Lamb, unpublished notes, AAS!) and are probably referable to U. antarctica, although I have examined material from the type locality, also cited by Dodge, which belongs to U. sphacelata. Both species are present in collections identified as U. subpapillata in US. Similarly Dodge described a further two species from an adjacent locality in Queen Mary Land. Usnea laxissima is a decumbent form of U. sphacelata, whilst U. pustulata is synonymous with U. antarctica. Occasionally, specimens from eastern Antarctica have been misidentified as Usnea acromela- na, (for example, Golubkova & Schapiro 1970; Filson, 1975), although in Antarctica the species is confined to the Antarctic peninsula. Lamb (1939a) described two forms of U. acromelana from Antarctica which are now recognised as belonging to U. sphacelata. Sometimes specimens of U. sphacelata have a very smooth, slightly waxy, unpigmented surface and a somewhat compact medulla. These features, combined with the production of black nodular soralia, suggest some affinities with forms of U. acromelana, although specimens lack the blackened annulations and compact medulla that are features of that species. The form of vegetative propagules is often species specific, but in rare instances there may be an intergradation between granular soredia, pseudoisidia, and true isidia, often with erosion and secondary regeneration. True isidia are only known in one species, U. acanthella, in Neuropo- gon. The formation of various propagules is discussed under ‘Morphology’ (p. 9). Examples include corticate outgrowths in soralia of Usnea acromelana and U. antarctica which may not be readily distinguished from the pseudoisidia of U. durietzii and U. patagonica. U. patagonica may be regarded as an intermediate species between U. antarctica and U. durietzii (Table 3). Some taxa are now regarded as conspecific which were originally distinguished on the form of the soralium; for example in U. acromelana and var. decipiens (Lamb, 1939a). If such distinctions are maintained this should only be at infraspecific level, although sometimes the range of variation can be observed within a single thallus. In some instances it is difficult to distinguish asexually reproducing species where several species overlap in their distribution. This is generally the case in subantarctic South America (Patagonia) where U. antarctica, U. acromelana, U. durietzii, U. patagonica, U. sphacelata, and U. subantarctica are all known to occur. In addition the area is poorly collected. Frequently thalli examined are small or somewhat moribund and consequently have not developed sufficient features characteristic of a particular species. Many of the species are in the depsidone-deficient phase and so chemistry cannot be used as an additional guideline. Where distributions overlap it is also likely that forms intermediate between species may occur. In addition species are reaching their distributional limits and as a result often produce atypical forms. In some instances altitude may have the same effect on the form of the species as latitude. Such a phenomenon is often observed in New Zealand populations of U. acromelana USNEA SUBGENUS NEUROPOGON 39 where thalli from lower altitudes may become discoloured and produce contorted or grotesque forms, often with proliferation of soralia to produce corticate outgrowths resembling pseudo- isidia. In such instances the only species liable to cause confusion is U. torulosa. Recent advances in microchemical techniques resulting in the identification of lichen sub- stances, in particular the development of rapid methods of TLC, have led to differing opinions on the taxonomic status of chemical variants of a species. Some workers regard chemical variants as distinct species, although there are no morphological differences; others prefer to regard them as races of the single species concerned. A well-known example is the range of opinion concerning the Ramalina siliquosa complex which is summarised by Krog & James (1977). Whilst delimiting species within Neuropogon I have attempted, as with morphological variation, to evaluate each case of chemical variation individually, based on the study of a large amount of material. No taxonomic value is attached to accessory substances, for example UV + unknowns, which vary from abundance to absence within a given species. Similarly the occurrence of psoromic acid is rarely considered to be species specific, although it may rarely occur as acommon denominator that unites morphologically uniform chemotypes, for example, in Parmelia direagens (Krog & Swinscow, 1981). The chemistry of Neuropogon species is not as complex as in some other genera in the Parmeliaceae since most of the comparatively few depsidones and depsides that are known are closely related chemically. Chemical data have supported morphological evidence that Usnea aurantiaco-atra and U. melaxantha are conspecific. Thalli are occasionally found with a mixed chemistry in areas where the two depsidone-containing races overlap and cannot be disting- uished morphologically or from depsidone deficient material. This is discussed more fully under U. aurantiaco-atra (p. 71) and is a further example of an instance of where extremes in variation were previously thought to represent distinct taxa. Various epithets have been applied to races of U. aurantiaco-atra at different times by previous authors and these are summarised in Table 4. Chemical data, in some instances, may prove useful in the recognition of species groups and species pairs. The concept of a species pair: a fertile species and a derived asexual species, has been accepted or rejected by various authors, usually the former. Du Rietz (1924) proposed two types of clones based on extant or extinct primary species and this concept has been followed up by Hale (1965), Poelt (1970), Swinscow & Krog (1978), and Krog & Swinscow (1981). Poelt (1970) referred to a ‘species pair’ when both the fertile and asexual counterparts were known and to ‘secondary species’ where the primary species is unknown, as is frequently the case in some fruticose groups. In contrast, Tehler (1982, 1983) considers that secondary asexual taxa are best expressed as formae rather than as distinct species. In Neuropogon, in the few instances where obvious species pairs occur, I prefer to regard the taxa as distinct species. Otherwise it would become increasingly difficult to delimit taxa at species level besides making allowances for the wide range of infraspecific variation and Table 4 Epithets applied to chemical races of Usnea aurantiaco-atra (Neuropogon aurantiaco-ater) by major authors. Author norstictic/salazinic acid fumarprotocetraric (+) Motyka (1936-38) melaxantha aurantiaco-atra aurantiaca fasciata strigulosa Lamb (1939a) melaxantha aurantiaco-atra aurantiaca strigulosa . Lamb (1948a) melaxantha aurantiaco-atra Lamb (1964) aurantiaco-atra fasciata Dodge (1973) aurantiaca aurantiaco-atra melaxantha fasciata siplei (?) strigulosa Lindsay (1975) aurantiaco-atra fasciata 40 F. J. WALKER chemical variation that already occurs. The chemical races of Usnea aurantiaco-atra have already been mentioned above in the context of species delimitation. U. antarctica, from similarities in morphology and anatomy, is thought to be the asexual counterpart. In addition U. antarctica is sometimes found fruiting and also the same two depsidone-containing races as well as a depsidone-deficient race are known. The norstictic-salazinic acid race is extremely rare and is only known from a single collection from the centre of distribution of the corresponding race of U. aurantiaco-atra. Similarly members of other species pairs may have more than one chemotype with no obvious morphological differences. Such chemotypes are regarded as races rather than distinct taxa. Either the primary or derived species may exhibit more than one chemical race. Examples exist in the Usnea ciliata complex which consists of four species dominated by norstictic acid and salazinic acid containing thalli. U. acromelana is without doubt the sorediate counterpart of U. ciliata, sharing a range of morphological features including a waxy, annulate surface, a compact medulla, and, when fertile, apothecia with rays and a blackened disc. In Australasia the two species overlap and only one chemical race, with norstictic and salazinic acids, is usually encountered; depsidone deficient material of U. acromelana is confined to a single locality in Victoria. U. acromelana has a more widespread distribution and is a rare species in south- ernmost South America, the Antarctic peninsula and islands. Within this South American— antarctic distribution three chemical races are known: (1) norstictic acid and salazinic acid, (2) psoromic acid, (3) depsidone deficient, indicating greater diversity at distributional limits. Two other Australasian species, U. subcapillaris and U. pseudocapillaris, belong to the complex and are derived from U. ciliata and U. acromelana respectively. Conversely only a norstictic- salazinic acid race is known in U. pseudocapillaris whilst three morphologically uniform chemical races occur in U. subcapillaris: (1) norstictic acid and salazinic acid, (2) squamatic acid + hypothamnolic acid, (3) psoromic acid. Races 2 and 3 have a more limited distribution and occasional thalli with mixed chemistry are known. The origin of race 2 is particularly intriguing since these substances do not occur in any other species in Neuropogon. Amongst the remaining species it is not so easy to pinpoint close relationships. There is often not sufficient evidence to indicate species pairs and also more asexual species exist than possible fertile, primary counterparts. Usnea sphacelata and U. perpusilla possibly form a species pair, based on the range of morphological and anatomical variation found in both species. Both species lack a depsidone-containing race, apart from the freak occurrence of psoromic acid. Specimens previously included in U. sphacelata, containing norstictic acid and/or salazinic acid, are here included in U. subantarctica; a species also separated on morphological and distribu- tional features. The distinction of U. subantarctica as a species from U. sphacelata might be considered to be rather tenuous, particularly in the depsidone-deficient phase. However, the rare occurrence of fertile material indicates other affinities which do not fall into the possible concept of an U. perpusilla—U. sphacelata species pair. The discovery of fertile U. sphacelata with the ‘perpusilla’ type of apothecia would finally settle this dilemma. The existence of a sorediate counterpart to Usnea trachycarpa remains uncertain, although two possible candidates exist: U. patagonica is often found in the same habitat in South America but has fewer fibrils, more or less delimited, blackened holdfast, is not known to contain depsidones (i.e. norstictic acid), but does contain the same or similar fatty acids as often occur in U. trachycarpa. The other, more likely, possibility is U. subantarctica which again is less fibrillate, more extensively pigmented, has ‘trachycarpa’ type of apothecia, often contains norstictic acid and/or salazinic acid, but lacks the fatty acids. It is possible that the sterile U. neuropogonoides may be derived from U. trachycarpa, but they do not represent a species pair. Lamb (1939a) described the sorediate Usnea insularis from Marion Island and indicated that the species may have closest affinities to U. taylorii. However, U. insularis is here reduced to synonymy with U. antarctica on the basis of morphology, anatomy, and the presence of fumarprotocetraric acid, a depsidone that is extremely rare in U. taylorii. Further collections may reveal an asexual counterpart to U. taylorii. USNEA SUBGENUS NEUROPOGON 41 Generic concept and infrageneric classification The genus Usnea s. lat. has been divided into various genera or subgenera of which three, Neuropogon, Protousnea, and Lethariella, are frequently accepted as distinct genera. Other genera, for example Parmelia, have been subjected to a similar chequered existance and their delimitation may eventually rest on critical study of, for example, pycnidia, which are being found to be of value in delimitation of some orders, genera, and species (Krog, 1982; Hawksworth, pers. comm.). Meanwhile distinctions between neighbouring genera may remain somewhat obscure. This is particularly true of Neuropogon where some authors have accepted the group as a distinct genus, others as a subgenus of Usnea; two authors (Jatta, 1900, 1909; Lamb, 1939a, 1964) changed their opinion. The main arguments have centered around whether thallus colour and pigmentation, disc colour, saxicolous habitat, and restricted distribution are sufficient criteria for separation at generic or subgeneric level. Previous authors have interpreted Neuropogon in various ways. Jatta’s concept (1900) was based on two species that are now excluded from the subgenus. Du Rietz (1926) separated the subgenus from Usnea solely on the basis of apothecial disc colour and consequently had a much broader concept of Neuropogon than subsequent taxonomists. Eight out of the 13 species he included in his subgenus are now included in Lethariella and Protousnea (Krog, 1976). Motyka (1947) accepted Neuropogon as one of six subgenera of Usnea on the basis that there were not sufficient distinguishing characters to warrant generic status. Motyka (1936-38) further subdivided the subgenus into three sections: Sulphureae, Melaxanthae and Trachycarpae, grouping the species according to shared characteristics. All Motyka’s species are still included within the subgenus today, although six taxa (five species and one variety) have subsequently been reduced to synonymy. Two species, Usnea durietzii and U. neuropogonoides, were described by Motyka (1936-38) and placed in sections Glabratae and Foveatae of the subgenus Euusnea respectively. These species, as pointed out by Motyka, have many Neuropogon-type features and are here included in the subgenus for the first time. Both Lamb (1939a, 1948a) and Motyka (1936-38) may be regarded as having a more conservative view of Neuropogon which will here be termed Neuropogon s. str. Dodge (1948) based his infrageneric classification on that of Motyka and accepted Neuropogon as a subgenus. In addition Dodge (1948, 1973) excluded five taxa from the subgenus and instead placed them in section Laevigatae, subsection Roccellinae of the subgenus Euusnea (i.e. Usneas. str.) based on differences in the phycobiont. These taxa, all from the subantarctic islands of the southern Indian Ocean, were Usnea taylorii and four species that are here regarded as synonymous with U. antarctica. However, Dodge did consider these taxa to be somewhat intermediate between the two subdivisions and included them in the keys to both groups. A summary of the major taxonomic treatments is given in Table 5. Recently there has been a tendency by many lichenologists to accept at generic level subdivisions of established genera often based on detailed anatomical studies. For example, Brodo & Hawksworth (1977), using SEM showed that differences exist in the cortex structure in Alectoria s. lat. and used this as additional evidence to segregate genera. The SEM was used here to compare Usnea s. str. with Neuropogon and no anatomical differences were found. Results also compared favourably with previously published SEM work on Usneas. str. (LOpez-Figueras & Palacios-Prii, 1981). Some examples of instances where Neuropogon has been given generic status include Krog (1976, 1982), Galloway (1983, 1984), and Rogers (1981). Krog (1976) compared Neuropogon with Protousnea and listed a series of characters that could be used to distinguish the two genera. This may be an acceptable separation since there are many differences, including surface ornamentation, medullary chemistry, and habitat. Krog (1982) accepted six usneoid genera: Neuropogon, Usnea, Protousnea, Evernia, Letharia, and Lethariella, using colour and pruinos- ity of the apothecial disc as distinguishing criteria. She also proposed a hypothetical relationship in which Protousnea is more closely related to Evernia than to Usnea and Neuropogon. Following Krog’s classification the main difference between Usnea and Neuropogon lies in apothecial pigmentation and pruinosity. This is a much more acceptable distinction since, as will 42 F. J. WALKER Table 5 Examples of generic and infrageneric classification of Neuropogon. Source Classification A B Nees & Flotow (1835) Genus Neuropogon Jatta (1900) Subgenus Neuropogon 4 0 Du Rietz (1926) Subgenus Neuropogon 13 5 Motyka (1936-38) Subgenus Neuropogon sect. Sulphureae sect. Melaxanthae sect. Trachycarpae Subgenus Euusnea sect. Foveatae 0 1 0 Re Ooh Pe hN sect. Glabratae subsect. Pycnocladae 1 Lamb (1939a & 19482) Subgenus Neuropogon ee: gt Lamb (1964) Subgenus Neuropogon 1 Dodge (1948 & 1973) Subgenus Neuropogon 25 Subgenus Euusnea sect. Laevigatae subsect. Roccellinae 5 2 Walker (present study) Subgenus Neuropogon 15 15 Column A represents the number of species included in Neuropogon by the given author. Column B represents the seas area accepted here; * = one variety raised to specific rank. Where dates are combined, numbers of species are totalled. become clear from this study, other criteria such as thallus colour and pigmentation (see below) and habitat may not be so reliable. However, even apothecial characters may not fit generic divisions. Krog (1976, 1982) gives examples of species included in Usnea s. str. which have flesh coloured to brown epruinose apothecial discs and therefore have close affinities to Protousnea, possibly representing an intermediate or primitive group. Consequently I prefer to follow the classification established by Henssen & Jahns (1973) and regard Neuropogon as a subgenus of Usnea. It has become apparent from this study that Neuropogon has often been loosely defined and frequently used as a term of convenience when applied, in particular, to antarctic taxa. If only speciés confined to the arctic and antarctic were considered (cf. Lamb, 1964; Dodge, 1973) there would probably be sufficient character differences to favour generic status — namely thallus colour and pigmentation, a saxicolous habitat, and limited distribution — thus conforming to Neuropogon s. str. However, when subantarctic and, particularly, South American taxa and allied species are studied it is clear that the delimitation between Neuropogon and Usnea is often rather obscure. Several South American taxa are included here in the subgenus because they share many characteristic features. Since apothecia in these are unknown at present, and hence disc colour and pruinosity, their true systematic position cannot be ascertained. The species that may be regarded as belonging to Neuropogon s. lat. are Usnea acanthella, U. durietzii, U. neuropogonoides, and U. patagonica. The high Andean species U. acanthella was included in Neuropogon by Lamb (1939a) and described as a form of U. sphacelata (as U. sulphurea). The variable extent of pigmentation and affinities to U. durietzii, combined with a wider substrate range, may indicate that U. acanthella is somewhat intermediate between the subgenera Usnea and Neuropogon. It is possible that the development of pigmentation may have arisen independently in different groups in response to harsh, exposed environments. A parallel may be found in the development of pigment in the genus Ramalina. R. tigrina is a terricolous species from the mist or fog zone of the Atacama desert in Chile (Follmann, 1966) and is characterised by a yellow-green thallus with prominent bands of black pigment. USNEA SUBGENUS NEUROPOGON 43 Development of pigment is also variable in the genus Alectoria; for example apices of Alectoria sarmentosa ssp. sarmentosa may be occasionally striately blackened (Hawksworth, 1972). Usnea durietzii occurs throughout the Andean chain, occasionally occupying the same habitats as Neuropogon s. str. Thallus colour is the same green-yellow as U. acanthella and similarly thalli do not become as straminous or fuscous in herbaria as Neuropogon s. str. U. neuropogonoides is only known from a few aged collections and is a scrambling, sometimes terricolous, species from Patagonia. Thalli are sterile, and may have affinities with U. trachycar- pa. Similarly U. patagonica has limited pigmentation and shares common characteristics with U. antarctica and U. durietzii, the former species being accepted in Neuropogons. str. It could also be argued that the two species, U. subantarctica and U. trachycarpa, which have red-brown to brown rather than black epruinose apothecial discs, might form a separate grouping or lie somewhere between Neuropogons. str. ands. lat. U. trachycarpa is often scantily pigmented and has a subantarctic distribution whilst U. patagonica, a sorediate species that is rarely fertile, is more characteristic of Neuropogon s. str. and primarily has an antarctic distribution. If thallus pigmentation and saxicolous habitat were used as the main criteria for segregating Neuropogon many other species belonging to Usnea s. str. which exhibit some pigmentation would have to be included. However, a distinction has to be drawn at some point otherwise the delimitation of the group would become much more obscure. These species are excluded from Neuropogon s. lat. and, although occasionally sharing the same habitat, are either rarely pigmented or have pigmentation confined to apices or isidia. Three examples are given in Appendix I. Finally, thallus anatomy is sometimes used as a character for separating usneoid subgenera. The only Neuropogon species with a unique structure is Usnea taylorii in which the broad axis is invaded by medullary tissue, frequently resulting in sub-division or the formation of separate axial strands. In other species, for example U. antarctica and U. aurantiaco-atra, occasionally a small central cavity occurs in the axis without any significant penetration of medullary tissue or resultant segmentation. Dodge (1948) reported sub-divided axes in three Neuropogon species within the Roccellinae, although this only appears to be a constant feature of U. taylorii. Krog (1976) suggested that the axis of Neuropogon is most closely allied to that of Usnea subgenus Eumitria in which the axis is either tubular with a central cavity or is sometimes solid with a few longitudinal fissures (Swinscow & Krog, 1974). Krog (1976) also indicated similarities between the axes of Neuropogon and Lethariella subgenus Lethariella. The subgenus Neuropogon Usnea subgenus Neuropogon (Nees & Flotow, emend Nyl.) Jatta Sylloge lichenum italicorum: 54 (1900). — Neuropogon Nees & Flotow in Linnaea 9: 496 (1835). - Neuropogon Nees & Flotow, emend Nyl., Synopsis methodica lichenum 1: 272 (1860). Lectotype: Neuropogon antennarius Nees & Flotow (see Taxonomic review — p. 4). Description: Thallus fruticose, saxicolous, exceptionally terricolous or lignicolous, arising either from a small, delimited, or a broadly proliferating, basal holdfast, erect or subdecumbent, monopodial to + subdichotomous or irregular, richly branched above, with or without short, lateral fibrils or numerous, attenuated secondary branches. Branches greenish yellow, becom- ing yellow or orange-brown on storage, + variegated with violaceous black or black pigmenta- tion, especially towards the apices. Branches terete, or rarely angular, in transverse section. Surface smooth or sometimes becoming faveolate, shining-waxy or matt, pigmented-annulate or minutely scabrid, sometimes papillate to verrucose-rugose; rarely maculate. Cyphellae and pseudocyphellae absent. In section of three distinct zones; cortex, medulla, and axis. Cortex variable in thickness, (50)—100(—200) um, of indistinct, strongly gelatinised pseudoparanchyma, sometimes forming a pallisade-like layer towards the exterior. Medulla compact, lax, or sublax, of interwoven unorientated hyphae. Photobiont: coccoid Chlorophyceae, forming a + con- tinuous layer underlying the cortex. Axis chondroid, rigid, occupying 0-2-0-7(-0-9) of the branch diameter, cylindrical or slightly irregular, entire, very rarely sub-divided, of strongly 44 F. J. WALKER gelatinised longitudinal, fastigiate, paraplectenchymatous hyphae. Jsidia rare; pseudoisidia and soredia often present. Apothecia lecanorine, subterminal or lateral, subsessile to geniculate, with or without a subtending spur. Disc black, rarely rufous brown, matt or subnitid, epruinose. Thalline excipulum concolorous with the aes smooth, faveolate, scabrid or verrucose- papillate, with or without numerous, marginal, + pigmented rays. Thecium 60-75 um tall; epithecium aeruginose black or rarely brown, hymenium colourless below, blue-green or rarely brown above; hypothecium colourless to pale yellow. Asci clavate, c. 45 X 16 wm, tholus amyloid (I + blue); ascospores 8 per ascus, simple, hyaline, ellipsoid, 7-10(-12) x 5-7 um, thick-walled (c. 1 wm). Paraphyses capitate, simple or branched, conglutinate. Pycnidia rare, pigmented, immersed in terminal branches; conidia sublageniform to filiform, 9-11(-14) x 1-1-7(-2) xm. Chemistry: depsides, depsidones, fatty acids, UV + unknowns, usnic acid. Distribution: polar alpine, predominately southern hemisphere, one species also northern hemisphere. Key to the species la Sorediaor iwsidia absent, apothecia usually presents. 7. cu ison ess adecadcaxa cee vase ee avy sati as 2 1b DOLECIA. OF IsIdia Drekent, apotlecia Care i cavesevsensacs ch awecaolees ieee eke Bala Sate as 13 2a (la) Apothecia absent, thallus straggling or apices capillaceous, or + decumbent. (For erect, Sterile; juvenile thallisee 2D) e002 set So ovsdccetanyiaee thy ca fork teceduda aca tet meester 3 2b Apothecia present, thallus usually erect; tufted on: .35c550. cas ora cade Av csveedsy.v Meese ane 5 3a (2a) Thallus prostrate, scrambling. Main branches ornamented, rarely entirely smooth, not waxy, without black-edged annulations. Pigmentation scant. Medullary chemistry various, fumarprotocetraric acid sometimes present. Patagonia, Antarcticislands...... 4 3b Thallus subdecumbent with numerous extended, capillaceous, pigmented secondary branches. Main branches smooth, waxy, with black-edged annulations. Medullary chemistry various, never containing fumarprotocetraric acid. Australasia ................ 13. U. subcapillaris (p. 104) 4a (3a) Axis broad, greater than half branch diameter. Surface strongly verrucose or papillate. Medulla K + sordid brown, PD + red (fumarprotocetraric acid aggr.); K+ red, PD + Orange (norstictic and salazinic acids), or K—, PD— (no medullary substances). Antarctic islands, Falkland Is (abnormal form) ................. 4. U. aurantiaco-atra (p. 62) 4b Axis thin, less than half branch diameter. Surface smooth, faveolate or minutely papillate. Medulla K—, PD+ yellow (psoromic acid); or K—, PD— (+ fatty acids). SEARO A oo iar scons oak seas cap etece nes ph one enee ee nea Ne 7. U. neuropogonoides (p. 80) 5a (2b) Medulla lax, at least towards axis. Axis less than half branch diameter ..................00..05 6 Medulla compact. Axis half or more than half branch diameter ...................cccccceceeeees 7 6a (Sa) Apothecia + lateral, rarely subterminal, subsessile, often in series; mature disc black, marginal excipular rays sparse (10-20) or absent. Surface smooth, waxy, rarely minutely papillate (x 10 lens); rarely with fibrils. Medulla K—, PD— (no medullary substances); or very rarely K—, PD+ yellow (psoromic acid). Patagonia .................. 9. U. perpusilla (p. 85) 6b Apothecia + subterminal; mature disc rufous brown; marginal excipular rays numerous (20+). Surface + matt, faveolate to grossly papillate; with numerous fibrils. Medulla K+ red, PD+ orange (norstictic and salazinic acids); K—, PD+ yellow (psoromic acid); or K—, PD— (+ fatty acids). Kerguelia, Patagonia, Falkland Is...................... 15. U. trachycarpa (p. 110) 7a (5b) Axis thick, partially sub-divided, often protruding through the cortex as pale maculae. Medulla reduced, penetrating axial cavities. K—, PD— (no medullary substances), very rarely K—, PD + red (fumarprotocetraric acid). Kerguelia...... 14. U. taylorii(p. 108) 7b Axis entire, rarely with sinuose outline, not penetrated by the medulla. Medullary CHONUSUTY VOTIOUS 6. sews fog tuv snes castes cadedegh ences cancyac cage teu dexewdasuwudeek cay emeAeeoees ERS 8 8a (7b) Surface smooth, subfaveolate, fibrils absent ................0sceccesssesssosessvcccccesesccsseccceses 9 8b Surface papillate or verrucose; often with fibrils ..................cccccseceececceceeccsceeceeeeeees 12 9a (8a) 9b 10a (9a) 10b 1la (9b) 11b 12a (8b) 12b 13a (1b) 13b 14a(13a) 14b 15a(14a) 15b 16a(15a) 16b 17a(13a) 17b 18a(17a) 18b 19a(18a) 19b USNEA SUBGENUS NEUROPOGON 45 Black-edged annulations frequent on main branches. Excipulum smooth with conspic- MOUS MIATGINNET AVS AUSUEAIASIA cys.co23 5905 toss o atc o8co te bewns 62 cles vewesuathasdetishicesueuanedees 10 Black-edged annulations normally absent. Excipulum faveolate or rarely papillate, marginal rays sparse or absent. Patagonia, Antarctic peninsula andislands ............... 11 Thallus entirely erect. Apothecia subterminal, rarely lateral. Medulla K+ red, PD+ orange (norstictic and salazinic acids) ..........00s..cessesecsoserecossessaaves 5. U. ciliata (p. 74) Thallus subdecumbent with numerous extended, capillaceous, secondary branches. Apothecia lateral. Medulla K+ red, PD + orange (norstictic and salazinic acids, + protocetraric acid); UV ++ blue, K+ purple (squamatic, + hypothamnolic acids); or R= PDF yellow (psoromie aca) v5. oscteccdcdsversiecnceowssceess 13. U. subcapillaris (p. 104) Apothecia lateral, often in series; rarely subterminal, excipulum faveolate. Medulla K-—, PD- (no medullary substances); rarely K—, PD + yellow (psoromic acid). Patagonia (AUNOrmMal TOT) sctoc cscs oie oc aekadgcedoatenisctoia fies vAenes 9. U. perpusilla (p. 85) Apothecia subterminal, rarely lateral, excipulum smooth to minutely papillate or verrucose. Medulla K + red, PD + orange (norstictic and salazinic acids); K + sordid brown, PD + red (fumarprotocetraric acid aggr.); or K—, PD— (no medullary substances). Patagonia, Falkland Is., Antarctic peninsula and islands, including Houvetey (apacrmal Fork jis. ysis eis vest vay sani sou seecat dis 4. U. aurantiaco-atra (p. 62) Mature apothecial disc rufous brown, marginal excipular rays numerous (20+). Fibrils numerous on main branches. Medulla K + red, PD + orange (norstictic and salazinic acids); K—, PD + yellow (psoromic acid); or K—, PD— (+ fatty acids). Kerguelia, Patagonia, Falkland Is (abnormal form) .......................000005 15. U. trachycarpa (p. 110) Mature apothecial disc black (rarely brown when immature), marginal excipular rays sparse (10-20) or absent. Fibrils rare on main branches. Medulla K+ red, PD-— orange (norstictic and salazinic acids); K+ sordid brown, PD+ red (fumarpro- tocetraric acid aggr.) or K—, PD— (no medullary substances). Patagonia, Falkland Is., Antarctic peninsula and islands, including Bouvet@y ..... 4. U. aurantiaco-atra (p. 62) SUAP ANAS WAL EIAEE ASHI cox st wore sore cu, a d0N 22s we oadeas cae eet oan au Tec aaR a OTIC TARE acs eT 14 Tallis With SOLeata aNd) OF PSCUGOISIUIA. sc .25-5 5 veavceave tan canccears oa, ane Panter esate aet i Thallus yellow or yellow green; + pigmented; rarely with fibrils. Pseudocyphellae absent or inconspicuous. Norstictic and salazinic acids absent ..................cccceceeeeeeeeeeeeeeees 15 Thallus grey-green, with numerous fibrils. Pigmented isidia arising from prominent pseudocyphellae. Norstictic or salazinic acids usually present. South America........... [U. amblyoclada (p. 115)] Medulla lax throughout. Axis less than half branch diameter. Surface smooth to subpapilate faveclate tomate |i viedo soe nas saaceeats recess have eaae estos eccoenmeceeees 16 Medulla + compact, rarely sublax. Axis more than half branch diameter. Surface waxy, epapillate, not inflated. Isidia delimited, frequently pigmented and regenerating to form pseudoisidia which may erode. Australasia ....................6.066 [U. torulosa (p. 117)] Thallus corticolous, rarely saxicolous, + unpigmented, rarely subpapillate. Isidia scat- tered, often pigmented. Medulla K—, PD+ yellow, UV— (psoromic acid); K—, PD-, UV++ blue (squamatic acid); rarely K—, PD—, UV-— (+ fatty acid). Australasia...... [U. inermis (p. 117)] Thallus saxicolous, rarely terricolous, often pigmented, subpapillate. Isidia unpig- mented, arising from distinct tubercules. Medulla K—, PD-— (no medullary sub- stances). Peru, Ecuador, Bolivia (high altitudes) ...................0.. 1. U. acanthella (p. 47) Medulla lax in main branches. Axis half or less than half branch diameter .................... 18 Medulla compact in main branches. Axis more than half branch diameter.................... 23 Main branches extensively inflated or + articulate ......0.....20c..scsccevedecsconseeserasvassens 19 Main branches only faveolate or slightly expanded ................ccccecceececeeeeeceee eee eeneeeees 20 Thallus truly sorediate, extensively pigmented or variegated towards apices. Medulla K-—, PD- (no medullary substances). Peru, Ecuador, Bolivia. High altitudes (abnor- PERRIN essa gree can eee ocak ed cena cs Pale Chama Hie’ 11. U. sphacelata (p. 92) Thallus pseudoisidiate, pigmentation confined to pseudoisidia, thallus base and branch 46 20a(18b) 20b 21a(20b) 21b 22a(21a) 22b 23a(17b) 23b 24a(23a) 24b 25a(24b) 25b 26a(23b) 26b 27a(26a) 27b 28a(26b) 28b F. J. WALKER apices. Medulla K+ red, PD+ orange (norstictic and salazinic acids); rarely K—, PD-— (no medullary substances). South America ................0.c0000 6. U. durietzii (p. 78) Thallus with fibrils or grossly papillate, arising from a + proliferating holdfast. Soredia present, pseudoisidia rare. Medulla K+ red, PD+ orange (norstictic and salazinic acids); or K—, PD— (no medullary substances). Patagonia, Antarctic peninsula ........ 12. U. subantarctica (p. 99) Thallus smooth to subpapillate (10 lens), arising from a delimited, or rarely proliferat- ing holdfast. Soredia or pseudoisidia present. Medulla K—, PD— (no medullary substances or + fatty acids); rarely K—, PD+ yellow (psoromic acid); or K+ red, PD orange (norstictic. and salazinic AChas) ) 4 siserats sores vier vac nvvectecesiveriseace meredsaeke Zh Soralia delimited, often globose and pigmented. Thallus + extensively pigmented. Medullary chemistry Vann. 245.5 5300s savuvras crancunss aa maccesnaees ors pitta tices eh iene eaeeeucen 22 Soralia eroded, + effuse to ulcerose, with small blackened pseudoisidia. Thallus pigment confined to base and apices. Medulla K—, PD— (fatty acids). Patagonia, ee OULIN PALIICE a ccc araccnm tan eonec ant oon enavalnine ence banca arcane 8. U. patagonica (p. 82) Medulla containing norstictic acid (K + red, PD + orange) Patagonia (abnormal form) 12. U. subantarctica (p. 99) Medulla depsidone deficient (K—, PD—) or rarely containing psoromic acid (K—, PD+ MEI IW) TOL eres es dats eddy: tavconnbeatnsoeucen tanasops ciee Cao Re 11. U. sphacelata (p. 92) Thallus epapillate, waxy, black-edged annulations PLresent OF ADSENE.. 5 5, sno Mienrcveaseexe 24 Thallus papillate, subpapillate or with fibrils; rarely waxy or annulate ....................0.08. 26 Thallus bright yellow, torulose, lacking annulations. Pseudoisidia pigmented; regener- ating from true isidia. Medullary chemistry various but never containing norstictic and Salazimic acids. AUStt alasla is. tgua ey ahaa vive sacsiens <4 shea seve’ coeds 2) [U. torulosa (p. 117)] Thallus yellow-green (straminous in herbaria), monopodial to richly branched, usually at least with black-edged annulations. Medullary chemistry various, often containing MOMSHICH Cand SAlazinIC ACIGS 5 sae hoes cw sch ce as cp tens es dead sanecosunewadexatenaieaiess 25 Thallus + subdecumbent, richly branched from a delimited holdfast, with numerous, fragile, capillaceous, divergent ultimate branches. Soralia pale, punctiform. Medulla K+ red, PD+ orange (norstictic and salazinic acids). New Zealand....................00605 10. U. pseudocapillaris (p. 89) Thallus erect, + monopodial or moderately branched, often from a proliferating holdfast. Soralia plane, pale, rarely nodular, corticate then pigmented; pseudoisidia rare. Medulla K+ red, PD+ orange (norstictic and salazinic acids); K—, PD— (no medullary substances) (rare); or K—, PD + yellow (psoromic acid) (rare). Australa- sia, Patagonia; Antarctic peninsula and islands (rare). [If lacking annulations and from Antarctica see also U. sphacelata (p. 92) ............sccceeceeeees 2. U. acromelana (p. 48) Thallus + monopodial or moderately branched arising from a proliferating holdfast; CRLCUSIVELY ONDINE INOS ioe ca scsi cies Gcewracitneyeatadhete tats puk bar wec aetna ee Ueoeon ee eaad geet zi Thallus + subdichotomously to richly branched arising from a + delimited holdfast; Extent Of DISMENTATION VATIADIC 5... 5 70cnscuscavaavnetocsevns sawsaWncneahbateMedy tea tabu apiece tuceas 28 Surface + matt, with fibrils or grossly papillate. Medulla K+ red, PD+ orange (norstictic and salazinic acids), or K— PD— (no medullary substances). Patagonia, Amtaretic Weninswias asic. jose. etievedeaadueec sass eousn cased cates 12. U. subantarctica (p. 99) Surface waxy, subpapillate. Medulla K—, PD—, (no medullary substances). Antarctica (abnormal foray) ccc sez cos sccc is toes a Coeur ka vodadinee toe idee 11. U. sphacelata (p. 92) Soralia plane, crateriform; minute pseudoisidia rare. Thallus grossly papillate; usually matt; annulations absent. Medulla compact; K—, PD— (no medullary substances); or K+ sordid brown, PD + red (fumarprotocetraric acid); rarely K+ red, PD + orange (norstictic and salazinic acids — Falkland Is.). Antarctic continent, subantarctic islands, New Zealand (rare), Patagonia (rare) ..................00c00es 3. U. antarctica (p. 55) Soralia plane, eroded, ulcerose; minute pigmented pseudoisidia frequent. Thallus smooth, waxy to subpapillate; occasionally annulate. Medulla sometimes lax in part; K—, PD-— (fatty acids) Patagonia, ? South Africa .................... 8. U. patagonica (p. 82) USNEA SUBGENUS NEUROPOGON 47 The species 1. Usnea acanthella (Lamb) F. J. Walker, comb. nov. Fig. 9 Neuropogon sulphureus f. acanthella Lamb in J. Linn. Soc. (Bot.) 52: 210 (1939). Type: Peru, [Puno], Carabaya, above Limbani, 4410 m, 18 November 1937, Dora Stafford 1108 (BM! — holotype; BM!, FH! - isotypes). [TLC: no medullary substances, + traces of unidentified fatty acids, usnic acid. ] Description: Thallus 2-4 cm, arising from a delimited, blackened, + elongated, stalked holdfast, erect or rarely + subdecumbent, + subdichotomous to richly, + divergently branched above, without fibrils, with loosely interwoven, capillaceous, spinulose secondary branches. Branches terete, greenish yellow, with + broad bands of black pigment, inflated, + weakly articulated. Cortex thin. Surface + faveolate, matt, subpapillate. Medulla extremely lax, axis thin, occupying 0-2-0-3 of the branch diameter. Isidia present, fine, spinulose, unpigmented, c. 0-5 mm long, frequently eroding, arising in delimited clusters from partially corticate tubercules. Pseudoisidia and soredia absent. Apothecia and pycnidia not seen. TLC: no medullary substances, + traces of unidentified fatty acids, usnic acid. ~ ket cee ie M). : Fig. 9 Usnea acanthella. Holotype of Usnea suiphurea f. acanthella Lamb (B Top. Whole thallus (1-5). Bottom. Detail of isidia (10). 48 F. J. WALKER Distinguishing features: Usnea acanthella is characterised by its erect, spreading habit from a basal stalk and a richly branched, spinulose thallus, an inflated, subpapillate surface, a lax medulla lacking depsides and depsidones, a thin axis, and clusters of fine, unpigmented, true isidia. Distribution: Usnea acanthella is apparently restricted to saxicolous, or rarely musicolous- terricolous habitats, in open paramo at high altitudes in the northern part of the Andean chain. The species has been recorded from between 3500-4500 m in Peru, Ecuador, and Bolivia. Fig. 7. Chemistry: Only known in a depsidone deficient phase, with the occasional occurrence of traces of unidentified fatty acids. Variation: From the small number of collections studied, Usnea acanthella appears to be a constant species with little variation. The isidia often erode or appear nodular, but even when they are abraded or underdeveloped, the thallus is characterised by the prominent, pale tubercules from which they arise. Occasionally small fibrils may develop secondarily from such tubercules. There is some variation in the habit of the species, ranging from thalli with prominent, inflated main branches and relatively few ultimate branches, to richly branched, less inflated forms with extensively interwoven branches. Although the type material is uniform in its variegation, frequently with broad bands of pigmentation, other gatherings indicate that this may not necessarily be as constant a feature of this species. In recent collections from Ecuador some parts of the thalli are unpigmented, whilst other areas are totally blackened. Such presence or absence is reminiscent of the kind of blackening found in some corticolous species belonging to the subgenus Usnea, for example U. inermis (p. 117), where blackening only occurs in extremely exposed situations or when the thallus is moribund. However, the presence of some distinctly variegated thalli indicates that pigmentation is probably the norm for the species, although a wider range of material is required to verify its extent. Species concept: Lamb (1939a) described this taxon as a form of Usnea sphacelata (as U. sulphurea), interpreting the pale isidia as outgrowths from healed-over soralia rather than recognising their true nature. The development of true isidia in this species widens the range of asexual propagules found in the subgenus and their development is a sufficiently distinct feature, combined with the characteristic habit of the thallus, to warrant separation at species level. The species superficially is very similar to Usnea durietzii and U. sphacelata, sharing the common features of a lax medulla and normally saxicolous habitat. The development of a basal stalk below and branching are very reminiscent of U. durietzii, although the branches in U. acanthella are generally finer and more fragile. U. acanthella may be distinguished from all other asexual species of the subgenus by the presence of true isidia. Specimens examined ECUADOR. Chimborazo: Cerro Payacorral, near El Altar, 3450 m, 2 August 1980, Cambridge Exped. 2 (BM); Mt. Achipungo, near Osogochi, 4500 m, 7 September 1980, Cambridge Exped. 42 (BM); near El Altar, near Riobamba, 4150 m, 3 August 1980, Cambridge Exped. 5 p.p. (BM). PERU. Cuzco: Huaya Pass, above Cuzco, 4500 m, 14 June 1973, B. Mullins 29 (BM). Puno: prope Azangaro, June 1854, W. Lechler Pl. Peruvianae 1758 p.p. (BM); Cordillera de Carabaya, Limbani (type locality). BOLIVIA. La Paz: Larecaja, Sorata, 4500 m, April 1897, G. Mandon 1737 p.p. (PC). 2. Usnea acromelana Stirton Figs 10-12 in Trans. Proc. N.Z. Inst. 30: 388 (1898). — Neuropogon acromelanus (Stirton) Lamb in J. Linn. Soc. (Bot.) 52: 218 (1939). Type: New Zealand, Selwyn Gorge, May 1894, T. W. N. Beckett L11, ‘on trees’ (thalli saxicolous) (BM! — holotype; CANL 16943!, CHR 343153! — isotypes; GLAM NHB 1927-8-562! — ? isotype). [TLC: norstictic acid, salazinic acid, usnic acid. ] Neuropogon acromelanus var. decipiens Lamb in J. Linn. Soc. (Bot.) 52: 219 (1939). — Usnea acromelana var. decipiens (Lamb) Lamb in Br. Antarct. Surv. Sci. Rep. 38: 5 (1964). Type: Tasmania, summit of Table Mountain [= Mt. Wellington (Wilson, 1893)], R. Brown Iter Australiense, 1802-05, 523 (BM! - holotype; BM! — isotype). [TLC: norstictic acid, salazinic acid, usnic acid. ] USNEA SUBGENUS NEUROPOGON 49 Fig. 10 Usnea acromelana. A Convex-globose soralia X10 (holotype of Neuropogon acromelanus var. decipiens Lamb, BM). B, C Fertile thalli. B Antarctic peninsula, Joinville I. , Smith 2680 (AAS) x1-5. C New Zealand, Otago, Old Man Range, James 1597 (BM) x10. Description: Thallus (1-5—2—4(-6) cm, arising from a broadly proliferating or rarely delimited, pigmented holdfast, usually erect, + monopodial or subdichotomous, moderately branched above, usually lacking fibrils. Branches terete, yellow-green, + continuously pigmented violaceous black towards the apices. Cortex thick. Surface smooth or rarely subfaveolate, waxy, 50 F. J. WALKER epapillate, with conspicuous black-edged annulations on main branches. Medulla compact, axis thick, occupying c. 0-5 of the branch diameter. Soralia numerous on primary and secondary branches, plane and discrete, sometimes becoming confluent, rarely convex-globose and pulverulent. Soredia granular, unpigmented, or partially corticate then pigmented. Pseudoisi- dia rare, isidia absent. Apothecia rare, subterminal, as in U. ciliata. Pycnidia not seen. TLC: (1) norstictic acid, salazinic acid, + protocetraric acid, usnic acid; (2) psoromic acid, + 2’-O- demethylpsoromic acid, usnic acid; (3) no medullary substances, usnic acid. Distinguishing features: _Usneaacromelana is characterised by its erect, proliferating habit, and a monopodial to moderately branched thallus, often with violaceous black pigmentation, a smooth, waxy, black-annulate surface, a compact medulla usually containing norstictic and salazinic acids, a thick axis, and numerous emarginate soralia. Distribution: In Austraiasia Usnea acromelana occurs in the alpine regions of New Zealand and is mainly confined to the Southern Alps apart from isolated records from the North Island, Stewart Island, and Chatham Island; it is rather rare in Tasmania and is known only from a single locality in Victoria. The species is rarely found below c. 400 m, usually occurring between 900-1800 m, and is rare at higher altitudes, c. 2500 m, occasionally being replaced by U. sphacelata. Usnea acromelana is probably less frequent in southern South America (Patagonia) and the Antarctic peninsula than previously indicated (e.g. Follmann, 1965a; Lamb, 1948a). For example, specimens from central Chile are referable to U. patagonica, although the northern limit of U. acromelana is still uncertain. Lamb~(1939a) reported a single gathering of U. acromelana from Peru. This was based on a mixed collection (BM!) of U. acanthella and a norstictic acid-containing thallus that appears to be U. durietzii. However, Dennis (1960) reported affinities between the fungus flora of South America and Australasia, finding the same species in Tasmania and in the paramos of western Venezuela. Consequently the possible occurrence of U. acromelana in the Andes north of Patagonia cannot be completely dismissed. Usnea acromelana is rare on the Antarctic peninsula and is probably confined to the northern tip and the western coast, where material has been examined from Adelaide, Brabant, Joinville and Wiencke Islands, frequently mixed in gatherings with Usnea antarctica, U. aurantiaco-atra, and U. subantarctica. The species is also tentatively identified from a few depauperate specimens from the South Orkney Islands, where U. antarctica is the dominant species. The species is not known from continental Antarctica and previous reports (Filson, 1975; Rudolph, 1963, 1966) refer to U. sphacelata, including the infraspecific taxa described by Lamb (1939a). Fig. 6. Chemistry: Thalli containing norstictic acid and salazinic acid (Race 1) are by far the most frequent of the three chemical races recorded. In this race a trace amount of protocetraric acid is often present, but probably not always in sufficient quantity to enable detection by TLC. This is the most frequent race found in Australasia and is also the most widespread in the South American sector, being previously reported from Patagonia by Asahina (1967), and extends south to the Antarctic peninsula. The occurrence of psoromic acid (Race 2) is rare and unpredictable, and is known from isolated locations in Argentina and Chile, the former collection also including depsidone deficient thalli (Race 3). It is possible that there is a correlation between medullary substances and distribution, as Race 3 is chiefly confined to more southern latitudes; the only exception being the isolated record from Victoria, Australia. A parallel case occurs in Usnea antarctica where depsidone- containing thalli are only frequent towards the northern part of the distribution of that species. Variation: The above description is characteristic of the majority of specimens examined and is typical of much New Zealand material and, to a lesser extent, Tasmanian and South American- antarctic populations where a greater range of thallus morphology is often encountered. The greatest range of variation is found in branching, extent of pigmentation and form of the soralia. The extent of branching ranges from monopodial, with numerous primary branches arising from a proliferating holdfast, to richly branched, rarely from a solitary point of attachment. USNEA SUBGENUS NEUROPOGON Type Specimen asl Fig. 11 Holotype of Usnea acromelana Stirton (BM). Top. X1. Bottom. Detail of cortical annulations and plane soralia x10. 52 F. J. WALKER Study of a large number of collections, particularly from NewZealand (CHR), indicates that altitude may influence thallus morphology, since less characteristic thalli often occur at lower altitudes. For example, the type material of Usnea acromelana, from c. 600 m, includes two of the extreme forms encountered. Plants forming the holotype (BM) (Fig. 11) and one isotype (CANL) are infrequently branched, with only traces of pigmentation at the apices, lacking the waxy, violaceous black lustre, having inconspicuous annulations, and large (0-4-0-5 mm), plane soralia that are rarely pigmented-corticate. In contrast, isotype material in CHR (Fig. 12) is less robust, more richly branched, with scattered fibrils, fine, attenuate, pigmented secondary branches, prominent black-edged annulations, smaller (0-1-0-3 mm), unpigmented soralia, and a less densely interwoven medulla. Scantily pigmented forms are rare at higher altitudes where thalli tend to be smaller, more richly branched and more extensively pigmented, possibly as a response to greater exposure. In extreme instances extensive cracking, resulting from marked annulation formation, may give a slightly faveolate appearance. In typical specimens the soralia are pale, plane, or slightly excavate, sometimes with a - tendency to become convex or slightly confluent, characteristically with a small amount of blackening inside resulting from overlying cortical fragments which, in very extreme instances, may form minute pseudoisidia, or, when damaged, produce spinules. Less typically, soralia may be small and plane, resembling those of Usnea pseudocapillaris, or can be large, extensively blackened, convex and globular to nodulose, (Fig. 10) as in the variety decipiens (Lamb, 1939a). A range of soralia forms may be found on a single thallus. There appears to be a much wider range of variation in Tasmanian populations of Usnea acromelana than in New Zealand, particularly in soralia type and branching pattern; some specimens may lack annulations. Such unusual forms are occasionally found in other parts of the range of this species. In Tasmanian material two main types may be distinguished, but neither is here considered worthy of taxonomic status. The first conforms to variety decipiens and is small (2-4 cm), erect, richly branched, extensively pigmented, with large (0-5—1-5 mm), nodular, blackened soralia with compacted soredia. The second type is erect to subdecumbent, more divergently branched, and could be regarded as an intermediate between U. acromelana and U. pseudocapillaris. However this is considered to be a form of U. acromelana as secondary branches are notably coarser than those of U. pseudocapillaris. Ultimate branches are shortly attenuate and capillaceous, giving the thallus a slightly tasselled and interwoven appearance; the soralia are small, plane to punctiform, rarely pigmented, and confined to secondary branches. The thalli lack the segmented appearance, the extended, entangled secondary branches, and laxer medulla, characters which distinguish U. pseudocapillaris. In some respects South American and antarctic populations of Usnea acromelanaappear to be slightly different from those in Australasia. Thalli may frequently be more robust or more richly branched; short incipient fibrils are rare and are unrelated to papillae. In addition such thalli are usually extensively pigmented, including some banded or mottled variegation which is not generally a feature of this species. As in Australasian populations the extent of black-edged annulations is variable. Often folding and puckering of the surface may be more pronounced, becoming faveolate-ridged rather than simply annulate, which might lead to misidentification. Thalli still retain a violaceous tinge to the pigmentation and a waxy lustre, whilst soralia exhibit the same range of forms encountered in Tasmanian populations. Apothecia are rarely produced (Fig. 10) and are only known from a few localities, for example, from the Old Man Range, Otago, New Zealand (P. W. James 1597, BM!) and Joinville Island, Antarctic peninsula (R. I. L. Smith 3680 p.p., AAS!). The New Zealand specimens bear subterminal or rarely lateral apothecia with a rayed excipulum, which frequently bear soralia, and a buff-grey to greenish black disc. Although sometimes lacking pigment, the disc colour is distinct from that of Usnea trachycarpa which is rufous brown. The Antarctic peninsula specimen belongs to Race 1 and bears a single apothecium, c. 2 mm diameter, with a black disc but lacks excipular rays. Lamb (1948a) described a fertile specimen of this species from Wiencke Island, Antarctic peninsula. This has been examined (Lamb 1790 p.p. BM!) and is similar to the Joinville Island specimen. USNEA SUBGENUS NEUROPOGON 53 CHR 342153 BOTANY DIVISION, D.S.LR., NEW ZEALANT fo P< . ‘See Lo a heel? 1 1 Piaet titles Lae et mee i dy Shawn donk (2 tect 59 ais ie et Fe ye ol Sn pf Qu Lees Mey (P¢G Selwyn Gare Fig. 12 Isotype of Usnea acromelana Stirton (CHR) x1. Species concept: The diverse range of forms of Usnea acromelana that occur might appear to be distinct taxa if it were not for the existence of a range of intermediates. Initially, study of the varied type material of U. acromelana caused considerable speculation as to the delimitation of this species, however, these extremes are here considered to fall within the variation of a single species. This is particularly true of Tasmanian populations, and it is possible that the species is diverging into a range of entities, some of which already differ from New Zealand populations. Some of these forms may appear quite distinct when observed individually but en masse form a continuum. The diversity of chemical races in South American populations may indicate possible affinities with other species occurring in that sector. Such specimens are here referred to Usnea acromelana, despite some morphological ambiguities which are not sufficient to warrant recognition of separate taxa. Further collections and ecological data are essential to resolve this problem. Usnea acromelana is most closely related to U. pseudocapillaris and both belong to the U. ciliata complex. As frequently occurs within the subgenus, there are a few specific instances where it is difficult to conclusively separate the two species. However, study of populations indicates that there are sufficient distinguishing and constant characters. U. pseudocapillaris can normally easily be identified (p. 90) on morphological and chemical characters. On rare occasions in Australasia Usnea acromelana may be confused with Usnea torulosa 54 F. J. WALKER (Appendix I, p. 117). The two species may be separated by the twisted, entwined habit of U. torulosa, its brighter yellow colouration in the field (although this may be less obvious in stored material), lack of surface pigmentation, the presence of pigmented, true isidia, and by differences in depsidone content. The type of Neuropogon acromelanus var. inactivus (Lamb, 1939a) from Tasmania is U. torulosa. Usnea acromelana can be distinguished from U. antarctica by the waxy surface and absence of papillae, and margin to the soralia; from U. durietzii and U. patagonica by differences in habit and absence of pseudoisidia; and from U. sphacelata and U. subantarctica by a compact medulla and smooth surface. Selected specimens examined Race 1 CHILE. Magallanes: Seno Skyring, Estancia Maria, near sea-shore, 28 April 1940, R. Santesson 7058 (S, UPS); Tierra del Fuego, [54°32’S: 70°04’ W], 730 m, 24 February 1978, J. R. Peart s.n. (BM); Tierra del Fuego, Sierra Sorondo, N. slope, above Las Cotorras (c. 20km ENE. of Ushuaia), 800 m, 6 February 1940, R. Santesson 641d (S); Tierre del Fuego, Sierra Alvear, S. slope, above Las Cotorras (c. 20 km ENE. of Ushuaia), 700 m, 9 February 1940, R. Santesson 637d (S); Isla Navarino, Puerto Navarino, 10 m, 28 February 1940, R. Santesson 1232b (S); Canal Beagle, Yendegaia, by front of glacier, 50-100 m, 4 March 1940, R. Santesson 1373 (S), 1373 p.p. (UPS). ARGENTINA. Santa Cruz: Lago Argentino, near front of Ventrisquero Mayo, 105 m, March 1959, P. W. James 5053 (BM); Lago Argentino, Cerro Mayo, c. 1500 m, 25 February 1959, P. W. James 3605 (BM, S, UPS, US); Lago Argentino, Peninsula Magallanes, opposite Spegazzini Glacier, Ventrisquero Spegazzini, January 1959, P. W. James s.n. (BM); Calafate, 1959, P. W. James s.n. (BM); Lago San Martin, 1600 m, 2 February 1933, A. Donat 3 p.p. (H). Tierra del Fuego: Parque Nacional Tierra del Fuego, Ushuaia, ‘Weg zum’ Glaciar Martial, c. 500 m, 7 December 1973, A. Henssen & G. Vobis 244171 p.p. (MB). SOUTH ORKNEY IS. Coronation I.: Wave Peak Buttress, 225 m, 9 September 1973, T. N. Hooker 84 (AAS), T. N. Hooker 87 (AAS), T. N. Hooker 116 (AAS); Sunshine Glacier, 180 m, 12 March 1972, T. N. Hooker 66 (AAS). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°15’S: 55°45’W], Mt. Alexander, 200-500 m, 27 March 1981, R. I. L. Smith 2680 p.p. (fertile) (AAS); Mt. Cardinall [63°27’S: 57°10’W], 225 m, 14 December 1946, J. D. Andrew F.I.D.S. D115-12b (BM); Gerlache Channel, Brabant I. [64°15’S: 62°20'W], Exped. Antarct. Belge 249 p.p. (BM ex herb. Vainio 354, 355); Palmer Archipelago, Wiencke I. [64°48’S: 63°25'’W], N. buttress of Noble Peak, 225 m, 20 November 1944, J. M. Lamb 1790 p.p. (fertile) (BM); Loubet Coast, Adelaide I., Rothera Point [67°35’S: 68°00’W], 10 m, 29 January 1976, J. Fenton 23 (AAS). AUSTRALIA. Tasmania: Central Southern Tasmania, Mt. Mawson, 1220 m, 4 December 1965, G. C. Bratt 2931a (CHR 343400); Mt. Mawson, southern peak, 1220 m, 11 May 1968, G. C. Bratt 68/348 [Lich. Exs. COLO 247] (BM, CHR 343460); Mt. Mawson, 19 February 1968, R. Filson 10580 (MEL 1029344); Lake Augusta, outcrop c. 0-5 km E. of dam, 840 m, 2 March 1970, G. C. Bratt & M. H. Bratt Bratt 70/243 (HO 35238), Bratt 70/229 (HO 35237); Mt. Wellington Plateau, 11 January 1969, G. C. Bratt et al. Bratt 69/7 (HO 35193), summit area, 1270 m, 20 December 1964, G. C. Bratt 1872b (HO 35188), 1850, S. Mossman 796 (BM, E); Table Mtn, 1095 m, 18 June 1972, G. C. Bratt &J. A. Cashin Bratt 72/393 p.p. (HO 35179); Mt. Penny, 4 April 1969, G. C. Bratt & K. M. Mackay Bratt 69/162a&b (HO 35240). NEW ZEALAND. North Island. Wellington: Tongariro National Park, Tama Lakes, 1220 m, D. Scott 504 (OTA): unlocalised: Colenso C1776 (BM, WELT). South Island. Nelson: Cobb Valley, Cobb Ridge, 850 m, 19 December 1982, J. K. Bartlett 26252 (herb. Bartlett, BM); Mt. Technical, above Lewis Pass, 14 January 1979, D. J. Galloway s.n. (CHR 343160 p.p.); Mt. Arthur, March 1879, A. Mckay s.n. (WELT L1505). Marlborough: Inland Kaikoura Range, Mt. Tapuaenuku, 20 March 1934, J. S. Thomson 1523 p.p. (CHR 343806 p.p.), 2400 m, J. S. Thomson 1506 p.p. (CHR 343791 p.p.); Branch River, Range above Gordon Stream, c. 900-1200 m, 23 January 1984, J. K. Bartlett 26418b p.p. (herb. Bartlett), 26419 p.p. (herb. Bartlett). Canterbury: Banks Peninsula, Mt. Sinclair, 3 February 1979, D. J. Galloway s.n. (CHR 343147); Ben Ohau Range, Glen Lyon Station, 1830 m, October 1958, J. Murray Mason 29 & 30 (BM, OTA, S, UPS); Kirkliston Range, 1520-1680 m, 25 March 1978, D. J. Galloway s.n. (CHR 343230); Four Peaks Range, Blue Mtn, c. 1640 m, 23 April 1979, D. J. Galloway s.n. (CHR 343224); Torlesse Range, Foggy Peak, 1680 m, November 1972, D. J. Galloway s.n. (CHR 343430). Otago: Humboldt Mtns, Mt. Minos, 2010 m, 1 January 1970, D. J. Galloway s.n. (CHR 342824); Rock and Pillar Range, 1160-1190 m, 18 September 1981, F. J. Walker s.n. (BM, UPS); Dunedin, Maungatua, 880 m, 17 September 1981, F. J. Walker s.n. (BM, UPS); Dunedin, Middlemarch—Mosgiel road, nr. Sutton, c. 370 m, 18 September 1981, F. J. Walker s.n. (BM); Old Man Range, 1220 m, 1 February 1963, P. W. James 1597 (BM), 1579 (BM); USNEA SUBGENUS NEUROPOGON 55 Matukituki Valley, Mt. Avalanche, 2560-2590 m, 15 February 1969, L. D. Kennedy s.n. (CHR 343382), Mt. Sir William, 2560 m, 27 December 1970, D. J. Galloway s.n. (CHR 342786 p.p.); Shepherd’s Pass, 1980 m, January 1968, D. J. Galloway s.n. (fertile) (CHR 343411); Mt. Earnslaw, 2700 m, February 1972, A. A. Deans s.n. (CHR 342757); Remarkables, above Lake Alta, 1980 m, March 1967, L. D. Kennedy s.n. (fertile) (CHR 343440). Southland: Mid Dome, 1520 m, May 1970, G. Van Reenens.n. p.p. (CHR 342837 p-p.); Mt. Barrier, Homer Tunnel, March 1959, M. A. Chapman Murray 4180 (OTA). Stewart I.: Mt. Anglem, summit, 984 m, February 1966, D. J. Galloway s.n. (CHR 343356, CHR 343417, CHR 343389). Chatham Is: Chatham I., Travers s.n. (BM). Race 2 CHILE. Aisén: ‘in valle superiore fluminis Aysén’, c. 1400 m, 23 February 1897, P. Duséns.n. (UPS). ARGENTINA. Santa Cruz: Lago Argentino, Cerro Norte, c. 800 m, 22 December 1958, P. W. James 404 p.p. (BM). Race 3 CHILE. Magallanes: Tierra del Fuego, Isla Navarino, 300 m, 1963, G. Follmann 14586 p.p. (M). ARGENTINA. Santa Cruz: Lago Argentino, Glaciar Moreno, 22 January 1967, P. R. San Martin s.n. (FH); Lago Argentino, Parque Nacional Glaciares, Peninsula Magallanes, 17 December 1973, A. Henssen & G. Vobis 24516a (MB); opposite Spegazzini Glacier, P. W. James s.n. p.p. [as Race 1] (BM); Lago Argentino, Bilbao, 2-3 February 1914, C. M. Hicken 16450 (BM); Cerro Norte, P. W. James s.n. p.p. [as Race 2] (BM). Unlocalised: South Patagonia, 1900-01, comm. H. Prichard (BM). SOUTH ORKNEY IS: Coronation I., Wave Peak Buttress, 225 m, 9 September 1973, T. N. Hooker 85 (AAS), T. N. Hooker 86 (AAS), T. N. Hooker 115 (AAS), T. N. Hooker 117 (AAS), T. N. Hooker 118 (AAS). ‘AUSTRALIA. Victoria: Basalt Hill, Bogong High Plains, [c. 2000 m], 29 January 1967, A. C. Beauglehole s.n. (MEL 18755), 22 January 1967, R. B. Filson 9504 (MEL 1018193). For further localities of Race 1 in Canterbury and Otago see lists held in BM and collections in BM, CHR, HO and OTA. 3. Usnea antarctica Du Rietz Figs 13-14 in Svensk bot. Tidskr. 20: 93 (1926). — Neuropogon antarcticus (Du Rietz) Lamb in J. Linn. Soc. (Bot.) 52: 210 (1939). Type: Regio Antarctica, South Victoria Land, Admiralty Range, 2000’ s.m., 1900, C. R. Borchgrevink (UPS! — holotype; S!, O! — isotypes). [TLC: no medullary substances; + UV+ unknowns, usnic acid. | Neuropogon melaxanthus f. sorediifer Crombie in J. Linn. Soc. (Bot.) 15: 182 (1876). — Usnea melaxantha var. sorediifera (Crombie) Mill. Arg. in J. Linn. Soc. (Bot.) 32: 200 (1896). — Usnea sulphurea var. sorediifera (Crombie) Vainio, Rés. Voy. S. Y. Belgica, 1897-99, Botan., Lichens: 11 (1903). — Neuropogon antarcticus f. sorediifer (Crombie) Lamb in J. Linn. Soc. (Bot.) 52: 213 (1939). Type: Kerguelen Land, Royal Sound, Venus Transit Expedition, A. E. Eaton (BM! — lectotype, selected Lamb, 1939a; BM!, M!, UPS! — isolectotypes). [TLC: fumarprotocetraric acid aggr., usnic acid. ] Usnea sulphurea var. granulifera Vainio, Rés. Voy. S. Y. Belgica, 1897-99, Botan., Lichens: 11 (1903). — Usnea melaxantha var. granulifera (Vainio) Hue, Deux Exped. Antarct. Frang. Lichenes: 27 (1915). - Usnea granulifera (Vainio) Motyka, Lich. Gen. Usn. Stud. Monogr. 1: 35 (1936). Type: Détroit de Gerlache: dans les fentes d’une falaise rocheuse, Cap Anna Osterrieth, 64°33’ de latitude sud, Terre de Danco (9° débarquement, 197 p.p.), M. Emile G. Racovitza (TUR 443 herb. Vainio 358! — lectotype, selected Dodge, 1973; herb. Dodge — isolectotype, not seen). [TLC: no medullary substances, usnic acid.] (see Note 1) Neuropogon insularis Lamb in J. Linn. Soc. (Bot.) 52: 215 (1939). — Usnea insularis (Lamb) Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 211 (1948). Type: Prince Edward Group: Marion I., 26 December 1873, Challenger Exped. (BM! — holotype; BM! — isotype). [TLC: fumarprotocetraric acid aggr., usnic acid. ] Usnea crombiei [‘Crombii’| Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 212 (1948); nom. inval. (Article 36.1.). Spec. orig.: Heard I., between Atlas Cove and Corinthian Bay, B.A.N.Z.A.R.E. B140-36 (herb. Dodge, not seen). [TLC: fumarprotocetraric acid, usnic acid (Lamb, 1964) AD! — loc. classicus. Usnea see ne var. sublaevis Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 213 (1948); nom. inval. (Article 36.1) Spec. orig.: Heard I., between Atlas Cove and Corinthian Bay, B.A.N.Z.A.R.E. B 140-40 (herb. Dodge, not seen). [TLC: fumarprotocetraric acid, usnic acid (AD! - loc. classicus).] Usnea floriformis Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 214 (1948). Type: Heard I., Atlas 56 F. J. WALKER Cove and Corinthian Bay, B.A.N.Z.A.R.E. B 140-41 (herb. Dodge — holotype, not seen). [TLC: fumarprotocetraric acid, usnic acid (AD! — loc. classicus). ] Usnea propagulifera Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 213 (1948). Type: Heard I., Atlas Cove to Corinthian Bay, B.A.N.Z.A.R.E. B150-42 (herb. Dodge — holotype, not seen). [TLc: fumarprotocetraric acid aggr., usnic acid (AD! — loc. classicus). ] Usnea pustulata Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 203 (1948). Type: Queen Mary Land, Possession Nunatak [66°45’S: 98°30’E], C. T. Harrisson A.A.E. 85-1 (herb. Dodge — holotype, not seen). [TLC: no medullary substances, (Lamb, 1948a).] ?Usnea subfoveolata Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 202 (1948). Type: Queen Mary Land, Hippo Nunatak [66°26’S: 98°06’E], C. T. Harrisson A.A.E. 82-2 (herb. Dodge — holotype, not seen). [Chemistry: no medullary substances (Lamb, unpublished notes, AAS!)] AD! — loc. classicus = U. sphacelata. (see Note 2) ?Usnea subpapillata Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 204 (1948). Type: Queen Mary Land, Hippo Nunatak, C. T. Harrisson A.A.E. 82-3 (herb. Dodge -—holotype, not seen). (Chemistry: no medullary substances (Lamb, unpublished notes, AAS!).] AD! —loc. classicus = U. sphacelata. Usnea crassa Zammuto in Dodge in Trans. Am. microsc. Soc. 84: 521 (1965). Type: Antarctica, Melchior Is., Eta (Bailey) I. [64°19’S: 62°55'W], 5 March 1941, P. A. Siple 349 (herb. Dodge — holotype, not seen; US! — isotype). [TLC: no medullary substances, usnic acid (isotype).] Usnea pseudofruticosa Zammuto in Dodge in Trans. Am. microsc. Soc. 84: 521 (1965). Type: Antarctica, Melchior Is., Gordon Lien I., 7 March 1941, P. A. Siple 352 (herb. Dodge — holotype, not seen; US! — isotype). [TLC: no medullary substances, usnic acid (isotype). ] Note 1: Usnea sulphurea var. granulifera Vainio This taxon was based on four paratype collections, some of which were later further subdivided, in herb. Vainio (TUR). Although Lamb (1939a) illustrated part of herb. Vainio 360 as the type it does not appear that the taxon was formally lectotypified. A small part of this collection in BM! was later annotated as isotype by Lamb. Motyka (1936) referred to material from [le Auguste as being from the locus classicus but did not indicate which Vainio specimen was the type. This locality is cited by Vainio under Racovitza 208 p.p., which in herb. Vainio is represented by numbers 359, 360, and 361. Consequently later formal lectotypification by Dodge (1973) must be recognised. It is clear that Dodge did not examine all the paratype collections since he selected herb. Vainio 358 (Cap Anna Osterrieth) on the grounds of this being the only fertile material, which is not the case. Herb. Vainio 358 is a mixture of U. aurantiaco-atra and fertile U. antarctica. It is assumed that Dodge based his lectotypification on U. antarctica and that a duplicate specimen in herb. Dodge also belongs to the species. Other paratypes examined belong to U. antarctica. Note 2: Usnea subfoveolata Dodge The systematic position of this taxon remains uncertain. Dodge (1948) regarded the species as being somewhat intermediate between U. frigida (= U. sphacelata) and U. antarctica, since it morphologically resembles the former species but its anatomy was closer to the latter. Type material, from Queen Mary Land, has not been made available but was examined by Lamb in MO (Lamb, 1964), who considered it to be nearer to U. antarctica. Material from the type locality in AD has been examined and is nearer to U. sphacelata, along with additional specimens in US, possibly determined by Dodge’s student. Examination of a photograph of the type specimen (Lamb, unpublished notes, AAS!) shows some affinities with U. antarctica, although examination of the actual specimen is required for the systematic position to be finally ascertained. Description: Thallus (1-5)-2-S(-7-10) cm, arising from a + delimited, rarely pigmented, holdfast, erect, + dichotomous, richly branched above with numerous, attenuate branches, rarely with fibrils. Branches terete, yellow-green, + variegated above with bands of black to violaceous black pigment, + continuously pigmented towards the apices. Cortex variable in thickness. Surface matt, subpapillate to grossly papillate, papillae usually unpigmented, black- edged annulations absent. Medulla compact, axis thick, occupying 0-5 to 0-7 of the branch diameter. Soralia + extensive throughout thallus, plane to excavate, rarely pulvinate, arising from papillae, delimited, often with a distinct crateriform margin. Soredia granular, unpig- mented, rarely partially corticate then pigmented. Pseudoisidia rare, isidia absent. Apothecia rare, subterminal, asin U. aurantiaco-atra. Pycnidia not seen. TLC: (1) fumarprotocetraric acid, + protocetraric acid, + cph-1, + UV+ unknowns, usnic acid; (2) norstictic acid, salazinic acid, usnic acid; (3) no medullary substances, + UV+ unknowns, usnic acid. USNEA SUBGENUS NEUROPOGON S7 Fig. 13 Usnea antarctica. Top. Isotype of Usnea antarctica Du Rietz (O) x1. Bottom. Detail of soralia. South Shetland Is., Lindsay 471 (BM) X10. 58 F. J. WALKER Distinguishing features: Usnea antarctica is characterised by its erect habit, a richly branched thallus arising from a delimited holdfast, pigmented towards the apices, a grossly papillate surface, a compact medulla, a thick axis, and numerous, plane, discrete, more or less marginate soralia. It is the only asexual species of the subgenus known to occasionally contain fumarpro- tocetraric acid. Distribution: Usnea antarctica is a circumpolar antarctic species which has its main centre of distribution in the region of the Antarctic peninsula and the associated islands of the Scotia Arc. It also occurs on the subantarctic islands, for example: Bouvetdy, Kerguelen, Macquarie, and Marion, and is rare in the Andes of southern South America (Lamb, 1964) as well as at high altitudes in New Zealand (Mark & Bliss, 1970; Martin & Child, 1972). The species is less frequent in continental Antarctica (Dodge, 1962; Dodge & Baker, 1938; Filson, 1966, 1974; Lamb, 1964; Ovstedal, 1983) whilst it is the only asexual species of the subgenus on the South Shetlands, South Sandwich Islands, Bouvetgy, Iles Kerguelen, Heard Island, Mc.Donald Islands, Marion Island, Macquarie Island, and South Georgia. Fig. 4. Chemistry: ‘Thalli lacking medullary substances (Race 3) are most frequently encountered overall, whilst those containing fumarprotocetraric acid (Race 1) predominate, or are often the only race, in the subantarctic regions. Both Races 1 and 3 occur on the Antarctic peninsula, although Race 3 extends further south and is the only race found in continental Antarctica. Most South American specimens belong to Race 1 and any depsidone deficient material should be checked against Usnea patagonica and analysed by TLC for fatty acids. The presence of occasional traces of unidentified fatty acids in a few specimens of U. antarctica is not considered to be significant. Thalli containing high concentrations of fumarprotocetraric acid were initially regarded as a separate form, f. sorediifera, by Lamb (1939a). Traces of salazinic acid were occasionally detected in Race 1 whilst the existence of a norstictic and salazinic acid-containing race (Race 2) occurs in the only specimen known from the Falkland Islands. UV+ unknowns, identical to those found in U. perpusilla, occur sporadically in Races 1 and 3. Psoromic acid has not yet been demonstrated; previous reports (Golubkova & Schapiro, 1970; Lamb, 1939a) correspond respectively to an UV+ unknown and low concentrations of fumarprotocetraric acid that give a PD-+ yellow reaction but are not detectable by TLC (BM!). Variation: Lamb (1939a) considered Usnea antarctica to be one of the most variable species of the subgenus and discussed the problems involved in selecting suitable characters for delimiting the species. Frequently not all the distinguishing features are developed. However, the species can usually be separated from other asexual species solely on features of the cortex and soralia. Thallus size and extent of branching are variable, although the thallus almost always arises more or less dichotomously from a delimited holdfast. Secondary branching may be extensive with the production of numerous, relatively short, fine branches. Thalli may rarely become subdecumbent when growing in exposed situations or amongst bryophytes. The degree of violaceous black pigmentation is generally more extensive in richly branched specimens whilst in some instances pigment may be confined to branch apices or cortical fragments in the soralia. Pigment is usually lacking on primary branches, whilst the area above the holdfast is rarely pigmented. Primary branches are characterised by the presence of conspicuous unpigmented papillae. Papillation is sometimes very reduced particularly in smaller thalli, giving an almost faveolate or subfaveolate appearance. In such rare instances the thallus may have a slightly waxy lustre, rather than more characteristically dull or matt, thus resembling some forms of Usnea sphacelata. In these specimens the soralia tend to be very small and their margins become less prominent, or may even be lacking if the surface is exceptionally smooth. This modification has led to the description of several taxa which are here reduced to synonymy, although the interpretation of some of these has been difficult in the non-availability of holotype material. For example, U. pustulata represents an extensively sorediate form with a thin, compact, medulla, and an almost smooth, somewhat waxy, surface. From examination of material from near the type locality (AD!) and an unpublished photograph of the holotype taken USNEA SUBGENUS NEUROPOGON 59 by Lamb (AAS), it is clear that this taxon agrees in all details with U. antarctica, although U. sphacelata also occurs in a mixed collection from Possession nunatak made by Borchgrevink (UPS!). Usnea subfoveolata and U. subpapillata were both described from the same locality. From examination of additional cited specimens (AD!) of both species from the type locality, it is evident that Dodge’s original concepts (Dodge, 1948) of the taxa included some specimens of U. sphacelata. However, following Lamb’s observations (Lamb, 1964) on the type specimens and examination of his unpublished photographs (AAS!), it is likely that the type material of both taxa is closer to U. antarctica. The pale patches in the cortex of the type of Usnea insularis appear to be the result of erosion combined with incipient soralia formation, rather than maculae formed as a result of extension of the axis through the cortex as in U. taylorii. This type has been compared with U. antarctica from Iles Kerguelen which has a similar eroded cortex and only a few, small papillae. Thallus anatomy is constant in as far as the axis usually occupies half or more of the diameter in main branches and the medulla remains densely interwoven, at least towards the cortex. A very wide range of variation occurs in the relative widths of each tissue, particularly amongst robust populations from Iles Kerguelen and Marion and Prince Edward Islands. Such develop- ment has formed the basis for the description of a wide range of taxa that can no longer be regarded as distinct. For example, Usnea crassa is a very robust form of the species originally distinguished by an exceptionally thick axis, that is irregular in outline, and possesses a small central cavity, as well as a very thick cortex. The original description gives measurements of up to 260 «wm for the cortex, which presumably includes prominent papillae, since the maximum width for isotype material is c. 170 wm, whilst c. 100 wm is more usual in specimens from the Antarctic peninsula. Similarly U. pseudofruticosa was separated on slight differences in thickness of cortex, medulla, and axis. ; Robust material of Race 1 from Heard Island and Iles Kerguelen was reported to have a partially sub-divided axis like Usnea taylorii and recognised as a distinct species, U. insularis (Dodge, 1948; Lamb, 1939a; Lindsay, 1977b). Occasionally thalli examined from these loca- tions, and also from Marion Island, have axes with a small central lumen and slightly irregular outline, but I have not found any thalli with a distinctly divided axis. U. crombiei was distinguished for similar reasons, although the original material indicates that the slight invagination of the axis is not particularly pronounced. Papillae give rise to soralia throughout the thallus which may extend down main branches, rather than remaining confined to apices as in Usnea sphacelata. In robust thalli, with large papillae, the soralia are very characteristic since papillae from which they are derived form a distinctive crateriform margin. Soralia are usually unpigmented, plane to slightly concave- excavate, rarely convex, and smaller than the branch diameter, although they may become confluent on ultimate branches, a feature that is sometimes characteristic of Race 1 from the subantarctic regions. In southern South America a wider range of variation of form of soralia occurs. Sometimes small pseudoisidia are produced in the soralium, but these are never as large or distinct as in U. durietzii or U. patagonica. Other variations include small, plane soralia in more extensively pigmented thalli with fibrils; globular, pigmented soralia are characteristic of a few thalli all belonging to Race 1 which also have a slightly lax medulla and were found in a mixed collection with U. cf. subantarctica (Santesson 641c, S!). When damaged, small, spinule- like projections, may be produced from soralia (Santesson 637a, S!); this was regarded as a distinctive feature in U. propagulifera by Dodge (1948). Fertile material (Fig. 14) of Usnea antarctica is rare and apothecia are only produced in areas of optimum luxuriance, for example, the type of U. floriformis from Heard Island. Lamb (1939a, 1948a, 1964) reported fertile material from the Antarctic peninsula, South Georgia, and Tierra del Fuego. In addition, fertile material belonging to Races 1 and 3 has now been found amongst collections from the South Orkneys, South Shetlands, South Sandwich Islands, and Bouvet¢y; the only Falkland Island specimen (Race 2) also bears rudimentary apothecia. The apothecia are subterminal or lateral, or are sometimes produced in series along a single branch. They are usually small, cupular, or rarely expanded with an irregular to crenulate margin. The disc is 60 F. J. WALKER Fig. 14 Fertile thalli of Usnea antarctica. Antarctic peninsula, Anvers I., Lamb 8025 p.p. (FH) X1. black or rarely brown when immature. In fertile specimens soralia may be either abundant or scarce. One specimen (Race 1) from South Georgia (Lindsay 4327, AAS!) bears a superficial resemblance to U. ciliata in habit but has a verrucose surface and very scanty development of soralia. Species concept: The wide range of variation found in Usnea antarctica has led to the description and recognition of a number of species by various authors according to their particular species concepts (see synonymy), all of which here fall within the variation of the species. The holotype specimen of Usnea antarctica represents a less robust form and in some respects has some features in common with U. sphacelata. The thalli have a slightly lax medulla, slender, variegated secondary branches, are subpapillate, and have small, plane, eroded soralia, sometimes lacking the distinctive margin. It is surprising that Usnea antarctica was not recognised as a distinct species before Du Rietz’ treatment (Du Rietz, 1926) of the subgenus; this taxon previously being included as a variety of U. sphacelata. Du Rietz (1926) based the species on two varieties previously assigned to U. sulphurea. Of these U. sulphurea var. granulifera is more typical of populations from the Antarctic peninsula and var. sorediifera representative of richly sorediate material of Race 1 form Iles Kerguelen. Usnea antarctica is very probably the sorediate counterpart of U. aurantiaco-atra. Supporting evidence for this comes from the similarity of surface ornamentation and apothecia as well as from chemical data. The existance of three chemical races in the two species with similar distributions in South America and Antarctica lends support to this theory, in particular the validity of the single specimen of Race 3. This sorediate specimen is unique and was probably the result of a sporadic secondary formation from the norstictic-salazinic race of the fertile counterpart, on the Falkland Islands. It is unlikely that the specimen is misplaced since the remaining two specimens in the same herbarium packet belong to the norstictic-salazinic race of U. aurantiaco-atra which also has a restricted distribution (see p. 69). In areas where the distributions overlap, Usnea antarctica may be distinguished from U. sphacelata and U. subantarctica by the marginate soralia arising from large, unpigmented papillae, a compact medulla and broad axis; from U. durietzii and U. patagonica (Table 3) by USNEA SUBGENUS NEUROPOGON 61 differences in habit, basal pigmentation, a compact medulla, and absence of pseudoisidia; from U. neuropogonoides by habit and presence of soralia; and from U. acromelana and U. pseudocapillaris by the presence of papillae and lack of annulations, and sometimes also by chemical differences. Selected specimens examined Race 1 CHILE. Magellanes: Mt. Aymond, Straits of Magellan, 1872, Hassler Exped. s.n. (BM, FH, PC); Isla Navarino, Puerto Navarino, 10 m, 28 February 1940, R. Santesson 1234b (S); Tierra del Fuego, San Sebastian, 2 January 1896, P. Dusén 80 (BM); Canal Beagle, Yendegaia, by glacier, 50-100 m, 4 March 1940, R. Santesson 1373 p.p. (UPS). ARGENTINA. Santa Cruz: Cordillera Darwin, Cerro Mayo, above Seno Mayo, Lago Argentino, c. 1000 m, February 1959, P. W. James 73 (BM), near front of Ventrisquero Mayo, 90 m, March 1959, P. W. James 5052 (BM). Tierra del Fuego: Sierra Alvear, S. slope, above Las Cotorras, (c. 20 km ENE. of Ushuaia), 700 m, 9 February 1940, R. Santesson 637a (S, UPS), Sierra Sorondo, N. slope, above Las Cotorras, 800 m, 6 February 1940, R. Santesson 641c. p.p. (S). SOUTH GEORGIA. Cumberland East Bay, above Hope Point, 80 m, January 1973, D. C. Lindsay 4327 (fertile) (AAS); Whale Valley, 250 m, January 1973, D. C. Lindsay 3957 (fertile) (AAS); Royal Bay, 29 April 1902, C. Skottsberg s.n. (S); N. of Sandebugten, W. shore of Barff Peninsula, c. 15 m, 14 January 1961, S. W. Greene 939 (AAS, BM). SOUTH ORKNEY IS. Signy I.: Paal Harbour, 90 m, 2 April 1965, R. J. L. Smith 429 (AAS); Tern Cove, 15 m, 24 October 1973, T. N. Hooker 263 (fertile) (AAS). Coronation I.: Top of Wave Peak Buttress, 392 m, 29 September 1973, T. N. Hooker 194 (AAS). Laurie I.: Cape Dundas, 60 m, 15 February 1971, M. McManmon 195 (AAS). SOUTH SHETLAND IS. King George I.: Admiralty Bay, Keller Peninsula, 24 December 1960, B. J. Taylor 324 (AAS), 50-60 m, 5 January 1953, B. Frédin 21a (UPS). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°15’S: 55°48’W], Mt. Alexander, 200-500 m, 27 March 1981, R. I. L. Smith 3680 p.p. (AAS); Trinity Peninsula, Hope Bay [63°23'S: 57°00’ W], 105 m, 16 April 1945, F.J.D.S. D2375 p.p. (BM), Duse Bay [63°32’S: 57°15'W], 370 m, 6 January 1946, E. H. Back F.I.D.S. D2865 (BM); Palmer Archipelago, Wiencke I. [64°48’S: 63°25’W], N. buttress of Noble Peak, c. 210 m, 15 October 1944, J. M. Lamb Operation Tabarin 1307 (BM); Argentine Is., Galindez I. [65°15’S: 64°15'W], 27 December 1935, B.G.L.E. 1328-2 (BM); Falliéres Coast, Adelaide I. [c. 67°60’S: 68°20’ W], nunatak c. 18 km N. of base hut [Rothera], 10 December 1962, F. Gibbs Killingbeck 207b (AAS, BM). MARION I. Tafelberg, E. slope, c. 320 m, 10 May 1982, H. Hertel 24 593 (M); Skua’s Ridge, 80 m, 26 January 1972, A. de Villers 4-31 (BLFU); Johnny’s Hill, 4 January 1951, R. W. Rand 3310 (BOL). PRINCE EDWARD I. vicinity of Kent Crater, c. 50 m, 1 May 1982, H. Hertel 24 343 (M). iS. KERGUELEN. Cliffs above Lake du Val Studer, 11 February 1963, R. B. Filson 4665 p.p. (BM); Royal Sound, 1897-98, R. Hall s.n. (MEL 9230). HEARD I. between Rogers Head, Corinthian Bay, West Beach, and the foot of the glacier from Big Ben (Kaiser Wilhelm Peak), 28 November—2 December 1929, B.A.N.Z.A.R.E. B140-43 (AD). MC.DONALD IS. 13 March 1980, J. Jenkin s.n. (herb. Seppelt 11123). MACQUARIE I. between North Mount and Handspike Point, 7 December 1968, D. McVean 6909 (BM); Perseverance Bluff, 100 m, 29 January 1982, R. D. Seppelt 12748 (herb. Seppelt). NEW ZEALAND. Canterbury: Kirkliston Range, 1680-1830 m, 25 March 1978, D. J. Galloway s.n. (BM, CHR 343299). Otago: Mt. Pisa, 1920 m, March 1968, D. J. Galloway s.n. (CHR 343771); Mt. Earnslaw, 2240 m, May 1961, R. G. Cunninghame s.n. p.p. (BM, OTA); Old Man Range, c. 1370 m, 1 February 1963, P. W. James 1159 p.p. (BM). Race 2 FALKLAND IS. (unlocalised), 1824, Greville herb. (E). Race 3 SOUTH GEORGIA. Cumberland West Bay, Bore Valley, 105 m, 11 February 1961, S. W. Greene 1979 (AAS, BM, FH); Cumberland East Bay, Dartmouth Point, 30 m, 5 December 1971, D. C. Lindsay 3458 (BM); 1921-22 Shackleton-Rowett Exped. 10 p.p. (BM). SOUTH SANDWICH IS. Candlemas I.: 180 m, 5 March 1964, R. E. Longton 535 (fertile) (BM). Bellinghausen I.: 200 m, 10 March 1964, M. W. Holdgate 825c (AAS, BM). Visokoi I.: Finger Point, 6m, 9 January 1961, K. Archibald 35 (AAS, BM, FH). SOUTH ORKNEY IS. Signy I.: Borge Bay, Knife Point, 9 m, 8 October 1966, D. C. Lindsay 1255 (BM); Observation Bluff, 60 m, 21 January 1972, T. N. Hooker 1(AAS). Laurie I.: Scotia Bay, 11 March 1953, A. 62 F. J. WALKER E. Hunziker 10238 (FH). Powell I.: between Cape Disappointment and Falkland Harbour, 30 m, 30 January 1965, R. I. L. Smith 263 (AAS, BM). SOUTH SHETLAND IS. King George I.: Admiralty Bay, mountain slope between Petrified Forest Creek and Ornithologist’s Creek, 100 m, 26 December 1979, R. Ochyra 5000/79 (M). Deception I.: Kroner Lake, 30 January 1960, B. J. Taylor 29 (AAS, BM). Robert I.: 1963, G. Follmann 17441 (KASSEL). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°15’S: 55°45’W], Active Sound, 200 m, 27 March 1981, R. J. L. Smith 3735 (AAS); Palmer Archipelago, Anvers I. [64°45’S: 64°05'W], Arthur Harbour, Palmer Station, 10 m, 4 February 1965, J. M. Lamb Operation Tabarin 8025 p.p. (fertile) (FH); Marguerite Bay, Jenny I. [67°44’S: 68°25'W], 9m, 17 October 1948, B. Stonehouse & V. E. Fuchs F.1.D.S. E466-1a (BM). DRONNING MAUD LAND. [c. 15°W]. Vestfjella, Basen, c. 300 m, 1968-69, A. Hjelles.n. (O). EDWARD VIILAND. [c. 150°W]. Rockefeller Mountains, Mt. Marguerite Wade, 17 December 1940, R. G. Frazier & F. A. Wade U.S.A.S. 320 (US). VICTORIA LAND. [c. 165°E]. Geikie Land, 300 m, 1900, Southern Cross Exped. s.n. (BM); Hallett Peninsula, c. 300 m, 11 November 1962, E. D. Rudolph 62040 (LD). GEORGE V LAND. [c. 150°E]. Dreadnought or Horn Bluff, 21 December 1912, A. L. McLean A.A.E. 46 (AD). KNOX COAST. [c. 110°E]. Mitchell Peninsula, outcrop 1-5 km E. of Pidgeon I., 21 December 1982, R. D. Seppelt 013357 (herb. Seppelt). QUEEN MARY LAND. [c. 95°E]. Alligator Nunatak, 2 January 1913, C. T. Harrisson A.A.E.72 (AD). KAISER WILHELM II LAND. [c. 90°E]. Haswell I., 20 December 1957, V. Rozov 101 (AAS, FH). MAC.ROBERTSON LAND. [c. 70°E]. Tschuffert Peak, 9 February 1974, R. Filson 14900 Lich. Ant. Exs. 23 (AAS, BM, M, O); Hays Peak, Cape Bruce, 10 October 1962, R. Filson 4387 (AAS). MAC.ROBERTSON-ENDERBY LAND TRAVERSE. [c. 60°E]. 1964-65, N. Leid Bratt 3272a (HO 35190). BOUVET®Y. Rustadkollen, 340 m, 7 March 1979, T. Engelskjén s.n. (BG, BM); S. of Kapp Circon- cision, c. 15 m, 31 March 1964, M. W. Holdgate 868a (AAS, BM, FH). MARION I. 26 December 1873, Challenger Exped. s.n. (type of U. insularis Lamb) (BM). HEARD I. Dreadnought (Horn) Bluff, 21 December 1912, A. L. McLean A.A.E. 46 (AD). MACQUARIE I. Wireless Hill, 90 m, 8 December 1968, D. McVean 6907 (BM); near Lake Scoble, 7 December 1968, D. McVean 6935 (BM); Green Gorge, 220 m, 26 October 1983, R. D. Seppelt 14297 (herb. Seppelt). The following may be consulted for further localities: South Georgia (Lindsay, 1974), South Sandwich Is. (Longton & Holdgate, 1979), South Orkney Is. (Smith, 1973), South Shetland Is. (Lindsay, 1971a), Antarctic Peninsula (Lamb, 1964); together with lists held in BM and collections in AAS and BM. 4. Usnea aurantiaco-atra (Jacq.) Bory Figs 15-19 in Mém. Soc. Linn. Paris 4: 596 (1826). — Lichen aurantiaco-ater Jacq., Miscell. Austriac. 2: 369 (1781). - Neuropogon aurantiaco-ater (Jacq.) Lamb in J. Linn. Soc. (Bot.) 52: 221 (1939). Type: [Chile] Magellan Straits, 1767, Commerson, comm. D. Jussieu (PC! — lectotype, selected here; BM!; FI!, LINN (herb. Smith 1715.9)!, UPS (herb. Thunberg 26355)! — isolectotypes). [TLC: fumarprotocetraric acid aggr., usnic acid.] (see Note 1) Usnea melaxantha Ach., Method Lich.: 307 (1803). — Parmelia melaxantha (Ach.) Sprengel, Syst. Veg. 4 (1): 277 (1827). — Neuropogon melaxanthus (Ach.) Nyl. in Mém. Soc. Imp. Sci. Nat. Cherbourg 3: 170 (1855). Type: America [West Falkland Is.], Port Egmont, Cavanilles, Ach. 1887A (H-ACH! - lectotype; BM! — isolectotype). [TLC: norstictic acid, salazinic acid, connorstictic acid, protocetraric acid (trace), usnic acid.] (see note 2) Usnea fasciata Torrey in Am. J. Sci. 6: 106 (1823). — Usnea melaxantha var. y fasciata J. D. Hook., Flora Antarctica 2: 520 (1847). Type: New South Shetland, comm. Dr. Mitchill (NY! — lectotype, selected here). [TLC: fumarprotocetraric acid, protocetraric acid (trace), usnic acid.] (see Note 3) Cornicularia flavicans Pers. in Gaudichaud in Freycinet, Voyage autour du Monde, Botanique: 210 (1828). Type: Iles Malouines [Falkland Is.], 1820, C. Gaudichaud 130 (PC! —- holotype; G-DEL! — isotype; BM! — ?isotype). [TLC: norstictic acid, salazinic acid, protocetraric acid (trace), usnic acid. ] Neuropogon antennarius Nees & Flotow in Linnaea 9: 497 (1835). — Usnea antennaria (Nees & Flotow) Massal., Memor. Lichenogr.: 73 (1853). Type: ad rupes Chil. austr. in summo cacumine Pico de Pilque prope Antuco [37°20’S: 71°41'W], legit Poeppig, ex herb. Kunze (VER (herb. Massalongo)! —lectotype, selected here). [TLC: norstictic acid, salazinic acid, usnic acid.] (see Note 4) USNEA SUBGENUS NEUROPOGON 63 Usnea melaxantha var. a Acharii J. D. Hook., Flora Antarctica 2: 520 (1847); nom. illeg. (Article 26.1). Usnea melaxantha var. B Jacquinii J. D. Hook., Flora Antarctica 2: 520 (1847). Type: Lichen aurantiaco- ater Jacq. Usnea melaxantha var. subciliata Zahlbr. in Annls mycol. 1: 360 (1903). — Usnea sulphurea var. subciliata (Zahlbr.) Zahlbr., Cat. Lich. Univ. 6: 603 (1930). — Neuropogon strigulosus f. subciliatus (Zahlbr.) Lamb in J. Linn. Soc. (Bot.) 52: 231 (1939). Type: Patagonia, P. Neumann (W7177! — holotype). [TLC: fumarprotocetraric acid (trace), usnic acid. ] Usnea melaxantha var. subciliata f. strigulosa Zahlbr. in Annls mycol. 1: 360 (1903). — Usnea melaxantha f. strigulosa (Zahlbr.) R. H. Howe in Bryologist 18: 61 (1915). — Usnea sulphurea var. subciliata f. strigulosa (Zahlbr.) Zahlbr., Cat. Lich. Univ. 6: 603 (1930). — Usnea strigulosa (Zahlbr.) Motyka, Lich. Gen. Usn. Stud. Monogr. 1: 30 (1936). — Neuropogon strigulosus (Zahlbr.) Lamb in J. Linn. Soc. (Bot.) 52: 229 (1939). — Neuropogon aurantiaco-ater f. strigulosus (Zahlbr.) Lamb in Lilloa 14: 152 (1948). - Usnea aurantiaco-atra f. strigulosa (Zahlbr.) Lamb in An. Parg. nac. B. Aires 7: 156 (1959) [‘1958’]. — Usnea fasciata f. strigulosa (Zahlbr.) Lamb in Br. Antarct. Surv. Sci. Rep. 38: 14 (1964). Type: Patagonia, P. Neumann (W7116!—holotype). [TLC: + fumarprotocetraric acid, + protocetraric acid, + UV+ unknowns, usnic acid. ] Usnea sulphurea var. normalis Vainio, Rés. Voy. S. Y. Belgica, 1897-99, Botan., Lichens: 11 (1903) nom. inval. (Article 26.1). — Neuropogon aurantiaco-ater f. normalis Lamb in J. Linn. Soc. (Bot.) 52: 224 (1939) nom. inval. (Article 26.1.). Usnea sulphurea var. normalis f. activa Zahlbr. in K. svenska VetenskAkad. Handl. 57 (6): 44 (1917). — Usnea sulphurea f. activa (Zahlbr.) Zahlbr. Cat. Lich. Univ. 6: 603 (1930). Type: Falkland Inseln, Port Stanley, Sapper Hill, Schwedische antarktische Exped. 1901-03. (W 123 !— holotype). [ TLC: norstictic acid, salazinic acid, usnic acid. ] Usnea sulphurea var. spadicea Zahlbr. in K. svenska VetenskAkad. Handl. 57 (6): 45 (1917). — Usnea taylorii var. subspadicea (Zahlbr.) Motyka in Rasanen in Suomal. eldin-ja kasvit. Seur. van. kasvit. Julk. 2(1): 11 (1932) nom. illeg. (Article 63.1). —- Usnea melaxantha var. spadicea (Zahlbr.) Motyka, Lich. Gen. Usn. Stud. Mongr. 1: 35 (1936). — Neuropogon melaxanthus f. spadiceus (Zahlbr.) Lamb in J. Linn. Soc. (Bot.) 52: 228 (1939). Type: Falkland Inseln, Mt. Adams, Schwedische antarktische Exped. 1901-03, C. Skottsberg. (W121! — holotype). [TLC: norstictic acid, salazinic acid, usnic acid.] (see Note 5) Usnea melaxantha var. nigropallida Cengia-Sambo in Boll. Soc. bot. ital. 1: 91 (1926). — Neuropogon aurantiaco-ater f. nigropallida (Cengia-Sambo) Lamb in J. Linn. Soc. (Bot.) 52: 224 (1939). Type: Tierra del Fuoco, 1913, G. B. de Gasperi (FI! — holotype; FI! —isotype). [TLC: fumarprotocetraric acid, protocetraric acid, usnic acid.] Usnea taylorii var. kranckii Rasanen in Suomal. eldin-ja kasvit. Seur. van. Julk. 2(1): 10 (1932). Type: [Chile] Fuegia occ. Fjordo Martinez, Seno Pliischow, c. 500 m.s.m., reg. alp., Expeditio Fennica 1928-29, 21 February 1929, E. H. Kranck (H! - lectotype, selected here). [TLC: fumarprotocetraric acid, protocetraric acid, usnic acid.] (see Note 6) Usnea trachycarpa var. eciliata Rasanen in Suomal. eldin-ja kasvit. Seur. van kasvit Julk. 2(1): 10 (1932). Type: [Chile] Fuegia occ. Puerto Yartou, Pico Nariz, 750 m.s.m., reg. alp. Expeditio Fennica 1928-29, H. Roivainen (H! — holotype; S — isotype, not seen). [TLC: norstictic acid, salazinic acid, protocetraric acid (trace), usnic acid. ] Usnea aurantiaca Motyka, Lich. Gen. Usn. Stud. Monogr. 1: 29 (1936). — Neuropogon aurantiacus (Motyka) Lamb in J. Linn. Soc. (Bot.) 52: 229 (1939). Type: Falkland Is., D. Coleman, A. Zahlbr. Lich. Rar. Exs. 20 (W5133! — holotype; UPS! — isotype). [TLC: norstictic acid, salazinic acid, protocetraric acid (trace), usnic acid. ] Neuropogon aurantiaco-ater f. egentissimus Lamb in J. Linn. Soc. (Bot.) 52: 225 (1939). — Usnea aurantiaco-ater f. egentissima (Lamb) Dodge, Lich. Fl. Antarct. Cont.: 227 (1973). Type: Antarctica, Graham Land, Argentine Is., summit of Galindez I., 2 January 1936, Br. Graham Land (‘Penola’) Exped. 1934-37, 1340j (BM! — holotype). [TLC: no medullary substances, usnic acid. ] Neuropogon melaxanthus f. fibrillifer Lamb in Lilloa 14: 154 (1948). Type: Falkland Is., peat moors above Port Stanley, c. 60 m, 27 January 1946, J. M. Lamb, ‘Operation Tabarin’ 2873 (BM! - holotype). [TLC: norstictic acid, salazinic acid, protocetraric acid (trace), usnic acid. ] ?Usnea siplei Zammuto in Dodge in Trans. Am. microsc. Soc. 84: 522 (1965). Type: Antarctica [Graham Land], Melchior Is., Omega I. [= Lystad I.], 64°20’S: 62°56’ W, 14 March 1941, P. A. Siple 367 (herb. Dodge — holotype, not seen; US! — isotype). [TLC: fumarprotocetraric acid aggr., UV+ unknowns, usnic acid.] (see Note 7) 64 F. J. WALKER Note 1: Lichen aurantiaco-ater Jacq. (i) The hyphen should be retained in accordance with Article 73.1. (ii) There has been considerable confusion concerning the correct identity of this taxon. The holotype specimen has not been traced and Jacquin’s personal lichen herbarium in Vienna is regarded as lost (Motyka, 1936; Lamb, 1939a). Consequently assumptions have been made as to the medullary chemistry of the type specimen. This has resulted in subsequent changes in use of various specific epithets, all of which are here regarded as synonyms (Table 4). Jacquin (1781) based the name Lichen aurantiaco-ater on material collected by Commerson, probably from the Magellan Straits. Examples of Commerson’s collections have been traced in several herbaria and, since they presumably originated from PC, are regarded as isotypes. Two collections have been traced in PC of which one (herb. Jussieu !) very closely conforms with Jacquin’s original illustration (Tab XI, fig. 2) and description. This specimen is accordingly designated here as the lectotype (Fig. 15), with isolectotypes selected in other herbaria. The specimen contains fumarprotocetraric acid which follows Lamb’s original concept (Lamb, 1939a) of the type. Motyka annotated this specimen as Usnea aurantiaco-atra although wrongly listing it (Motyka, 1936) under U. aurantiaca, with the erroneous date of 1820. \ ATM ie, ¢ ® 3 ¢ jnea ruth x antha. me Ahan raseig 0 Ly Sbificfe jpovtey vaminl) < vet ‘ < Aad a rarne Cay abi tuba aig taste! eset detroit. dv pemgalln pamere sred é we, 1.5 te Fig. 15 Lectotype of Lichen aurantiaco-ater Jacq. (PC) X1. Most of Commerson’s collections contain fumarprotocetraric acid, apart from the collection in BM which also includes norstictic and salazinic acid-containing thalli. In this particular case only the fumarprotocetraric acid-containing thalli are selected as isolectotype material. This lectotypification reflects the predominance of Race 1 (see p. 69) in the Magellan Straits area. Note 2: Usnea melaxantha Ach. The type collection of Usnea melaxantha Ach. (Ach. 1887 A + B) consists of two plants from different localities, both containing norstictic and salazinic acids. One gathering, collected by Menzies, is from USNEA SUBGENUS NEUROPOGON 65 Wdsreea reiclacartlia as ach. Atcenge oie Acchetnng y+ stsea x co f - Paecthe. Fig. 16 Usnea aurantiaco-atra. Top. Isolectotype of Usnea melaxantha Ach. (BM) X1. Bottom. Detail of apothecia. Graham Land, GalindezI., B.G.L.E. 1340 p.p. (BM) x10. ‘Staaten Land’ and the other, from the Falkland Islands (Port Egmont), was collected by Cavanilles. Motyka (1936) regarded the Port Egmont specimen as the nomenclatural type from the classic locality. His selection is therefore considered to effect the lectotypification of this taxon. This lectotype is illustrated by Lamb (1939a, pl. 11, fig. 28). A duplicate collection in BM (Fig. 16) is recognised as an isolectotype although the two plants are unlocalised. Note 3: Usnea fasciata Torrey Torrey probably described this taxon on material from two sources; that collected by Captain Napier of the U.S. Sealing Expedition of 1820-21 (Dodge, 1973) and an unknown collector, both of which were sent 66 F. J. WALKER to him by Dr S. L. Mitchill (Torrey, 1823). Consequently his description is likely to have been based on a mixed gathering. Lamb (1939a) illustrated a fertile specimen of Usnea aurantiaco-atra (NY!) as the holotype, but he later (Lamb, 1964) retracted this because Torrey, in his original description, stated that specimens lacked apothecia, only possessing ‘cephalodia’ which, from study of his illustration, correspond to a lichen parasite. It is evident, from examination of the herbarium sheet, that Lamb was sent only part of one thallus of the NY collection in a separate capsule. The original collection (Fig. 17), which was not seen by him, bears an inscription in Torrey’s handwriting. Consequently, it may be assumed, despite the presence of fertile material, that this material is authentic, especially as the journal citation on the packet lacks specific details. This collection comprises the ‘parent’ thallus of the fertile specimen sent to Lamb, as well as a sterile thallus of the same species (both lacking parasites) and two small, distinctly variegated, parasitised thalli of U. antarctica. LECTOT ype. Suecneathtl | Type Specimen Fig. 17 Usnea aurantiaco-atra. Lectotype (centre thallus) of Usnea fasciata Torrey (NY) X1. USNEA SUBGENUS NEUROPOGON 67 Torrey’s illustration (Torrey, 1823; pl. 9 figs 1-4) which represents a large, conspicuously variegated thallus, lacking apothecia but clearly parasitised, must be taken into consideration. None of the thalli in the NY collection exactly correspond to this illustration, although the closest are the parasitised thalli of U. antarctica, despite difference in size and apparent lack of soralia. There is a remote possibility that Torrey may have misinterpreted the apothecia as well-developed ‘cephalodia’, since he described them as ‘scattered, sometimes crowded and irregular’, rather than recognising them as the same fertile structures that occur in the subgenus Usnea, although he might have regarded the fertile specimen as an older state of the same species. It is evident from the protologue (Torrey, 1823: 105) that he was fully aware of the distinction between apothecia and ‘cephalodia’-like structures in U. florida (=? U. strigosa). Consequently there are three options relevant to the typification of Usnea fasciata based on this NY collection. (i) to follow Lamb’s final interpretation (Lamb, 1964) and reject the collection as being the type of the name. A neotype would then have to be selected. (ii) Assume only part of the collection to be the type of the name and lectotypify the parasitised, sorediate material based on comparison with Torrey’s illustration. This would result in a change of nomenclature of U. antarctica. (iii) Assume the entire mixed collection to be the type of the name and lectotypify on one element (Article 9:2) so as to preserve current usage, following Recommendation 7B, since the name can no longer be rejected under Article 70. None of these solutions is entirely satisfactory, but it is important to stabilise the situation and to save further misapplication or nomenclatural changes. Thus Usnea fasciata is here lectotypified on the fertile specimen, reducing the taxon to synonymy with U. aurantiaco-atra and preventing a confusing name change for U. antarctica. Note 4: Neuropogon antennarius Nees & Flotow Motyka (1936) reported examining the fragmentary holotype specimen in herb. Flotow (B) which was subsequently destroyed during the Second World War (Krog, 1976). Material of various species from the classic locality, collected by Poeppig, was sent to Kunze at Leipzig (Sayre, 1975). Some of these collections were subsequently distributed by Poeppig and Kunze as part of an unpublished exsiccatum, Poeppig Coll. pl. Chil. N. antennarius does not form either of the two examples of the exsiccatum that have been traced (BM!), and authentic material has not been found in Poeppig’s personal herbarium (W), although collections of U. perpusilla from herb. Poeppig and herb. Kunze have been traced in M and PC, annotated U. fasciata and U. melaxantha respectively. The only authentic material of N. antennarius traced is in herb. Massalongo (VER!) and originates from herb. Kunze. This specimen is presumably an isotype, since, besides bearing the same data as the above exsiccatum, bears the inscription ‘Neuropogon antennarius Nees & Flotow’ in Massalongo’s handwriting and a small ink stamp he used to denote type material. This collection (Fig. 18) is consequently selected as the lectotype of Neuropogon antennarius, following Krog’s lectotypification of N. poeppigii (Krog, 1976) based on an isotype traced in S. Note 5: Usnea sulphurea var. spadicea Zahlbr. This variety was validly published by Zahlbruckner in 1917, although examination of the type specimen (W 121) indicated that he possibly intended the epithet ‘subspadicea’ to be used since this name appears in his handwriting on the label. Motyka in Rasinen (1932) published the combination ‘Usnea taylori var. subspadicea (Zahlbr.) Motyka’ based on this unpublished name as indicated on his determination label attached to herb. NYL 36372 (H!). As both names are of the same rank ‘Usnea taylori var. subspadicea’ must be rejected under Article 63.1 as a superfluous name for Usnea sulphurea var. spadicea Zahlbr. Note 6: Usnea taylorii var. kranckii Rasanen Examination of the two collections cited under this name by Rasanen (1932) has revealed that they are different species. One gathering from Martinez is fertile material of U. aurantiaco-atra and the other, from Yartou, is an infertile, immature specimen of U. trachycarpa. It is evident, from his notes on the herbarium packet, that Rasanen intended the fertile collection from Martinez to be the type of the variety since the presence of apothecia and spore measurements correspond with the published description. Note 7: Usnea siplei Zammuto This species was described from the Antarctic peninsula by Zammuto (in Dodge, 1965b), and, according to the description, the holotype is small and lacks apothecia and soredia. However, Dodge (1973) subsequently gave a similar description of the species but in the key describes it as being sorediate. A specimen, taken to be an isotype, bearing the same collection number (USAS 367, US!), and an additional collection (USAS 369, US!) from the same locality, both annotated U. siplei, have been examined. Both 68 F. J. WALKER yy e Veuvopepor~ v ¢ Ud rwpss ie Bee 20 : POS i Beas» me Vi Fae we. Jeg Aa R= jy oyna Moutaed > Fig. 18 Usnea aurantiaco-atra. Lectotype of Neuropogon antennarius Nees & Flotow (VER) X1. are immature specimens of U. aurantiaco-atra as previously stated by Lamb (1948a). The isotype bears a single, small, immature apothecium. There is always the possibility that the original gathering may not have been homogeneous, and for this reason the species is only tentatively included here. Additional material from the Melchior Archipelago, collected by the same expedition, has been distributed as Usnea fasciata (Vézda: Lich. Sel. Exs. 675) and is moderately fertile. USNEA SUBGENUS NEUROPOGON 69 Description: Thallus (3)-5—8(—10-13) cm, arising from a delimited or rarely proliferating + pigmented holdfast, erect, + dichotomous, richly branched above with numerous attenuate branches, fibrils rare. Branches terete or rarely angular, yellow-green, + variegated above with bands of black to violaceous black pigment, + continuously pigmented towards the apices. Cortex variable in thickness. Surface matt, + smooth at base, becoming verrucose-rugose to subfaveolate-papillate, grossly papillate or ridged-faveolate above. Medulla compact, variable in extent, axis thick, occupying 0-5—0-6(-0-8) of the branch diameter. Soredia, pseudoisidia and isidia absent. Apothecia frequent, subterminal or rarely lateral, + cupular, expanding on maturity. Disc black, excipulum verrucose-papillate, margin + prominent, rays rare. Pycnidia infrequent towards branch apices. TLC: (1) fumarprotocetraric acid, + protocetraric acid, + cph-1, + UV+ unknowns, usnic acid; (2) norstictic acid, salazinic acid, + protocetraric acid, usnic acid; (3) no medullary substances, + UV+ unknowns, usnic acid. Distinguishing features: Usnea aurantiaco-atra is characterised by its erect habit, a richly branched thallus which is pigmented towards the apices, a verrucose to papillate surface, a compact medulla, a thick axis, and frequent subterminal apothecia with a black disc, usually lacking marginal excipular rays. It is the only fertile species of the subgenus which frequently contains fumarprotocetraric acid. (Fig. 16) Distribution: Usnea aurantiaco-atra has a more restricted distribution than U. antarctica and is more or less confined to the west coast of the Antarctic peninsula, the islands of the Scotia Arc, including Bouvet@y, but excluding the South Sandwich Islands, and extends into subantarctic South America, including the Falkland Islands. The species does not occur in continental Antarctica (cf. Dalenius & Wilson, 1958) or Australasia. Specimens cited from Iles Kerguelen, collected by Hooker, are erroneously labelled, having been subsequently mixed with collections of U. taylorii. Fig. 4. Chemistry: Three chemical races occur in Usnea aurantiaco-atra. Of these, specimens contain- ing fumarprotocetraric acid (Race 1) and the depsidone deficient Race 3 are the most commonly encountered and have a much wider distribution than the norstictic-salazinic acid containing Race 2. Race 1 is apparently slightly more frequent than Race 2, with its centre of distribution in the South Orkneys and South Shetlands Islands; this race is also known from the Antarctic peninsula, South Georgia, Tierra del Fuego and Chile as far north as c. latitude 46°S. Race 3 extends further north, to c. 37°S, and further east to Bouvetgy, than Race 1. Race 2 has its centre of distribution in the Falkland Islands, where Race 1 is only known from a few, possibly misplaced, collections. Race 2 overlaps Race 1 in southern South America, but is less frequent. It is confined to Tierra del Fuego apart from a single, isolated, northerly occurrence which forms the type specimen of Neuropogon antennarius: it is absent from the Antarctic peninsula. There are reports of occasional outliers of Race 2 from South Georgia (Lindsay, 1975) and rather tentatively from the South Shetlands (Motyka, 1936). Of these Lindsay’s records were based on K and PD reactions which may have been misinterpreted since a high concentration of fumarprotocetraric acid can give a K+ red-brown reaction. In spite of these records, so far I have only confirmed (by TLC) two collections of Race 2 from South Georgia. Thalli of one gathering (R. J. L. Smith 259, AAS!) are extensively blackened and bear a superficial resemblance to Usnea ciliata, possibly due to the extremely exposed habitat given as a south-facing scree overlooking a glacier. Very rarely thalli with a mixed chemical complement of Races 1 and 2 are encountered, particularly where the distributions of the two races overlap. For example, thalli may contain fumarprotocetraric, protocetraric, salazinic, and norstictic acids, or Race 1 may additionally contain salazinic acid, or Race 2 may either lack norstictic or salazinic acid and have a higher concentration of protocetraric acid. The implications of such thalli with mixed or intermediate chemistries are discussed under ‘species concept’ below. Variation: Usnea aurantiaco-atra is a very variable, but usually easily recognised species, even when sterile. It exhibits a wide range of growth form, branch anatomy, and degree of pigmentation. The account of U. antarctica (p. 58) should be referred to for discussion of much 70 F. J. WALKER of the variation in branching, morphology, and anatomy. Thalli may rarely become subdecum- bent or straggling and then may be sparsely pigmented, sterile, and infrequently to richly branched; such specimens superficially resemble U. neuropogonoides. In rare instances pigment may be confined to branch apices and the apothecial disc, which seem to be more prevalent in Race 2. In contrast to Usnea antarctica thalli are often larger, though rarely more than 10 cm. In U. aurantiaco-atra a wider range of variation is found in surface ornamentation and branch anatomy, which, although frequently correlated with medullary chemistry, is not sufficiently distinct to merit taxonomic separation. For example, the lectotype of Lichen aurantiaco-ater, typical of Races 1 and 3, is minutely verrucose-papillate and is extensively branched with continuously pigmented ultimate branches. The axis occupies more than half the branch diameter and in transverse section branches are more or less terete and have a narrow medulla, c. 200 um. In contrast, the type of Usnea melaxantha, typical of Race 2, has branches which are somewhat angular-indented in section resulting from faveolation and deeper depressions. The axis of U. melaxantha is somewhat irregular in outline and occupies slightly less than half the diameter coupled with a correspondingly wider medulla of up to 300 um. Ornamentation ranges from almost smooth to obscurely papillate to coarsely verrucose- papillate becoming distinctly faveolate-ridged. False annulations, resembling those of Usnea ciliata, only occur in exceptionally smooth, scantily papillate or weakly verrucose thalli that have been extensively weathered, for example, as in the types of U. trachycarpa var. eciliata and Neuropogon antennarius. On occasions a range of ornamentation may be exhibited by a single thallus. Fibrils are only rarely produced as extended papillae or verruculae and are never as extensively developed as those of U. trachycarpa. Fibrillate forms previously given taxonomic status include N. melaxanthus var. fibrillifer and U. melaxantha var. nigropallida; one taxon, U. melaxantha var. subciliata f. strigulosa, was even raised to specific rank (Lamb, 1939a; Motyka, 1936). The axis may be somewhat irregular in outline and can vary in thickness together with the width of the medulla, which tends to be broader in Race 2. Overall it is rare for the axis to occupy more than 0-7 of the branch diameter. Exceptions include the type of Usnea taylorii var. kranckii, which is here treated as a synonym, as well as specimens examined from Bouvetgy (BG!); in these the axis occupies 0-7 to 0-8 of the branch diameter and the medulla is narrowed to c. 100 wm in primary branches, suggesting a possible affinity with U. taylorii. Apothecia are normally subterminal, rarely with a geniculate appendage, or may be lateral. In some instances the margin may become excluded and the apothecium irregular and reflexed, or even slightly crenulate in well-developed thalli. Only rarely is the disc pigmentation not fully developed (for example, R. J. L. Smith 2573, AAS!). The excipulum is papillate or minutely faveolate; irregular rays are only rarely produced and then in thalli which develop fibrils on main branches. Species concept: To date various taxa comprising the Usnea aurantiaco-atra—U. melaxantha group have been considered to be distinct species by different authors (Table 4). Dodge (1973) recognised six species, Motyka (1936) five; Lamb initially (Lamb, 1939a) accepted four species but finally modified his concept to include only two (Lamb, 1964). Apart from the ensuing nomenclatural confusion the delimitation of each species was by no means clear and depended on small variations in the relative size of axis and medulla, surface ornamentation or presence of fibrils, thallus size or the extent of branching. Variation in chemical reactions was also considered to be significant; for example the depsidone-deficient Neuropogon aurantiaco-ater f. egentissimus as well as Usnea sulphurea var. normalis f. activa which gave an intense K+ red reaction. Motyka (1936) considered that the species could be separated primarily on morphological features, but Lamb later (Lamb, 1948a) considered chemistry to be the only reliable feature and used thallus spot tests to distinguish Usnea melaxantha from U. aurantiaco-atra (i.e. Races 1 and 3 from Race 2). Lindsay, (1975) used chemistry initially to distinguish between the two taxa, but included differences in surface ornamentation in his descriptions. Eventually Lamb (1964) USNEA SUBGENUS NEUROPOGON 71 concluded that there were morphological and distributional differences between the two species which were supported by chemistry. These differences, however, were only apparent when contrasting whole populations rather than considering individuals. This approach is, however, in my estimation impractical, as admitted by Lamb (1964), since many thalli with intermediate characters may occur, particularly where the distributions of chemical races overlap. This leaves chemistry as apparently the only reliable criterion for separating U. aurantiaco-atra from U. melaxantha, These two taxa are here considered to form chemical races of a single species -edrigress as all the substances involved have a close biosynthetic relationship (Huovinen & Ahti, 1982). During this investigation it has been found that even chemistry may not, on very rare occasions, be sufficiently reliable to separate ‘melaxantha’ and ‘aurantiaco-atra’ type thalli. TLC studies indicate that chemical data are not always correlated with minute morphological differences. Morphological similarities between the two chemical races are particularly appa- rent in material from the Magellan Straits area, where Races 1 and 2 overlap at the western limit of Race 2 and both races are often collected together. In particular Menzies’ collections of 1787 from Isla de los Estados (Staten Island) include a diverse range of chemistries in an apparently morphologically and anatomically uniform gathering. These collections were widely distributed throughout herbaria and represent paratype material of Usnea melaxantha (BM, E, H (ACH), LINN, PC, UPS, US). Out of 32 thalli examined by TLC one plant was depsidone deficient, 20 belonged to Race 1 and 11 to Race 2 although often lacking either norstictic or salazinic acid, but sometimes with traces of protocetraric acid. A further specimen from the same area (Castellanos 1542, BM!) only contained salazinic acid. Other examples of specimens with a mixed chemistry include a collection from Ushuaia (Henssen & Vobis 24 417a, MB!) in which two thalli contained salazinic acid in addition to the substances of Race 1, and a specimen from the Falkland Islands (R. I. L. Smith 2572, AAS!) which contained norstictic, salazinic, fumarprotocetraric and protocetraric acids. Examination of transverse sections from main branches of thalli in one of the Menzies collections (E), Fig. 19, representing both chemical races, are identical, with the axis occupying approximately half the branch diameter and with cortex and medulla widths 70-75 um and 170-200 zm respectively. An additional specimen from Isla de los Estados (H36372!) has a somewhat wider medulla and is more angular in transverse section and is characteristic of the so-called ‘melaxantha’ form. However, this thallus contains fumarprotocetraric acid (Race 1) instead of norstictic acid (Race 2). Surface ornamentation is frequently not so distinct in some of these specimens; there is a tendency in both races for the thallus to be smoother with less pronounced ornamentation, particularly towards the base, to occasionally become subnitid, but only rarely rupture to form annulations. Typically, fumarprotocetraric acid containing speci- mens (Race 1) have been described as being verrucose-papillate, rarely becoming scrobiculate- corrugated, whilst norstictic and salazinic acid containing specimens are described as being sparsely papillate becoming confluent and scrobiculate-corrugated (Lindsay, 1975). However, all these states are frequently found on the same thallus and are probably associated with its age and the degree of exposure. Slight difference in thallus colour has also led to the recognition of separate taxa that are here regarded as synonyms; for example Cornicularia flavicans. Likewise Motyka (1936) distinguished Usnea melaxantha from other taxa on the width and pinkish colour of the medulla, a feature that was subsequently found to be a storage artefact involving the breakdown of salazinic acid. Usnea aurantiaco-atra has most frequently been confused with U. ciliata and U. perpusilla. Apart from differences in distribution the species may be distinguished from U. ciliata by the ornamented surface, which lacks a waxy lustre and the typical pigmented annulations, and the frequent absence of excipular rays. The medulla of U. aurantiaco-atra is more compact than is usually found in U. perpusilla and the apothecia are frequently subterminal (Fig. 2) rather than lateral in series. The species may be distinguished from U. trachycarpa by differences in disc colour, abundance of fibrils and width of the medulla; and from U. taylorii by the latter’s unique anatomy. 72 F. J. WALKER Fig. 19 = Usnea aurantiaco-atra. a = Race 1, b = Race 2. Staten Land, February 1787, Menzies (E) X1. USNEA SUBGENUS NEUROPOGON 73 Selected specimens examined Race 1 CHILE. Aisén: Coyhaique, Cerros Divisaderos (Cordon de Bella Vista), 1300 m, 13 November 1940, R. Santesson 6843 (S), 1400 m, 13 November 1940, R. Santesson 7355 (CANL 16965, S). Magallanes: Punta Arenas, Cerros Mina Rica, c. 500 m, 22 December 1940, R. Santesson 5244 (S, UPS); Tierra del Fuego, Porvenir, Morro Piedra, 300 m, 30 December 1940, R. Santesson 5398 (S); Isla Navarino, Puerto Navarino, 10 m, 28 February 1940, R. Santesson 1233 a & b (S); Cabo de Hornos, Hermite I., Forster’s Peak, 1842, R. McCormick s.n. (BM); Tierra del Fuego, Canal Whiteside, Nose Peak, R. Santesson 5965, Lich. austram. ex Herb. Regnelliano 422 (BM, C, H, S, UPS). ARGENTINA. Chubut: Comodoro Rivadavia, 1924 ‘Euero’ 22 (BM). Tierra del Fuego: Sierra Alvear, S. slope, above Las Cotorras (c. 20 km ENE. of Ushuaia), 800-900 m, 7 February 1940, R. Santesson 639a (S, UPS); Montes Martiales, above Ushuaia, 10 March 1965, J. M. Lamb 8146 (FH, M); Beagle Channel, February 1963, E. E. Shipton s.n. (BM); Isla de los Estados, February 1787, A. Menzies s.n. [+ Races 2 & 3] (BM, E, H (ACH), LINN, PC, UPS, US). SOUTH GEORGIA. Cumberland West Bay, 2 km N. of Mt. Hodges, 28 February 1972, D. C. Lindsay 4285 (AAS, BM); Cumberland West Bay, near head of Sphagnum Valley, c. 150m, 1 February 1961, S. W. Greene 1617 (AAS); Grytviken, 25 December 1909, C. A. Larsen s.n. (O, UPS). SOUTH ORKNEY IS. Signy I.: Factory Bluff, NE., 19 January 1965, J. Price 9 (BM); Observation Bluff, 107 m, 6 February 1966, D. C. Lindsay 867 (AAS). Coronation I.: Foot of Wave Peak Buttress, Marshall Piedmark, 210 m, 20 August 1950, W. J. L. Sladen F.1.D.S. H602/3 (BM); Olivine Point, 30-60 m, 17 January 1965, R. I. L. Smith 156 (AAS, BM, FH). Laurie I.: Cape Geddes, 15-60 m, 13 February 1971, M. McManmon 140 (AAS). SOUTH SHETLAND IS. King George I.: Admiralty Bay, Keller Peninsula, Mt. Flagstaff, 265 m, 9 January 1980, R. Ochyra 416/80 (M); Fildes Peninsula, 168 m, 16 February 1966, B. S. John & D. E. Sugden 25 (AAS, BM). Livingston I.: Robbery Beaches, Byers Peninsula, 75 m, 30 December 1965, D. C. Lindsay 518 (AAS). Half Moon I.: 75 m, 5 January 1966, D. C. Lindsay 576 (AAS, BM, FH). Robert L.: English Strait, Copper Mine Cove, c. 60 m, 31 December 1934, ‘Discovery’ Exped. 14851 (BM). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°15’S: 55°45'W], Mt. Alexander, 200-500 m, 27 March 1981, R. J. L. Smith 3680 p.p. (AAS); Palmer Archipelago, Melchior Is., Omega [Lystad] I. [64°20'S: 62°56’W], 28 January 1951, A. Martinez s.n. (FH), 6-9 m, 14 March 1941, P. A. Siple U.S.A.S. 369 (US), Anvers I. [64°45’S: 64°05’W], Arthur Harbour, 20 m, 6 February 1965, 1. M. Lamb & M. Zimmerman 8091 (FH), Wiencke I. [64°48’S: 63°25’ W], N. buttress of Noble Peak, 225 m, 20 November 1944, J. M. Lamb Operation Tabarin 1790 p.p. (BM), J. M. Lamb Operation Tabarin 1789 (BM, CANL 16961, FH); Argentine Is., Galindez I. [65°15’S: 64°15’W], Woozle Hill, 35-50 m, 5 March 1981, R. J. L. Smith 3304 (AAS), summit, 1 January 1936, B.G.L.E. 1340 p.p. (BM, FH), Uruguay I. [65°14’S: 64°14’ W], 15 m, 25 October 1964, R. W. M. Corner 603 (AAS); Graham Coast, near Cape Tuxen [67°44’S: 68°25’ W], 26 January 1961, K. Archibald 33 (AAS). Race 2 CHILE. Bio Bio: Type of Neuropogon antennarius (VER). Magallanes: Tierra del Fuego, Canal Whiteside, Puerto Yartou, Nose Peak, 700 m, 5 February 1941, R. Santesson 6820 (S); Cabo de Hornos, Hermite I., 1839-43, J. D. Hookers.n. (BM, E); Magellan Straits, Cerros Yartou, 8 March 1928, herb. Th. Fries (UPS). ARGENTINA. Tierra del Fuego: Cerro Garibaldi, SE. of Lago Escondido, between Ushuaia and Rio Grande, 1961, R. M. Schuster 58346 p.p. (CHR 342819, FH); Isla Navarino, Puerto Navarino, 10 m, 28 February 1940, R. Santesson 1232c (S); Canal Beagle, W. of Lapataia Bay, 1898, M. E. G. Racovitza 188 p.p. (herb. Vain. 344- TUR 458). FALKLAND IS. East Falkland I.: Stanley, Sapper Hill, 4 April 1965, J. Price s.n. (BM), Stanley, 30 January 1946, J. M. Lamb Vézda: Lich. Sel. Exs. 496 (BM, M, MB); Mt William, near Stanley, near sea-level, 30 January 1946, J. M. Lamb Operation Tabarin 2891 (CANL 17185), Operation Tabarin 2888 (BM); Mt. Longdon, 174 m, 2 April 1967, D. C. Lindsay 1659 (AAS, H); between Darwin and Goose Green, 6 m, 17 September 1963, R. W. M. Corner 53 (AAS, FH); N. of Wireless Hill, 100 m, 28 February 1977, R. I. L. Smith 2574 (AAS). West Falkland Is.: Roy Cove, 1909-11, E. Vallentin 88 (BM). SOUTH GEORGIA. c. 1 km SE. of Brocken, 180 m, 23 January 1972, D. C. Lindsay 4036 (AAS); E. of Swinhoe Peak, between Hamburg Lakes and Hamburg Glacier, 690-695 m, 6 November 1976, R. J. L. Smith 2519 (AAS). Race 3 CHILE. Bio Bio: Antuco, Reynolds 141 (BM). Cautin: Andes de Villarrica, 1891, Neyer s.n. (M). Magallanes: Cape Spencer, J. D. Hooker s.n. (E); Cabo de Hornos, Hermite I., St. Martin’s Cove, R. 74 F. J. WALKER McCormick s.n. (BM); Cabo de Hornos, Voyage of H.M.S. Adventure and Beagle 1826-30, King s.n. (BM). ARGENTINA. Neuquén: Parque Nacional Lanin, N. of Lago Lacar, Cerro Malo, c. 1900 m, 28 January 1968, J. H. de Haas 1290 (U 313673b). Rio Negro: Cerro Rigi, near Lago Frias, c. 1780 m, 15 February 1950, J. M. Lamb 6045 (CANL 16962, UPS), 1660 m, J. M. Lamb 6043 (CANL 16964, FH, H, US). Tierra del Fuego: Fuegia med., Cerro Milladeo, 850 m, 17 January 1929, H. Roivainen s.n. (H). SOUTH GEORGIA. Head of Sphagnum Valley, near Echo Pass, Cumberland West Bay, 15 January 1961, E. A. Coleman Greene 1071 (AAS, BM, FH); Wilson Harbour, 19 January 1927, ‘Discovery’ Exped. s.n. (BM). SOUTH ORKNEY IS. Signy I.: Hill between Factory Cove and Paal Harbour, 105 m, 20 December 1961, M. W. Holdgate 225 (AAS). Coronation I.: Saunders Point, 0-9 m, 8 October 1950, W. J. L. Sladen F.I.D.S. H 612/21 (BM). SOUTH SHETLAND IS. King George I.: Keller Range, 21 February 1947, D. Nicholson & A. Reece Vézda: Lich. Sel. Exs. 972 (BM). Livingston I.: New Plymouth, Byers Peninsula, 19m, 14 December 1965, D. C. Lindsay 366 (AAS). Nelson I.: Harmony Cove, 2 December 1954, O. Kiihnemann 35075 (FH). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°15’S: 55°45’W], Mt. Alexander, 250 m, 27 March 1981, R. J. L. Smith 3682 (AAS); Palmer Archipelago, Wiencke I. [64°48’S: 63°25’W], N. buttress of Noble Peak, 225 m, 20 November 1944, J. M. Lamb Operation Tabarin 1789 (BM); Argentine Is., Galindez I. [65°15’S: 64°15’W], above Stella Creek, 24 m, 21 April 1964, R. W. M. Corner 542 (BM), Corner I. [65°16’S: 64°14’S], 6m, 18 August 1964, R. W. M. Corner 566 (AAS), Graham Coast, Loubat Point [65°04’S: 63°56’W], Lemaire Channel, 300 m, 19 March 1964, J. Clennell Kennett 56 (AAS, BM). BOUVET®Y. Rustadkollen SW., 323 m, 7 March 1979, T. Engelskjgn s.n. (BG, BM). Races 1 + 2 (see p. 71) ARGENTINA. Tierra del Fuego: Parque Nacional Tierra del Fuego, ‘Weg zum’ Glaciar Martial, c. 500m, 7 December 1973, A. Henssen & G. Vobis 24 417a (MB). FALKLAND IS. East Falkland I.: to N. of Wireless Hill, 28 February 1977, R. I. L. Smith 2572 (AAS). The following may be consulted for further localities: South America (Lamb, 1948a), South Georgia (Lindsay, 1975), South Orkney Is. (Smith, 1973), South Shetland Is. (Lindsay, 1971a), Antarctic Peninsula (Lamb, 1964); together with lists held in BM and collections in AAS and BM. 5. Usnea ciliata (Nyl.) Du Rietz Figs 20-21 in Svensk. bot. Tidskr. 20: 91 (1926). — Neuropogon melaxanthus var. ciliatus Ny. in J. Linn. Soc. (Bot.) 9: 245 (1866). — Neuropogon ciliatus (Nyl.) Krempelh. in Ver. zool.-bot. Ges. Wien. 18: 313 (1868). — Usnea melaxantha var. ciliata (Nyl.) Mill. Arg. in Bull. Soc. r. Bot. Belg. 31(2): 26 (1892). Type: New Zealand, Tarndale, Nelson Mountains, January 1861, Dr A. Sinclair. (H-NYL 36365! — holotype; BM!, E! — isotypes). [TLC: norstictic acid, salazinic acid, + protocetraric acid, usnic acid.] Note: The combination Usnea ciliata (Mill. Arg.) Vainio (Vainio, 1909) was invalidly published in synonymy (Article 34.1) and consequently does not predate the name U. ciliata (Nyl.) Du Rietz. Further, Vainio, in later publications (Vainio, 1913, 1915, 1923), made it clear that he intended the name to be published as U. trichoidea * U. ciliata, thus making a combination below specific rank. Description: Thallus (-3)-5-10(-12) cm, arising from a broadly proliferating, pigmented holdfast, erect, + monopodial or subdichotomous, moderately branched above, fibrils absent, lacking extended secondary branches. Branches terete, yellow-green, + continuously pig- mented violaceous black towards the apices. Cortex thick. Surface smooth, or rarely sub- faveolate, waxy, epapillate, with conspicuous black-edged annulations. Medulla compact, axis thick, occupying c. 0-5 of the branch diameter. Soredia, pseudoisidia and isidia absent. Apothecia frequent, subterminal, geniculate with a subtending spur, or additionally lateral; cupular or plane becoming reflexed on maturity. Disc black, + excluded margin, excipulum smooth or subfaveolate, marginal rays + limited in number, stout, branch-like, pigmented. Pycnidia not seen. TLC: norstictic acid, salazinic acid, + protocetraric acid, usnic acid. Distinguishing features: Usnea ciliata is characterised by its erect habit, arising from a proliferating holdfast, and a monopodial to moderately branched thallus, often with violaceous black pigmentation, a smooth, waxy, black-annulate surface, a compact medulla containing USNEA SUBGENUS NEUROPOGON 75 Fig. 20 Usnea ciliata. Isotype of Usnea melaxantha var. ciliata Nyl. (BM) x1. norstictic and salazinic acids, a thick axis, and subterminal, geniculate apothecia with a black disc and conspicuous excipular rays. Distribution: Usnea ciliata is confined to Australasia and is only known with certainty from New Zealand, where it has a similar, but slightly more restricted distribution, to U. acromelana, often absent at lower altitudes. Its presence in the North Island has now been confirmed by recent collections made by Bartlett (p. 22), although the species is undoubtedly rare and less frequently fertile there; occasionally Alectoria nigricans has been mistaken for such sterile thalli (for example, Mt. Ruahine, Colenso 1164A WELT!). The species is also rare on Stewart Island. Tasmanian records remain uncertain and are either based on damaged material lacking either apothecia or soredia (for example, Bratt, CHR342744!), or have not been traced (for example, Dodge, 1948). However, it is possible that U. ciliata does rarely occur in Tasmania, although this cannot be verified in the absence of fertile material. Lamb (1939a, 1948a, 1959) cited several collections of Usnea ciliata from South America. Many of these have been examined and are less typical, almost smooth, forms of either Usnea 76 F. J. WALKER Fig. 21 Usnea ciliata. New Zealand, Otago, Rock & Pillar Range, February 1967, Galloway (BM). Left. Detail of cortical annulations X10. Right. Detail of apothecium x10. aurantiaco-atra or, alternatively, U. perpusilla, in which the medulla is not characteristically lax. In both instances the apothecia bear some excipular rays and any annulations present are of a spurious nature, merely the result of weathering. The specimen figured by Lamb (1939a pl. 7 fig. 13, herb. Vainio 344 TUR 458!) is U. aurantiaco-atra (Race 2). Fig. 6. Chemistry: To date only one chemical race, that containing norstictic and salazinic acids, is known from the large number of collections examined. Variation: Usnea acromelana should be referred to (p. 50) for the account of variation in branching, pigmentation, morphology and anatomy, which may, to a similar extent, be influenced by altitude. However, U. ciliata does not exhibit such a wide range of variation as U. acromelana. The degree of violaceous black pigmentation is often extensive in more richly branched forms, but in extreme instances it may only be present in the apothecial disc, annulations and branch and ray apices. The thalli are often taller than those of Usnea acromelana and tend to show less variation in the proliferating nature of the holdfast. Small, tufted, densely branched forms, with fine, tapering secondary branches may be distinguished from U. subcapillaris by their erect habit and shorter, stouter branches (see p. 106). Apothecia are usually subterminal and conspicuously geniculate with a subtending spur that may be longer than the excipular rays. Additional, lateral, apothecia may sometimes be produced which tend to be subsessile. Their size is variable, as is the presence, number, length, and occasional branching, of excipular rays, which are not as extensively produced as in Usnea trachycarpa. Young apothecia are cupular, becoming expanded or sometimes convex at maturity, when they are irregular to crenulate. Only in rare instances is the black pigmentation of the disc more or less lacking or not fully developed. The excipulum is usually smooth but may sometimes be subfaveolate, thus reflecting the subtending branch morphology; the mar**~ ° often excluded. USNEA SUBGENUS NEUROPOGON Ta Species concept: Usnea ciliata is a comparatively uniform species which is considered to be the primary species related to the sorediate U. acromelana. Although it is closely allied to U. subcapillaris, only in very rare instances are thalli encountered that appear to be intermediate between the two taxa. U. ciliata may be distinguished from U. subcapillaris by its erect rather than subdecumbent habit, the coarser, shorter secondary branches, and subterminal, rather than lateral, apothecia. Usnea ciliata may be separated from other fertile species by distribution, although it is readily distinguishable on morphological characters. Selected specimens examined NEW ZEALAND. North Island. Gisborne: Mt. Hikurangi, c. 1740 m, 14 November 1983, J. K. Bartlett 25965 (BM). Hawke’s Bay: Mt. Kaweka, c. 1840 m, 9 November 1983, J. K. Bartlett 25960 (BM), J. K. Bartlett 25961 (BM). Wellington; Mt. Ruapehu, Turoa Site, 1740 m, 6 July 1969, D. J. Galloway s.n. (CHR 342790, CHR 343281, CHR 343292, CHR 343339); near Wellington [? Tararua Range], J. Buchanan s.n. (BM, GLAM NHB 1927-8-347); North Ruahine Range, c. 1000 m, 17 October 1983, J. K. Bartlett 26688 (herb. Bartlett). South Island. Nelson: Mt. Cobb, c. 1740 m, 19 December 1982, J. K. Bartlett 24724a (herb. Bartlett, BM); near Dunn Saddle, 1460 m, 12 January 1983, J. K. Bartlett 25962 (BM); Kakapo Peak, c. 1520 m, 16 December 1982, J. K. Bartlett 26253 (herb. Bartlett, BM), J. K. Bartlett 25812 (herb. Bartlett, BM); Mt. Robert, Lake Rotoiti, 1430 m, 16 January 1960, D. Scott 426 (BM); St. Arnaud Range, 1680 m, 22 December 1967, A. F. Mark s.n. (CHR 343290 p.p., CHR 343321); Mt. Technical, above Lewis Pass, 14 January 1979, D. J. Galloway s.n. (CHR 343160 p.p.); Mt. Aorere, J. K. Bartlett s.n. (CHR 343235); Lake Sylvester, 1620 m, 18 December 1967, A. F. Mark s.n. (CHR 342797, CHR 342798). Marlborough: Mt. Black Birch, 1220 m, 1 January 1969, B. V. Sneddon s.n. (BM, CHR 342822); Blue Mtn, near head of Waihopai River, c. 1830 m, 1934, W. Martin s.n. (CHR 375942); Upper Awatere Valley, Shingle Peak, 1310 m, 6 January 1970, A. F. Mark s.n. (OTA 27124); Awatere, Mt. Harkness (collector unknown) (CHR 160678); Inland Kaikoura Range, Mt. Tapuaenuku, 20-March 1934, J. S. Thomson 1523 p.p. (CHR 343806 p.p.), 2700 m, August 1969, P. Lusk s.n. (CHR 343309), February 1961, B. C. Aston s.n. (WELT L193), 1859, Sinclair s.n. (BM); Inland Kaikoura Range, Mt. Mitre, 27 January 1954, R. Mason & D. R. McQueen s.n. (CHR 160686 p.p.); Upcot, February 1916, B. C. Aston s.n. (WELT L190). Canterbury: Torlesse Range, Foggy Peak, 1680 m, 18 December 1962, P. W. James 1918 p.p. (BM), 12 November 1972, G. C. Bratt 72/1880c (HO 35166); Mt. Torlesse, March 1934, J. S. Thomson 1618 (CHR 343800); Four Peaks Range, Blue Mountain, c. 1640 m, 23 April 1979, D. J. Galloway s.n. (CHR 343225); Mt. Peel, 1740 m, January 1972, D. J. Galloway s.n. (BM, CHR 343437), c. 1680 m, H. H. Allan 2 (UPS); Mt. Peel, Rangitata River, 1520 m, 6 May 1960, D. Scott 458 (OTA); Kirkliston Range, 1680-1830 m, 25 March 1978, D. J. Galloway s.n. (CHR 343254); Two Thumb Range, Mt. Richmond, November 1968, A. F. Mark s.n. (CHR 343302); Two Thumb Range, Mt. Dobson, 1830 m, 15 January 1959, D. Scott 302 (OTA); Craigieburn Range, 1520 m, October 1968, L. J. W. Strang s.n. (CHR 342783); Temple Basin, Arthur’s Pass, 21 February 1943, V. D. Zotov s.n. (CHR 160683); Cass, Day Creek, 1070 m, 6 February 1936, M. Sutherland s.n. (WELT L194); Ben Ohau Range, Glen Lyon Station, 1830 m, October 1958, Mason 161 & 162 (OTA); Porter’s Pass, February 1874, 910 m, S. Berggren s.n. (UPS); Banks Peninsula, Castle Rock, 460 m, October 1967, P. F. Johnson s.n. (CHR 342785). Otago: Rock and Pillar Range, 1160-1190 m, 18 September 1981, F. J. Walker s.n. (BM, UPS), c. 1020 m, 4 April 1970, G. Degelius NZ-346 (herb. Degelius), 2000 m, 1 December 1969, N. M. Adams s.n. (WELT L359); Old Man Range, 1370 m, 1 February 1963, P. W. James 1576 (BM), 1680 m, April 1968, D. J. Galloway s.n. (BM, CHR 343341); Mt. Sir William, 2560 m, 27 December 1970, D. J. Galloway s.n. (CHR 34278 p.p.); Humboldt Mtns, Mt. Nox, 1950 m, 31 December 1969, D. J. Galloway s.n. (CHR 342791 p.p.); Remarkables, 1220 m, February 1968, D. J. Galloway s.n. (CHR 343334); Matukituki Valley, Mt. Avalanche, 1680 m, 5 April 1969, L. D. Kennedy s.n. (CHR 342756); Mt. Maungatua, 910 m, March 1954, J. Murray 554 (OTA); Lake Ohau, Mt. Sutton, 1070 m, May 1958, J. Murray 1783 (BM); Mt. Roy, 1 November 1972, G. C. Bratt 72/1507 (HO 35174); Mt. Pisa, 1860 m, March 1968, D. J. Galloway s.n. (CHR 342799); Silverpeaks, Gap Ridge, 610 m, 19 March 1961, D. J. Galloway s.n. (CHR 342754). Southland: Mid Dome, 1520 m, May 1970, G. Van Reenen s.n. (CHR 342837 p.p.); West Dome, 1070 m, 11 January 1970, P. N. Holdsworth s.n. (CHR 342806); Ridge between Takahe Valley and Ettrick Burn, 1400 m, 16 February 1969, G. Van Reenen s.n. (CHR 342818); Thomson Mtns, 1370 m, October 1967, A. F. Mark s.n. (CHR 342813); Grave-Talbot Pass, Milford Track, 1830 m, 25 January 1963, O. Fletcher s.n. (CHR 160684). Stewart I.: Mt. Anglem, 992 m, February 1966, D. J. Galloway s.n. (CHR 342749). For further localities in Canterbury and Otago see lists held in BM and collections in CHR, HO and OTA. 78 F. J. WALKER 6. Usnea durietzii Motyka Fig. 22 Lich. Gen. Usn. Stud. Monogr. 2: 503 (1937). Type: [Chile] W. Lechler: Plantae Magellanicum, Insula Elizabethae [54°07’S: 73°11’W] Oct. med. 1882 (UPS! — holotype; BM!, M!, PC! — isotypes). [TLC: norstictic acid, salazinic acid, usnic acid. ] Description: Thallus2-3(-4) cm, arising from a single, + elongated, blackened holdfast, erect,* richly branched, often 0-5—1-0 cm above the base, main branches clustered, fibrils absent, with short, recurved, capillaceous secondary branches. Branches terete, greenish yellow, + articu- late, conspicuously inflated above a + constricted base, black-pigmented only at the apices. Cortex thin. Surface matt, coriaceous, usually epapillate. Medulla broad, very lax in main branches, axis thin, occupying 0-2-0-4 of the branch diameter. Pseudoisidia numerous on all branches, in soralia-like clusters, small (x10 lens), spinulose, black-pigmented, often becoming confluent or eroding. Isidia and soredia absent. Apothecia and pycnidia not known. TLC: (1) norstictic acid, salazinic acid, usnic acid; (2) no medullary substances, usnic acid. = 5 f LAU TIA a Kaed <. ZA tagt. re Z ere ee a is ee a ell ¢ . AS as — Ste 2 ie a erp +. oe tt Fig. 22 Usnea durietzii. Top. Holotype of Usnea durietzii Motyka (UPS) x1. Bottom. Detail of pseudoisidia. Peru, Ancash, July 1979, Gibby & Barrett (BM) x10. USNEA SUBGENUS NEUROPOGON 79 Distinguishing features: Usnea durietzii is characterised by its erect, often stalked, tufted habit, with short, irregular laterals and inflated, articulated main branches; a smooth, matt surface with numerous clustered, pigmented pseudoisidia which give a sooty appearance to the thallus; and a lax medulla, usually containing both norstictic and salazinic acids. Distribution: Usnea durietzii has a rather disjunct, predominately western distribution throughout the Andean Cordillera from Panama and northern Venezuela to the Magellan Straits and Tierra del Fuego, although the species is very rare in Chile and Argentina, virtually being replaced there by U. patagonica. The species is characteristic of dry, exposed, rather than necessarily alpine, habitats. It is usually confined to high altitudes, c. 3000-4000 m, rarely occurring at lower levels towards the southern limit of its distribution as, for example, in the type locality. It has previously been recorded from the east side of the Andes in Prov. Mendoza, Argentina (Rasanen, 1939), and an illustration of Usnea cf. condensata by Asahina (1967) from Patagonia is clearly this species. In southern Patagonia U. durietzii has been collected with U. patagonica and U. trachycarpa (Santesson, 525 S!, Santesson 1920, S!). Fig. 8. Chemistry: Usnea durietzii is characteristically found to contain norstictic and/or salazinic acids (Race 1); depsidone-deficient populations (Race 2) are rare and are apparently confined to northern part of the range. Variation: Usnea durietzii is a rather variable species with a wide range of growth forms resulting from the irregular, repeated branching which occurs at a short distance above the holdfast. Frequently there is a proliferation of ultimate branches producing an untidy, tufted, ‘witches-broom’-like structure consisting of numerous recurved branchlets with pigmented apices. Sometimes the basal black, stalk-like structure is absent and the thallus proliferates directly with a cluster of laterals. Fibrils, such as occur in U. amblyoclada (Appendix I, p. 115) and U. trachycarpa, are absent. Pigmentation is confined to the thallus base and apices and to the pseudoisidia. The degree of development of pseudoisidia is variable and they may be incompletely developed or erode to form soredia. The pseudoisidia are always black-pigmented and tend to be produced in soralia-like clusters dispersed throughout the thallus. Such pseudoisidia are larger than those of Usnea patagonica and consequently can be distinguished from the flatter, partially corticate structures that are sometimes produced in other asexual species. Papillae are usually absent although they rarely occur on main branches in those specimens that are of uncertain taxonomic position, which seem to have affinities with Usnea amblyoclada or U. sphacelata. In these specimens the medulla is not so characteristically lax as in U. durietzii. The holotype specimen (Fig. 22) is a grotesque, knarled form of the species with proliferating branchlets and eroded pseudoisidia, although it is still characterised by a lax medulla, matt surface and tufted habit. Isotype collections are more typical. As the species often grows in exposed situations some features in consequence may not be fully developed as, for example, laxness of the medulla or development of pseudoisidia. Species concept: Usnea durietzii is here included in the subgenus by virtue of habitat, distribution, and pigmentation. Fertile material of the taxon, or the recognition of a fertile counterpart, is required in order to confirm this assumption. This is a well-defined species, which may have affinities with the subgenus Usnea, for example with U. amblyoclada and U. nigropapillosa. The distribution overlaps that of U. amblyoclada from which it may be distinguished by the lack of fibrils and pseudocyphellae and also by the presence of clustered pseudoisidia rather than scattered true isidia. It also occurs with U. bogotensis which is a much more robust, unpigmented species with conspicuous true soralia that are only rarely pigmented, a compact medulla, and prominent white annulations and reticulations. Usnea durietzii has some affinities with Usnea patagonica but may usually be distinguished by habit, surface features, propagule size, and medullary chemistry (Table 3). The presence of pigmented pseudoisidia, rather than pale true isidia, distinguish the species from U. acanthella. It may be separated from other asexual species within the subgenus by differences in soralia and surface characters, and often by habitat and distribution. 80 F. J. WALKER Specimens examined Race 1 PANAMA. Chiriqui: Chiriqui, volcano crater’s edge, 3300-3450 m, 12 December 1948, P. F. Scholander 169534 (US, CANL 17249). VENEZUELA. Merida: Valle del Mufafi, paramo de Mucuchies, Sierra Nevada, 3650-3750 m, 9 April 1975, M. E. Hale & M. Lépez Figueiras 44650 (US); trail between Laguna Negra and Mucubaji, Sierra Nevada, 3500 m, 8 April 1975, M. E. Hale & M. Lopez Figueiras 44455 (US); Rangel, Sierra Nevada de Santo Domingo, paramo de Mucubaji, close to Laguna Grande (Laguna de Mucubaji), c. 3500 m, 11 October 1981, M. Lindstrém 526 (GB); [unlocalised], 5500 m, 1846, Voyage de Funck & Schlim 987 (PC). COLUMBIA. Santander: Paramo del Almorzadero, 3970 m, 17-19 November 1978, J. Aguirre 1090 (U 387342b). Boyaca: Paramo de La Rusia, Laguna Negra, 3745 m, 14 December 1972, A. M. Cleef 7229 (BM); Sierra Nevada del Cocuy, Alto Valle Lagunillas, SE. of La Laguna Cuadrada, 4080 m, 26 November 1972, A. M. Cleef & P. A. Florschiitz 5558 (U 390939), 5559 (U 390940). ECUADOR. Pinchincha: Volcan Sincholahua, plateau along Rio Pita, c. 3600 m, 30 May 1973, L. Holm-Nielsen et al. 6655 (GB); Cerro Iliniza, c. 4400 m, 7 March 1972, L. Arvidsson & D. Nilson 945 (BM, GB). Cotopaxi: Cotopaxi National Park, c. 60 km SE. of Quito, Pampa de Limpios, 3900 m, 13 June 1976, S. R. Gradstein, H. Sipman & T. de Vries 164 p.p. (BM, VU). PERU. Ancash: Quebrada Honda, Cordillera Blanca, 4260 m, July 1979, M. Gibby & J. Barretts.n. (BM). Junin: Huytapallana, above Huancayo, c. 4600 m, 19 May 1973, B. Mullins 25 (BM); Cerro de Pasco, Conception, 4260-4560 m, 1969, B. Mullins s.n. (BM). Cuzco: Huaya, Huaya Pass, above Cuzco, 4500 m, 14 June 1973, B. Mullins 29 (BM); Pisac, near Cuzco, 3700 m, 14 April 1973, B. Mullins 24 (BM); above Cuzco, 3500-3600 m, 16 June 1973, B. Mullins 30 (BM). Ayacucho: near Ninabamba, 3900 m, 25 May 1973, B. Mullins 27 (BM). Apurimac: between Pic¢éas and Huancaramay, 1932, M. M. Wood s. n. (BM). Puno: prope Azangaro, June 1854, W. Lechler Pl. Peruvianae 1758 (BM, M). BOLIVIA. La Paz: Copacabana, near Lake Titicaca, 3800 m, 10 July 1973, B. Mullins 31 (BM). CHILE. Malleco: c. 32 km SW. of Angol, 16 February 1958, W. J. Eyerdam 10794 (BM, FH). Magallanes: Is. Grafton, I. Elisabeth [54°07’S: 73°11'W] (type locality); prope Sandy Point, W. Lechler Pl. Magellani- cae 108 (M); Rio de los Cruzeros, 60 km NNE. of Punta Arenas, 26 April 1940, R. Santesson 1920 p.p. (S). ARGENTINA. Mendoza: Las Heras, Quebrada del Portero Puerta, near Cacheuta, 1800 m, June 1939, R. Leal s.n. (LD). Tierra del Fuego: Ushuaia, small island in Beagle Channel off the town, 30 January 1940, R. Santesson 532 p.p. (S). Unlocalised: ‘Jahina’, Peruviae, W. Lechler Pl. Magellanicae 139 (M). Race 2 VENEZUELA. Merida: [unlocalised], 1842, Funck & Schlim 9 & 7 (BM, PC); Hale & Lopez Figueiras 44650 p.p. (as Race 1) (US); Rangel, Sierra Nevada de Santo Domingo, paramo de Mucubaji, close to Laguna Grande (Laguna de Mucubaji), c. 3500 m, 11 October 1981, M. Lindstrém 519 (GB); Paéramo de Mucubaji, on highest point of road Merida-Caracas, track from Laguna de Mucubaji to Laguna Negra, 3500 m, 24 January 1979, H. Sipman & M. Lopez Figueiras 11289 (UV). COLUMBIA. Cundinamarca: prope Bogota, J. Weir 12 (BM). BOLIVIA. Larecaja: near Sorata, Rampe de l’Apacheta, 4500 m, 1857, G. Mandon Pl. Andinum Boliviensium 1737 (BM, PC). 7. Usnea neuropogonoides Motyka Fig. 23 Lich. Gen. Usn. Stud. Monogr. 1: 73 (1936). Type: Argentina: terr. Santa Cruz, Rio Fosiles, c. 1000 m, in rupibus, May 1905, P. Dusén. (UPS! — holotype). [TLC: no medullary substances, usnic acid. ] Description: Thallus up to 13 cm long, suberect to scrambling-prostrate, often lacking a distinct holdfast, divergent, + dichotomous, infrequently branched to form a lax, spreading habit, rarely with fibrils, with short, divaricate, capillaceous secondary branches with attenuate, subcornute apices. Branches + terete, occasionally subinflated or slightly angular, yellow- green, minutely variegated or black-pigmented only at the apices. Cortex c. 100 wm. Surface matt, smooth to faveolate or papillate, often fracturing. Medulla broad, lax, or sublax, axis thin, occupying c. 0-25 of the branch diameter. Apothecia, pycnidia, soredia, pseudoisidia and isidia not known. TLC: (1) psoromic acid, + 2’-O-demethylpsoromic acid, + fatty acids (murolic acid complex), usnic acid; (2) depsidone deficient, + fatty acids (murolic acid complex), usnic acid. Distinguishing features: Usnea neuropogonoides is characterised by its lax, suberect to scramb- ling habit, divergent branching, scant pigmentation, faveolate to papillate surface, lax medulla often containing psoromic acid, and lack of sexual or vegetative propagules. USNEA SUBGENUS NEUROPOGON 81 Fig. 23 Holotype of Usnea neuropogonoides Motyka (UPS). Top. Whole thallus x1. Bottom. Detail of branching X10. 82 F. J. WALKER Distribution: Usnea neuropogonoides is only known from a few collections from Patagonia, and is apparently characteristic of the windswept mesetas to the east of the Andean Cordillera. Fig. 8. Chemistry: From the few collections (six) examined it appears that thalli more frequently contain psoromic acid (Race 1) than lack depsidones. Traces of two or three fatty acids of the murolic acid complex were found in some thalli. Variation: It is difficult to assess the extent of variation in this species from the few extant collections. The suberect or sprawling habit and loosely interwoven branches with pigmented apices appear to be constant. Pigmentation is scarce on the main branches, being confined to fractures and, rarely, papillae, thus bearing resemblance to the rare, straggling forms of Usnea aurantiaco-atra. Although fibrils are infrequent, the surface faveolation and papillation, the sublax medulla, and the thin axis are reminiscent of some of the variation found in U. trachycarpa. The lack of reproductive structures suggests that this species is possibly disseminated by thallus fragmentation or by abrasion of fibrils or papillae. One specimen from Fuegia, ‘San Isideo Point’ (BM!), cited by Crombie (1876b), possibly belongs to this species, but is somewhat moribund and has a partially eroded cortex which could indicate the incipient production of isidia or pseudoisidia. Occasionally, in other thalli, nodular, white, soralia-like outgrowths are formed on main branches as a result of cortical damage or thallus fracture; these are anomalous structures and do not appear to have any taxonomic significance. Species concept: Usnea neuropogonoides is included in Neuropogon since, although sterile, it has several characteristic features of the subgenus. Examination of further material may prove that this is an extreme form of another species, the most likely being U. trachycarpa, or that it even belongs to the subgenus Usnea, only producing pigmentation in very exposed habitats or when moribund as is seen in U. torulosa (p. 120). The presence of papillae and depsidones rather than depsides (i.e. divaricatic acid) and different habitat requirements, indicate that although superficially similar, this species should not be included in Protousnea as delimited by Krog (1976). In addition, the main branches remain virtually terete and do not become so markedly angular in section or inflated at branch points, as, for example, in P. scrobiculata. However, in spite of this, certain similarities do exist, notwithstanding the limited morphological characters, which also define Protousnea. Usnea neuropogonoides can be distinguished from decumbent forms of other Neuropogon species by the matt, faveolate to papillate surface, thin axis, broad, sponge-like, more or less lax medulla, and lack of propagules. Specimens examined Race 1 ARGENTINA. Santa Cruz: Lago San Martin, 4 February 1903, P. Dusén s.n. (H); between Lago San Martin and Lago Viedma, 2 February 1903, Spegazzini s.n. (BM, H); Chilean border, Lago San Martin, Laguna Theuen Aiken, [48°-49°S], 4 February 1903, C. Hoberg 121 (BM); Estancia Librun, [c. 51°S: 71°E], Shipton Exped. 1958-59, P. W. James s.n. p.p. (BM). Race 2 ARGENTINA. Santa Cruz: Belgrano Pass, 22 December 1908, C. Skottsberg (UPS); Estancia Librun (as Race 1), P. W. James s.n. p.p. (BM). 8. Usnea patagonica F. J. Walker, sp. nov. Fig. 24 Diagnosis: Thallus fruticosus, pigmento nigro in cortice ad apices basimque suffusus. Rami extensi teretes saepe fibrillosi, papillis sparsis vel numerosis. Medulla sublaxa. Soralia pseudoisidiis minutis nigrescentibus excavata. Apothecia ignota. Acidum usnicum continens, et + acidia aliphatica ad acidum murolicum pertinentia. Typus: Argentina, Santa Cruz, Patagonia, Lago Argentino [49°80’-51°S: 72°- 73°30'W], Cordillera Cristales, 2000 m, on boulder in valley, 26 December 1958, P. W. James 31 (Shipton Exped.) (BM! — holotype; UPS!, US!—isotypes). [TLC: 3 fatty acids of the murolic acid group, usnic acid. ] Description: Thallus 1-5—3(—4—6) cm, arising from a delimited, pigmented holdfast, erect, + subdichotomous, richly branched a short distance above, with numerous, clustered, inter- USNEA SUBGENUS NEUROPOGON 83 Fig. 24 Holotype of Usnea patagonica F. J. Walker (BM). Top. Whole collection x1. Bottom. Detail of eroded soralia with pseudoisidia x 10. woven, extended lateral branches, + fibrils and capillaceous, + flaccid ultimate branches. Branches terete, greenish yellow, black-pigmented only at or towards the apices. Cortex thin, 50-75 um. Surface subnitid, subfaveolate-papillate (x10 lens) then scabrid, occasionally rupturing. Medulla lax or sublax, at least towards axis, axis thick, occupying c. 0-5—0-6 of the branch diameter. Soralia extensive + throughout thallus, plane, + irregular or ulcerose, rarely becoming effuse to confluent and excavate, arising from small papillae, + an inconspicuous margin, with numerous, minute (x10 lens), pigmented pseudoisidia. Soredia rare, true isidia absent. Apothecia and pycnidia not known. TLC: no medullary substances, + 1+ fatty acids (murolic acid complex), usnic acid. Distinguishing features: Usnea patagonica is characterised by its erect, richly branched, touselled habit with extended, lateral branches which rarely bear fibrils; a subnitid, subpapillate surface with numerous, minute, pigmented pseudoisidia, produced in ulcerose soralia, which give the thallus a dusted, sooty appearance, and a sublax medulla, frequently containing fatty acids. 84 F. J. WALKER Distribution: Usnea patagonica is mainly confined to the southern half of South America and is a species of the transitional arid-montane zone, frequently between the altitudes 500-1500 m, often occurring with U. trachycarpa and, less frequently, with U. durietzii or even U. perpusilla, having a slightly more eastern distribution. U. patagonica has been most frequently collected from the region of the Patagonian Lakes, for example Lago Argentino, but is rare further north, and is known from a single collection from Bolivia. Specimens cited by Follmann (1965a) from central Chile also appear to belong to this species. A single collection from South Africa is tentatively assigned to this species. Fig. 8. Chemistry: All specimens examined were depsidone-deficient, containing usnic acid and usually one to four fatty acids, of Rf classes TDA 2+4, HEF 3-4, belonging to the murolic acid complex, which also occurs in Usnea trachycarpa. The presence of these fatty acids and lack of a depsidone-containing race may be regarded as additional characters for recognising U. patago- nica as a distinct species. Traces of the UV+ unknowns are occasionally present. Variation: The general form of Usnea patagonica shows little variation apart from the extent of production of secondary branches and extended laterals, which usually replace fibrils. In a single gathering thalli may either bear numerous, capillaceous, ultimate branches or may entirely lack laterals and instead have truncated apices. Thalli are characteristically repeatedly branched, sometimes a short distance above the blackened holdfast, giving a tufted, tasselled habit. The surface may be subnitid to waxy, and in smaller, immature thalli, is occasionally devoid of papillae which lack pigmentation. Rarely annulations are formed resembling those of Usnea acromelana, although in U. patagonica this is usually confined to the finer, laterals rather than main branches. The laxness of the medulla may vary, but even when not well developed, the hyphae are more loosely interwoven in the proximity of the axis. Such variation is similar to that found in Usnea trachycarpa; the primary branches do not become inflated as in U. durietzii. There is little variation in the form of the soralia; the production of small, pigmented pseudoisidia is a characteristic feature of the species. The pseudoisidia are rarely as well- developed as in Usnea durietzii and arise in more or less delimited, discrete soralia which rarely become confluent as in that species. Occasionally, soralia may resemble the less well-developed forms found in U. antarctica, but generally they are more eroded in U. patagonica and lack the distinctive crateriform margin. Table 3 summarises the differences between these three species and Fig. 3 illustrates their asexual propagules. Black pigmentation is normally confined to the holdfast, pseudoisidia, and branch apices, although the ultimate branches may rarely be variegated or extensively pigmented. High altitude material from Cedarberg, South Africa (Schelpe 1961, BOL!, CANL 16944!), originally determined by Lamb as Usnea acromelana, very closely conforms to U. patagonica, and is tentatively included in this species. Some thalli have a blackened base, are richly branched above with pigmented apices, and have excavate, ulcerose, soralia-like areas which contain small, pigmented pseudoisidia. Thalli also lack diagnostic medullary substances, containing traces of three to five fatty acids of the murolic acid complex. Other thalli in the same collection do not resemble U. patagonica so closely, and may belong to another taxon, since they are less extensively pigmented, have more fibrils, a markedly faveolate surface, and a laxer medulla lacking fatty acids. However, they do possess similar soralia-like areas that, less frequently, produce poorly developed pseudoisidia. Species concept: Many specimens of Usnea patagonica have been previously determined as U. acromelana or U. durietzii according to the extent of pigmentation, branching, or development of pseudoisidia. In many respects this species might be regarded as an intermediate entity between several asexual species that occur in South America, and is, for these reasons, included within the subgenus despite the lack of fertile material. Usnea patagonica appears to be most closely related to U. durietzii with which it shares many common features. The two species may be distinguished by differences in their habit and branching which, in U. durietzii, is much more irregular with the production of clusters of fibril-like, stunted branchlets rather than fine, extended laterals of U. patagonica. In U. USNEA SUBGENUS NEUROPOGON 85 patagonica branches are never inflated and pseudoisidia are less prominent. The holotype of U. durietzii is very close to, but distinct from, more robust forms of U. patagonica and, in addition, contains traces of norstictic acid. The presence of fatty acids rather than depsidones, preferred habitat and distribution may, conversely, indicate affinities between Usnea patagonica and Race 3 of U. trachycarpa with fibrils of the latter species being replaced by extended laterals bearing soralia. In contrast, the general habit of the new species is similar to depauperate forms of U. antarctica from the South Orkney and South Shetland Islands, although the thallus is less robust with somewhat flaccid ultimate branches. The extent of pigmentation is also similar and is frequently sparse; unlike the majority of specimens of U. antarctica the thallus always has a blackened basal portion above the holdfast. Usnea patagonica may be distinguished from U. subantarctica and U. sphacelata by the form of the soralium, presence of. pseudoisidia, less extensive pigmentation, and different ecological parameters; from U. acromelana by the presence of papillae and pseudoisidia, a laxer medulla and by fewer, usually unpigmented, cortical annulations. Specimens examined BOLIVIA. La Paz: Prov. Murillo, Valle de Chuquiaguillo, Incachaca, 4200 m, 7 April 1921, E. Asplund 56 (UPS). CHILE. Santiago: Cordillera Central, SW., 3000 m, 1964, G. Follmann 13446-L (LD), 13435-L (KAS- SEL), 13442-L (UPS), 13443-L (UPS). Cautin: Cordillera Lonquimay, 2050 m, 4 November 1930, R. P. A. Hollermayer s.n. (H). Aisén: Estancia Nirehuao, Bano Nuevo, 23 September 1940, R. Santesson 5010 p.p. (S), 5021 (S); Estancia Nirehuao (25-30 km N. of Rio Coyhaique), 20 November 1940, R. Santesson 4821 (S), 25 November 1940, R. Santesson 4865 (S); Estancia Coyhaique Alto (near Cerro Coyhaique), c. 100 m, 18 November 1940, R. Santesson 4632 p.p. (S); Coyhaique Alto, 1000 m, 18 November 1940, R. Santesson Lich. austroam., ex herb. Regnelliano 423 p.p. (C, H, M, S); Coyhaique, Cerros Divisaderos (Cordon de Bella Vista), 1200 m, 13 November 1940, R. Santesson 4435a (S), 4435b (S, UPS). Magallanes: Rio de los Cruzeros (60 km NNE. of Punta Arenas), 26 April 1940, R. Santesson 1920 p.p. (S); Natales, Cerro Dorotea, 9 May 1940, R. Santesson 2137 p.p. (S), 8254 p.p. (S); Lago del Toro (Lago Maravilla), La Peninsula, 10 March 1941, R. Santesson 6325 (S); Tierra del Fuego, Isla Navarino, 300 m, 1963, G. Follmann 14591 (UPS), 13978 (KASSEL), 14587 (KASSEL), 14586 p.p. (M); 14589 (LD); Isla Navarino, Puerto Navarino, 10 m, 28 February 1940, R. Santesson 1234a (S, UPS); Paine National Park, Lake Pehoe, 129 km N. of Puerto Natales, 18 m, 11 March 1974, C. Neher 76 (LAM 202156). ARGENTINA. Rio Negro: Cerro Leones, near summit, W. bank of Lago Nahuel Huapi, 1 January 1974, A. Henssen & G. Vobis 24625 (MB); Parque Nacional Nahuel Huapi, Cerro Catedral, Liftstation, c. 2225 m, 6 January 1974, A. Henssen & G. Vobis 24674f p.p. (MB); Cerro Otto, c. 10 km W. of San Carlos de Bariloche, 1200 m, 29-30 December 1980, K. Kalb s.n. (herb. Kalb). Santa Cruz: Lago Viedma, 2 February 1903, P. Duséns.n. p.p. (H); N. coast of Lago Viedma, 1200 m, 2 April 1903, Hoberg 123 (BM); Lago Argentino, Calafate, weg nach Punta Bandera, Campo Anita Fuss des Cerro Moyano, 300-400 m, 20 December 1973, A. Henssen & G. Vobis 24535d (MB); Calafate, Cuevas de Hualichu, 18 December 1973, A. Henssen & G. Vobis 24523a (MB); near Calafate, 1959, P. W. James 4/120b (BM); Parque Nacional Los Glaciares, Lago Roca, Jeronima, 16 December 1973, A. Henssen & G. Vobis 244991 (MB); Lago Roca, Cordon de los Cristales, c. 1000 m, 26 December 1958, P. W. James s.n. (BM); Cordillera Cristales (type locality); Lago Roca c. 1000 m, December 1958, P. W. James 16 (BM); 20 (BM); Lago Roca, Cerro del Fraile, January 1959, P. W. James s.n. (BM); Rio Fosiles, c. 1000 m, April 1905, P. Dusén s.n. p.p. (M, WU 2997); Uppsala Glacier, Estancia La Christina, 16 December 1958, P. W. James 5/49 p.p. (BM), 5/10 (BM). Tierra del Fuego: Ushuaia, La Peninsula, 3 January 1940, R. Santesson 559 p.p. (S); Sierra Sorondo, N. slope above Las Cotorras (c. 20 km ENE. of Ushuaia), 800 m, 6 February 1940, R. Santesson 641f p.p. (S); Sierra Alvear, S. slope, above Las Cotorras, 700 m, 9 February 1940, R. Santesson 637b (UPS). Uncertain determination SOUTH AFRICA. Cape Province: Cedarberg. Between Tafelberg (Table Mt.) and Spout, 1830 m, 18 January 1947, E. Schelpe 1961 p.p. (BOL, CANL 16944). 9. Usnea perpusilla (Lamb) F. J. Walker, comb nov. Figs 25-26 Neuropogon perpusillus Lamb in J. Linn. Soc. (Bot.) 52: 234 (1939). Type: Chile, Pico de Pilque, prope Antuco, Poeppig Pl. Chil. III, 278(56) (BM! — holotype; B, G — ?isotypes (Motyka, 1936), not seen). [TLC: no medullary substances, usnic acid. ] 86 F. J. WALKER Neuropogon rohmederi Lamb in Lilloa 14: 158 (1948). — Usnea rohmederi (Lamb) Lamb in An. Parg. nac. B. Aires 7: 157 (1959) [‘1958’]. Type: Argentina, Chubut, Lago Futalaufquen, 1800-2000 m, 1945, G. Rohmeder (LIL 2275 — holotype, not seen; BM!, CANL 17205!, H!, UPS!, US! — isotypes). [TLC: no medullary substances, + UV+ unknowns, usnic acid. ] Neuropogon rohmederi f. ushuaiensis Lamb in Lilloa 14: 160 (1948). Type: Argentina, Tierra del Fuego, Sierra Alvear, the southern slope, above Las Cotorras (c. 20 km ENE. of Oshuaia), 900-1000 m, 7 February 1940, R. Santesson 640c (640a p.p.) (S!- holotype; CANL 17209!, UPS! — isotypes). [TLC: no medullary substances, usnic acid. ] Description: Thallus (2)-5—-10(-14) cm, arising from a proliferating or rarely delimited, unpigmented, holdfast, erect, + dichotomous, infrequently to richly branched above. Bran- ching often divergent with short, subcapillaceous, sometimes shortly attenuate then deflexed, laterals. Fibrils very rare. Branches terete, yellow-green, + variegated with bands of violaceous black pigment, + continuously pigmented towards the apices. Cortex variable in thickness. Surface smooth, subnitid to waxy, + incomplete fractures, often becoming markedly faveolate, never verrucose, rarely + scabrid with minute, pigmented papillae (x10 lens). Medulla lax, rarely sublax, axis thin occupying 0-25-0-5 of the branch diameter. Soredia, pseudoisidia and isidia absent. Apothecia frequent, 1-8(—12) mm diameter, lateral, subsessile, often in series, rarely subterminal with a geniculate spur, + reniform or irregular on maturity. Disc black, excipulum smooth to faveolate-reticulate, margin thin, often + excluded, rays rare. Pycnidia rare. TLC: (1) psoromic acid, + 2'-O-demethylpsoromic acid, + 1 to 4 UV + unknowns, usnic acid; (2) no medullary substances, + 1 to 4 UV+ unknowns, usnic acid. Distinguishing features: Usnea perpusilla is characterised by its erect, moderately branched thallus, often extensively pigmented towards the apices, a more or less smooth, waxy, subfaveolate surface, a lax medulla normally lacking medullary substances, a thin axis, and lateral or rarely subterminal apothecia with a black disc, with a faveolate-reticulate excipulum, usually lacking marginal rays. Distribution: Usnea perpusilla is confined to the Andean Cordillera in southern South America, occurring in Argentina and Chile from Tierra del Fuego northwards to about latitude 37°S. It is characteristic alpine-southern temperate species, often found at high altitudes, between 1000 and 2000 m, in communities with such species as U. aurantiaco-atra and, occasionally, U. trachycarpa and U. patagonica. Fig. 7. Chemistry: The majority of specimens examined lack medullary substances although some may contain localised high concentrations of three or even four UV+ unknowns (p. 15). Specimens containing psoromic acid (Race 2) are only known from a single locality towards the northern limit of the distribution of the species. Variation: Usnea perpusilla is a moderately variable species exhibiting a range of growth form, branch anatomy, and apothecial form. The size of the thallus is very variable, ranging from small thalli, c. 2cm, which bear small, cupular apothecia, as in the type specimen, to larger, c. 14cm, erect forms that may become subdecumbent. The extent of branching is also variable, ranging from almost monopodial forms arising from a proliferating holdfast to lax, spreading forms, arising from a delimited holdfast, as in the type of U. rohmederi. Where branching is extensive the thallus may produce short, fibril-like, recurved, subcapillaceous, ultimate branches. Specimens recently collected from Prov. Rio Negro, Argentina (herb. Kalb!, BM!) illustrate well two features of the variation found in this species; namely, seemingly superficial morpholo- gical similarities to Usnea ciliata, and an intermediate range of thallus size between the types of U. perpusilla and U. rohmederi. The main branches are usually unpigmented near the base, with apices and secondary branches being either conspicuously variegated or continuously pigmented violaceous black towards the tips. The surface is characteristically smooth and waxy and may become faveolate or slightly inflated if the underlying medulla is very lax. In such instances the cortex may fracture forming incomplete, unpigmented annulations that are not a constant diagnostic feature as in Usnea USNEA SUBGENUS NEUROPOGON 87 Fig. 25 Usnea perpusilla. A-Isotype of Neuropogon rohmederi Lamb (CANL). Top. Whole thallus <1. Bottom. Detail of excipulum x10. B(inset)- Holotype of Neuropogon perpusillus Lamb (BM) x2. 88 F. J. WALKER Fig. 26 Usnea perpusilla. Isotype of Neuropogon rohmederi f. ushuaiensis Lamb (CANL) X1-5. ciliata. The thallus is never strongly verrucose-papillate, as in U. aurantiaco-atra, and only rarely, in more robust forms where fibrils are present, do small, usually black-pigmented, papillae occur, giving the thallus a slightly scabrid texture, as in the type of U. rohmederi f. ushuaiensis (Fig. 26). Typically the axis is very thin in main branches, occupying about a third of the branch diameter. The degree of laxness of the medulla is very variable, and in some instances may only be looser and arachnoid in close proximity to the axis. Specimens in which the medulla is more compact and where the axis correspondingly occupies a greater proportion of the diameter, have previously been mistaken for Usnea ciliata or U. aurantiaco-atra; they may usually be disting- uished from these species by other well-defined characters. Positioning and size of apothecia may vary in Usnea perpusilla. In well-developed thalli the apothecia are often produced serially along a branch, a feature more rarely encountered in other fertile species, for example U. ciliata and U. aurantiaco-atra. Less frequently, in more richly branched thalli, the apothecia are subterminal, and then often have a geniculate subtending spur which may in turn produce additional apothecia, thus reflecting the characteristic habit of the species. The apothecia are subsessile, having a broad area of attachment; frequently various stages of development may be observed on a single branch, ranging from a small, rounded, cupular form to the more typical reniform shape with a deflexed, irregular outline and a virtually excluded thalline margin. Faveolation of the excipulum is usually a constant feature. Marginal excipular rays are infrequent and, when present, may vary in number, length and extent of pigmentation. Their formation may be correlated with the extent of branching since they are most likely to be present in richly branched specimens. Species concept: Examination of the type specimens of Usnea perpusilla and U. rohmederi, including f. ushuaiensis, and study of additional material has shown that these taxa fall within the variation of a single species. The holotype of U. perpusilla (BM!) is very fragmentary (Fig. 25), although additional collections (M!, PC!) that may be part of Poeppig’s original gathering, are USNEA SUBGENUS NEUROPOGON 89 better developed. Examination of slides of sections of the holotype prepared by Lamb (BM!) show that mature asci are very rare, an indication that apothecia are in fact immature, and that the medullary tissue, although not expanded, shows signs of becoming arachnoid-lax in the proximity of the axis. Lamb (1948a) separated Usnea rohmederi f. ushuaiensis on the presence of minute, pig- mented papillae, an almost smooth excipulum with marginal rays, and slight differences in spore size and thecium height, all of which are here accepted as infraspecific variation. Usnea perpusilla has often previously been mistaken for U. ciliata and may be distinguished by the lax medulla, absence of conspicuous, pigmented annulations, a frequently variegated, rather than continuously pigmented, thallus, and often by the serial position of the apothecia. (Fig. 2). The two species have a marked difference in distribution. In U. ciliata apothecia are normally terminal or sublateral, also with a geniculate spur, whilst in U. perpusilla they are more frequently produced laterally, often up to five in series, with a much broader area of attachment, sometimes producing an acute geniculation of the branch. Forms with fibrils may be distinguished from Usnea trachycarpa by the difference in disc colour; the species can be distinguished from U. aurantiaco-atra by the degree of ornamentation and differences in branch anatomy. Specimens examined Race 1 ARGENTINA. Rio Negro: Cerro Rigi, near Lago Frias, c. 1750 m, 15 February 1950, J. M. Lamb 6046 (CANL 17016, UPS). Race 2 CHILE. Bio Bio: ‘in summ. And. cacum.’. Kunze s.n. (M); In cacum. montis, Pico de Antuco, 1835, Kunze s.n. (PC); Pico de Antuco, ex Kunze, s.n. (PC); Poeppig Pl. Chil. III [c. 37°S] (type locality). Cautin: Cordillera Lonquimay, 2050 m, 4 November 1930, R. P. Hollermayer s.n. (H). Unlocalised: ‘Chil. bor. rupes marit.’ Poeppig s.n. (PC). ARGENTINA. Neuquén: Cordillera Suangulo [38°-41°S], 2130 m, 16 January 1926, Kew Andes Exped., H. F. Comber 470 (BM, E); Paso Pino Hachado — Lonquimay [Chilean Border], 1900 m, 10 January 1948, A. Pfister 8123 (CANL 17014, UPS); Parque Nacional Nahuel Huapi, Brazo Rincén, Cerro Dormilon, Pérez Moreau 6793 p.p. (BM, H), 2 February 1940, Pérez Moreau 4543 p.p. (H); Parque Nacional Lanin, Cerro Malo, N. of Lago Lacar, c. 1900 m, 28 January 1968, J. H. de Haas 1290-A (U 313666b). Rio Negro: Parque Nacional Nahuel Huapi, Cerro Rigi, Lago Frias, 23 January 1940, Pérez Moreau, s.n. (Sic: Lamb 6046 (as Race 1) (BM, UPS); Parque Nacional Nahuel Huapi, Cerro Catedral, Liftstation, c. 2225 m, 6 January 1974, A. Henssen & G. Vobis 24674f (MB), 24677d (MB), 24677g (MB); Parque Nacional Nahuel Huapi, Cerro Catedral, c. 20 km SW. of San Carlos de Bariloche, 1850 m, 2 January 1981, K. Kalb s.n. (herb. Kalb); Parque Nacional Nahuel Huapi, Cerro Catedral, near Bariloche, 2000 m, 10 February 1950, I. M. Lamb 5949 (BM, CANL 17206, FH, H, UPS), 5951 (CANL 17207, UPS), 5956 (CANL 17208), 5962 (CANL 36562), 5964 (CANL 36563); Parque Nacional Nahuel Huapi, Cerro Otto, c. 10km W. of San Carlos de Bariloche, 1250 m, 29-30 December 1980, K. Kalb s.n. (BM, herb. Kalb); Parque Nacional Nahuel Huapi, Capitan, 30 April 1933, E. & A. Ljungner 1367 (S); Cerro Goye, 1670 m, 25 January 1944, J. C. Montiel s.n. (CANL 17204); Lago Nahuel Huap(, Puerto Manzano, 19 January 1966, H. & F. Walter 170 (M). Chubut: Chilean frontier [44°28’S: 71°34’W], 1500 m, 13 February 1902, Hoberg s.n. (BM); Lago Mendez, Cerro Torrecillas, c. 1000 m, 6 December 1940, N. Kiihnemann 4792 (BM); Lago Futalaufquen, (type locality — N. rohmederi). Santa Cruz; Lago Viedma, c. 1400 m, Shipton Exped., January 1959, G.-C. Bratt s.n. (BM, CHR 343330, FH); Lago Argentino, Cerro Mayo, Seno Mayo, c. 1100 m, Shipton Exped. February 1959, P. W. James s.n. (BM). Tierra del Fuego: Cerro [unlocalised] S. of Estancia “La Marina’, 500 m, 1921, Argentina Faculty of Science Exped. 564 p.p. (BM); Sierra Alvear (type locality — N. rohmederi f. ushuaiensis), 800-900 m, 7 February 1940, R. Santesson 639d (S); Sierra Sorondo, above Las Cotorras, c. 20 km ENE. of Ushuaia, 800 m, 6 February 1940, R. Santesson 641e (UPS, S); Monte Marcial, SE. slope, above Ushuaia, 700 m, 29 January 1940, R. Santesson 450c (UPS, S). For further localities see Lamb (1948a). 10. Usnea pseudocapillaris F. J. Walker, sp. nov. Fig. 27 Diagnosis: Usneae subcapillari affinis, sed thallo minore et soraliis parvis punctiformibus differt; apothecia rara. Typus: New Zealand, South Island, Otago, Humboldt Mountains, Mt. Nox, 1950 m, 31 90 F. J. WALKER December 1969, D. J. Galloway (CHR 343226! — holotype; BM! — isotype). [TLC: norstictic acid, salazinic acid, + protocetraric acid, usnic acid. ] Description: Thallus 2-3 cm, arising from a delimited, + pigmented holdfast, erect, becoming subpendulous or subdecumbent. Brancing extensive, divergent, + dichotomous, with numer- ous, delicate, capillaceous, spreading branches and short, attenuate, deflexed laterals; usually lacking fibrils. Branches terete, yellow-green, + continously pigmented or variegated violaceous black towards the apices. Cortex thin. Surface smooth, waxy, epapillate, easily fracturing, forming + regular, black-edged annulations. Medulla sublax towards the axis, axis occupying 0-3 — 0-5 of the branch diameter. Soralia small, punctiform, plane to concave or eroded. Soredia farinose, unpigmented. Pseudoisidia absent. Apothecia rare, immature, as in U. subcapillaris. Pycnidia not seen. TLC: norstictic acid, salazinic acid, + protocetraric acid, usnic acid. Distinguishing features: Usnea pseudocapillaris is characterised by its spreading to subdecum- bent habit and a richly branched thallus with numerous, fragile, divergent, flexuose-capillaceous secondary branches bearing small, unpigmented soralia. This species also has a waxy, pig- mented-annulate surface, and a sublax medulla containing depsidones. Distribution: Usnea pseudocapillaris appears to be confined to the South Island of New Zealand, occurring in alpine habitats with other species of the U. ciliata complex. It is so far only known from a restricted area in Central Otago, lying within the distribution of U. subcapillaris, and a single locality in NW. Nelson. It is possible that this species may also occur in Tasmania, where both U. acromelana and U. subcapillaris are known. Some Tasmanian specimens examined are morphologically very similar to this species but, as they lack soredia and apothecia, they are therefore probably best regarded as immature thalli of U. subcapillaris (for example: Mt. Wellington, herb. Degelius A-414!) pending. the discovery of more typical material. Fig. 6. Chemistry: Only one chemical race, that containing norstictic and salazinic acids, has been detected. However, it is possible that other races may be discovered since both the related Usnea subcapillaris and U. acromelana have more than one chemical race. Variation: ‘The thalli of this new species are small, rarely exceeding 4-5 cm, are characteristi- cally richly, dichotomously branched, and arise from a delimited holdfast. The fine, capil- laceous, divergent secondary branches form a lax, subdecumbent, loosely-interwoven network, whose fragility is accentuated on storage in herbaria. The primary branches are frequently widely diverging and produce a characteristic angulose network of secondary branches which also occurs in Usnea subcapillaris; however, in U. pseudocapillaris these are not as extensive or extended. The diameter of secondary branches may vary; typically they are short, capillaceous, 0-1-0-3 mm diameter, resembling those of Usnea subcapillaris. Rarely secondary branches may be up to 0-5 mm in diameter and in such instances there is a more gradual transition in width from main branches. In all specimens the ultimate branches are short, divergent or often reflexed and shortly attenuate, giving a netted appearance to the thallus. This is also a feature of richly branched forms of U. acromelana and less well-developed forms of U. subcapillaris. Formation of a secondary holdfast and ensuing regeneration may occur in this species, and in U. subcapillaris, where decumbent branches are in contact with the substrate, as for example in the holotype of this new species. The smooth, waxy surface is characteristic of the Usnea ciliata complex, along with the rupturing of main branches to form black-edged annulations. Such annulations are more widely dispersed than in U. acromelana, although rarely absent; they tend to accentuate the character- istic divergent branching of the thallus. Occasionally the effect of the laxness of the underlying medulla in conjunction with cortical fracturing may give rise to partially inflated segments. The primary branches are usually unpigmented, apart from the annulations, whilst the extent of pigmentation in secondary branches ranges from complete blackening to narrow bands of variegation. USNEA SUBGENUS NEUROPOGON 91 , a vas Fig. 27 Holotype of Usnea pseudocapillaris F. J. Walker (CHR). Top. Whole collection x1. Bottom. Detail of branching and soralia x10. The soralia are usually minute and indistinct and only occasionally become convex, globose, confluent or pigmented in more robust specimens. The presence of soralia may account for the shorter and stouter nature of the secondary branches in this species when compared with Usnea subcapillaris. Apothecia are extremely rare and only immature examples are known on two thalli which form part of the type collection. Species concept: Usnea pseudocapillaris belongs to the U. ciliata complex and may be regarded as the sorediate counterpart to U. subcapillaris. Plants are generally smaller and slightly more erect than U. subcapillaris and have shorter, less trailing, secondary branches. Unlike U. ciliata 92 F. J. WALKER and U. subcapillaris the delimitation between this species and U. acromelana may not always be so easily discerned, since occasional thalli exhibit intermediate characteristics. However, this is a rare occurrence and, despite the seemingly close relationship, the persistence of a distinct, divergent branching pattern, capillaceous secondary branches, and a much more flaccid, fragile nature are here considered to merit specific rank. It is generally possible to separate coarser specimens of U. pseudocapillaris from the finer forms of U. acromelana using a combination of some of the characteristic features of the former, even though a single thallus may not exhibit all these features. Short, divergent primary branches are typical of U. pseudocapillaris; more richly branched forms of U. acromelana tend to be more compact with less divergent branches which lack segmentation, and have more numerous, closely arranged annulations. Usnea pseudocapillaris may easily be distinguished from typical forms of U. acromelana which are sparingly branched, erect, and arise from a proliferating holdfast, and from U. antarctica and U. sphacelata by differences in habit, branching, ornamentation, and medullary chemistry. Specimens examined NEW ZEALAND. South Island. Nelson: Kakapo Peak, c. 1520 m, 16 December 1982, J. K. Bartlett 25814 (herb. Bartlett, BM); Tasman Mountains, Douglas Range, c. 1400 m, 17 December 1983, J. K. Bartlett 36109d p.p. (herb. Bartlett, BM). Otago: Park Pass, 1200 m, 19 February 1968, D. J. Galloway s.n. (CHR 343384 p.p.), 1430 m, May 1968, D. J. Galloway s.n. (CHR 343380 p.p.); Humboldt Mountains, Mt. Amphion, above Park Pass, 1830 m, February 1971, D. J. Galloway s.n. (BM, CHR 343485); Humboldt Mountains, Mt. Nox (type locality); Sugar Loaf Saddle, 1070 m, May 1966, D. J. Galloway s.n. (CHR 343446 p.p.; BM, CHR 343413 p.p.). 1280 m, February 1968, D. J. Galloway s.n. (CHR 343408 p.p.); Forbes Mountains, western slopes, 1680 m, 2 December 1967, A. F. Mark s.n. (CHR 343462); Earnslaw Burn Valley, 1220 m, January 1968, D. J. Galloway s.n. (CHR 343362 p.p.); Wilkin Valley, Mt. Jumbo, 1830 m, January 1969, A. F. Mark s.n. (CHR 343385); Young Range, 1430 m, March 1968, D. J. Galloway s.n. (CHR 343436 p.p., CHR 343447 p.p.), 1520, March 1968, R. J. Nilsson s.n. (CHR 343396 p.p.); unnamed Virgin, N. of Pope’s Nose, 2350 m, 11 February 1969, L. D. Kennedy s.n. (CHR 343366 p.p.); Mt. Roy, above Wanaka, 1 November 1972, G. C. Bratt 72/1506 (HO 35175 p.p.). Uncertain determination Otago: Mt. Ward, summit, 2590 m, January 1961, R. G. Cunninghame Murray 5629 (OTA). 11. Usneasphacelata R. Br. Figs 28-29 Chloris melvilliana: 49 (1823 [‘1821’]). — Usnea melaxantha var. sphacelata (R. Br.) J. D. Hook., Bot. Ant. Voyage ‘Erebus & Terror’ 1: Flora Antarctica 2: 520 (1847). — Usnea sulphurea var. sphacelata (R. Br.) Vainio, Ré. Voy. S. Y. Belgica, 1897-99, Botan., Lichens: 11 (1903). Type: Melville I., Mr James Ross 114 (BM! - holotype; BM! — isotypes). [TLC: no medullary substances, usnic acid.] (see Note 1) Lichen sulphureus J. Konig in Olafsen & Povelsen, Reise igien. Island Appendix: 16 (1772), non Lichen suphureus Retz. (1769) [Article 64.1]. — Usnea sulphurea Th. Fr. in K. svenska VetenskAcad. Hand. 7(2): 9 (1867) [Article 72, note 1]. — Neuropogon melaxanthus f. sulphurea (Th. Fr.) Hue in Nouv. Archs Mus. Hist. nat. Paris Ser. 3. 2: 272 (1890). — Neuropogon sulphureus (Th. Fr.) Hellbom in Bih. K. svenska VetenskAkad. Hand. 21 (3/13): 21 (1896). Type: Iceland (not extant). (see Note 2) Lichen pallidus Retz., Fl. Scandin. Prodrom.: 234 (1779), non Lichen pallidus Schreber (1771). [Article 64.1]. Type: Lichen sulphureus J. Konig. (see Note 2) Usnea frigida Dodge & G. Baker in Ann. Mo. bot. Gdn 25: 603 (1938). Type: Marie Byrd Land, Edsel Ford Range, Mt. Rea-Cooper, P. Siple, F. A. Wade, S. Corey & O. D. Stancliff R1 (Herb. Dodge — holotype, not seen). Neuropogon acromelanus var. inactivus f. picatus Lamb in J. Linn. Soc. (Bot.) 52: 220 (1939). — Usnea picata (Lamb) Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. 7: 205 (1948). Type: [South Victoria Land] Cape Adare or Sastrugi, Br. Antarct. ‘Terra Nova’ Exped. 1910 (BM! — holotype). [TLC: no medullary substances, usnic acid. } Neuropogon acromelanus var. inactivus f. scabridulus Lamb in J. Linn. Soc. (Bot.) 52: 220 (1939). — Usnea scabridula (Lamb) Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B 7: 204 (1948). Type: Antarctica [unlocalised], Campbell D. Mackellar (BM! — holotype). [TLC: no medullary substances, usnic acid.] Neuropogon ciliatus var. subpolaris Lamb in J. Linn. Soc. (Bot.) 52: 217 (1939). — Usnea subpolaris (Lamb) Dodge, Lich. Fl. Antarctic Cont. 237 (1973). Type: South Victoria Land, Cape Sastrugi, Evans Cove, Br. Antarct. ‘Terra Nova’ Exped. 1910 (BM! — holotype). [TLC: no medullary substances, usnic acid. ] Usnea laxissima Dodge in Rep. B.A.N.Z. Antarctic Res. Exp. B, 7: 198 (1948). — Neuropogon antarcticus USNEA SUBGENUS NEUROPOGON 93 var. laxissima (Dodge) J. Murray in Trans. R. Soc. N.Z. (Bot.) 2: 71 (1963). Type: Queen Mary Land, Possession Nunatak, 15 December 1912, C. T. Harrisson, AAE 84 (herb. Dodge — holotype, not seen; ssi ma — isotype, CHR! — isotype). [TLC: no medullary substances, usnic acid (isotype).] (see ote Neuropogon lambii Imshaugh in Rhodora 56: 154 (1954). Type: U.S.A., Washington, Mt. Rainier National Park, Yakima Park, 1830 m, 19 August 1942, P. F. Scholander (FH! — holotype). [TLC: no medullary substances, + UV+ unknowns, usnic acid. | ?Usnea striata Zammuto in Dodge in Trans. Am. micros. Soc. 84: 522 (1965). Type: Edward VII Peninsula, Rockefeller Mountains, Mt. Breckinridge, 78°03’S: 155°28'W, R. G. Frazier & F. A. Wade 315 (herb. Dodge — holotype, not seen). (see Note 4) Note 1: Usnea sphacelata R. Br. Type material is present in the BM. Material incorporated into collections bearing the species number and Brown’s handwriting is recognised as holotype material (Fig. 28). This conforms with current research into Brown’s bryophyte collections in BM (Harrington & Ellis, unpublished). Several isotypes are known, including boxed material of lichens and phanerogams forming ‘Flora Antarctica’ of Captain Parry’s First Voyage. The name Usnea sphacelata was originally published by Brown (1823) in Chloris Melvilliana which was a preprint of his account in the Appendix to Capt Parry’s Voyage (Brown, 1824) with independent pagination (Stafleu & Cowan, 1976); the 1824 reference has always been cited by previous authors (Zahlbruckner, 1930; Motyka, 1936; Lamb, 1939a). Note 2: Lichen sulphureus J. Konig. This name is a later homonym of Lichen sulphureus Retz. (Retzius, 1769) and is consequently invalid (Article 64.1). Retzius (1779) gave the taxon a new name, Lichen pallidus, but this is also invalid, being a later homonym of Lichen pallidus Schreber. The correct name for this taxon is consequently Usnea sphacelata R. Br. Note 3: Usnea laxissima Dodge Isotype material (Fig. 29) represents a weathered, decumbent form of U. sphacelata. Murray (1963) wrongly regarded this taxon to be a variety of U. antarctica, although a record from Macquarie Island (Filson, 1981) is probably referable to that species. Note 4: Usnea striata Zammuto This taxon is only known from the type collection from Edward VII Peninsula (Dodge, 1973) which has not been made available for study. The original description indicates that the taxon is synonymous with U. sphacelata. Description: Thallus 1-5-5 cm, arising from a + delimited or proliferating, rarely pigmented holdfast, erect, sparsely to richly branched above with capillaceous, attenuate branches. Fibrils usually absent. Branches terete, yellow-green, conspicuously variegated above with bands of black pigment or + continuously pigmented violaceous black towards the apices. Cortex variable in thickness. Surface subnitid or matt, smooth to faveolate, rarely inflated, + scabrid with minute, often pigmented papillae (x10 lens). Medulla lax or rarely sublax, axis thin, occupying 0-2-0-4 of the branch diameter. Soralia numerous, + confined to ultimate branches, plane, emarginate, becoming convex-pulvinate to globose on maturity. Soredia granular, frequently partially corticate then pigmented. Pseudoisidia rare, isidia absent. Apothecia and pycnidia not seen. TLC: (1) psoromic acid, + 2’-O-demethylpsoromic acid, usnic acid; (2) no medullary substances, + 2-3 UV+ unknowns, usnic acid. Distinguishing features: Usnea sphacelata is characterised by its erect, usually richly branched habit, a subnitid to subpapillate surface with prominent bands of pigment, a lax medulla, usually lacking depsidones, a thin axis, and plane to nodular, often pigmented, soralia more or less confined to secondary branches. Distribution: Usnea sphacelata is the only known bipolar species of the subgenus. In the arctic its distribution is almost circumpolar including the New Siberian Islands in the east to Melville Island in the west. The species is known from Greenland, Iceland, Svalbard, Franz Joseph Land, Novaya Zemlya, Jan Mayen, and a few islands of arctic Canada, with its main distribution in the Canadian eastern arctic; it is rare in western arctic Canada. Its distribution has been adequately mapped by Lynge (1941) and Thompson (1972) and there are few recent additions. Figs 5 & 7. 94 F. J. WALKER aia | HOLO Type thas iit ' Ml, all [mr ae, : uf iis : ia oi iacecme i Fig. 28 Holotype of Usnea sphacelata R. Br. (BM) X1. Inset. Detail of soralia x10. In Greenland Usnea sphacelata has a northerly distribution, although it is absent from the north coast. The species is frequent north of latitude c. 75°N on the east coast, rarely extending to latitude 68—70°N, and on the west coast as far south as Disko (Lynge, 1941; Lamb, 1939b). The species has only recently been discovered in southern Greenland (E. Hansen, 1982) at Nakalaq (C!) slightly south of the area investigated by K. Hansen (1971) who failed to find the species. In the arctic Usnea sphacelata is characteristically, but not obligately, an alpine species USNEA SUBGENUS NEUROPOGON 95 occurring, for example in Greenland, on the upper levels of rock falls and precipices (Lynge, 1932) and only occasionally at lower altitudes (K. Hansen, 1962). Towards the southern range of distribution in the arctic the species is confined to higher altitudes, and rarely occurs below 500-600 m in Iceland (Lynge, 1941) and western Svalbard (Lynge, 1941; Weber, Lich. Exs. 591); in the northern part of its range it occurs down to sea-level, for example in Franz Josef Land. The species is very rare in the U.S.A., being only known from the type locality of Usnea lambii in Washington State and an additional record nearby (W. Weber, 1973). A single gathering from c. 4400 m in Mexico (Mt. Orizaba, Metzger, FH!, UPS!) forms a link between the North American distribution and that of the northern Andes. In South America, Usnea sphacelata occurs in Ecuador at very high altitudes, and is very rare in Venezuela and Peru as far south as latitude c. 15°S. South of this latitude, apart from isolated, mainly high-alpine, subantarctic localities in New Zealand and Patagonia, there appears to be a significant gap in the distribution before the circumpolar antarctic populations are encountered. Many previous records from South America (as U. sulphurea) are erroneous and are referable to U. patagonica, U. durietzii, and U. subantarctica. The species is absent, and is replaced by Usnea antarctica, from the Falkland Islands, South Orkney, and South Shetland Islands, as well as the South Sandwich Islands. On the antarctic continent U. sphacelata is circumpolar and is more frequent than U. antarctica, although occasionally misidentified as that species (for example, Follmann Lich. Exs. 399, BM!). As in the arctic it is frequently a species of high altitude, exposed locations, although also occurring at lower altitudes (see Bowra et al, 1966; Kashiwadani, 1970; Lindsay, 1972; @vstedal, 1983). On the Antarctic peninsula the species occurs at a range of altitudes (Lamb, 1964) on the west coast, mainly south of the Antarctic Circle, and throughout the east coast, although it is often replaced at lower altitudes by U. subantarctica in the north-east and south-west. Chemistry: Race 1, containing psoromic acid, is extremely rare and is only known froma single collection from the Andes in Peru tentatively assigned to this species. All other specimens examined were found to be depsidone-deficient; occasionally containing traces of UV+ unknowns. Specimens from Patagonia and the Antarctic peninsula containing norstictic and/or salazinic acids, previously referred to this species (Lamb, 1948a, 1964), belong to Usnea subantarctica, and, from the northern Andes, to U. durietzii. Variation: Arctic populations of Usnea sphacelata are much more uniform than those from the southern hemisphere and are characterised, as found in the type specimen, by a richly branched, strikingly variegated thallus, with pigmented, nodular soralia. The thallus may arise from a delimited holdfast, although this is more frequently proliferating and spreading. Branching is more or less dichotomous and regular with the production of extended, variegated laterals which in turn may give rise to capillaceous, extensively pigmented, ultimate branches. The thallus may be smooth to subfaveolate and is usually subnitid to waxy or rarely matt; it lacks pigmented annulations. Small, often pigmented, papillae are usually present; only rarely in a few arctic specimens are the main branches waxy, epapillate and unpigmented, as, for example, the type of Usnea lambii; the medulla is usually lax and arachnoid in main branches, but in some instances may not be fully expanded and then the axis occupies a greater proportion of the branch diameter. Soralia are characteristically large, pulvinate, emarginate, sometimes geniculate; they tend to occur at intervals towards the apices of secondary branches, and are often broader than the subtending branch. Soredia often become partially corticate and pigmented but do not produce distinct pseudoisidia; they only lack black pigment when poorly developed as small punctiform soralia, or if the thallus is weathered or moribund. In the northern Andes variation within populations is more diverse but is difficult to assess since the species appears to be rare. The 20 specimens examined are often extensively pigmented or lack several distinctive features of the species. Some thalli reflect the variation found in arctic populations. Others differ in having a delimited holdfast, are richly branches with extended laterals bearing minute, unpigmented, eroded soralia on a subnitid, subfaveolate to 96 F. J. WALKER subpapillate thallus. Other variants resemble Usnea acromelana and are virtually monopodial, arise from a proliferating holdfast, and are infrequently branched with large, pale, excavate soralia; however, they may be distinguished by a lax or sublax medulla and absence of annulations. Rarely the medulla may become markedly inflated or small pseudoisidia are produced, thus superficially resembling U. durietzii. Occasionally thalli, tentatively referred to this species, are found in collections of U. durietzii; these are extensively pigmented and papillate, and have plane soralia and a compact medulla (for example, Arvidsson & Nilson 945 p.p., GB!). Material conforming to arctic populations is still present, but less frequent, in the antarctic regions and appears to be confined to lower altitudes where it is often replaced by Usnea subantarctica in areas where their distributions overlap. In such instances the two species may be separated by the way in which secondary branches are produced and sometimes by their medullary chemistry. Material described as fertile U. sulphurea (Lindsay, 1969) is referable to U. subantarctica (p. 102). Thalli of Usnea sphacelata from Antarctica, particularly from high altitudes, are erect or rarely subdecumbent and are often more or less monopodial arising from a proliferating holdfast, occasionally branching extensively towards the apices. Rarely in subdecumbent thalli, are the secondary branches extensive, divergent and capillaceous with flexuose apices; produc- ing a fragile, interwoven network which resembles, but is not as extensive as, that of Usnea subcapillaris and U. pseudocapillaris (for example, Dronning Maud Land, H. U. Sverdrupfijella, Angard, TROM!). Pigmentation is confined to apices and tends to be continuous rather than variegated and is violaceous black. The cortex is often thicker and the surface subnitid, sometimes epapillate, rarely faveolate and fracturing, whilst the medulla may only be sublax. Consequently such thalli have sometimes been mistaken for species of the U. ciliata complex (Lamb, 1939a, 1948a; Dodge, 1973; Murray, 1963) and described as distinct taxa; Neuropogon ciliatus var. subpolaris is a sparsely sorediate, decumbent form of U. sphacelata whilst in N. acromelanus var. inactivus f. picatus and f. scabridulus the medulla is only lax towards the axis and weathering of the thallus has given rise to development of untypical annulations. Specimens from New Zealand and Patagonia resemble those antarctic populations that bear a superficial resemblance to Usnea acromelana. In these the medulla may only be slightly lax, the surface epapillate, and the soralia small, plane and unpigmented. In New Zealand the two species may easily be distinguished by differences in medullary chemistry, whilst in Patagonia and the Antarctic peninsula more critical examination of morphological features is required. Species concept: Although the range of variation of antarctic populations of Usnea sphacelata is much greater than that in the arctic, I do not consider this sufficient for the recognition of separate taxa. In addition thalli resembling the type from the arctic are also present in Antarctica, as well as a range of intermediate forms. The only distinction that has been made here is the recognition of a new species, U. subantarctica (p. 99), which is characterised by a more open branched habit with dispersed fibrils, often forming tassel-like apices; in contrast U. sphacelata has fewer, broader, extended laterals, usually lacking fibrils, and lacking a norstictic acid-containing race. Dodge & Baker (1938) only recognised Usnea sphacelata from Patagonia northwards, whilst Dodge later (1973) referred to this as solely an arctic species, describing most continental antarctic material as a distinct species, U. frigida, in addition to his other taxa that are here also regarded as synonyms. From the original description and illustrations (Dodge & Baker, 1948), and from Lamb’s subsequent report (Lamb, 1964) on a prepared slide of the holotype of U. frigida and his examination of material from the type locality ex MO, (Lamb, unpublished notes, AAS!) it is clear that this taxon is a synonym of U. sphacelata. In addition specimens examined from a nearby locality (KASSEL 24772, ex herb. Dodge!) and material distributed by OS as U. frigida (BM!, CANL!, KASSEL!) though depauperate, are also clearly referable to this species. Some thalli of Usnea sphacelata bear a superficial resemblance to those of Usnea acromelana, particularly from New Zealand and Patagonia. This might suggest either a parallel evolution of characters from a common ancéstry or, remotely, some indication of hybridisation between the USNEA SUBGENUS NEUROPOGON Fig. 29 Usneasphacelata. Variation in southern hemisphere populations. Top. New Zealand, Otago, Mt. Aspiring, Kennedy (CHR 343354) X1. Bottom. Isotype of Usnea laxissima Dodge (MEL 1012296) x1-5. two species. However, on evidence, it is more likely that U. sphacelata has closest affinities with U. perpusilla. Features common to U. sphacelata and U. perpusilla include a diverse range of habit and similar branching, pigmentation, surface ornamentation, variation in medulla width, and lack of chemistry. 98 F. J. WALKER ‘ Occasionally thalli are encountered that are somewhat intermediate between Usnea sphacela- ta and U. antarctica (see synonymy in both species), but these similarities are superficial and are most likely to occur in immature specimens. Close examination reveals the characteristic anatomical, surface, and soralia features of the two species. The soralia of U. sphacelata tend to be more globose than in U. antarctica and lack the distinctive crateriform margin, and are less widely distributed throughout the thallus. The species may be distinguished from U. subantarc- tica by differences in branching and papillation; from U. acromelana by a laxer arachnoid medulla and lack of pigmented annulations; from U. durietzii and U. patagonica by the absence of pseudoisidia; from U. acanthella by the absence of true isidia. Selected specimens examined Race 1 PERU. Puno: San Antonio de Esquilache [16°08’S: 70°22'W], 4750 m, 20 May 1937, D. Stafford 762 (BM, FH). Race 2 JAN MAYEN. [71°00'N: 9°00’ W], Eskkrateret, 22 July 1930, J. Lids.n. (BM). ICELAND. SyO6ri Bjargholl [c. 65°40’N: 16°45'W], 8 km NE. of Reykjahlid, Sudur Pingeyjarsysla, c. 550 m, 11 August 1982, C. D. & D. H. Dalby s.n. (BM); Nordur-Mialasysla, Austurfjallgardur, Médrudal- sOrafi [65°20'N: 15°42’W], 680 m, 10 July 1979, H. Hertel 21586 (M); Ytri Baegisé, Akureyki [65°41’N: 18°04'W], 610 m, August 1963, B. A. Rowland L17 (BM); Tungnafjellsjékull [64°45’N: 17°55’W], 1300 m, 8 August 1967, H. Kristinsson 23095 Vézda: Lich. Sel. Exs. 886 (BM); Kjallfell, 26 July 1895, Stefansson s.n.(C). GREENLAND. Disko I.: Lyngmarksfjeldt [69°16’N: 53°35’ W], 200 m, 16 July 1974, P. Mellergard & E. S. Hansen s.n. Lich. Groen. Exs. C 102 (BM, C, M), head of Nordfjord [67°57'N: 54°19’W], 26 June 1952, P. Gelting Lich. Groen. Exs. C 152 (BM, C, M); Svartenhuk, Simiutaq [71°53’N: 52°25’W], 1200 m, August 1949, N. Berg s.n. (C); Angmagssalik district, S. of Pourquoi-Pass glacier [66°39’N: 35°40’ W], 1500 m, 8 August 1966, M. Zumbiihl s.n. (C); Nakalaq [60°59'N: 45°55’W], 1400 m, 20 August 1975, D. Olsen L-1405 (C). CANADA. North West Territories: Ellesmere Land, North Kent I. [76°30’N: 90°00’W], 13 July 1901, Simmons s.n. (BM); Franklin district, Bathurst I., E. side of May Inlet, N. of Purcell Bay [76°23’N: 100°47’W], c. 25 m, 9 July 1963, Weston Blake 19a (C, UPS); Parry Is., Melville I [c. 75°N: 112°W] (type locality U. sphacelata) J. Ross s.n. (BM). NOVAYA ZEMLYA [74°40’S; c. 55°E]. see Lynge (1941). NEW SIBERIAN IS. [c. 76°N: 140°E]. see Lynge (1941). FRANZ JOSEF LAND. Hooker I. [81°S: 53°E], Ssedov ‘promitory’, 1930, V. P. Savicz Savicz: Lich. Rossica (5) 43 (M), [Northbrook I.] Cape Flora, 1901, Palibin s.n. Elenkin: Lich. Flor. Rossiae 113a (BM, FH, US). SVALBARD. Spitzbergen: Isfjord area, near Longyearbyen [78°12'N: 15°40’E], Mt. Nordenskjold, 100 m, 3 August 1975, H. Hertel & H. Ullrich s.n. Lich. Exs. COLO 591 (BM, C, M); Svalhardhytta, c. 200 m, A. Hoeg & J. Lid s.n. Krypt. Exs. Vindobon. 3070 (BM, C, M, WU 2886); Wahlenbergsbay (Hinlopen Strait), 1861, A. J. Malmgrens.n. Fries. Lich. Scand. Exs. 51 (BM, M); Brandewijnsbay, 150m, O. Torrell s.n. Zahlbr.-Redinger, Lich. Rar. Exs. 384 (BM, WU3085). UNITED STATES. Washington: (type locality of Neuropogon lambii). MEXICO. Veracruz: SE. of Mt. Orizaba [18°51'N: 97°08’ W], Citlaltepetl, 4330-4540 m, 17 August 1966, U. V. Metzgers.n. (FH, UPS). VENEZUELA. Merida: paramo de Campanario, 4000 m, 19 September 1938, J. Hanbury-Tracy 168 (BM). Barinas: Pico de las Piedras Blancas, 4762 m, 25 May 1952, V. Vareschi 1259 p.p. (US). COLUMBIA. Caldas: Nevado del Ruiz, NW. side, c. 1500 m, 3 February 1979, H. Sipman & H. Valencia 10423 (BM, UV). ECUADOR. Pichincha: Quito, Pinchincha, crater margin, 30 June 1939, E. Asplund s.n. Lich. austroam. ex herb. Regnelliano 360 (BM, C, H, LD); E. slopes Cerro Iliniza, c. 4400 m, 7 March 1972, L. Arvidsson & D. Nilson 945 p.p. (GB); summit of Coraz6n, 4861 m, E. Whymper 1323 (10) (BM). Napo: Antisana, 4900 m, E. Whymper 1329 (2) (BM). Bolivar: W. side of Chimborazo, 4780 m, 1967, Cambridge Lichen Exped. s.n. (BM). Chimborazo: NW. face of Chimborazo, 3700-4300 m, January 1859, Wagner s.n. (M). ARGENTINA. Santa Cruz: Patagonia, Lago Viedma, Volcan nunatak, c. 13 km from nearest land in Hielo Continental, January 1959, G. Bratt s.n. (BM). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°18’S: 57°56’W], N. end of Active Sound, 200 m, 27 March 1981, R. I. L. Smith 3736 p.p. (AAS), Crown Prince Gustav Channel, Alectoria I. [63°59’S: USNEA SUBGENUS NEUROPOGON 99 58°37' W], 30-60 m, 18 August 1945, J. M. Lamb Operation Tabarin 2465 (BM), Nordenskjold coast [c. 64°30’S: 59°00’ W], nunatak 6-4 km NW. of head of Larsen Inlet, c. 910 m, 23 September 1960, C. G. Brading 105a (AAS), Oscar II coast, N. side of Churchill Peninsula [c. 66°30'S: 62°50’W], 460 m, November 1963, R. Tindall 18 (AAS), Foyn coast, Cape Robinson [c. 67°S: 64°W], E. of Mt. Hayes, 6 October 1964, G. Stubbs B.A.S. Misc. 6 (AAS), Falliéres coast, Adelaide I. [c. 67°15’S: 68°30’ W], ‘Reptile Ridge’, Yellow Bluff, 350 m, 9 March 1981, R. J. L. Smith 3453 p.p. (AAS). Palmer Land: Wilkins coast [69°20'S: 63°41’W], 1070 m, 23 October 1965, M. J. Cousins 22 (AAS), Alexander I., Ablation Valley [70°48’S: 68°30’ W], c. 5m, January 1979, D. England 2692 (AAS), Alexander I., Two-Step Cliffs [71°51'S: 68°17'W], c. 600 m, 4 February 1979, D. England 2688 (AAS), Black coast, Cape Bryant area [72°19’S: 60°40’ W], 45 m, 23 January 1948, K. S. P. Butler & B. Stonehouse F.1.D.S. E1228 (BM), George VI Sound, Eklund Is. [73°20’S: 72°00’ W], 20 November 1949, V. E. Fuchs et al. F.I1.D.S. E604 (BM, FH). DRONNING MAUD LAND. [c. 15°W]. H. U. Sverdrupfijella, Jutulrgra [c. 20°W], 1500 m, 11 December AG J. Angard s.n. (BG), Vestfjella [c. 13-16°W], Miiren, 21 January 1977, L. Somme 204(102) (BG, BM). ELLSWORTH LAND. [c. 72-74°W]. Johnson nunatak, survey point, 7 January 1962, J. T. R. Molholm 6 (BM, CANL 21331, KASSEL 26669), Barnes nunatak, c. 1560 m, 9 January 1962, J. T. R. Molholm 10 (AAS). MARIE BYRD LAND. Edsel Ford mountains [c. 145°W], peak 1207, 9 December 1940, H. P. Gilmour U.S.A.S. 234 (US) (type locality of Usnea frigida Dodge & G. Baker), Mt. Grace McKinley [c. 148°W], 1934, Second Byrd Exped. (KASSEL 24772). EDWARD VII LAND. [c. 150°W]. Rockefeller Mountains, Mt. Paterson, 18 December 1940, R. G. Fitzsimmons U.S.A.S. 278 (US), Mt. Breckenridge, 14 December 1940, R. G. Frazier & F. A. Wade U.S.A.S. 312 (US). VICTORIA LAND. [c. 165°E]. Yule Bay, Birthday Ridge, 17 December 1981, L. Kappen 3001 (KIEL), Follmann: Lich. Exs. 399 (BM), Hallett Peninsula, 10 January 1963, J. Cranfield 7 (BM). KNOX COAST. (c. 110°E). Bailey Peninsula, near Casey Station transmitter building, 35 m, 13 December 1982, R. D. Seppelt 13103 (herb. Seppelt). QUEEN MARY LAND [c. 98°E]. Hippo nunatak, 29 December 1912, C. T. Harrissons.n. A.A.E. 71-2 (AD), A.A.E. 71-3 (AD). MAC.ROBERTSON LAND. [c. 70°E]. Falla Bluff, 9 February 1974, R. Filson 14910 Lich. Ant. Exs. 22 (AAS, BM, M, O). ENDERBY LAND. [c. 50°E]. 3 March 1961, E. Korotkevish 70 (AAS), 1961, G. Konovalov 72 (FH). PRINCE OLAV COAST. [c. 44°E]. Molodyozhnaya, c. 40 m, 8 February 1968, H. KashiwadaniJ.A.R.E. 4118 (FH, H). SOYA COAST. [c. 39°E]. c. 20 m, 12 January 1968, H. Kashiwadani J.A.R.E. 3823 (H), J.A.R.E. 3773 (H). NEW ZEALAND. Nelson: Cobb Valley, c. 1490 m, 18 December 1982, J. K. Bartlett 25810 (herb. Bartlett, BM). Otago: Mt. Aspiring, NE. to Coxcomb Ridge, 2790-2850 m, 13 February 1969, L. D. Kennedy s.n. (CHR 343354), 2290 m, January 1957, B. J. Wilkins s.n. Murray 1040 (OTA), NW. Ridge, 2590 m, 27 January 1969, D. J. Galloway s.n. (CHR 342745); Pope’s Nose, NE. Ridge, 2650 m, 8 February 1969, L. D. Kennedy s.n. (CHR 343319); Mt. Sir William, 2560 m, 27 December 1970, D. J. Galloway s.n. p.p. (CHR 342781 p.p.); Matukituki Valley, Mt. Avalanche, 2560-2590 m, 15 February 1969, L. D. Kennedy s.n. p.p. (CHR 343358 p.p.). The following may be consulted for further localities: arctic regions (Lynge, 1941; Thomson, 1972), Antarctic peninsula (Lamb, 1964) (excluding specimens here referred to Usnea subantarctica), continental Antarctica (Bowra et al., 1966; Dodge, 1973; Kashiwadani, 1970; Lindsay, 1972; Ovestedal, 1978); lists held in BM and collections in AAS and BM. 12. Usnea subantarctica F. J. Walker, sp. nov. Figs 30-31 Diagnosis: Thallus fruticosus, pigmento nigro in cortice ad apices basimque conspicue coloratus. Rami irregulares teretes fibrillosi, papillis numerosis nigriscentibus. Medulla laxa vel sublaxa. Soralia convexa vel nodulosa nigrescentia. Apothecia rara disco rufescenti, apotheciis Usneae trachycarpae similia. Acidum usnicum et acidum norstictum continens. Typus: Antarctic peninsula: Western shore of bay east of old base, on west, coast of Horseshoe I., Marguerite Bay, Falliéres Coast, 7-5 m, 23 February 1965, R. E. Longton 1275 (AAS! — holotype; BM! — isotype). [TLC: norstictic acid, + UV+ unknowns, usnic acid.] Description: Thallus 1-5-3-5 cm, arising from a proliferating, rarely pigmented, holdfast, erect or rarely subdecumbent, moderately branched above with short, + divergent, flexuose, 100 F. J. WALKER attenuate secondary branches. Fibrils + extensive, irregularly dispersed, to give an open, spinulose to tassel-like habit. Branches terete, yellow-green, + continuously black pigmented towards the apices or variegated with bands of pigment. Cortex thin. Surface matt, conspicuous- ly scabrid with small, pigmented papillae. Medulla lax or sublax, axis thin, occupying 0-3-0-5 of the branch diameter. Soralia numerous, + confined to ultimate branches, plane becoming convex to pulvinate or nodular, rarely marginate. Soredia granular, often partially corticate then pigmented. Pseudoisidia rare, isidia absent. Apothecia rare, as in U. trachycarpa. Pycnidia not seen. TLC: (1) norstictic acid, salazinic acid, usnic, acid; (2) no medullary substances, usnic acid. Distinguishing features: Usnea subantarctica is characterised by its erect, spreading, richly branched, irregular habit, a matt, papillate, a more or less extensively pigmented surface, a lax or sublax medulla, often containing norstictic and/or salazinic acids, and nodular, often pigmented, soralia more or less confined to secondary branches. Distribution: Usnea subantarctica has a distribution similar to that of U. aurantiaco-atra, although it is largely restricted to the Antarctic peninsula; it is rare in southern South America. The species is absent from continental Antarctica and the islands of the Scotia Arc, but may eventually be found elsewhere in the subantarctic regions. On the Antarctic peninsula the distribution is similar to that of Usnea sphacelata, being more frequent on the north-east coast and at lower latitudes on the west coast. The species has been found in association with U. aurantiaco-atra, U. acromelana, and U. antarctica (R. I. L. Smith 3680, AAS!) and also with U. antarctica and U. sphacelata (R. I. L. Smith 3736, AAS!). In this area the species is usually confined to lower altitudes, frequently replacing U. sphacelata, and is rarely found above c. 500 m where U. sphacelata predominates. Its ecological requirements appear to be somewhat intermediate between those of U. antarctica and U. sphacelata. The majority of specimens on which Lamb (1964) based his distribution map of depsidone- containing material of U. sphacelata (as U. sulphurea) have been examined and are referable to this species as well as some depsidone-deficient material. Usnea subantarctica is less frequent in Patagonia, often being replaced by other asexual species, including U. patagonica, and is there confined to higher altitudes in the alpine region of the Andes, mainly between 1000-2000 m, where it has been collected with U. antarctica and U. trachycarpa. Fig. 5. Chemistry: Two chemical races have been detected in Usnea subantarctica. The dominant race contains norstictic acid (Race 1) with occasional traces of salazinic or connorstictic acids or rarely just salazinic acid, whilst the other (Race 2) is depsidone-deficient. UV+ unknowns may occur, but are rare and only present in low concentrations. Similarly traces of unidentified fatty acids have also been detected, but these are not a constant feature as in U. trachycarpa or U. patagonica and hence do not have taxonomic significance. Both races have similar distributions and are of approximately the same frequency; however, the presence of norstictic acid does appear to be of salient importance in circumscribing the species. Variation: Usnea subantarctica is usually characterised by an irregular habit that is reminiscent of an ‘untidy’ specimen of U. sphacelata, but usually has more fibrils, especially towards the apices giving a tassel-like appearance. Indeed, immature, small thalli of the two species, particularly from the Antarctic peninsula, may be indistinguishable on morphological charac- ters, although chemical and ecological data may assist in identification. Thalli may be sparingly branched, with extensive, small, blackened papillae, or may be richly branched and possess fibrils. Secondary branches are produced irregularly along the main axis, giving an open, spreading, divergent, habit; only infrequently may main branches remain in a close cluster or are richly branched from the base, as found in some forms of Usnea sphacelata. Rarely thalli may resemble northern hemisphere forms of U. sphacelata but are usually more irregularly branched with fibrils. Variation in surface ornamentation and branch anatomy is similar to that of Usnea trachycar- pa, and much of the discussion of that species is referable here (p. 113). However, some differences do occur: pigmentation is often more extensive, occasionally resulting in prominent USNEA SUBGENUS NEUROPOGON 101 Fig. 30° Holotype of Usnea subantarctica F. J. Walker (AAS). Top. Whole thallus x1. Bottom. Detail of apothecium and soralia x10. variegation, even of the fibrils; papillae on primary branches may less frequently give rise to fibrils; the surface is rarely faveolate or subnitid, although may occasionally fracture due to collapse of the underlying lax medulla. Soralia are more or less confined to branch apices or secondary branches and are usually convex to globose, often pigmented, well spaced and wider than the subtending branch, and are similar to some forms of Usnea sphacelata, particularly from the arctic. Soralia production tends to foreshorten the ultimate branches (cf. U. patagonica) often resulting in flexuose geniculation of the branch. Soralia appear to arise directly from the cortex, by localised breakdown, and are 102 F. J. WALKER not usually derived from papillae, although occasionally a surrounding margin, similar to that of U. patagonica or U. antarctica, is produced in instances where cortical papillae are particularly numerous and prominent. Apothecia are rare and are identical to those of Usnea trachycarpa. They are only known from the holotype where they are immature, and an additional collection (Fig. 31) in which they are well-developed (R. I. L. Smith 829, AAS!). The fruits of the latter specimen were described by Lindsay (1969) and ascribed to Usnea sulphurea. Fig. 31 Fertile thalli of Usnea subantarctica. Antarctic peninsula, Horseshoe I., Smith 829 (AAS) X1-5. Some specimens from Patagonia are more variable and, because of the range and variation of species found, may require more critical examination and are only tentatively included under this species. Others tend to have more conspicuous, stouter, spreading fibrils. Specimens tentatively referred to this species include one cited by Lamb (1948a), as Usnea sulphurea, from Sierra Alvear, Tierra del Fuego (Santesson 640e, S!), containing norstictic acid, and a depsi- done-deficient thallus from a nearby locality (Santesson 641c, S!) mixed with U. antarctica. These show some similarities to papillate forms of U. perpusilla, which might indicate affinities with U. sphacelata, since they have fewer fibrils and have less prominent papillae. Species concept: Although morphologically very similar to Usnea sphacelata, U. subantarctica is regarded as a distinct species, by virtue of differences in habit and branching, the presence of prominent fibrils and papillae, and apothecia that are identical to those of U. trachycarpa. Differences between the two species have been discussed above and also under U. sphacelata (p. 96). It might be argued that some specimens of U. subantarctica are very similar to some northern hemisphere forms of U. sphacelata. However, arctic forms of the latter species have extended laterals rather than short, undivided fibrils and lack the short, spreading, attenuate fibrils on primary branches. Despite the lack of fertile material it is tentatively proposed (p. 40) that Usnea sphacelata is the sorediate counterpart of U. perpusilla and consequently would be expected to have a black rather than rufous brown apothecial disc. Consequently it appears that U. subantarctica has a closer relationship to U. trachycarpa than to U. sphacelata—U. perpusilla. This supposition is enhanced by the presence of norstictic acid in a significant proportion (c. 60%) of the specimens. However, a number of depsidone deficient gatherings are only tentatively referred to this species. If there were excluded the incidence of Race 1 would be 70%. Although traces of fatty acids have been detected in U. subantarctica, it is not certain that these have affinities with the murolic acid complex of U. trachycarpa. For this reason there must remain some doubt as to USNEA SUBGENUS NEUROPOGON 103 whether these taxa represent a species pair. However, specimens are often very similar to high-alpine forms of U. trachycarpa, originally described as f. elatior by Lamb (1948a), from Patagonia which are extensively pigmented and have scattered, short, attenuate fibrils and frequently lack medullary substances and fatty acids. The absence of fatty acids might be the consequence of more exposed habitats and this would explain their absence from U. subantarc- tica, particularly in the Antarctic peninsula. It is evident from study of the synonymy of Usnea sphacelata that there is no existing name for the new species. Furthermore, existing names under U. sphacelata refer to material from continental Antarctica, outside the distributional range of U. subantarctica. The epithet ‘subantarctica’ is selected to refer to the distribution of the species, which although limited, does extend into the subantarctic area. It is likely that the species may eventually be found to be more widespread. A possible relationship to alpine forms of Usnea trachycarpa is also indicated, since that species also has a characteristic, albeit wider, distribu- tion in the subantarctic. The distribution may eventually be compared to that of generally accepted species pairs, for example U. ciliata-U. acromelana and U. aurantiaco-atra-U. antarctica, in which the asexual species extends further south than the fertile counterpart. Usnea subantarctica may be separated from other asexual species of Neuropogon by its untidy to tassel-like appearance and close resemblance to some forms of U. trachycarpa. The form of the soralium may resemble some variants of U. sphacelata and U. acromelana or may sometimes be marginate, although this is as non distinct as the plane, crateriform soralium of U. antarctica. The lack of distinct pseudoisidia separate the species from U. durietzii and U. patagonica whilst the lax medulla and the matt, surace with papillae and fibrils distinguish the species from U. acromelana. Specimens examined Race 1 CHILE. Aisén: Lago San Martin [49°S], 1600 m, 2 February 1933, A. Donat 3 p.p. (H). ARGENTINA. Santa Cruz: Peninsula Magallanes, near Puerto Bandera, c. 1000 m, December 1958, P. W. James 59 p.p. (BM); Rio Fosiles, c. 1000 m, April 1905, P. Dusén s.n. p.p. (H). ANTARCTIC PENINSULA. Graham Land: Joinville I. [63°18’S: 55°48’W], Mt. Alexander, 200-500 m, 27 March 1981, R. I. L. Smith 3680 p.p. (AAS); Trinity Peninsula, Duse Bay [63°48’S: 57°17'W], NE. of unnamed nunatak, [63°36’S: 57°01'W], 385 m, 27 March 1946, J. D. Andrew F.I.D.S. D109-6 p.p. (BM), Bald Head, 60-150 m, 18 November 1945, J. M. Lamb Operation Tabarin 2801 p.p. (BM), Duse Bay, [63°33’S: 57°22'W], 13 November 1945, G. Davies F.1.D.S. D2632 (BM, FH), Duse Bay, View Point [63°36'S: 57°01’W], c. 15 m, 10 November 1945, J. M. Lamb F.1.D.S. D2622 (BM), Crown Prince Gustav Channel, Beak I. [63°37’S: 57°20’ W], c. 9m, 28 December 1945, J. M. Lamb F.1.D.S. D2712 (BM), Egg I. [63°41'S: 57°42'W], 120 m, 11 November 1945, J. M. Lamb F.1.D.S. D2756 (+ Race 2) (BM), Pitt Point [c. 63°S: 58°W], c. 30 m, 17 August 1945, J. M. Lamb Operation Tabarin 2448 (BM), Operation Tabarin 2452 p.p. (BM), Operation Tabarin 2454 p.p. (BM), Operation Tabarin 2456 p.p. (BM), Church Point, [63°41'S: 57°54’W], 75 m, 10 December 1946, J. D. Andrew F.I.D.S. D114-2 (BM), F.I.D.S. D114-3 (BM), foot of East Russell Glacier, [63°44’S: 58°17'W], 550 m, 14 December 1946, A. Reece F.I.D.S. D369-8a (BM), ‘Mt. Fitzroy’ [63°48’S: 58°29’W], 240 m, 19 December 1946, A. Reece F.I.D.S. D37 (BM), Vega I. [63°50’S: 57°25’ W], False Island Point, 6-18 m, 5 December 1945, J. M. Lamb Operation Tabarin 2724 (BM), D2722 (BM), Tabarin I. [63°52’S: 57°00'W], 150 m, 6 January 1946, E. H. Back Operation Tabarin 2852 (BM); James Ross I. [63°47’S: 57°47'W], Cape Lachman, c. 30 m, 21 November 1945, /. M. Lamb F.1.D.S. D2677 (BM p.p., CANL 17256), F.I.D.S. D2778 (BM), James Ross I., the Naze, 6-22-5 m, 26 November 1945, J. M. Lamb Operation Tabarin 2789 p.p. (+ Race 2) (BM); Palmer Archipelago, Wiencke I. [64°49’S: 63°22’W], E. of Wall Range, 370 m, 8 October 1944, J. M. Lamb F.1.D.S. A1323 (BM); Falliéres Coast, Adelaide I. [67°15’S: 68°30'W], ‘Stork’ nunatak, 550 m, 9 March 1981, R. J. L. Smith 3416 (AAS); Falligres Coast, Marguerite Bay, Bourgeois Fjord [67°40’S: 67°05'W], 15 December 1936, B.G.L.E. 1518-3 (BM), Ridge I. [67°42'S: 67°06’ W], 4 August 1936, B.G.L.E. 1484-3 (BM), Jenny I. [67°44’S: 68°25'W], E. coast, 15 m, 30 January 1961, B. J. Taylor 444b (AAS), Horseshoe I. [67°51’S: 67°12'W], (type locality), 7-5 m, 23 February 1965, R. E. Longton 1275 (BM), 24 February 1967, R. 1. L. Smith 829 (fertile) (AAS), 6-10 m, 22 February 1977, R. I. L. Smith 2165 (AAS), between Lystad Bay and former B.A.S. station, 20-30 m, 22 February 1977, R.I.L. Smith 2168 (AAS, BM), Camp Point, (between Square Bay and Calmette Bay), [67°58’S: 67°19'W], 27 October 1949, B. Stonehouse F.I.D.S. E627a (BM), Debenham Is. [68°08’S: 67°07’W], 39 m, 7 December 1947, B. Stonehouse F.1.D.S. E1116 (BM), 104 F. J. WALKER Neny Fjord, Red Rock Ridge [68°18’S: 67°05’ W], 120 m, 19 January 1948, A. R. C. Butson F.1.D.S. E1158 p.p. (BM), c. 12 m, 19 January 1948, B. Stonehouse F.I1.D.S. E1176 (BM), Refuge I. [68°21’S: 67°10’ W], 21-36 m, 29 November 1940, H. M. Bryant U.S.A.S. 32 (US); unlocalised, ‘Terra Firma Land’, 21 June 1936, B.G.L.E. 1482 (BM). Uncertain determination ARGENTINA. Tierra del Fuego: Sierra Alvear, S. slope, above Las Cotorras (c. 20 km ENE. of Ushuaia), 900-1000 m, 7 February 1940, R. Santesson 640e (640a p.p.) (S). Race 2 CHILE. Aisén: Lago San Martin, Glaciares, c. 1500 m, 13 February 1933, A. Donat s.n. (H). ARGENTINA. Rio Negro: Parque Nacional Nahuel Huapi, Cerro Catedral, c. 2225 m, 6 January 1974, A. Henssen & G. Vobis 24677f (MB). Santa Cruz: Rio Fosiles, c. 1000 m, April 1905, P. Duséns.n. p.p. (FI). ANTARCTIC PENINSULA. Graham Land: Joinville I., N. end Active Sound [63°18’S: 57°56’W], 200 m, March 1981, R. I. L. Smith 3736 p.p. (AAS); Trinity Peninsula, Cape Longing [64°33’S: 58°50’W], 15-30 m, March 1961, J. Killingbeck 84 (AAS, BM, FH), 85 (AAS), 86 (AAS, FH), Duse Bay (as Race 1) F.I.D.S. D109-6 p.p. (BM), Crown Prince Gustav Channel, Egg I. [63°41’S: 57°42’W], 120 m, (as Race 1) F.I.D.S. D2756 (FH), Alectoria I. [63°59’S: 58°37'W], 30-60 m, 18 August 1945, J. M. Lamb F.1.D.S. D2467 (BM), foot of East Russell Glacier [63°44’S: 58°17’W], 14 December 1946, A. Reece F.I.D.S. D369-12a (FH), Vega I. [63°50’S: 57°25’ W], False Island Point, 6-18 m, 5 December 1945, J. M. Lamb F.I.D.S. D2718 (BM), James Ross I. [63°55'S: 57’40°W], Herbert Sound, c. 90 m, 23 November 1945, V. Russell F.1.D.S. D2734 (BM), James Ross I., Cape Gage [64°12'S: 58°16’ W], c. 6m, 29 November 1945, J. M. Lamb F.1.D.S. D2843 (BM); Falliéres Coast, Marguerite Bay, Neny Fjord, Roman Four Promontory [68°13’S: 66°58’W], 27 m, 8 December 1947, B. Stonehouse F.I1.D.S. E1072a (BM); George VI Sound, Alexander I. [72°11'S: 69°05’W], Stephenson nunatak, c. 520 m, 5 December 1949, V. E. Fuchs & R. J. Adie F.I.D.S. E616-7 (BM), Alexander I., SE. corner, 385 m, 4 December 1949, V. E. Fuchs et al. F.I.D.S. E612 (BM). Uncertain determination . ARGENTINA. Tierra del Fuego: Sierra Sorondo, N. slope above Las Cotorras (c. 20 km ENE. of Ushuaia), 800 m, 6 February 1940, R. Santesson 641c p.p. (S). For details of specimens of uncertain determination (Race 2) from the Antarctic peninsula see specimens in AAS, BM and FH and list held in BM. 13. Usnea subcapillaris (D. Galloway) F. J. Walker, comb. nov. Fig. 32 Usnea ciliata var. subcapillaris D. Galloway in N.Z. Jl Bot. 6: 470 (1968). — Neuropogon subcapillaris (D. Galloway) D. Galloway in N.Z. Jl Bot. 21: 195 (1983). Type: New Zealand, South Island, Otago, Remarkables Range, 2000 m, on rock, February 1968, D. J. Galloway s.n. (CHR 343756 [OTA 68-222]! — holotype; CHR! — isotypes (2), BM! — isotype). [TLC: norstictic acid, salazinic acid, + protocetraric acid, usnic acid. | Description: Thallus (2)-S(-15) cm, arising from a + delimited, pigmented holdfast, pendu- lous, rarely subdecumbent and spreading. Branching extensive, divergent, + dichotomous, with numerous extended, delicate, capillaceous secondary branches predominating, and short attenuate, deflexed laterals; usually lacking fibrils. Branches terete, yellow-green, + con- tinuously pigmented or variegated violaceous black towards the apices. Cortex thin. Surface smooth, waxy, epapillate, easily fracturing, forming + regular black-edged annulations. Medulla sublax towards the axis; axis occupying 0-3-0-5 of the branch diameter. Soredia, pseudoisidia and isidia absent. Apothecia rare, lateral, as in U. ciliata. Pycnidia not seen. TLC: (1) norstictic acid, salazinic acid, + protocetraric acid, usnic acid; (2) squamatic acid, + hypothamnolic acid, usnic acid; (3) psoromic acid, + 2’-O-demethylpsoromic acid, usnic acid. Distinguishing features: Usnea subcapillaris is characterised by its subdecumbent to pendulous habit, and a richly branched thallus with numerous, extended, fragile, divergent, flexuose- capillaceous secondary branches. It has a waxy, pigmented-annulate surface, a sublax medulla, containing depsides or depsidones, and occasionally apothecia of the ‘ciliata’-type. Distribution: Usnea subcapillaris occurs mainly in the South Island of New Zealand; it is widely distributed in alpine localities, generally between 1000 and 2000 m, often alongside U. ciliata, although tending to favour slightly more sheltered aspects. This species is only known in 105 USNEA SUBGENUS NEUROPOGON Fig. 32. Usnea subcapillaris. Holotype of Neuropogon ciliatus var. subcapillaris D. Galloway (CHR). Top. Whole thallus x1. Bottom. Detail of apothecia and cortical annulations x 10. 106 F. J. WALKER the North Island from an unlocalised gathering (Colenso 2086, BM!, s.n., PC!) which was probably collected on the Ruahine Range. It is rare in Tasmania, being confined to a few high-altitude locations and the species was first identified from there by Bratt & Cashin (1976). Fig. 6. Chemistry: Three chemical races have now been identified in Usnea subcapillaris (Galloway, 1984). Race 1 predominates whilst the other two races are very rarely encountered and are restricted to a few localities in mixed populations with Race 1. Protocetraric acid is only present in high concentrations in Race 1 and such thalli subsequently lack, or only contain traces of, norstictic and/or salazinic acids (for example, CHR 343473, herb. Bartlett 24724c). Interesting- ly, such chemical diversity does not occur in U. ciliata and U. pseudocapillaris or in the majority of Australasian populations of U. acromelana. The presence of squamatic and hypothamnolic acids (Race 2) in the medulla of this species is unique within the subgenus and may easily be demonstrated by a brilliant white medullary fluorescence under UV light and a K+ purple reaction. Race 3, containing psoromic acid, is only known from a few localities, one of which, Mt. Hutt (CHR 343463, CHR 343483!), is unusual since some thalli have a mixed chemistry of two, or even all three, races. Variation: The accounts of Usnea ciliata (p. 76), U. acromelana (p. 50), and U. pseudocapil- laris (p. 90) may be referred to for much of the variation in branching, pigmentation, morphology, and anatomy found in U. subcapillaris. This species most closely resembles U. ciliata but differs in the pendulous habit, a more or less confined, rarely proliferating holdfast, repeated, divergent branching, and extensive, capillaceous, interwoven secondary branches. The medulla may also be slightly laxer, occupying a larger proportion of the branch diameter. The surface has more regularly spaced, conspicuous annulations which sometimes result in thallus fragmentation. When frequent on main branches, such annulations produce a character- istic segmented appearance, sometimes resulting in slight subsequent constrictions. Secondary branches are more extensive than in Usnea pseudocapillaris, tending to form the most distinctive feature of the thallus, and are often up to two or three times the length of primary branches. The fragile and fragmentary nature of the secondary branches becomes more pronounced on storage. Adjacent thalli of richly branched specimens, with diverging ultimate branches, often become mutually entangled. U. pseudocapillaris and U. subcapillaris are only likely to be confused when they are immature and lack any reproductive structures. In less typical forms the secondary branches are somewhat coarser, although thalli are still moderately to richly branched and retain the characteristic divergent habit with short, attenuate ultimate branches. This is a particular feature of some Tasmanian collections in which there is a gradual transition between the coarse primary branches and the capillaceous secondary branches which are shorter, broader and more frequently divided than in the majority of New Zealand specimens examined. Apothecia are rare in New Zealand whilst in Tasmania they are only known from a single collection (HO 35239!). They are usually lateral on secondary branches and have a subtending, extended apical branch or spur which frequently divides. They are usually smaller, c. 5 mm, than in Usnea ciliata and pigmentation of the disc may rarely be undeveloped. Marginal excipular rays vary in number but are usually longer, finer and may divide, thus resembling secondary branches. Their scarcity may be a reflection of the ease at which the thallus fragments and regenerates, thus providing an alternative method of reproduction. This might explain the wider distribution of this species than U. ciliata in Australasia. Species concept: Usnea subcapillaris is now considered (Galloway, 1983) to be a distinct species from U. ciliata and a parallel can now be found between the related species, U. pseudocapillaris and U. acromelana. U. subcapillaris may also be regarded as the fertile counterpart to U. pseudocapillaris within the U. ciliata complex. It may be distinguished from U. ciliata by the pendulous or subdecumbent habit resulting from repeated, more or less divergent, dichotomous, division of extensive, capillaceous, secondary branches which give a fragile, lax, combed or frequently entangled appearance. Other characteristic features include the shorter, USNEA SUBGENUS NEUROPOGON 107 often widely divaricately branched main branches and sometimes the slightly laxer nature of the medulla and deep fissured annulations. It is extremely rare for thalli to be encountered that are difficult to assign to U. subcapillaris or U. ciliata. Coarser, suberect, or subdecumbent forms from Tasmania are included within the accepted variation. There does not appear to be any correlation between chemical race and morphological variation. Usnea subcapillaris may be distinguished from the other fertile species of Neuropogon by its restricted distribution besides morphological characters. Selected specimens examined Race 1 AUSTRALIA. Tasmania: Mt. Wellington, summit, 1250 m, 15 March 1970, G. Degelius A-414 (herb. Degelius), 1250 m, 20 December 1964, G. C. Bratt 1872a (CHR 343280), ‘Table Mountain’ [Mt. Wellington], (part of type gathering of U. acromelana var. decipiens Lamb (BM)); Central Plateau, Mt. Penny, near Arthur’s Lake, 1134 m, 4 April 1969, G. C. Bratt & K. M. Mackay 69/161 (CHR 343323, HO 35239 p.p.); Table Mountain, 1095 m, 18 June 1972, G. C. Bratt & J. A. Cashin Bratt 72/393 p.p. (HO 35178), Bratt 394 (HO 35179); Sandbank Tier, 5 April 1969, G. C. Bratt 69/212 (HO 35195); Seager’s Lookout, c. 10 km NNW. of Maydena, 1240 m, 30 May 1970, G. C. Bratt & F. N. Larkin Bratt 70/680b p.p. (HO 35236 p.p.). NEW ZEALAND. North Island. unlocalised [Ruahine Range?], Colenso 2086 (BM), s.n. (PC). South Island. Nelson: saddle between Mt. Aorere and Mt. Cobb, c. 1580 m, 19 December 1982, J. K. Bartlett 247246 p.p. (BM); Mt. Robert, Lake Rotoiti, 1430 m, 16 January 1960, D. Scott s.n. (BM, OTA); St. Arnaud Range, Lake Rotoiti, 1520 m, February 1959, Mason 647 (BM, OTA), St. Arnaud Range, 1680 m, 22 December 1967, A. F. Mark s.n. (CHR 343290 p.p., CHR 343476); Mt. Technical, above Lewis Pass, 14 January 1979, D. J. Galloway s.n. (CHR 343275); Lake Sylvester, 1620 m, 18 December 1967, A. F. Mark s.n. (CHR 343488); Lake Peel, 1430 m, J. K. Bartlett s.n. (CHR 343223). Marlborough: Black Birch Range, nr. Altimarlock trig, 10 January 1971, L. B. Moore s.n. (CHR 162621); Inland Kaikoura Range, Mt. Mitre, 2 January 1954, R. Mason & D. R. McQueen 2760 (CHR 160686). Canterbury: Mackenzie Country, Lower Godley River Valley, 1830 m, 21 December 1958, D. Scott 99 (BM, OTA); Torlesse Range, Foggy Peak, summit rocks, 1680 m, 18 December 1962, P. W. James 1918 (BM), 1680 m, November 1972, D. J. Galloway s.n. (CHR 343491), 12 November 1972, G. C. Bratt 72/1880b (HO 35170); Kirkliston Range, 1680-1830 m, 25 March 1978, D. J. Galloway s.n. (CHR 343178, CHR 343252 p.p.), 1830 m, December 1964, C. J. Burrows s.n. (CHR 343477); Mt. Peel, 1740 m, January 1972, D. J. Galloway s.n. (CHR 343437 p.p., CHR 343499); Mt. Cook National Park, Mt. Annan, 2740 m, R. B. Filson s.n. (MEL 1026826); Arthur’s Pass, Mt. Bealey, 1680 m, 19 August 1968, L. D. Kennedy s.n. (CHR 343452); Two Thumb Range, Mt. Richmond, November 1968, A. F. Marks.n. (CHR 343489 p.p.). Otago: Rock and Pillar Range, 1160-1190 m, 18 September 1981, F. J. Walker s.n. (BM), S. end, 980 m, June 1967, T. S. Choate s.n. (CHR 343347), 1480 m, February 1967, D. J. Galloway s.n. (CHR 343490), 980 m, June 1967, D. J. Galloway s.n. (CHR 342766); Young Range, 1430 m, March 1968, D. J. Galloway s.n. (CHR 343447 p.p., CHR 343472); Old Man Range, 1490 m, November 1962, P. W. James 443b (BM), 1130 m, 1 February 1963, P. W. James 1579 (BM), 1220'm, 1 February 1963, P. W. James 1597 (BM), 1680 m, April 1968, D. J. Galloway s.n. (CHR 343467, CHR 343478, CHR 343497), 1968, D. J. Galloway s.n. (CHR 343492), 1490 m, 30 August 1968, L. D. Kennedy s.n. (CHR 343479), 1520 m, A. F. Marks.n. (CHR 343470); Mt. Pisa, 1920 m, March 1968, D. J. Galloway s.n. (CHR 343468, CHR 343475, CHR 343480, CHR 343494), 1860 m, March 1968, D. J. Galloway s.n. (CHR 343473, CHR 343486), March 1968, D. J. Galloway s.n. (CHR 343448); Rees Valley Slopes, Leary Peak, 1680 m, January 1968, D. J. Galloway s.n. (CHR 343474, CHR 343287); Coronet Peak, 1520 m, February 1968, D. J. Galloway s.n. (CHR 343471); Humboldt Mtns, Mt. Minos, 2010 m, 1 January 1970, D. J. Galloway s.n. (CHR 343338, CHR 343488, CHR 343499); Mt. Erebus, 1980 m, 14 January 1970, D. J. Galloway s.n. (CHR 343754); Bedford Valley, 1680 m, 26 December 1970, D. J. Galloway s.n. (CHR 343482); Remarkables, 1980 m, March 1966, D. J. Galloway s.n. (CHR 343487); Coronet Peak, 1520 m, February 1968, D. J. Galloway s.n. (CHR 343755); Shepherd’s Pass, 1980 m, January 1968, D. J. Galloway s.n. (CHR 343450); Mt. Brewster, 2130 m, March 1968, D. J. Galloway s.n. (CHR 343493); Mt. Roy, 1 November 1972, G. C. Bratt 72/1506 (HO 35175); Unnamed Virgin, N. of Pope’s Nose, 2350 m, 11 February 1969, L. D. Kennedy s.n. (CHR 342787 p.p.); Mt. Pisgah, c. 1600 m, J. S. Thomson 1983 (CHR 343797). Race 2 NEW ZEALAND. South Island, Nelson: above Cobb Lake, 1070 m, December 1967, A. F. Mark s.n. (CHR 343498). Canterbury: Four Peaks Range, Blue Mountain, c. 1640 m, 23 April 1979, D. J. Galloway s.n. (CHR 343228), 23 April 1979, D. J. Galloway s.n. (CHR 343179); Mt. Peel, 1740 m, January 1972, D. 108 F. J. WALKER J. Galloway s.n. (CHR 343500); Mt. Hutt, 1520 m, C. J. Burrows s.n. (CHR 343495 p.p.), 1830 m, C. J. Burrows s.n. (CHR 343483 p.p.); Two Thumb Range, Mt. Richmond, November 1968, A. F. Mark s.n. (CHR 343489 p.p.). Otago: Sugarloaf Saddle, 1070 m, May 1966, D. J. Galloway s.n. (CHR 343446 p.p.), 1280 m, February 1968, D. J. Galloway s.n. (CHR 343408 p.p.); Young Range [as Race 1] (CHR 343477 p.p.), 1520 m, March 1968, R. Nilsson s.n. (CHR 343481); Humboldt Mtns, Mt. Nox, 1950 m, 31 December 1969, D. J. Galloway s.n. (CHR 342791, CHR 343469). Race 3 NEW ZEALAND. South Island, Canterbury: Mt. Hutt, C. J. Burrows s.n. [as Race 2] (CHR 343463 p.p., CHR 343483 p.p.); Four Peaks Range, Tripps Peak, 24 April 1979, D. J. Galloway s.n. (CHR 343337 p.p.). Otago: Rock and Pillar Range, 1280 m, December 1964, D. J. Galloway s.n. (CHR 343286, CHR 343451), 1400 m, July 1968, L. D. Kennedy s.n. (CHR 343496), 1400 m, February 1967, D. J. Galloway s.n. (BM). For further localities see Galloway (1968) and lists held in BM. 14. Usnea taylorii J. D. Hook. Figs 33-34 in Hooker & Taylor in Lond. J. Bot. 3: 657 (1844). — Alectoria taylorii (J. D. Hook.) Nyl. in Mém. Soc. Imp. Sci. Nat. Cherbourg 5: 98 (1857). — Neuropogon taylorii (J. D. Hook.) Nyl., Synops. Lich. 1: 273 (1860). Type: Kerguelen’s Land, Antarctic Expedition of H.M.S. Discovery ships ‘Erebus’ and ‘Terror’ 1839-1843, J. D. Hooker (BM! — lectotype, selected here; BM!, E!, FH, not seen, M! — isolectotypes). [TLC: no medullary substances, usnic acid. ] Note: The epithet ‘taylori’ is corrected to ‘taylorii’ under Article 73.10 following Recommendation 73C.1. Many original collections were widely distributed by Hooker and the species is best lectotypified on the collection illustrated by Lamb (1939a) in BM in preference to the herb. Taylor collection (FH) indicated by Dodge (1948). Description: Thallus (4)-S—7(-10) cm, arising from a proliferating, rarely pigmented, holdfast, erect, monopodial to + dichotomous, infrequently branched above with + flexuose, tapering to subcornute apices. Branches terete, corneous, yellow-green, continuously or irregularly pig- mented with black pigment towards the apices. Cortex thin. Surface + subnitid, epapillate, + smooth but mottled with slightly raised, unpigmented maculae. Medulla compact, reduced, invading axial cavities. Axis occupying c. 0-9 of the branch diameter, partially sub-divided, forming several strands, frequently abutting the cortex and protruding to form pale maculae. Soredia, pseudoisidia and isidia absent. Apothecia frequent, subterminal with a prominent, geniculate spur or rarely lateral and subsessile; + cupular, plane or sinuose-deflexed on maturity. Disc black, excipulum smooth or minutely faveolate, margin + excluded, rays absent. Pycnidia rare towards apices. TLC: (1) fumarprotocetraric acid (trace), usnic acid; (2) no medullary substances, usnic acid. Distinguishing features: Usnea taylorii is characterised by its erect, proliferating habit and a monopodial to infrequently branched, often extensively pigmented, corneous thallus; a subnitid maculate surface, a much reduced medulla, usually lacking medullary substances, a broad, sub-divided axis and subterminal, geniculate apothecia with a black disc lacking excipular rays. Distribution: Usnea taylorii is endemic to Kerguelia. Material has been examined from iles Kerguelen and [les Crozet and Dodge & Rudolph (1955) have recorded the species from Heard Island (A.N.A.R.E. 250, MEL, not seen). Specimens from South America misidentified as U. taylorii by Rasanen (H!) are referable to U. perpusilla. Specimens collected by Hooker, apparently from South America, are erroneously labelled (see p. 69). U. taylorii replaces U. aurantiaco-atra in Kerguelia and is often found in communities there with U. antarctica and U. trachycarpa. Fig. 4. Chemistry: All collections examined from Iles Kerguelen lack medullary substances, including fatty acids. Race 1, containing low concentrations of fumarprotocetraric acid, is only recorded from the single collection from [les Crozet. Variation: This is probably the most distinctive species of the subgenus. It has a unique axis structure throughout the thallus giving rise to the formation of separate axial strands that are USNEA SUBGENUS NEUROPOGON 109 Lecto-Type Specimen ee 4. Dillwyn Liovelyn, Reed. 1889, ° 1839 ths, SDA Fig. 33 Lectotype of Usnea taylorii J. D. Hook. (BM) x1. invaded by medullary tissue, resembling a coaxial cable; as illustrated by Rienke (1895). The extrusion of the axis through the narrow medulla and the otherwise cortex produces the characteristic pale, raised maculae that resemble the pseudocyphellae of Alectoria ochroleuca on an otherwise smooth surface. This often results in a mottled, rather than variegated, pattern on the extensively pigmented ultimate branches. Very rarely these maculae may form papilla- like structures which remain ecorticate. Collections are mostly uniform, the only variation being in the extent of thallus branching and pigmentation which range from scantily pigmented unbranched thalli to more richly branched forms that are extensively pigmented towards the apices. Main branches are usually thick and corneous, and are often flexuose with tapering, subcornute apices, giving the thallus a sinuose habit. Apothecia are characteristically subterminal and are particularly conspicuous on sparingly branched thalli. In contrast, in more richly branched thalli apothecia tend to be smaller, slightly cupular, subsessile, and lateral. Pycnidia are rare, and may be confused with a range of 110 F. J. WALKER an € 4 ~ Fig. 34 Usnea taylorii. Left. Detail of maculae. Challenger Exped. 1874, Molseley (BM) X10. Right. Detail of apothecia. Is. Kerguelen, January 1960, Tilman (BM) x10. parasites, including Lecidea alectoriae which was originally described (W. Lindsay, 1859) from this species. Species concept: Usnea taylorii appears to be a highly evolved species which may be closely related to U. aurantiaco-atra. U. taylorii replaces U. aurantiaco-atra in the Kerguelen region and shares several morphological characteristics besides the existence of a race containing fumarpro- tocetraric acid. U. aurantiaco-atra does not occur east of Bouvetéy where populations lack depsidones, have a very thick axis, and a reduction in the extent of papillation. A sorediate counterpart is not known, although some populations of Usnea antarctica, previously described as distinct taxa, for example U. crombiei (Dodge, 1948) and U. insularis (Lamb, 1939a), have slightly irregular but undivided axes. Usnea taylorii may be distinguished from all other fertile species within the subgenus by the unique branch anatomy with the production of maculae. Specimens examined Race I Is. CROZET. (unlocalised) c. 610 m, 1959-60, W. H. Tilman s.n. (BM). Race 2 is. KERGUELEN. Cliffs above Lake du Val Studer, 11 February 1963, R. B. Filson 4665 p.p. (BM); Swain’s Bay and Observatory Bay, Venus Transit Exped. 1874-75, A. E. Eaton s.n. (BM, E, M), A. Balfour s.n. (E); Royal Sound, A. E. Eaton s.n. (UPS), Royal Sound, nr. Port Jeanne d’Arc, c. 460 m, 11 February 1930, B.A.N.Z.A.R.E. B176 (AD, FH); Crater Hill, Christmas Harbour and Cumberland Bay, Ross’ Antarctic Exped. 1839-43, R. McCormick s.n. (BM); Baie des Baleiniers, Petit Mt. Ballon, 300 m, January 1960, W. H. Tilman s.n. (BM, FH); unlocalised — Challenger Exped., January 1874, H. N. Moseley s.n. (BM); Challenger Exped. (GLAM NHB 1927-8-348, GLAM NHB 1927-8-349); O. Ring s.n. (O); March 1931, A. de la Rue s.n. (UPS); December 1898, W. Schimper s.n. (UPS). HEARD I. see Dodge & Rudolph (1955). 15. Usnea trachycarpa (Stirton) Mill. Arg. Fig. 35 in Nuovo G. bot. ital. 21: 37 (1889). — Neuropogon trachycarpus Stirton in Scott. Nat. 6: 105 (1881). Type: Kerguelen’s Land (So. Antarctic), [January, 1875], Challenger Exped. 6 (BM! — holotype; BM! -— isotype). [TLC: norstictic acid, fatty acids, usnic acid.] (see Note) USNEA SUBGENUS NEUROPOGON 111 Usnea naumannii Mill. Arg. in Bot. Jb. 4: 54 (1883). Type: Kerguelen, Betsys Cove, 1875, Dr Naumann (G! - holotype). [TLC: norstictic acid, + fatty acids, usnic acid. ] Usnea melaxantha var. angulosa Mill. Arg. in Flora, Jena 71: 528 (1888). — Usnea sulphurea var. angulosa (Mull. Arg.) Zahlbr., Cat. Lich. Univers. 6: 603 (1930). Type: Argentina, Patagonia [unlocalised], Claraz (G! - holotype). [TLC: + norstictic acid, usnic acid. ] Usnea trachycarpa var. sublaevis Mill. Arg. in Hedwigia 34: 139 (1895). Type: Lich. Exot. 141, [Argentina] Patagonia, Moreno, 1894, Otto Kuntze 713 (G! — holotype). [TLC: no medullary subst- ances, usnic acid. | Usnea trachycarpa var. trachycarpoides Vainio, Rés. Voy. S. Y. Belgica, 1897-99, Botan., Lichens: 12 (1903). — Neuropogon trachycarpus f. trachycarpoides (Vainio) Lamb in J. Linn. Soc. (Bot.) 52: 233 (1939). — Usnea trachycarpoides (Vainio) Dodge, Lich. Fl. Antarct. Cont.: 238 (1973). Type: Argentine, Ile des Etats, Golfe Saint Jean, lat. 55°24’S, sur les parois verticales, 1898 M. Emile G. Racovitza 182 (TUR! - holotype). [TLC: norstictic acid, salazinic acid, + protocetraric acid, usnic acid.] Usnea hyyppae Rasanen in Suomal. eldin-ja kasvit. Seur. van. kasvit. Julk. 2(1): 11 (1932). Type: [Argentina] Fuegia media, Cerro Milladeo, reg. alp. 800 m.s.m., Expeditio Fennica 1928-29, H. Roivainen (H! — holotype; H! — isotype). [TLC: no medullary substances, usnic acid. } Usnea taylorii var. subciliata Rasanen in Suomal. eldin-ja kasvit. Seur. van. kasvit. Julk. 2(1): 11 (1932). Type: [Chile] Fugia media, Cerro Chico, reg. alp. 550 m.s.m., Expeditio Fennica 1928-29, H. Roivainen (H! - holotype). [TLC: no medullary substances, usnic acid. ] Neuropogon substrigulosus Lamb in J. Linn. Soc. (Bot.) 52: 231 (1939). — Neuropogon trachycarpus f. substrigulosus (Lamb) Lamb in Lilloa 14: 156 (1948). — Usnea substrigulosa (Lamb) Dodge. Lich. FI. Antarct. Cont: 237 (1973). Type: Falkland Islands, (no collector given) (BM! — holotype). [TLC: norstictic acid, salazinic acid, + protocetraric acid, fatty acids, usnic acid. | Neuropogon trachycarpus f. elatior Lamb in Lilloa 14: 157 (1948). Type: [Argentina] Tierra del Fuego, Sierra Alvear, the Southern slope, above Las Cotorras (c. 20 km ENE. of Ushuaia), rocks in the alpine region, 900-1000 m, 1940, R. Santesson 640b, (S! — holotype; S!, CANL 17258! — isotypes). [TLC: no medullary substances, usnic acid. | Note: The specimens figured by Lamb (1939a) are only part of the holotype material of Neuropogon trachycarpus and were selected from Stirton’s herbarium by Miss A. L. Smith and are here regarded as an isotype. The original capsule bearing Stirton’s handwriting was mislaid and not traced by Lamb or Dodge (1948). This capsule has recently been traced in the BM and bears the inscription ‘Kerguelen’s Land (So. Antarctic) Challenger Expedition (6) — melaxanthus trachycarpus (Strn.) axis rather solid, compact. Med. fibres arachnoid. K—; I—. Type.’ This material forms the holotype and consists of two slightly larger thalli than the isotype, one of which bears three small apothecia. Description: Thallus (2-3)-4(-7-9) cm, arising from a proliferating, unpigmented, holdfast, erect, monopodial or + dichotomous, infrequently to moderately branched above. Fibrils numerous on all branches, short, c. 5 mm, spreading, + variegated or continuously black- pigmented. Branches terete or rarely slightly angular, yellow-green, + continuously pigmented towards the apices. Cortex variable in thickness. Surface matt, + smooth at the base becoming markedly faveolate to richly papillate or scabrid with numerous conspicuous fibrils above. Medulla lax or sublax, axis occupying 0-3-0-5 of the branch diameter. Soredia, pseudoisidia and isidia absent. Apothecia frequent, subterminal, + cupular, expanding on maturity. Disc rufous brown, excipulum faveolate to verrucose-papillate with numerous marginal, attenuate, + pigmented rays. Pycnidia infrequent towards apices. TLC: (1) norstictic acid, + salazinic acid, + protocetraric acid, + 2-6 fatty acids (murolic acid complex), usnic acid; (2) psoromic acid, 2'-O-demethylpsoromic acid, + 2-6 fatty acids (murolic acid complex), usnic acid; (3) no medullary substances, + 2-6 fatty acids (murolic acid complex), usnic acid. Distinguishing features: Usnea trachycarpa is characterised by its erect, proliferating habit, an infrequently branched thallus with numerous fibrils, a faveolate-papillate surface, a lax to sublax, arachnoid, medulla, often containing depsidones and fatty acids, a thin axis, and subterminal apothecia with a rufous brown disc with numerous marginal and submarginal excipular rays. Distribution: Usnea trachycarpa is known from southern South America (Patagonia and Tierra del Fuego) as far north as latitude c. 42°S, the Falkland Islands and iles Kerguelen, and has also been recorded by Dodge & Rudolph (1955) from Heard Island (Gilchrist 2, MEL, 112 F. J. WALKER Fig. 35 Usnea trachycarpa. Top. Holotype of Neuropogon trachycarpus Stirton (BM) x1. Bottom. Detail of apothecium. Patagonia, James 28 (BM) x10. USNEA SUBGENUS NEUROPOGON 113 not seen). A single, sterile specimen from the Antarctic peninsula is tentatively referred to this species (R. I. L. Smith 3453 p.p., AAS!), although it is not known elsewhere in Antarctica or the islands of the Scotia Arc. A thallus fragment amongst the type of U. acromelana var. decipiens (BM!) from Tasmania appears to belong to this species, but is probably misplaced since the species is not otherwise known in Australasia. Usnea trachycarpa is a characteristic species of dry, exposed conditions and is frequently found at relatively low altitudes, for example near sea-level to c. 200 m on Iles Kerguelen and the Falkland Islands. It has a broader altitudinal range in South America, ranging from 30 to 1000 m in Tierra del Fuego and Santa Cruz up to c. 2250 m further north in Rio Negro. In the Falkland Islands this species is often replaced by Usnea aurantiaco-atra whilst in southern South America it is sometimes found in communities with U. aurantiaco-atra and U. perpusilla and a range of asexual species, particularly U. patagonica. Fig. 5. Chemistry: The most common race throughout the range of Usnea trachycarpa is Race 1, containing norstictic acid, usually with salazinic acid, and frequently with detectable (by TLC) concentrations of connorstictic acid and/or protocetraric acid. An additional unknown subst- ance that was yellow after charring (Rf class TDA 1, HEF 2-3) was found in some thalli from [les Kerguelen, but did not appear to be of taxonomic significance. Race 2, containing psoromic acid, is very rare and is only known from a few collections from a single locality in Argentina. Up to six fatty acids of the murolic acid complex (see p. 14) occur in Usnea trachycarpa and have been demonstrated by TLC in all three chemical races, although their presence and number may vary within a single collection. They are particularly persistant in Race 1 from Iles Kerguelen, whilst from elsewhere their distribution appears to be more spasmodic, for instance only occurring in about half a selection of 30 South American specimens tested. The UV+ unknowns were only rarely detected in this species. Variation: Usnea trachycarpa is, especially when fertile, an easily recognised and uniform species throughout its range. The extent of branching is reminiscent of U. ciliata (p. 76). Thalli range from virtually monopodial forms, often scantily pigmented at the apices of branches and fibrils, to more richly branched, extensively pigmented forms that are characteristic of higher altitudes and more exposed localities. Papillae are only pigmented in the more extensively pigmented, high-altitude forms. Some populations are more robust, up to c. 9 cm tall, and have previously been recognised as distinct taxa, for example Neuropogon substrigulosus and N. trachycarpus f. elatior. The number and extent of fibrils is variable although they are nearly always present; forming a characteristic feature of the species. The surface is smooth, matt and free from fibrils near the holdfast, but becomes papillate-faveolate above with the production of small, uniform fibrils of c. 5mm in length. Only very rarely is the thallus smooth to minutely papillate throughout, with fewer fibrils. Various taxa have been described based on the extent of fibril production and range from specimens virtually free of fibrils, including Usnea trachycarpa var. sublaevis and U. taylorii var. subciliata from Argentina, to extensively fibrillar forms, including Neuropogon substrigulo- sus from the Falkland Islands. The type specimen from Iles Kerguelen, although small, is fairly typical of the species. However, the medulla is more compact than is frequently found in more robust specimens, as seen in the type of Usnea naumannii from the same island group, although it still possesses an arachnoid texture, and slight inflation and characteristic faveolation of main branches. The degree of laxness and hence relative widths of medulla and axis, are the most variable feature of this species. Many gatherings from Patagonia are typical of a laxer form, for example the types of U. melaxantha var. angulosa and U. hyyppae, whilst in Neuropogon trachycarpus f. elatior the medulla is extensive and lax with the axis only occupying about a third of the branch diameter. Apothecia are uniform and are normally subterminal. When young they are cupular but are partially expanded on maturity, sometimes becoming irregular. The disc is always rufous brown in freshly collected specimens and quite distinct from the colour of the thallus. The disc only rarely becomes partly blackened when moribund. The extent and length of excipular rays may 114 F. J. WALKER vary. These are usually fine, short, unbranched, black-pigmented or variegated, and are numerous around the margin or the excipulum and less frequent over the rest of the surface. Variation in number, thickness and length of rays has led to the description of distinct taxa, including Usnea taylorii var. subciliata and Neuropogon substrigulosus. Species concept: Variation in thallus size, ornamentation, morphology, pigmentation, and anatomy in Usnea trachycarpa is not considered sufficient to recognise additional or infraspecific taxa; a parallel can be drawn within U. aurantiaco-atra. Reduction in the extent of black pigmentation, including the presence of a rufous brown pigment in the apothecial disc, may indicate some affinities with species of Usnea subgenus Usnea (see p. 43), for example U. hieronymii (var. adusta) and U. densirostra, which are saxicolous, have fibrils, a pale buff disc, and exhibit very limited pigmentation. These species have a more northern distribution and are not characteristic of montane areas. Usnea trachycarpa is possibly the primary species of U. subantarctica and may also be closely related to U. patagonica and U. neuropogonoides (see p. 42). It may easily be distinguished from all other fertile species of the subgenus by the rufous brown apothecial disc with numerous short rays and, even when sterile, by the numerous fibrils on all branches. Selected specimens examined Race 1 CHILE. Magallanes: Magellan Straits, Punta Arenas, Steinmann s.n. (BM, H, M, PC); Natales, Cerro Dorotea, 9 May 1940, R. Santesson 2135 (S), R. Santesson 2136 (S); Tierra del Fuego, Isla Navarino, Puerto Navarino, 10m, 28 February 1940, R. Santesson 1232a (UPS, S); Cabo de Hornos, Cape Spencer, J. D. Hooker s.n. (BM). ARGENTINA. Santa Cruz: Lago Argentino, Cerro del Fraile, near Estancia Lago Roca, 270 m, 1958-59, P. W. James 764 (BM); Lago Argentino, Cordillera Cristales, Cerro del Fraile, c. 1000 m, 26 December 1958, P. W. James 29 (BM); hills above Calafate, 1235 m, 1958-59, P. W. James 420a (BM); Calafate, ‘weg nach’ Punta Bandera, Campo Anita Fuss des Co. Moyano, c. 500 m, December 1973, A. Henssen & G. Vobis 24540b (MB); Lago Viedma, 1200 m, 2 April 1903, P. Dusén s.n. (H); Rio Fésiles, c. 1000 m, 1975. P. Duséns.n. (FH, H, M p.p., WU 2997 p.p.); Depto. Guar Aiken, 60 km SW. of Rio Gallegos, 30 m, 4 January 1939, W. J. Eyerdam et al. 24093 (BM p.p., FH). Tierra del Fuego: Parque Nacional Tierra del Fuego, Ushuaia, ‘weg zum’ Glacier Martial, c. 750 m, 7 December 1973, A. Henssen & G. Vobis 24420} (MB); Ushuaia, small island in Beagle Channel, 30 January 1940, R. Santesson 525 p.p. (S); Sierra Alvear, S. slope, above Las Cotorras, c. 20 km ENE. of Ushuaia, 650 m, 9 February 1940, R. Santesson 636b (S, UPS): FALKLAND IS. East Falkland Is.: Goose Green, Fish Creek, 9 m, 22 September 1963, R. W. M. Corner 67 (AAS); Mt. Longdon, near Port Stanley, 174 m, 2 April 1967, D. C. Lindsay 1657 (AAS), D. C. Lindsay 1660 (AAS), D. C. Lindsay 1661 (AAS); Fairy Cove, near Port Stanley, near sea-level, 30 January 1946, J. M. Lamb F.1.D.S. 2892 (BM, CANL 17257); N. of Wireless Hill, 100 m, 28 February 1977, R. J. L. Smith 2571 (AAS); Port Stanley, W. Lechler, pl. ins. Maclovian. 69c (BM, M); Murray Heights and Lookout Rocks, Stanley, 30 March 1965, J. Price s.n. (BM). West Falkland Is.: Crooked Inlet, Roy Cove, 31 August 910 (collector unknown) (BM); Cooke Hill and Roy Cove, 1909-11, E. Vallentin 89 (BM). Is. KERGUELEN. Royal Sound, Venus Transit Exped. 1874-75, A. E. Eaton s.n. (BM, E, M, UPS); Swain’s Bay, Venus Transit Exped. 1874-75, A. E. Eaton s.n. (BM, E, M); Observatory Bay, Venus Transit Exped. 1874-75, A. E. Eatons.n. (BM, E, M); Molloy Point, Venus Transit Exped. 1874-75, J. P. Kidder s.n. (FH); Baie Islandaise (Baie des Baleiniers), 210 m, January 1960, W. H. Tilman s.n. (BM, FH); above Lake du Val Studer, 11 February 1963, R. Filson 4665 p.p. (BM). Race 2 ARGENTINA. Santa Cruz: Depto. Guar Aiken [ as Race 1], W. S. Eyerdam et al. 24093 (BM), Guar Aiken, 18 January 1940, R. Santesson 300a (S, UPS), R. Santesson 300b (S). Race 3 CHILE. Aisén: Coyhaique Alto, 1000 m, 18 November 1940, R. Santesson 4600 (S), R. Santesson 4632 p.p. (S), Lich. Austro-amer. ex Herb. Regnelliano 423 (BM, M, UPS, S). ARGENTINA. Neuquén: Paso do Pino Hachado, 13 November 1941, Pérez Moreau 5982 (H). Rio Negro: Parque Nacional Nahuel Huapi, Cerro Catedral, c. 2225 m, 6 January 1974, A. Henssen & G. Vobis 24677e (MB); Cerro Leones, 1 January 1974, A. Henssen & G. Vobis 24625 p.p. (MB). Chubut: Rio Corcovado, February 1903, Jllin 553 (BM); Pampa Chica, 13 November 1908, C. Skottsberg s.n. (UPS). Santa Cruz; Patagonia, Lago Argentino, C. Megluno s.n. (BM); Rio Gallegos, Estancia Stag River, R. USNEA SUBGENUS NEUROPOGON 115 Tweedie 71 (BM); Rio Fosiles, c. 1000 m, April 1905, P. Dusén s.n. (FI, H, M, UPS). Tierra del Fuego: Parque Nacional Tierra del Fuego, Ushuaia, ‘Weg zum’ Glacier Martial, c. 750 m, 7 December 1973, A. Henssen & G. Vobis 24431a (MB); Sierra Alvear (type locality of Neuropogon trachycarpus f. elatior Lamb) 800-900 m, 7 February 1940, R. Santesson 639b (UPS, S), 650 m, 9 February 1940, R. Santesson 636b p.p. (UPS); Sierra Sorondo, N. slope, above Las Cotorras, c. 20 km ENE. of Ushuaia, 800 m, 6 February 1940, R. Santesson 641b (S, UPS); Monte Marcial, above Ushuaia, 700 m, 29 January 1940, R. Santesson 450b (UPS, S). Is. KERGUELEN. part of type collection (BM); December 1898, W. Schimper (UPS). Uncertain determination ANTARCTIC PENINSULA. Graham Land: Adelaide I. [c. 67°15’S: 68°30'W], ‘Reptile Ridge’, Yellow Bluff, 350 m, 9 March 1981, R. J. L. Smith 3453 p.p. (AAS). For further localities see lists held in BM. HEARD IS. see Dodge & Rudolph (1955). Appendix I. Allied taxa Descriptions and brief notes on the following three taxa, Usnea amblyoclada, U. inermis, and U. torulosa, are appended to assist in the identification of some of the species of Usnea subgenus Usnea that can occur in communities with Neuropogon species and may rarely be somewhat darkly pigmented. In general, this pigmentation is scant in all three and lacks the violaceous lustre which is a characteristic of many species of Neuropogon; more extensive pigmentation only seems to occur in damaged or moribund specimens. In Australasia only two species of the subgenus Usnea, U. torulosa and, to a lesser extent, U. inermis, occupy similar habitats to Neuropogon, both appear to virtually replace the latter subgenus in alpine habitats. They may be distinguished, particularly from species of the U. ciliata complex, by the develop- ment of true isidia. A larger number of saxicolous Usnea species have been described from South America including a well-defined group of related species which Motyka (1938) assigned to the subsection Roccellinae of the Laevigatae. In general they are robust species, often with large amounts of usnic acid, and are rarely pigmented. Examples include U. bogotensis, a yellow-green species with more or less globose soralia, and the non-sorediate, fertile, U. roccellina, which probably form a species pair. Motyka also included the fertile species U. amaliae and U. hieronymii (and its var. adusta) in this subsection. However, U. hieronymii appears to be closely allied to, or possibly the same as, U. densirostra, a species which Motyka (1937) assigned to a completely different subsection, the Densirostrae within the section Setulosae, U. densirostra is the only species in this subsection which could be mistaken for a species of Neuropogon. This species resembles, in particular, U. trachycarpa in habit, but is uniformly grey-green and has a pale, not a rufous brown, apothecial disc; it also has a more northern distribution. Motyka also included U. capensis (South Africa), U. amblyoclada (South America) and U. glomerata (Australasia) in the same subsection. Of these species U. amblyoclada is possibly the sorediate counterpart of U. hieronymii. Several taxa, for example Usnea igniaria (UPS — holotype, not seen) and U. nidulifera (UPS! — holotype) which are usually corticolous and only rarely saxicolous, also occasionally occur in similar, mainly upland, habitats in southern South America. These two species usually lack pigmentation and superficially resemble, but replace, U. inermis; both sometimes contain psoromic acid. U. nidulifera may sometimes be extensively pigmented (cf. U. inermis), but when fertile, has a pale disc (for example, Argentina, Rio Negro, Cerro Otto, 1980, herb. Kalb!). 1. Usnea amblyoclada (Miill. Arg.) Zahlbr. Fig. 36 Cat. Lich. Univ. 6: 534 (1930). — Usnea barbata var. amblyoclada Mill. Arg. in Flora, Jena 72: 509 (1889). Type: Serra Ventana, in Argentinia merid., Lorentz (G! — holotype; BM! — isotype). FLLG: norstictic acid, salazinic acid, usnic acid. ] Note: The combination ‘Usnea amblyoclada (Mill. Arg.) Motyka’ has not formally been made (Motyka, 1937) and would be superfluous. Description: Thallus saxicolous, rarely lignicolous, 2-3 cm, arising from a delimited, + pigmented, holdfast, erect, richly branched above with clustered laterals and subcornute or slightly deflexed apices. Fibrils numerous, slightly articulate, often eroding. Branches terete, grey-green, rarely black-pigmented at the apices. Cortex thin, cartilagineous. Surface matt, papillate, rarely slightly inflated, then fracturing; pseudocyphellae numerous. Medulla compact or sublax, axis thick, occupying 0-5 of the branch diameter. Isidia numerous on ultimate branches and fibrils, arising from pseudocyphellae, apices black-pigmented, 116 F. J. WALKER often eroding. Pseudoisidia and soredia absent. Apothecia and pycnidia not known. TLC: (1) norstictic acid, salazinic acid, galbinic acid, usnic acid; (2) fumaprotocetraric acid, protocetraric acid, salazinic acid, usnic acid; (3) no medullary substances, usnic acid (rare — lignicolous). Distribution: Usnea amblyoclada is apparently confined to the northern part of the South America, where it is either rare or under-collected; it is recorded from Brazil, Argentina, Uruguay, and Peru (Motyka, 1937; Osorio, 1980; Swinscow & Krog, 1976). Previous reports of U. pulvinata from South America are assumed to refer to this taxon. Recent collections from Bolivia, Ecuador, and Peru (BM!) contain material referable to this species. Chemistry: The primary medullary substances are norstictic acid usually with salazinic acid. In addition to type material only six collections have been examined; in these galbinic acid was found as an accessory substance in two samples. A further specimen contained salazinic, protocetraric and fumarprotocetraric acids. Lignicolous material, from Bolivia, lacked medullary substances, although norstictic acid occurred in saxicolous thalli. It is likely that other chemical races may occur and in this diversity the species would resemble U. pulvinata (Swinscow & Krog, 1976). Fig. 36 Usnea amblyoclada. Holotype of Usnea barbata var. amblyoclada Mill. Arg. (G). Top. Whole thallus x1. Bottom. Detail of isidia and pseudocyphellae x10. USNEA SUBGENUS NEUROPOGON Wg Discussion: The taxonomic position of this taxon remains uncertain. Swinscow & Krog (1976) initially accepted Usnea amblyoclada to be conspecific with Usnea pulvinata, although subsequently they (Swins- cow & Krog, 1979) expressed some doubt about their original interpretation. I have examined the holotypes of both taxa (in G and L respectively) and, pending a more detailed study of South American and African material, prefer to regard the two taxa as distinct species, possibly in different aggregates. U. pulvinata belongs to the U. bornmuelleri aggregate which is characterised by the presence of blackened, true isidia, a cartilagineous cortex, and usually saxicolous habitat. U. nigropapillosa, a saxicolous endemic from Tristan da Cunha (Jérgensen, 1977), belongs to the same aggregate, and is characterised by the presence of fibrils, blackened papillae and branch apices, but lacks true isidia (O! — holotype). In contrast to U. pulvinata, U. amblyoclada appears to have closer affinities with U. densirostra, a saxicolous, fertile South American species. Usnea amblyoclada is included here since it could occasionally be confused with U. durietzii. However, the former is grey-green, rather than yellow-green, has true isidia, not pseudoisidia, is more copiously fibrillate, and lacks the inflated main branches and a stalked holdfast, the features which characterise U. durietzii. Isidia in U. amblyoclada are produced extensively throughout on secondary branches and fibrils, and are not in delimited clusters as in U. acanthella. 2. Usneainermis Motyka Fig. 37 Lich. Gen. Usn. Stud. Monogr. 1: 109 (1936). Type: Australia, Victoria, ad flumen Murray, in silvis, Wawra (W! - holotype). [TLC: psoromic acid, 2'-O-demethylpsoromic acid, usnic acid. ] Description: Thallus corticolous, rarely saxicolous, 1-2(-5) cm, arising from a + delimited, usually unpigmented, holdfast, erect to subpendulous, + dichotomous to irregular, repeatedly branched above with numerous, + subarticulate laterals and reflexed, subcornute apices. Short fibril-like branches sometimes present. Branches terete or irregular, green to yellow-green, sparsely black-pigmented at the apices. Cortex thin. Surface + waxy, smooth to faveolate, rarely subpapillate, unpigmented annulations frequent. Medulla lax, rarely sublax, axis thin, occupying less than 0-5 of the branch diameter. Isidia frequent throughout thallus, dispersed, arising from small pseudocyphellae, + pigmented apices, becom- ing extensive then confluent, often eroding. Pseudoisidia and soredia absent. Apothecia rare. TLC: (1) squamatic acid, usnic acid; (2) psoromic acid, 2’-O-demethylpsoromic acid, usnic acid; (3) no medullary substances, usnic acid. Distribution: Usnea.inermis is apparently confined to Australasia. In New Zealand it is characteristically a corticolous or lignicolous species, chiefly occurring at low altitudes and rarely above 600 m, although it is often as important element of the lichen flora of subalpine scrub on twigs of, for example, Discaria and Leptospermum. Similarly, in Tasmania it is primarily a corticolous or lignicolous species of dry forests from the coast up to the subalpine zone. However, in Victoria and New South Wales, U. inermis frequently shares saxicolous habitats with U. torulosa at higher altitudes, between 1500 and 2200 m. Chemistry: Traces of an unidentified fatty acid were occasionally found in all three races. The psoromic acid race was found to be less frequent than the squamatic acid-containing race. Discussion: Usnea inermis should rarely be mistaken for members of the subgenus Neuropogon since it has many distinguishing features, besides different ecological parameters. For example, the thallus is much greener than the majority of Neuropogon species, and may easily be separated from Australasian taxa by the characteristic lax medulla and randomly scattered true isidia. Thallus blackening often appears to be more prevalent in thalli growing in very exposed situations and is often the result of tissue necrosis rather than pigmentation, although a tendency to limited pigmentation at the branch apices appears to be characteristic of the species. It may be distinguished from U. torulosa by the laxer medulla and the dispersed, rather than delimited, isidia. 3. Usnea torulosa (Miill. Arg.) Zahlbr. Fig. 38 Cat. Lich. Univ. 6: 594 (1930). — Usnea dasypogoides f. torulosa Mill. Arg. in Flora, Jena 66: 19 (1883). Type: Mt. Koscuisko, New South Wales, Findlay 554 (G! — holotype). [TLC: squamatic acid, usnic acid. ] Usnea glomerata Motyka, Lich. Gen. Usn. Stud. Monogr. 2: 315 (1937). Type: Nova Hollandia, saxicola, 1876, Archer (O — holotype, not seen). Usnea aurescens Motyka, Lich. Gen. Usn. Stud. Monogr. 2: 561 (1938). Type: New Zealand, Cave Hill, Dunedin, (J. S. Thomson T245) M23 (herb. Motyka — holotype, not seen, BM!, CHR 343970! — isotypes). [TLC: barbatic acid, 4~-O-demethylbarbatic acid, squamatic acid, usnic acid. ] 118 F. J. WALKER ACADEME Reise 4. Prinz. Pil. a, Ang. ¥. 8. Lene % if & a 1872 74 YS ae Os bot He Z ’ oo It Ao a et seat ete Or, oe Lane Ce A Ag caiik bes 5 wan tA Ce tne 8 oo ee “awe Fig. 37 Usnea inermis. Top. Holotype of Usnea inermis Motyka (W) X0-5. Bottom. Detail of isidia. A - holotype x 10. B— New South Wales, Filson (MEL 1018181) x10. USNEA SUBGENUS NEUROPOGON 119 rete a UR APA De AV »* < ae = eye Fig. 38 Usnea torulosa. A—holotype of Usnea dasypogoides f. torulosa Mill. Arg. (G) X1. B— Isotype of Usnea aurescens Motyka (CHR) X1. C— Detail of isidia. New Zealand, Otago, Old Man Range, James 1579 (BM) x10. 120 F. J. WALKER Neuropogon acromelanus var. inactivus Lamb in J. Linn. Soc. (Bot.) 52: 220 (1939). Type: Tasmania, Mt. Wellington, 1876, W. Campbell, ex herb. Stirton (BM! — holotype; BM! — isotype). [TLC: + squamatic acid, usnic acid. | Description: Thallus saxicolous, (3)-4-6(-8) cm, arising from a proliferating or rarely delimited, pigmented, holdfast, erect to subdecumbent, + dichotomous, richly branched above with numerous, short, clustered, entwined laterals with capillaceous apices. Fibrils rare. Branches terete, pale yellow, unpigmented or rarely blackened at the apices. Cortex thick, rigid. Surface waxy, rarely subfaveolate or annulate, papillae absent. Medulla compact, rarely sublax, axis thick, occupying 0-5—0-6 of the branch diameter. Isidia forming + delimited clusters, arising from minute pseudocyphellae, + pigmented apices, often eroding to from soralia-like areas. Pseudoisidia infrequent. Soredia absent. Apothecia rare. TLC: (1) squamatic acid, usnic acid; (2) psoromic acid, 2’-O-demethylpsoromic acid, squamatic acid, usnic acid; (3) barbatic acid, 4-O-demethylbarbatic acid, + squamatic acid, usnic acid; (4) no medullary substances, usnic acid. Distribution: Usnea torulosa is widely known from saxicolous alpine or subalpine habitats in New Zealand and Australia, occurring with or sometimes replacing Neuropogon species. The species has a much wider ecological amplitude, and is found at lower altitudes; it is also more catholic in its choice of substrates. It seems more able to withstand competition from large foliose lichens and to tolerate some degree of nutrient enrichment, as often occurs in bird-perch communities with Parmelia signifera. U. torulosa also has some preference for habitats near standing water, often colonising depressions in boulders or rocks by lake sides. It also extends into areas with wetter climates, for example on the west coast of South Island, New Zealand, areas where Neuropogon is absent. Chemistry: The squamatic acid containing race (Race 1) was found to be the most common, with the barbatic acid race (Race 3) being less frequent and the psoromic acid race (Race 2) rare. Discussion: The taxonomic position of Usnea aurescens remains somewhat uncertain, although it is here included within the wide range of variation of U. torulosa. The isotype (Fig. 38) is a much less robust entity with fine, extended secondary branches with small eroded soralia-like areas that only produce a few true isidia. It is possible that some of the barbatic acid-containing specimens may eventually prove to belong toa distinct taxon. These are characterised by the presence of pronounced globular soralia-like structures which only rarely produce small pseudoisidia and appear to lack true isidia, although these entities are included within the variation of this species for the present. This probably represents another phase in the erosion-regeneration cycle of isidia production, where isidia regenerate to form pseudoisidia but ultimate- ly erode to produce large, usually excavate, soralia-like structures. Usnea torulosa is included in this appendix since it is frequently found associated with U. acromelana and might, in instances where the characteristic habit or the isidia are not well-developed, be mistaken for scantily pigmented forms of that species. In the field the two species are easily distinguished since U. torulosa is a much brighter yellow, in contrast to the yellow-green colour of U. acromelana. Pigmentation is scarce, being confined to the holdfast, isidia, and rarely the apices of secondary branches. Medullary chemistry is particularly useful in cases where identity is uncertain, since norstictic and salazinic acids, which are a feature of Australasian populations of U. acromelana, do not occur in U. torulosa. Usnea torulosa may be distinguished from U. inermis by the differences in habit, branch anatomy, and, frequently, habitat. Only rarely do the isidiate areas in U. torulosa become confluent towards the branch apices and then resemble the random, dispersed distribution found in U. inermis. Appendix IT. Excluded taxa Letharia wandelensis Hue, Expéd. Antarc. Franc. 1903-1905, Botan., Lichens: 6 (1908). Type: Graham Land, Booth-Wandel I., Expéd. Antarc. Franc. 277, 299 (PC! — lectotype, selected here, CANL 16959! — isolectotype). From the original description and examination of the type material it is obviously that this species was based on a mixture of two taxa; namely a moribund, weathered specimen of Usnea antarctica overgrown by, amonst other lichens, a species of Caloplaca. Zahlbruckner (1926) subsequently created a new genus, Lethariopsis , to accommodate this ‘species’ based on the Caloplaca-type spores. Lamb (1948)) discussed the identity of Letharia wandelensis and reported that, after careful study of the apothecia, it was impossible to determine the Caloplaca (or Teloschistes) species concerned. Since Hue (1908) mentioned the occurrence of Polycaulonia (Caloplaca) regalis and Polycaulonia coralligera (i.e. Xanthora candelaria — Lamb, 1948b) as associated species, it is possible that the apothecia may belong to one of these. Lamb (19485) considered the former species to be the most likely, although he also found USNEA SUBGENUS NEUROPOGON 121 fragments of other lichens, including a species of Physcia, overgrowing the thallus. Dodge (1973) retained the genus Lethariopsis but suggested that Lamb’s interpretation was referable to Usnea pseudofruticosa (U. antarctica) parasitized by Caloplaca cinericola. Examination of the type material (Fig. 39) shows that there is not sufficient material present to ascertain the identity of the Caloplaca species. Some clue to its identity may come from the parasite found in the apothecia described by Hariot (in Hue, 1908) as Endococcus wandelensis. This is a synonym of Polycoccum rugulosarium (Hawksworth in Pegler et al., 1980) which is reported from the apothecia of Caloplaca regalis and Caloplaca rugulosa. There is apparently no material of the parasite still associated with the type specimen (D. Hawksworth, pers. comm.). Fig. 39 Type of Letharia wandelensis Hue (PC) X1:°5. Under the Code (Article 9.2) the original description could adequately be used to lectotypify either the Usnea or the Caloplaca species concerned, since the taxon can no longer be rejected under Article 70. If the Usnea part was selected as the lectotype of Letharia wandelensis the name would predate Usnea antarctica. Consequently Letharia wandelensis Hue is here lectotypified on the fertile part, as an unidentified species of Caloplaca. This follows Recommendation 7B of the Code in selecting a lectotype so as to preserve the current usage of the epithet ‘antarctica’. Ramalina scopulorum var. ¢ J. D. Hook., Flora Antarctica 2: 522 (1847): Spec. orig.: dry granite rocks, Cape Horn, J. D. Hooker (BM!); Kerguelen’s Land, Anderson (not traced). Material of this unnamed variety from Iles Kerguelen was thought to be a species of Neuropogon (Crombie, 1879a; Dodge, 1948), possibly Usnea trachycarpa. However, examination of original material from Hermite Island, Cape Horn, J. D. Hooker 66 (BM!) and 76 (BM!), shows it to be Ramalina terebrata. It is possible that the Kerguelen specimen may have been mislabelled or misplaced, since according to Crombie (1879a) the genus Ramalina does not occur there. Usnea barbata var. 6 sulphurea Taylor & J. D. Hook., Flora Antarctica 1: 194 (1845). This taxon was described from the Auckland and Campbell Islands and, although the type has not been traced, is probably referable to Usnea xanthopoga. Zahlbruckner (1930: 602) gives this variety as a synonym of U. sulphurea (i.e. U. sphacelata). Usnea cornicularia Ach., Lich. Univ.: 619 (1810). Type: New Zealand, Forster (UPS — herb. Thunberg 26348!). Zahlbruckner (1930: 601/2) cited this taxon as a synonym of Usnea sulphurea (i.e. U. sphacelata) whilst Motyka (1936) excluded it from the subgenus. The type specimen is a corticolous Usnea-like species of Ramalina (Galloway, 1985). Usnea falklandica Motyka, Lich. Gen. Usn. Stud. Monogr. 2: 472 (1937). Type: Falkland Islands, unlocalised (W — not traced). From the brief description of this species it could either represent a species of Protousnea or Usneas. lat., although not cited in the former by Krog (1976). Consequently this taxon may belong to the subgenus Usnea or even represent a scrambling form of U. aurantiaco-atra with scantily pigmented apices. 122 F. J. WALKER Usnea lutescens Stirton in Trans. Proc. N.Z. Inst. 30: 388 (1898). The unlocalised type, presumably from Australasia, has not been traced in BM or GLAM. If corticolous it might be referable to U. ciliifera (Motyka, 1937: 544), but if saxicolous it could be U. ciliata, and would then become the valid name for that species. Acknowledgements My sincerest thanks go to Mr P. W. James for his guidance, encouragement, and patience throughout the preparation of this work. I thank Mr J. K. Bartlett, Professor G. Degelius, Dr K. Kalb, and Dr R. D. Seppelt for loans of specimens and the directors and curators of the herbaria AAS, AD, BG, BLFU, BOL, C, CANL, CHR, E, FH, FI, G, GB, GLAM, H, HO, KASSEL, KIEL, L, LAM, LD, LINN, M, MB, MEL, NSW, NY, O, PC, S, STU, TRH, TROM, TUR, VER, W, WU, U, UPS, and US for the loan of material in their care. I thank staff as AAS, CHR, OTA, and WELT for all their help whilst working on their collections. I am also indebted to Dr R. I. L. Smith of the British Antarctic Survey for giving me access to the manuscript notes of Dr I. M. Lamb. My thanks go to Professor G. T. S. Baylis and Dr C. D. Meurk for assistance with field excursions in New Zealand. I also thank Dr D. J. Galloway, Mr E. S. Hansen, Mr P. W. James, Professor P. M. Jgrgensen, Dr H. Krog, Dr D. O. Ovstedal, and Dr R. I. L. Smith, amongst others, for informative discussion on distribution, ecology, and biogeography based on their own observations. Recognition for advice on various nomenclatural matters goes primarily to Mr J. R. Laundon, and also to Dr O. Almborn, Mr A. O. Chater, Professor P. M. Jorgensen, and Dr N. K. Robson. I thank Dr B. J. Coppins and Professor D. L. Hawksworth for assistance with interpretation of fine structures. I am also indebted to Miss K. P. Kavanagh of the British Museum (Natural History) for help in preparation of Latin diagnoses and to Miss A. M. Burnet and Dr A. Melderis for their language expertise. The photographs were taken by Mr P. R. Hurst of the Photographic Unit, BM, and thanks also go to Miss L. G. M. Hosking for typing the manuscript. References Acharius, E. 1803. 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An asterisk (*) denotes a figure or table. acanthella 2, 7, 10*, 11, 12, 13*, 15,19" :26;:31,.34, 38,42; 43,45, 47*, 48, 50, 79, 98, 117 Acharii 63 acromelana 5, 6, 7, 10, 12, 13*, 18 28s 22,23, 24,.274-30,.51, 35, 36, 37, 38, 40, 46, 48, 49*, 50, nf aes Vian aap ae cS HW ae Ly 77, 84, 85, 90, 92, 96, 98, 100, 103, 106, 120 activa 63, 70 adarense (Rhizocarpon) 31 adusta 114, 115 aeneofusca (Menegazzia) 30 Alectoria 7, 11, 24, 25, 29, 41, 43 alectoriae (Lecidea) 110 amaliae 115 amblyoclada (Mill.Arg.) Motyka 115 amblyoclada (Miill.Arg.) Zahlbr. LL 45,79, 185; 116" 177, angulosa 111, 113 anisomera (Buellia) 28 antarctica’5/6:°75:8" = 10* <1. 135. 14,19, 16%) 21°; 22,23, 204 20; 21, 205 295 DU, 31, 355,54; 995 905 38, 40, 41, 43, 46, 50, 54, 55, 56, Si yo8, 09, 00-5 OL, 02, 00,07, 69, 70, 84, 85, 92, 93, 95, 98, 100, 102, 103, 108, 110, 120, 121 antarctica (Umbilicaria) 26 antennarius (Neuropogon) 4, 11, 43, 62, 67, 68*, 69, 70 arboricola 4 aspidophora (Lecanora) 27 aurantiaca 39* , 63, 64 aurantiaco-atra 2, 5, 6, 7, 8*, 9*, D2 138s AAO 216" 21,22, 23524526; 21, 20s 294). 91; Sey 33; 34, 35, 36, 39*, 40, 43, 44, 45, 50, 56, 60, 62, 63, 64*, 65*, 66%, 07,06. 5 09270. 74.72". 135 74: 76, 82, 86, 88, 89, 100, 103, 108, 110, 113, 114, 121 aurescens 117, 119*, 120 barbata 121 bellidiflora (Cladonia) 25 blanda (Lecanora) 30 bogotensis 31, 79, 115 bornmuelleri 117 Bryoria 32 Buellia 29 Caloplaca 120, 121 candelaria (Xanthoria) 120 capensis 24, 115 castanea (Menegazzia) 30 Cetraria 37 ; Chlorea 4 ciliata (Mill.Arg.) Vainio 74 ciliata (Nyl.) Du Rietz 2, 5, 6, 7, Br 9" 12,15", 445 187 21 Ze, 25, 26, 27, 30, 32, 35, 40, 45, 50, 33;:60;,69. 70,71; 74, 75" 16", 77, 86, 88, 89, 90, 91, 96, 103, 104, 106, 107, 113, 115, 122 ciliifera 122 cinericola (Caloplaca) 121 condensata 79 contexta 35 coralligera (Polycaulonia) 120 coriacea (Siphula) 30 cornicularia 121 crassa 56, 59 crombiei 55, 59, 110 crystalligenum (Rhizocarpon) 31 cylindrica (Umbilicaria) 25, 31 dactylina (Pertusaria) 30 decipiens 38, 48, 49*, 52, 113 decussata (Umbilicaria) 31 densirostra 114, 115, 117 Densirostrae 115 direagens (Parmelia) 39 dunetza.15:3;:6.7,.10*, 11, -1372:15, ZO 2h 5 2) 31, 325 4, 385 AL; 42, 43, 46, 48, 50, 54, 59, 60, 78*, 79, 80, 84, 85, 95, 96, 98, 103, 117 dusenii (Protousnea) 11 eciliata 63, 70 egentissima 63, 70 elatior (Neuropogon) 11, 103, 111, 113 elegans (Xanthoria) 27 ericetorum (Cetraria) 37 Eumitria 43 Euusnea 3, 41, 42* Evernia 32, 41 falklandica 121 fasciata 2, 28, 29, 39*, 62, 65, 66*, 67, 68 fibrillifer (Neuropogon) 63, 70 flavicans (Cornicularia) 62, 71 florida 67 floriformis 55, 59 Foveatae 41, 42* frigida (Ochrolechia) 29 frigida (Usnea) 56, 92, 96 geographicum (Rhizocarpon) 30, 31 gilva (Pseudocyphellaria) 24 Glabratae 41, 42* glabratula 9 globosus (Sphaerophorus) 29 glomerata 115, 117 granulifera 55, 56, 60 hieronymii 114, 115 Himantormia 29 hyyppae 111, 113 igniaria 35, 115 inactivus (Neuropogon) 54, 120 inermis 21, 24, 35, 45, 48, 115, 117, 118*, 120 insularis 29, 33, 40, 55, 59, 110 irrubens (Lecidea) 30 islandica (Cetraria) 37 Jacquinii 63 kerguelensis (Orceolina) 33 kranckii 63, 67, 70 Laevigatae 41, 42*, 115 lambii (Neuropogon) 93, 95 laxissima 22, 38, 92, 93, 97* Lecanora 7, 29 Lecidea 29, 30, 31 Letharia 41, 121 Lethariella 4, 41, 43 Lethariopsis 120, 121 lucens (Menegazzia) 30 lugubris (Himantormia) 29 lugubris (Hypogymnia) 30 lutescens 122 macularis (Buellia) 30 melaxantha 2, 4, 11, 21, 22, 24, 36, 39* , 62, 64, 65*, 67, 70, 71 Melaxanthae 41, 42* Menegazzia 32, 34, 35 mexicana (Xanthoparmelia) 30 miniuscula (Alectoria) 29 mitis (Cladonia) 37 mougeotina (Parmelia) 30 muralis (Lecanora) 14 naumanii 111, 113 Neuropogon 4, 41, 42*, 43, 44 neuropogonoides, 1, 5, 7, 12, 13*, 14°20" ; 21,26; 27,.31,.52, 40,41, 42, 43, 44, 61, 70, 80, 81*, 82, 114 nidulifera 35, 115 nigricans (Alectoria) 22, 30, 37, 75 nigropallida 63, 70 nigropapillosa 79, 117 nobilis 35 normalis 63 nothofagi (Menegazzia) 30 nylanderiana (Umbilicaria) 31 ochroleuca (Alectoria) 109 olivacea (Parmelia) 25 130 pallida Motyka (Usnea) 35 pallidus Retz. (Lichen) 2, 92, 93 pallidus Schreber (Lichen) 92, 93 palmicola (Coccocarpia) 30 Parmelia 30, 41 Parmeliaceae 4, 7, 11 patagonica 1, 6, 7, 8*, 10*, 11, 13*, 147°155,207 {215 24s 2) ol, oes 38, 40, 42, 43, 46, 50, 54, 58, 59, 60, 79, 82, 83*, 84, 85, 86, 95, 98, 100, 101, 102, 103, 113, 114 perforata (Parmelia) 12 perpusilla 2, 6, 7, 8*, 9*, 11, 13%, 1415, 19% 21S 2731, 344.35; 38, 40, 44, 45, 58, 67, 71, 76, 84, 85, 86, 87*, 88*, 89, 97, 102, 108, 113 Pertusaria 29 petriseda (Parmelia) 30 Physcia 121 picata 92, 96 Placopsis 32, 34 poeppigii (Neuropogon) 4, 67 Polycaulonia 120 polytropa (Lecanora) 30 propagulifera 56, 59 Protousnea 4, 12, 31, 32, 36, 41, @2; 62, 121 prunastri (Evernia) 11 pseudocapillaris 1, 5, 6, 7, 10, 13%, 18*, 22, 26, 40, 46, 52, 53, 61, 89, 90, 91*, 92, 96, 106 Pseudocyphellaria 32 pseudofruticosa 56, 59, 121 pseudosorediosa (Parmelia) 30 pubescens (Pseudephebe) 29, 31 pulvinata 24, 116, 117 pustulata 38, 56, 58 Pycnocladae 42* Ramalina 42, 121 rangiferina (Cladonia) 29 regalis (Caloplaca) 27, 120, 121 regalis (Polycaulonia) 120 reticulata (Parmelia) 30 Rhizocarpon 29 roccellina 115 Roccellinae 41, 42*, 43, 115 F. J. WALKER rohmederi 2, 11, 86, 87*, 88 roseola 6 rugulosa (Caloplaca) 121 rugulosarium (Polycoccum) 121 russa (Buellia) 28 sarmentosa (Alectoria) 43 scabridula 92, 96 scopulorum (Ramalina) 121 scrobiculata (Protousnea) 82 Setulosae 115 signifera (Parmelia) 30, 120 siliquosa (Ramalina) 39 siplei 39* , 63, 67 soleirolii 4 sorediifera 55, 58, 60 spadicea 63, 67 sphacelata 2, 5, 6, 7, 8*, 10, 12, 19°, 14150 17, 19°, 21225233 25; 26,215: 28; S14: 34; 09; 9140s 40, 42, 45, 46, 48, 50, 54, 56, 58, 59, 60, 79, 85, 92, 93, 94*, 95, 96, 97*, 98, 99, 100, 101, 1025403321 Sphaerophorus 29 spongiosa (Solorina) 35 Steinera 36 Stereocaulon 29, 31 straminea (Cetraria) 13 striata 93 strigosa 67 strigulosa 39* , 63, 70 subantarctica 1, 6, 7, 10, 13*, 15, IT" 721g 24,215 ols ot o0sol: 38, 40, 43, 46, 50, 54, 59, 60, 85, 95, 96, 98, 99, 100, 101*, 102*, 103, 104, 114 subaurifera (Parmelia) 11 subcapillaris 2, 5, 6, 7, 12, 13*, 18*, 21, 22, 26, 30, 35, 40, 44, 45, 76, 77, 90, 91, 92, 96, 104, 105*, 106, 107, 108 subciliata Rasanen 111, 113, 114 subciliata Zahlbr. 63 subfloridana 9 subfoveolata 38, 56, 59 sublaevis Dodge 55 sublaevis Mill.Arg. 111, 113 subpapillata 38, 56, 59 subpolaris 92, 96 subrudecta (Parmelia) 30 subspadicea 67 substrigulosa 111, 113, 114 sulcata (Parmelia) 12, 30 sulphurea Taylor & J.D. Hook. 121 sulphurea Th.Fr. 2, 22, 28, 42, 48, 60, 92, 95, 96, 100, 102, 121 Sulphureae 41, 42* sulphureus J. K6énig (Lichen) 2, 92, 93 sulphureus Retz. (Lichen) 92, 93 superba (Pertusaria) 30 tasmanica (Xanthoparmelia) 30 taylorii5; 6, 7,8", 11,12, 139". 16", 21, 23, 29, 30, 32,36, 38, 40; 41, 43, 44, 59, 67, 69, 70, 71, 108, 109*, 110* Teloschistes 120 terebrata (Ramalina) 27, 121 tigrina (Ramalina) 42 torulosa 11, 12, 21, 22, 24, 30, 35, 39, 45, 46, 53, 54, 82, 115, 117, 119*, 120 trachycarpa 6, 7, 11, 12, 13*, 14, AS21225 235 2) 205 OUs Oly oss 34, 40, 43, 44, 45, 52, 67, 70, 71, 76, 79, 82, 84, 85, 86, 89, 100, 102, 103, 108, 110, 111, 112*, 1S) 444,145, 121 Trachycarpae 41, 42* trachycarpoides 111 trichoidea 74 Umbilicaria 25, 29, 30 ushuaiensis (Neuropogon) 86, 88*, 89 Usnea 4, 41, 42, 43 wandelensis (Endococcus) 121 wandelensis (Letharia) 120, 121* Xanthoparmelia 30 xanthopoga 22, 35, 121 Xanthoria 25 : yw Th a a: = ee ne - _ = "44 1 ep - : / aT, a a on _= . - ; > 6 a Uy 7 : gw | : » oem vy a. - LU ct - 7 : “ @ : ae a us _ aoe British Museum (Natural History) Ferns of Jamaica A guide to the Pteridophytes G.R. Proctor This flora records and describes the 579 species and 30 varieties of ferns occurring in Jamaica. The succinct species descriptions include relevant synonymy and incorpo- rate distributional data both within and outside Jamaica. Special emphasis is given to the subtle distinctions between closely related species and all genera are illustrated. Keys to the genera and species facilitate a wider use of the flora in the West Indies and northern South America. The author, one time Senior Botanist in charge of the Herbarium of the Science Museum, Kingston, Jamaica, is an outstanding field botanist and his expertise is reflected in the practicality of the flora and especially in the habitat and ecological information. This volume represents an important addition to our knowledge of the flora of the West Indies. 1985, 650pp (approx), 135 line illustrations, 22 maps. Hardback. 0 565 00895 1 £50.00 Titles to be published in Volume 13 The lichen genus Usnea subgenus Neuropogon. By F. Joy Walker | Cytotaxonomic studies of the ferns of Trinidad (3 papers). By A. C. Jermy & T. G. Walker Some genera of the Biddulphiaceae (diatoms) with interlocking linking spines. By Robert Ross & Patricia A. Sims Photoset by Rowland Phototypesetting Ltd, Bury St Edmunds, Suffolk Printed in Great Britain by Henry Ling Ltd, Dorchester Bulletin of the British Museum (Natural History) Cytotaxonomic studies of the ferns of Trinidad A.C. Jermy & T. G. Walker Botany series Vol 13 No 2 30 May 1985 The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. Papers in the Bulletin are primarily the results of research carried out on the unique and ever-growing collections of the Museum, both by the scientific staff of the Museum and by specialists from elsewhere who make use of the Museum’s resources. Many of the papers are works of reference that will remain indispensable for years to come. Parts are published at irregular intervals as they become ready, each is complete in itself, available separately, and individually priced. Volumes contain about 300 pages and several volumes may appear within a calendar year. Subscriptions may be placed for one or more of the series on either an Annual or Per Volume basis. Prices vary according to the contents of the individual parts. Orders and enquiries should be sent to: blications Sales, “CATIONS romwell Road, . London SW7 5BD, England. fy A | © Trustees of the British Museum (Natural History), 1985 The Botany series is edited in the Museum’s Department of Botany Keeper of Botany: Mr J. F. M. Cannon Editor of Bulletin: Mr J. R. Laundon Assistant Editor: Dr A. J. Harrington Editor’s Assistant: Miss M. J. Short ISBN 0 565 08005 9 ISSN 0068-2292 Botany series Vol 13 No 2 pp 131-276 British Museum (Natural History) Cromwell Road London SW7 5BD Issued 30 May 1985 Cytotaxonomic studies of the ferns of Trir Contents 1. The climate, geology, and vegetation of Trinidad with particular reference to nc ecmmavoriems, By Ay CG Jerniyss iin .ey eh ocv corners caw ewsawechacere cok 2. The cytology and taxonomic implications. By T. G. Walker....................0. 3. Descriptions of new species and hybrids and a new combination. ey rag G2 Perper Tr. WAUKCT ook s 5 .sac cas gancionsnenspiasonedascahysnvd¥anpeushinens' casters ‘e. Cytotaxonomic studies of the ferns of Trinidad 1. The climate, geology, and vegetation of Trinidad with particular reference to the ecology of ferns Anthony Clive Jermy Department of Botany, British Museum (Natural History), Cromwell Road, London SW7 5BD Contents VNU SIS sf roctaarsetvasedaacin scene ctr oraciiwiccawddlehe sven setine o doa 1-0-1-7 Submedian region (sm) 1-7-3-0 >1-7-3-0 Subterminal region (st) 3-0-7-0 >3-0-7-0 Terminal region (t) 7-Q—00 >7:0-<0 Terminal point (T) 00 00 length of the short arm of the chromosome, L/S. In the original paper the values for the ratios overlap at one or both end-points in each centromere range and this can lead to ambiguity e.g. a chromosome with a ratio of 3-0 could be classed as having its centromere either in the submedian or in the subterminal region (see Table 1). To obviate such ambiguities I have as standard practice eliminated the points of overlap, thus a particular ratio value corresponds to only one centromere position. Attention should be drawn to the fact that the T position is the least satisfactory one, all the others being easily determined. Here the centromere is deemed to be at the terminal point when no staining piece of chromosome can be detected distal to it. Such centromeres are very common in fern karyotypes but probably the T value quoted is an inflated one as it has been observed (Walker, unpub.) that a centromere may appear to be in the T position when the chromosomes are very contracted but may in fact be seen to be truly in the subterminal region (t) when the chromosomes are more relaxed. It is more probably the sum of the T + t centromeres that is important rather than both separately, although I have continued to record them as two categories. In general, partly because of the large numbers of chromosomes involved and partly because even both members of an homologous pair do not always contract to exactly the same length it is not possible to say with certainty which chromosome is homologous to which other one, only to establish degrees of affinity, except in certain well-defined cases, e.g. those with median point centromeres, satellites, etc. However, this lack of absolute precision does not affect the overall results and conclusions. For several species, in addition to the karyograms and Tables of centromere positions, the chromosome lengths have been presented in the form of histograms to illustrate specific points, and in particular to show deviations from the normal distribution curve which is typical of so many species. In a few cases conclusions drawn from the karyotypic data are stated without entering into detailed explanations as to how these conclusions have been reached. Such conclusions are based on more extensive work on ferns from other parts of the world and will be reported on in detail elsewhere. Karyotyping of ferns is still in its infancy and whilst it has been possible in a number of instances to draw conclusions it is equally important to collect as much data as possible which may be used to make comparisons and from which general principles may be extrapolated in the future. It is to these ends that the information is given here in what it is hoped may become a standard system of presentation, or at least one that can be adapted with a minimum of effort. Spore and stomata measurements Spore lengths are quoted in a number of cases and these are based on samples of 50 individual measurements made on specimens mounted in Euparal. The length is taken to include the perispore wing when present and the means, minima and maxima quoted have been rounded to the nearest 0-5 wm. The same sample sizes and approximations apply also to any stomatal lengths that are quoted. Stomatal lengths were measured on reconstituted, stained herbarium material, prepared as follows. Conveniently sized pieces of lamina were placed in a 6% aqueous potassium hydroxide solution to which an equal quantity of decolourised Fuelgen reagent was 154 FERNS OF TRINIDAD added and the whole incubated in an oven or on a hot-plate at c. 60°C overnight. After draining off the reagent and rinsing two or three times in water the material was taken up to 50% alcohol for examination and measurement. This treatment fully re-expands the cells and provides sufficiently intense magenta staining for accurate measurement. Notes on individual taxa Table 2 summarises the cytological results of this survey and gives the names of the authors of the taxa discussed. Both there and in the following text the term agamospory or agamosporous has been used in opposition to the term sexual. This replaces the inaccurate but very widely used terms apogamous or apogamy. For readers unfamiliar with the details of the several patterns of sporogenesis included under these terms comparative accounts are to be found in Lovis (1977) and Walker (1966b & 1979). Table 2. List of taxa and chromosome numbers. Collection numbers prefixed with J are collections of A. C. Jermy, those with T are of T. G. Walker. Locality numbers refer to map in Fig. 1. I and II indicate univalents and bivalents respectively. In Hymenophyllaceae the ploidies are given in parentheses to indicate the comparative levels attained as the original base numbers are debatable (see p. 179). Taxon Voucher Locality Chromosome Ploidy collection No. reference number FAM. I. MARATTIACEAE Danaea elliptica Smith T6715, T7066 14b n= 80 4x D. nodosa (L.) Smith T6580 33 n=c. 80 4x FAM. II. SCHIZAEACEAE Schizaea pennula (Swartz) Hook. T6294, T6301 T6307, T6327 30 T7374, T7378 aoe : T7380, T7388 Lygodium venustum Swartz J10844:1 12 2n = 116 4x L. micans Sturm J11001 8 2n = 58 Pa Anemia pastinacaria Prantl T6027, T6028 ‘F6036, T6038 12 ‘n’ = 114 IIs and 3x T6040, T6041 38 Is + 38 IIs agamosporous T6043, T6044 A. phyllitidis (L.) Swartz Fay 417 8 n=c. 76; 4x sexual 2n = c. 152 FAM. III. ADIANTACEAE: ADIANTOIDEAE Adiantopsis radiata (L.) Fée J2045 12 2n = 60 2x J10999:3 10 2n = 60 2x Pityrogramma calomelanos (L.) T6354 30 ¢. 761s + ¢..37 Hs, 5x sterile Link meiosis irregular hybrid Hemionitis palmata L. T6088 12 n= 30 2x Adiantum latifolium Lam. T6444 15a n = 60; 2n = 120 4x A. lucidum (Cav.) Swartz T11066, T11072 3 n = 30; 2n = 60 2x 17397, T11067 3 on = 60 2x T11068, T11071 J10996, J10978:3 10 2n = 60 2x A. macrophyllum Swartz T6667 18 n= 30 2x J11047 16 n = 30 2x A. petiolatum Desv. T6064 12 n= 30 2x T10523 12 2n = 60 2x J10945 16 n=c. 30 2x J11332 Tobago 2n = 60 2x A. pulverulentum L. T10632 7 n=c. 30 2x T10633 7 2n = 60 2x T10634 Tr n=c. 30; 2n = 60 2x T6614 37 n= 122 hyper-8x CYTOLOGY 155 Table 2 — cont. Taxon Voucher Locality Chromosome Ploidy collection No. reference number A. terminatum Kunze T6111 12 n= 60 4x T6435 15a n= 60 4x A. tetraphyllum Humb. & Bonpl. T10548 12 2n = 62 2x aneuploid ex Willd. J10874:1 15b 2n = c. 60 Bidin (1980) 2n = 58 2x J10874:2 15b 2n = c. 60 2x J10930:1 29 2n = c. 120 2n = 117 Bidin 4x aneuploid (1980) J10930:2 29 n= 60 4x J11065:1 2, 2n = c. 120; 2n = 114 Bidin 4x aneuploid (1980) J11279 Tobago 2n = c. 120; n = 58 Bidin 4x (1980) Simmons 171 13 2n = 58 Bidin 2x (1980) A. X variopinnatum Jermy & J11061 Z 90 chromosomes, 3x sterile T. Walker meiosis irregular hybrid (= A. latifolium xX petiolatum) J10993 10 90 chromosomes, 3x sterile meiosis irregular hybrid T6122, T6123 12 90 chromosomes, 3x sterile meiosis irregular hybrid A. villosum L. T11085 3 2n = 60 Pa T11082 3 n = 30; 2n = 60 2x sexual A. X villosolucidum Jermy & T10588, T10589 12 2n = 60; 2x sterile T. Walker meiosis irregular hybrid (= A. lucidum x villosum) T10590, T10591 2 On = 60 2x sterile T10592 hybrid FAM. III. ADIANTACEAE: VITTARIOIDEAE Polytaenium cajenense (Desv.) T7269 19 n= 60 4x Benedict P. feei (Schaffner ex Fée) J11260 14a 2n = 120 4x Maxon Anetium citrifolium (L.) T7037 14a n= 60 4x Splitg. FAM. III. ADIANTACEAE: PTERIDIOIDEAE Pteris arborea L. T7084 l4a n= 58 4x P. inaequalis (Fée) Jenman T6220 7 n= 58 4x T6792 6 n= 58 4x T10652, T10660 a T10763, T10765 ‘ on 16 a J11235 6 2n = c. 116 4x J11010:3 44 2n = c. 116 4x P. longifolia L. T11061 3 n= 58 4x T11062 3 n = 58; 2n = 116 4x J11064:2 Z n=c. 58 4x P. tripartita Swartz T6167, T6168 33 n=58 4x T7060 17 n= 58 4x T11026 7 2n =c. 116 4x Acrostichum danaeifolium T6935 42 n=c. 30; Fd 4 Langsd. & Fischer 2n = c. 60 T10917 30 2n = 60 2x 156 Table 2 — cont. FERNS OF TRINIDAD Taxon Voucher Locality Chromosome Ploidy collection No. reference number FAM. IV. HYMENOPHYLLACEAE Mecodium polyanthos (Swartz) T6825, T6920 6 n= 28 (2x) Copel. ¥7273 19 n= 28 (2x) Sphaerocionium hirsutum (L.) T6828, T6829 6 n = 36 (2x) CPreal Dish? 7 n= 36 (2x) S. X tucuchense Jermy & T6898 6 72 chromosomes, (2x) sterile T. Walker T6571 15a meiosis irregular hybrid (= S. ?elegans Sprengel x hirsutum) Vandenboschia hymenophylloides T7036 14a n= 36 (2x) (Bosch) Copel. T11012 6 n= 36 (2x) Trichomanes arbuscula Desv. T6383, T6386 30 ears (4x) T6393, T6396 T. crispum L. T6899 6 n= 128 (8x) T. crispum X ?robustum s.1. T6821 6 192 chromosomes; (6x) sterile meiosis irregular hybrid T. fimbriatum Backhouse ex T6830 6 n=c. 64 (4x) T. Moore T. pinnatum Hedw. T7062, T7064 12 n = 32 (2x) Feea osmundoides s.\. hybrid T6555, T6556 15b 64 chromosomes; (2x) sterile T6557, T6565 meiosis irregular hybrid Selenodesmium rigidum (Swartz) T7194 15a n = 33 (2x) Copel. Davalliopsis elegans T6698, T6704 os (LC. Rich.) Copel. T6707 ae no (2x) Didymoglossum angustifrons T7040 14a n= 34 (2x) Fée Microgonium kapplerianum T7038 14a n=c. 68 (4x) (Sturm) Pichi-Serm. Lecanolepis membranacea T7032, T7266 19 n = 34 (2x) (C. Presl) Pichi-Serm. Jermy s.n. 16 n= 34 (2x) FAM. V. GLEICHENIACEAE Dicranopteris pectinata T6083 12 n= 43 2x (Willd.) L. Underw. T6420 15a n= 43 2x T7321 7 n= 43 2x T10300, T10301 2 T10303 14b n= 43 2s re aaa 15a n= 43 2x Gleichenia bifida (Willd.) T10331 14b n= 34 2x Sprengel T10800 15a n = 34 2x G. interjecta Jermy & T10332 14b n= 68 4x T. Walker G. remota (Kaulf.) Sprengel T10335 14b n= 34 2x G. X pseudobifida Jermy & T10324, T10327 34 Is + 34 IIs; 3x sterile T. Walker T10328, T10329 14b meiosis irregular hybrid (= G. bifida xX interjecta) T10330, T10333 T6414, aed 15a 34 Is + 34 IIs; 3x sterile T6417 meiosis irregular hybrid T10801, T10805 T10806, T10807 15a 34 Is + 34 IIs; 3x sterile T10808, T10810 meiosis irregular hybrid T10811 G. X subremota Jermy & T6416 15a 34 Is + 34 IIs; 3x sterile T. Walker meiosis irregular hybrid (= G. interjecta X remota) G. brittonii (Maxon) C.Chr. T6789 6 n = 34 2x CYTOLOGY 15) Table 2 — cont. Taxon Voucher Locality Chromosome Ploidy collection No. reference number FAM. VI. POLYPODIACEAE: PLEOPELTOIDEAE Dicranoglossum desvauxii* (Klotzsch) Proctor T7076 14a n=c. 72 4x FAM. VI. POLYPODIACEAE: POLYPODIOIDEAE Polypodium loriceum L. T6809 6 n= 37 2x (= subg. Polypodium) P. sororium Humb. & Bonpl. T6233 a n= 74 4x ex Willd. T6925 15a n=74 4x (= subg. Polypodium) P. triseriale Swartz T6486, T6547 15a n= 37 2X (= subg. Polypodium) T6344 30 n = 37 2x T6349 30 n = 37; 2n = 74 2x P. ptilodon var. pilosum T7262 19 n = 37; 2n = 74 4x A. M. Evans (= subg. Polypodium) P. polypodioides (L.) Watt Trinidad sine 45 n= 74 4x (= subg. Polypodium) coll. et no. P. aureum L. T6628 a7 n=74 4x (= subg. Phlebodium) J11325:1 Tobago 2n = 148 4x J11325:2 Tobago 2n = 148 4x P. decumanum Willd. T6990, J2817 39 2n = 74 2x (= subg. Phlebodium) T7212 7 2n = 74 2x P. latum (T. Moore) T. Moore T10605 7 Myson 4 2x ex Sodiro J11044:1 16 n=37;2n=74 2x (= subg. Campyloneurum) J11214 16 n = 37 Ps 4 J11041:1, J11057 16 2n = 74 2x J10986 8 2n = 74 2x P. phyllitidis L. T7253, T7256 20 n= 74 4x (= subg. Campyloneurum) T7255 20 n = 74; 2n = 148 4x T11060 3 2n = c. 148 4x J10994:1 10 2n = 148 4x J10986:3, J10984 8 n= 74 4x J10986:2 8 2n = c. 148 4x J10986:1 8 n = 74; 2n = 148 4x J11326, J11366 Tobago 2n = c. 148 4x P. ciliatum Willd. T6199 33 n= 37 2x (= subg. Microgramma) P. lycopodioides L. T10883 15a n = 37 2x (= subg. Microgramma) FAM. VII. GRAMMITIDACEAE Grammitis taenifolia (Jenman) T6811 6 2n = 74 2x Proctor Cochlidium linearifolia (Desv.) T6810 6 n=c. 36 2x Maxon Xiphopteris serrulata (Swartz) T10976 6 ‘n’ = 105 Is 3x Kaulf. , agamosporous Trousdell 77 6 ‘n’ = 105 Is 3x agamosporous FAM. VIII. CYATHEACEAE Cyathea aspera (L.) Swartz T6412 15a n = 69 2x (= Trichipteris) C. microdonta (Desv.) Domin T7018 19 n = 69 Pa (= Trichipteris) J10984 15a n= 69 2x C. sagittifolia (Hook.) Domin T6831 6 n= 69 2x (= Trichipteris) Trousdell 69 6 2n = c. 138 2x * A specimen collected in Brazil (hort. Kew) proved to be n = 36 (2x). 158 Table 2 — cont. FERNS OF TRINIDAD Taxon Voucher Locality Chromosome Ploidy collection No. reference number C. surinamensis (Miq.) Domin T6487 1Sa n= 69 2x (= Sphaeropteris) T6713 14b n= 69 2x C. spectabilis (Kunze) Domin T6068 12 n = 69 2x (= Cnemidaria) T6991, T6992 15a n= 69 2x C. tenera (Hook.) T. Moore T7082 14a n= 69 2x (= Cyathea) FAM. IX. DENNSTAEDTIACEAE: DENNSTAEDTIOIDEAE Dennstaedtia bipinnata (Desv.) J11141 6 n=c. 94 4x Maxon JIATSS 14b 2n = c. 188 4x D. obtusifolia (Willd.) T10600 7 n= 46 2x T. Moore T10795 15a n= 46 2x Pteridium aquilinum var. T11056 3 2n = 104 4x arachnoideum (Kaulf.) Brade FAM. IX DENNSTAEDTIACEAE: LINDSAEOIDEAE Lindsaea lancea vat. falcata T10779 17 n= 41-44 2x (Dryander) Rosenst. L. portoricensis Desv. T6647 17 =c. 88 4x T10355 14b n = 86-88 4x L. stricta (Swartz) Dryander T6070 12 =c. 88 4x var. stricta L. stricta var. parvula T6357, T6368 30 n=c. 88 4x (Fée) Kramer FAM. X. THELYPTERIDACEAE Amauropelta oligocarpa (Humb. & 110674, T10688 6 n= 29 2x Bonpl. ex Willd.) Pichi-Serm. A. opposita (Vahl) Pichi-Serm. J11071 15a 2n = 58 2x J11296 Tobago 2n = 58 2x Macrothelypteris torresiana T6258, J2235 7 2n = 124 4x (Gaud.) Ching Goniopteris paucijuga (Klotzsch) T7056 14a 2n = 72 2x Pichi-Serm. G. pennata (Poiret) Pichi-Serm. T10555, T10557 12 n= 36 2x G. poiteana (Bory) Ching T6138 12 n= 72 4x T10891 7 n=c. 72 4x J11331 Tobago n=c. 72, 4x 2n = c. 144 G. nephrodioides (Klotzsch) Proctor T6796 6 n=72 4x G. X tabaquitensis Jermy & T6191, T6193 33 108 chromosomes; 3x sterile T. Walker T6194 meiosis irregular hybrid (= G. paucijuga X tetragona) G. tetragona (Swartz) C. Presl T7206 a2 n= 72 4x J11336 Tobago 2n =c. 144 Meniscium nesioticum T7013, T7014 19 n=72 ve (Maxon & C. Morton) T7016 Jermy & T. Walker T10479, T10480 12 n= 72 4x M. serratum Cav. T6160 33 n= 36 2x T6267, T6268 T6269, T6270 23 n = 36 2x T6272, T6273 J10930 29 2n = c. 72 2x Christella dentata (Forssk. ) T11029 7 n= 72 4x Brownsey & Jermy J10943 16 2n=c. 144 4x C. hispidulum (Decne) Holttum T6184 33 n= 36 2x T10548 12 n= 36 2x J11095 15a 2n = 72 2x CYTOLOGY 159 Table 2 — cont. Taxon Voucher Locality Chromosome Ploidy collection No. reference number C. patens (Swartz) Holttum T6781, T6782 18 n= 36 2x var. patens T10311 18 2n = 72 2x J11078, J11101 = J11108:1 15a 2n = 72 2x Amphineuron opulentum (Kaulf.) | 110312, 710340 18 n=72 4x Holttum J10920 24 n= 72 4x FAM. XI. ASPLENIACEAE: ASPLENIOIDEAE Asplenium abcissum Willd. T6845 6 n = 36 2x A. cristatum Lam. J2382, J11258:10 14a 2n = c. 144 4x A. hostmanniis.1. T6617 37 n = 72; 2n = 144 4x J11370 Tobago 2n = 108, 3x sterile meiosis irregular, hybrid C36)Is'-36)lis T7102 14a c.144chromosomes; 4xsterile meiosis irregular hybrid A. juglandifolium Lam. T7044, T7046 14a n= 144 8x A. macilentum Kunze ex T6833 6 ‘n’ = 288 Is, 8x Klotzsch 2n = 288 agamosporous A. salicifolium L. T6595, T6596 a: T6599 33 n= 144 8x A. serra Langsd. & Fischer J3004 14a 2n = c. 288 8x A. serratum L. T6164 mF 2n = c. 288 8x A. subhastatum Hook. T6806 6 n=c. 144 8x FAM. XI. ASPLENIACEAE: ATHYRIOIDEAE Diplazium caracasanum (Willd.) J10962:2 6 2n = 82 2x Kunze J11198 16 2n = 82 2x D. X papyraceum Jermy & T6176, T6179 37 123:Is: 3x sterile T. Walker T6180 meiosis irregular hybrid D. aff. centripetale (Baker) T7182 14a n=c. 82 4x Maxon D. cristatum (Desv.) Alston T6121 7 n=c. 82 4x T10500 12 2n = c. 164 4x D. grandifolium (Swartz) Swartz T6608, T6609 33 n=c. 164 8x D. aff. striatum (L.) C. Presl T6216 y n= 164 8x Hemidictyum marginatum (L.) T6409, aes = C. Pres 710792 oe neat = J10933:1, J11161 15a 2n = 62 2x J11194 15b n = 31; 2n = 62 2x FAM. XI. ASPLENIACEAE: TECTARIOIDEAE Ctenitis aripensis (C.Chr. & T7041 14a n= 41 2x Maxon) Lellinger C. kallooi Jermy & T. Walker T6794 6 n= 41 2x C. protensa var. funesta T7252 oT n=c. 82 4x (Kunze) Proctor C. sloanei (Poeppig ex Sprengel) T6676 14b n= 82 4x Morton Lastreopsis effusa subsp. T10613 7 n = 82 4x divergens (Willd. ex Schkuhr) T10573 12 2n = c. 164 4x Tindale T10568, T10569 12 n = 82; 2n = 164 4x Tectaria X bulbifera T6175 33 120 chromosomes; 3x sterile Jermy & T. Walker meiosis irregular hybrid (= T. incisa X vivipara) T. heracleifolia (Willd. ) J10989 8 2n = c. 160 4x L. Underw. 160 Table 2 — cont. FERNS OF TRINIDAD Taxon Voucher Locality Chromosome Ploidy collection No. reference number T. incisa Cav. T6136 12 2n = 160 4x T6148 i n=c. 80 4x T6972 36 n= 80 4x J10971:1, J10971:2 15a 2n = c. 160 4x J10976:3 8 2n = c. 160 4x J11368 Tobago n= 80 4x T. plantaginea Maxon T6691, T6695 = paige T6696, T6731 | a Bese = T. orbicularis Jermy & J10941:1 16 2n = c. 80 2x T. Walker T. ramkissoonii Jermy & T7088 14a n= 80 4x T. Walker T. trifoliata (L.) Cav. T6748 14b n= 40 2x T. vivipara Jermy & T. Walker TOL71;. T6173 BK) n= 40 2x Hypoderris brownii J.Smith J10970 15a n=c. 40 2x T6205 i n = 40; 2n = 80 2x Cyclopeltis semicordata T7202, T7203 32 n= 41 2x (Swartz) J.Smith Didymochlaena truncatula T6456 14a 2n = c. 82 2x (Swartz) J.Smith FAM. XI. ASPLENIACEAE: DRYOPTERIDOIDEAE Polybotrya caudata Kunze T6996 15a n=c. 41 2x J11158 15a n= 41 2x J10826 24 n= 41 2x P. cervina (L.) Kaulf. T6215 7 n=41 2x T6998 15a n=41 2x T7261 19 n= 41 2x J10857 15b n= 41 2x J10958 110966:1, 310966:2) A ee * P. osmundacea Humb. & Bonpl. J10924:1 27 2n = c. 82 2x ex Willd. FAM. XI. ASPLENIACEAE: LOMARIOPSIDOIDEAE Bolbitis hemiotis (Maxon) Ching J11156 14b n = 41; 2n = 82 2x T10317 14b 2n = c. 164 4x B. portoricensis (Sprengel) T/221 7 2n = c. 82 2x Hennipman Lomariopsis marginata Kuhn T6214 r n= 41 2 T6161 37. n= 41 2x FAM. XI. ASPLENIACEAE: ELAPHOGLOSSOIDEAE Elaphoglossum crinitum (L.) T10989, T10990 6 2n = 82 2x Christ E. glabellum J.Smith T7316 6 2n = c. 82 2x E. herminieri (Borg & Fée) T7340 7 n= 41 2x T. Moore E. lingua (Raddi) Brackenr. J2692 6 2n = 82 2x E. longifolium (Jacq.) J.Smith T7030 19 2n = c. 82 2x T7085 l4a n= 41 2x 311123:5 6 n=c. 41 2x E. pteropus C.Chr. T6895 6 2n = c. 82 2x E. rigidum (Aublet) Urban J11192:3 15b n= 41 2x E. schomburgkii (Fée) T. Moore J11183:1 15a 2n = c. 82 2x FAM. XI. ASPLENIACEAE: OLEANDROIDEAE Oleandra articulata (Swartz) T6405 30 n= 41 2x C. Presl CYTOLOGY 161 Table 2 — cont. Taxon Voucher Locality Chromosome Ploidy collection No. reference number Nephrolepis biserrata (Swartz) T6987 39 n= 41 2x Schott N. rivularis (Vahl) Mett. T6353 30 n= 41 2x FAM. XII. BLECHNACEAE Blechnum Xcaudatum Cav. 17226; 1.7232 7 93 chromosomes; 3x sterile (= B. fraxineum X occidentale) 17260, T10717 meiosis irregular hybrid T10915 7 2n = 93; 3x sterile meiosis irregular hybrid B. fraxineum Willd. T6243 7 n= 31 2x J10981 8 2n = 62 2x Fay s.n. s.loc. 2n = 62 2x T7230 7 n= 62 4x Fay NY3, Fay NY6 s.loc. n = 62, 2n = 164 4x B. occidentale L. T6137, J10837 12 n= 62 4x T7241, sie 7 ae 4 T10908 ae . =e 15a 2n = 124 4x J11278 Tobago n= 62 4x J11282, J11283 Tobago 2n = 124 4x B. serrulatum L. C. Rich. T6937 42 n= 36 2x (B. indicum sensu T. Walker, JA9295:1, J11215:3 30 2n = 72 2x 1966a) Salpichlaena volubilis (Kaulf.) T6413 15b n= 40 Pe 4 J.Smith T10831 15a n= 40 2x J10915 15a 2n = 80 2x J11293 Tobago 2n = 80 2x I. MARATTIACEAE 1. Danaea Smith Walker (1966a, 1973b) reported on the cytology of three species of this genus, namely D. jenmanii L. Underw. from Jamaica, D. elliptica from Trinidad and D. simplicifolia Rudge from Surinam. Each had a chromosome count of n = 80 or 2n = 160, which were assumed to be at the tetraploid level on a base number of x = 40 which is common to the five genera which have been examined in the family, results lacking only for Archangiopteris and Protomarattia. Although x = 39 has been found in some species of Marattia other members of the genus show x = 40 and the former number is considered to be secondarily derived. That the base number is indeed 40 in Danaea and not, for example, 20 is further supported by the finding in Jamaica (Walker, 19662) of a triploid hybrid between D. jenmanii and D. jamaicensis L. Underw. which shows 40 bivalents and 40 univalents at meiosis. The count of n = 80 for a Trinidadian plant of the small species D. elliptica was photograph- ically validated (Walker, 1966a) and the same result has now been obtained from a second plant from the Aripo Valley. The much larger species, D. nodosa, with fronds up to 2 m long has also proved to be tetraploid with n = 80. Sorsa (in Odum & Pigeon, 1970) has recorded n = 116 for this species in Puerto Rico but this count is clearly discordant with present evidence and needs further investigation. Because of the very characteristic morphology and the distribution restricted to the neotro- pics, Danaea has been separated off by some authors as a family Danaeaceae. However, the cytology does not warrant a split and details of the karyotype (Walker in prep.) indicates the affinity of Danaea to other members of Marattiaceae. 162 FERNS OF TRINIDAD Il. SCHIZAEACEAE 1. Schizaea Smith Schizaea pennula grows locally in relative abundance on the raised banks well above the wet-season water level of Aripo Savanna. Despite the shortly creeping character of the rhizomes the fronds are very tightly tufted. Digitate fertile regions or sorophores seen on the fronds of this species characterise a small group having a wide world-distribution and which some authors, e.g. Lellinger (1969), Bierhorst (1971) and Pichi Sermolli (1977), maintain as a distinct genus Actinostachys, in contrast to members of Schizaea s.str. which have pinnate sorophores. Cytologically the two genera or subgenera, if they be recognised as such, are very similar in having high chromosome numbers and S. pennula is no exception, with n = 134 being very clearly demonstrated in two specimens (Fig. 3) and approximately confirmed in another six plants. A very wide range of chromosome numbers, up to n = c. 540, has been demonstrated for the dozen or so species which have been examined and these are set out in Table 3. Other unpublished counts by myself on several plants from Papua New Guinea and Sarawak confirm the general picture with gametic numbers ranging from n = c. 76 ton = c. 100. It is evident that in Schizaea there is a somewhat parallel situation to that found in Ophioglossum in which high chromosome numbers are involved and which undoubtedly represent high levels of polyploidy coupled with loss or gain of individual or small numbers of chromosomes. No doubt individual genes are present in multiplicate so that loss or gain of a few chromosomes has little effect on the viability or fertility of the plant, thus permitting the accumulation of a series of numbers which make little or no arithmetical sense. What is certain is that the assertion that these chromosome numbers probably derive from base numbers of 9, 11, and 12 (Pichi Sermolli, 1977) cannot be maintained on present evidence. Fig.3 Schizaea pennula, T7378, meiosis showing 134 bivalents, x 1000. CYTOLOGY 163 Table 3 Chromosome numbers in Schizaea s. lat. Species Chromosome Locality Author number Subgenus SCHIZAEA S. fluminensis Miers ex Sturm n=c. 72 Brazil Araujo (1976) S. asperula Wakef. n=77 New Zealand Lovis (1958) S. dichotoma (L.) Smith n=77 New Zealand Lovis (in Holttum, 1959) S. fistulosa Labill. var. australis (Gaudich.) J. D. Hook. n= 94 New Zealand Brownlie (1965) S. robusta Baker n= 96 Hawaii Wagner (1963) S. pulsilla Pursh n= 103 U.S.A. Wagner (1963) S. incurvata Schkuhr n=c. 154 Brazil Tryon, Bautista & Araujo (1975) S. fistulosa Labill. n=c. 270 New Zealand Brownlie (1965) S. dichotoma (L.) Smith n=c. 540 New Zealand Brownlie (1961) Subgenus ACTINOSTACHYS S. pennula (Swartz) Hook. n= 134 Trinidad Walker (present comm.) S. boninensis (Nakai) H. Ohba n= 140 Bonin Island Mitui (1973) S. digitata (L.) Swartz n = 325 + 30 Sri Lanka Lovis (in Holttum, 1959) n = 350 — 370 S. India Abraham, Ninan & Mathew (1962) 2. Lygodium Swartz Roy & Manton (1965) demonstrated the existence in Lygodium of three base numbers forming an aneuploid series, namely x = 28, 29, and 30. L. micans and L. venustum are two common Trinidad species, climbing in secondary forest, abandoned farm land or at the edge of primary forest where the light intensity is relatively high. Both species are based on x = 29, the former species being diploid with 2n = 58 (Figs 4A & SA) and the latter tetraploid with 2n = 116 (Figs 4B & 5B). Whilst the chromosome lengths of L. micans show a normal distribution those of L. venustum clearly shows a bimodal distribution (Fig. 6A) suggesting the presence of two structurally different genomes and hence an alloploid origin of the latter species. This situation is also paralleled in members of the x = 28 series as seen in the illustration by Roy & Manton (1965) showing tetraploid L. flecuosum from North Borneo (2n = 112) as having chromosomes of two size classes whilst those of the diploid members were more uniform in length. Fay (1973) reported a putative hybrid between L. venustum and L. micans from Trinidad but this was sterile and no cytological information is available for this interesting plant. A sporeling which was alleged to be of this hybrid was sent to Newcastle by A. C. Jermy but unfortunately did not survive long enough to be cytologically examined. A fully mature fertile specimen in herb. T. G. Walker was overlooked until attention was drawn to it byC. D. Adams. It had sheda golden mass of spores in its folder as do fertile species, but on examination these spores were all misshapen and obviously non-viable (Fig. 4F). It may be noted that a heavy shedding of abortive spores on this scale is most unusual in the majority of sterile fern hybrids. The hybrid clearly shows heterosis, the fertile ‘pinnae’ being much longer than those of either of the parental species (compare Fig. 6D with Fig. 6B & C) and the same is true of the sterile plant illustrated by Fay. This latter specimen was collected by her near Guayaguayare in south-east Trinidad, whilst T6960 came from the south-west corner at Irois. This hybrid appears not to be rare and has been named L. xX fayae in honour of Dr Alice Fay. A comparison of the morphological features of the fertile fronds of L. x fayae and its parents is given in Table 4. A species which is very similar in appearance to L. micans is L. volubile Swartz and doubts have been expressed as to whether or not L. micans and L. volubile may be synonymous. However, L. volubile in Jamaica at least differs from L. micans in Trinidad in cytology, the 164 FERNS OF TRINIDAD Fig. 4 Lygodium. A, L. micans, J1101, mitosis, 2n = 58, x 1000. B, L. venustum, J10844, mitosis, 2n = 116, x 1000. C, L. volubile ,T4389 (Jamaica), spores, x 650. D, L. venustum, T6013, spores, x 650. E, L. micans, T6526, spores, X 650. F, L. x fayae, T6960, spores, x 300. 165 CYTOLOGY \ aS 12 3 TTL TL 10 a 7 0-33 wm. Fig.5 Lygodium. A, L. micans, J11001, karyogram, 2n = 58. B, L. venustum, J10844, karyogram, 2n 116. Each unit of length 166 FERNS OF TRINIDAD 17} i No of chromosomes ro) = NO CB OO St OO 7890 1112 84 5 6 17 8 Chromosome length Fig.6A Lygodium venustum, J10844, histogram of chromosome lengths. Each unit of length = 0-33 wm. Fig. 6B-D Lygodium. B, L. micans, T6144, silhouette of fertile pinna, x 1/4. C, L. venustum, T6013, silhouette of fertile pinna, x 1/4. D, L. x fayae, T6960, silhouette of fertile pinna, x 1/4. CYTOLOGY 167 Table 4 Comparison of Lygodium venustum, L. micans, and their hybrid L. x fayae. Character L. venustum L. X fayae L. micans 1. Pinna length short (c. 16 cm) long (c. 30 cm) short (c. 16cm) 2. Pinnule rachis very hairy intermediate more sparsely hairy 3. Number of pinnules c. 6 pairs c. 7 pairs 2-3 pairs 4. Pinnule dissection deeply lobed at base deeply lobed at base entire or pinnate or pinnate 5. Pinnule length (L) short (40 mm) long (100 mm) long (100 mm) 6. Pinnule breadth (B) narrow (c. 8 mm) narrow (c. 10 mm) broad (c. 18 mm) 7. Pinnule L/B ratio aS c. 10 c. 5-6 8. Fertile segments few (20-40) numerous (80—100+) numerous (80—-100+) per pinnule 9. Spores well-filled abortive well-filled former being hexaploid (Walker, 1966a) and the latter diploid (present comm.). There are also appreciable differences in spore morphology (Fig. 4C & E). The spore morphology of these two species contrasts markedly with that of L. venustum (Fig. 4D). 3. Anemia Swartz Two species of this predominantly American genus have been investigated from Trinidad, namely A. phyllitidis and A. pastinacaria. The former species was raised at Newcastle from spores collected from a dried specimen sent to me by Dr Alice Fay and it proved to be a sexual tetraploid with n = c. 76 and 2n = c. 152. This is in agreement with plants of this species from Mexico (Sorsa in Fabbri, 1965; Smith & Mickel, 1977) and Costa Rica (Gomez-Pignataro, 1971). Similar additional counts have been obtained from Sri Lanka, where it is an introduced species (Manton & Sledge, 1954) and from several sources of botanic garden material. Mickel (1982) reported meiotic counts of 114 for two specimens of A. pastinacaria from Mexico and n = 106 and 119 respectively for a further two plants. There is a discrepancy in that, in his Table 2, Mickel shows this species as being hexaploid but in the text (p. 409) he states that the spores show some abortion, suggesting that it is a triploid apomict, at least in Mexico. In Trinidad A. pastinacaria proved to be a triploid agamosporous species with those spore mother cells which were destined to give rise to functional spores showing 114 bivalents at meiosis (Fig. 7C & D). Cells from other sporangia showed an irregular meiosis, the chromosomes being associated as 38 univalents and 38 bivalents (Fig. 7A & B). At maturity there was a mixture of very spinous, ridged, well-filled spores intermixed with non-functional misshapen ones, a feature which when considered in conjunction with the cytological details indicates that this is agamospory of the common Dépp-Manton type. Only one other case of agamospory has been reported in Anemia, namely A. tomentosa var. anthriscifolia (Schrader) Mickel and this was triploid also (Mickel, 1962). The important contribution to the cytology of Anemia by Mickel (1962) in the reporting of results for 11 taxa has been overlooked by both Fabbri (1963, 1965) and Léve, Love & Pichi Sermolli (1977) in their compilations of chromosome numbers. In all, 15 taxa, representing each of the three subgenera (Anemia, Anemiorhiza, and Coptophyllum) had been cytologically investigated and comprise diploids, triploids, tetraploids, and hexaploids. All are based on a chromosome number of x = 38, which has also been found for Mohria (Lovis & Roy, 1964) and contrasting with the somewhat indeterminate nature in Schizaea (q.v.) and the number found in Lygodium (x = 28, 29 and 30). Pichi Sermolli (1977) has used the distinctive chromosome number, together with other morphological evidence to separate Anemia and Mohria as a family, Anemiaceae. Similarly, he recognises Schizaeaceae and Lygodiaceae as the other components of what is usually recognised as a single family Schizaeaceae. 168 FERNS OF TRINIDAD Fig. 7 Anemia pastinacaria, T6638. A, meiosis, showing 38 bivalents + 38 univalents, Pape se. & — << ak - Fig. 10 Adiantum pulverulentum. A, T6614, meiosis, n = 122, x 1000. B, T10633, mitosis, 2n = 60, x 1000. C, explanatory diagram of B (a few chromosomes are completely out of focus in the photograph), x 1000. Vida, 1968) but all have had fewer chromosomes than expected and variously rank as hypotetraploids, hypooctoploids, and hypodecaploids. A. pulverulentum is most remarkable in that the great difference in ploidy between the two cytotypes (2x versus c. 8x) is not accompanied by morphological differences, and I have been unable to distinguish between these cytotypes on any criteria other than that of chromosome number. It seems highly probable that autoploidy is involved here with suppression of multivalent formation at meiosis and a comparison of the karyotypes of the two forms would have been most instructive. However, living material is no longer available for this purpose. A. tetraphyllum is another case in which both ploidy differences and aneuploidy occur. The single representative of this species reported from Jamaica was tetraploid and sexual in which the chromosome number could not be determined with complete accuracy and was recorded as n = 58-60, 2n = 116-120 (Walker, 1966a). A further Jamaican plant from a totally different locality has since been found to be tetraploid also. Eight plants have been investigated from several areas in Trinidad and Tobago, half the plants being diploid and the other half tetraploid. The two ploidies were represented in at least three different localities each, hence the conclusion is that a given cytotype is not particularly restricted in its distribution but is widespread in the country. Aneuploidy is also superimposed on the situation, small deviations from strict multiples of the base number being found in both diploids and tetraploids. Thus, the somatic 172 FERNS OF TRINIDAD numbers 2n = 114, 117 and 118 were found in three different tetraploid plants and 2n = 62 ina diploid plant. In these instances it is clear that both loss or gain of up to a few chromosomes are tolerated equally well. It may be pointed out here that although the pinnules of A. tetraphyllum vary considerably in morphology, ranging from shortly oblong to being much longer and with a very attenuated tip, this variation is not apparently correlated with cytological differences. The bipinnate, tetraploid A. latifolium is a common fern in Trinidad and frequently grows intermixed with the simply pinnate, diploid A. petiolatum. Both these species have a regular meiosis, forming 60 bivalents and 30 bivalents respectively. However, five plants were collected from four different localities in the Northern Range which proved to be triploid with irregular meiosis. More detailed analyses showed a range of chromosome pairing from 22 bivalents plus 46 univalents to 30 bivalents plus 30 univalents. All these triploid plants are clearly sterile hybrids of A. latifolium x A. petiolatum and their affinity to both parents is strikingly illustrated in Fig. 11C & D which show two fully fertile fronds collected in the field from the same individual plant. Whilst one of the fronds (Fig. 11C) is simply pinnate and shows a strong resemblance to A. petiolatum (Fig. 11A) the other frond (Fig. 11D) is bipinnate, albeit weakly so, and is close in appearance to A. Jatifolium (Fig. 11F). Because of the variable appearance of this hybrid it is » > ~~ ~ 7% mas } A G D F gl Sa = , Fig. 11 Adiantum. A, silhouette of A. petiolatum (2x), < 1/4. B, pinna of A. petiolatum, x 1. C & D, silhouettes of A. X variopinnatum (3x), X 1/4. E, pinna of A. X variopinnatum, X 1. F, silhouette of A. latifolium (4x), X 1/4. G, pinnule of A. latifolium, x 1. y CYTOLOGY 173 being given the name A. X variopinnatum. As has been noted above, this hybrid has been found in several localities in Trinidad and almost certainly occurs elsewhere in the Caribbean and on the mainland. Supporting evidence for this is the comment by Proctor (1977) in his Flora of the Lesser Antilles — Pteridophyta that the pinnae are simple in A. petiolatum but that rarely the basal ones are pinnate. The undersides of the fronds of A. /atifolium, A. petiolatum, and A. Xx variopinnatum are markedly glaucous, especially in the living state, and bear numerous discrete sori on the margins in sharp contrast to the other species of Adiantum with which they might be confused. A comparison of the features of these three taxa is given in Table 6. Typical pinnae and pinnules are shown in Fig. 11B, E, & G. Table6 Comparison of Adiantum petiolatum, A. latifolium, and their hybrid A. X variopinnatum. Character A. petiolatum A. X variopinnatum A. latifolium 1. Rhizome short, creeping intermediate, long, creeping creeping 2. Frond spacing shortly spaced intermediate widely spaced 3. Pinnation simply pinnate simply pinnate or bipinnate bipinnate 4. Lateral pinnae absent one pair only; short up to 2 or 3 pairs in comparison with + equal in length terminal pinnae to terminal pinnae 5. Cytology diploid sexual, triploid sterile, tetraploid sexual, meiosis regular meiosis irregular meiosis regular 6. Spores well-filled, viable abortive, non-viable well-filled, viable Several species of Adiantum grow along the dry, exposed path-sides in the uppermost part of Lady Chancellor’s Drive in the hills overlooking Port of Spain. Two of them, A. lucidum and A. villosum, proved to be sexual diploids each having 60 somatic chromosomes and a regular meiosis with the formation of 30 bivalents. Young plants which were identified in the field as A. lucidum were also collected from the Caura Valley and sent back to Newcastle for cultivation. These were cytologically examined on reaching maturity and all proved to be diploid but whilst some consistently showed the formation of 30 bivalents at meiosis the others showed irregular pairing. An analysis of 10 cells is presented in Table 7 and clearly shows that the pairing relationships of the chromosomes are not constant, varying from instances in which only half the chromosomes are paired to those in which only bivalents are formed. This latter pattern of behaviour allows for the possibility of a small percentage of viable spores being formed with genetical and morphological consequences that will be considered more fully later. These plants with irregular meiosis were diagnosed as being hybrids between A. lucidum and A. villosum and have been described as A. X villosolucidum (Jermy & Walker, 1985). Immature plants of A. lucidum, A. villosum and A. X villosolucidum are very similar in appearance (Fig. 12 B, E, & H) not only in being simply pinnate but also in a number of other details such as the pinna shape, type of scales on the fronds, the dark green colouration, etc. However, when fully mature, A. villosum and A. lucidum differ greatly, the former being bipinnate with short pinnules and the latter simply pinnate with very long pinnae (Fig. 12A & G). There are also marked differences in the texture in that the pinnae of A. lucidum are markedly thick and fleshy contrasting with the thin and papery character of A. villosum, the hybrid A. x villosolucidum occupying an intermediate position. All have single linear sori occupying the upper and lower pinna/pinnule margins (Fig. 12C, F, & I) in contrast to the numerous discrete sori seen in the A. Jatifolium—A. petiolatum complex. This character therefore clearly distinguishes A. X villosolucidum from A. latifolium and A. X variopinnatum with which it might be confused (cf. Fig. 11E & G). A comparison of A. villosum, A. lucidum, and their hybrid is presented in Table 8. 174 FERNS OF TRINIDAD Table 7 Analysis of meiosis in two plants of Adiantum x villosolucidum. No. of cells Chromosome pairing 1 30 I Bi 2511 + 101 2 Zoi 161 3 1911 +221 Z 15 II + 301 ——_ SS" Fig. 12 Adiantum. A, silhouette of A. villosum (2x) mature, x 1/4. B, silhouette of A. villosum, immature, X 1/4. C, pinnule of A. villosum, x 1. D, silhouette of A. X villosolucidum (2x), mature, X 1/4. E, silhouette of A. X villosolucidum, immature, X 1/4. F, pinnule of A. x villosolucidum, x 1. G, silhouette of A. /ucidum (2x), mature, x 1/4. H, silhouette of A. lucidum, immature, X 1/4. I, pinna of A. lucidum, X 1. CYTOLOGY 175 Table8 Comparison of A. villosum, A. lucidum, and their hybrid A. x villosolucidum. Character A. villosum A. X villosolucidum A. lucidum 1. Pinna arrangement bipinnate up to bipinnate up to simply pinnate 6 pairs 3 pairs numerous 2. Pinnules crowded, overlapping numerous, distant absent 3. Texture thin, papery intermediate thick, fleshy 4. Petioles polished polished usually dull 5. Cytology diploid sexual, diploid sterile, diploid fertile, meiosis regular meiosis mainly meiosis regular irregular 6. Spores well-filled, viable mainly abortive, well-filled, viable non-viable In cultivation A. X villosolucidum is very slow to reach full maturity, its hybrid nature in the earlier stages sometimes being betrayed by the presence of an irregularly-shaped (see Fig. 12E) or forked lowest pinna. Sometimes several years may pass before the final form is reached and indeed even after this the plant may revert to producing the simple form fronds for a period. The two examples quoted above of naturally-occurring hybrids in Adiantum illustrate some of the complexities and difficulties of interpretation of a basically simple situation had there been no knowledge of the cytological background or of the behaviour of the plants in cultivation. The A. latifolium—A. petiolatum situation is the simplest where the two very different-looking parents give rise to a sterile hybrid which may produce mature sporangia-bearing fronds resembling either one parent or the other fairly closely, or may indeed produce both simul- taneously on the same rootstock. Without this background knowledge it would be perfectly possible to classify two fronds taken from the same rhizome as belonging to the two different parental species. The situation is more complex in the A. /ucidum — A. villosum group. Here the fully mature fronds of both species and hybrids are strikingly different from one another but less mature fronds are all simply pinnate and look very much alike. These latter fronds may nevertheless produce sori (as is the case in ‘immature’ A. villosum in Fig. 12B) and could be mistaken for a fourth taxon. A further complication may arise out of the meiotic behaviour in the sporangia of the hybrid A. x villosolucidum (Fig. 13A-F). Here, although the large majority of the spores produced are abortive as a result of the irregularity of bivalent formation in a high percentage of spore mother cells, nevertheless some spore mother cells undergo regular meiosis and are potentially capable of producing viable spores. As a result the possibility exists that there may be introgression of genes from one species to the other on a small scale and concommitantly a further range of morphological forms due to genetic segregation. To test this possibility spores need to be sown which have been gathered from plants of A. Xx villosolucidum which have been grown in isolation from other members of the genus. Taking an overall view it appears that some at least of the members of Adiantum are showing a cytological behaviour which is largely unfamiliar in ferns. Speciation in the case of A. villosum and A. lucidum seems to be by an accumulation of genetic differences accompanied by a much slower breakdown of chromosome homologies, such that pairing in the hybrid is not fixed but shows a variable response, and the same may be true of A. petiolatum and one of the parental species of A.latifolium. Whilst aneuploidy is often characteristic of different groups of species in a genus, e.g. in Blechnum with base numbers ranging from x = 28 to x = 36, each species is itself very stable and has a single chromosome number (or direct multiple). By contrast, in Adiantum not only may different species show deviations from exact multiples of the basic chromosome number but this may also occur within species. It would appear that in marked contrast to other ferns Adiantum is extraordinarily well-buffered against possible adverse effects of such changes, differences in chromosome numbers also being found in diploids and not just confined to high polyploids where loss or gain of a few chromosomes may reasonably be assumed to be less harmful, as in the case of Ophioglossum, Schizaea, etc. 176 FERNS OF TRINIDAD bt 1®e r a Ye gt o eee ot ace 3 ‘? ae 0 Oo? 333; & Pa. os NS “ss onsairé B D ° FNSe, Fig. 13. Adiantum X villosolucidum, T10590. A, meiosis, showing 15 bivalents + 30 univalents, x 1000. B, explanatory diagram of A (bivalents solid, univalents outlined), x 1000. C, meiosis, showing 19 bivalents + 22 univalents, x 1000. D, explanatory diagram of C, x 1000. E, meiosis, showing 30 bivalents, oat 4 9 es ‘8 ge 5 oa : ye < 14 Ps 5 > es ce C ; 12+ 11+ o of Or o 8+ 0 S385 7t = aso Zo0 6+ 0 ° Q oe 3 ra oo 8 S ° al 0 & o Pi he 98 3r a) at Q \ 1 0 Yo 5567S 9D NRBMB BT 8 Chromosome length D Fig. 26 Polypodium (subgenus Phlebodium). A, P. auream, AAU 3183 (2x), karyogram, each unit of length is 0:33 wm. B, P. aureum, J 11325 (4x), histogram of chromosome lengths. C, putative spontaneous triploid hybrid of P. aureum (4x) x P. decumanum (2x), meiosis, X 1000. D, explanatory diagram of C showing 111 univalents, x 1000. 200 FERNS OF TRINIDAD A Fig.27 Polypodium (subgenus Phlebodium). A, silhouette of P. decumanum (2x), X 1/7. B, silhouette of putative spontaneous triploid hybrid, P. aureum (4x) x P. decumanum (2x), X 1/7. C, silhouette of P. aureum (4x), X 1/7. B C Subgenus Campyloneurum P. phyllitidis and P. latum are common ferns in Trinidad and superficially look alike with their large simple fronds. They are, however, reasonably distinct here in the absence versus presence of stipe, the yellow-green versus dark green colour, and the flat versus undulate surface of the lamina. An additional feature which appears to have been overlooked is the presence of small hairs on the under-surface of the frond in P. latum and which are lacking in P. phyllitidis. Stolze (1981) states that he considers P. latum to be only a variety of P. phyllitidis, as in his view many of the features used to separate the two species are not always constant. However, as far as Trinidad and Tobago are concerned, they are distinct and certainly there is a sharp cytological discontinuity between them. Plants from several different localities of these two taxa show P. latum to be diploid and sexual with n = 37, 2n = 74, whilst P. phyllitidis is a sexual tetraploid with n = 74, 2n = 148. Previous reports for these species have shown P. phyllitidis to be also tetraploid from Florida (Evans, 1963; Wagner, 1963), Jamaica (Walker, 1966a, 1973b), and the Galapagos (Jarret, Manton & Roy, 1968), although Sorsa (in Fabbri, 1965) recorded a diploid cytotype under this name from Peru. Specimens of P. latum from Florida were diploid (Evans, 1963) and Smith & Mickel (1977) confirmed the diploid status of Trinidadian material on a plant collected by Dr A. Fay and subsequently grown at the New York Botanical Garden. An earlier, tetraploid count for Jamaica (Walker, 1973a) must be discounted due to misidentification, the specimen quoted (Walker T4983) actually being that of P. repens (Aublet) C. Presl and not P. latum. Details of the somatic chromosomes of both P. phyllitidis and P. latum are shown in Figs 28A-C & 29 and Table 14. The range of chromosome length is similar in the two species and although two satellites appeared to be present in P. /atum they could not be detected in P. phyllitidis. Again, it may be noted from Fig. 28C that P. phyllitidis shows a bimodal distribution of chromosome lengths, although not as marked as the 4x P. aureum implying an allopolyploid origin. CYTOLOGY 201 e" af 2 o . ~% _- ;, 3 AS NT a tg Mies \ Sen fi _ ee ae — ~ FS by Mi Wyk’ KAI « 2 Fig. 28 Polypodium (subgenus Campyloneurum). A, P. phyllitidis,T10986, mitosis, 2n = 148, x 1000. B, P. latum, T10605, mitosis, 2n = 74, x 1000. C, P. phyllitidis, T10986, karyogram. Each unit of length = 0-33 wm. 202 FERNS OF TRINIDAD 10 9 Fig. 29 Polypodium (subgenus Campyloneurum). Karyogram of P. latum,T10605. Each unit of length = 0-33 wm. Subgenus Microgramma Members of this group have thin, very long-creeping rhizomes, bearing at intervals small simple dimorphic fronds. The commonly occurring eiphytic P. ciliatum and P. lycopodioides are both diploid in Trinidad with n = 37. The latter species has been found to be diploid also in Jamaica (Walker, 1966a) and in Puerto Rico (Sorsa, 1970). Karyotyping has not been possible in the last-mentioned genus Microgramma, because of lack of adequate living material. However, of the eight species which have been karyotyped, despite belonging to three different subgenera (Campyloneurum, Phlebodium, and Polypodium), all show some overall similarity in that median centromeres (either truly median at the median point M, or nearly so at the median region m) are extremely rare and range from 0% in some species up to a maximum of 5-4% in P. triseriale. The same is also true for the Australian Dictymia brownii (Wikstr6m) Copel., another member of Polypodiaceae s.s., which has 2n = 70 and is based on x = 35 (Walker & Page, 1982). It has only four chromosomes with centromeres in the M and m positions, representing 5-7% of the total. This rarity of M and m centromeres in Polypodiaceae contrasts for example with members of Blechnaceae where M + m centromeres are much more abundant, ranging from 11-1% in B. serrulatum to a maximum of 22:6% in B. occidentale. Much more work needs to be done in this field before one can state that such differences are characteristic of families or other taxonomic groupings, but such comparisons are of great potential interest and value. VII. GRAMMITIDACEAE 1. Grammitis Swartz This generic name has been used to encompass a large group of species, numbering some 400 according to Proctor (1977) and Stolze (1981). Grammitis sensu lato is pantropical and has been split into a number of genera or subgenera by various authors. Despite the size of the group relatively little of the cytology is known, only some 30 species having been examined and of these more than a quarter of the chromosome numbers are quoted as approximations. Among the reasons for the lack of information is the fact that very many of the species are small and tend to grow mixed with mosses, etc., on tree trunks and frequently get overlooked. More importantly, with few exceptions they are not amenable to cultivation, nor to raising from the frequently green and very short-lived spores. Hence, as in the case of Lindsaea, most of the fixations have to CYTOLOGY 203 be made in the wild, with little chance of second or more attempts if good cytological preparations are not obtained the first time. Furthermore, personal observations suggest that meiosis slows down considerably or even comes to a halt in dry periods, which are the times usually most favoured by collecting expeditions. Despite these shortcomings it is already clear that Grammitidaceae is cytologically diverse, with base numbers of x = 32, 33, 35, 36, and 37 having been reported definitely and substantiated by good photographic evidence. Experience suggests that this aneuploid series will be extended as more results become available. Both the differing opinions regarding possible generic limits and the cytological diversity already revealed in the small percentage of the family which has been sampled help to confirm that a thorough monographic treatment on a world-wide basis is needed. Léve, Love & Pichi Sermolli (1977) quote results for a number of species of Grammitis under the generic name of Xiphopteris, with accurate determinations of x = 37 quoted for X. cornigera (Baker) Copel. by Manton & Sledge (1954), and for X. myosuroides (Swartz) Kaulf. by Walker (1966a); and x = 33 in X. hartii (Jenman) Copel. (Walker, 1966a) as well as several other approximate counts. F. S. Wagner (1980) has determined X. limula Christ as having n = 32. Grammitis taenifolia is one of the more conspicuous members of the genus with its deeply pinnatifid fronds which closely approach in general appearance those found in many members of Polypodiaceae s.s. This species has been placed in the genus Xiphopteris (see below), but I prefer to consider it here as a member of Grammitis. Tapetal mitotic nuclei showed 2n = 74 fairly clearly (Fig. 30A & B) and the species is therefore a diploid based on x = 37, acommonly occurring number in the family (see Love, Love & Pichi Sermolli, 1977, for references). de aa sae io a 2 UF OB Fig. 30 Grammitis taenifolia. A, T6811, tapetal mitosis, 2n = 74, x 1000. B, explanatory diagram, x 1000. * 2. Cochlidium Kaulf. This genus, bearing coenosori along the midrib has been associated in the past with the vittarioid ferns. Christensen (1929) in a detailed study showed that this association was not soundly based and that the genus was polypodioid in the broad sense, and Cochlidium is considered today as a member of the Grammitidaceae. F. S. Wagner (1980) published a very elegant photograph demonstrating n = 33 in a plant of C. rostratum (Hook.) Maxon ex C.Chr. from Costa Rica. The sole Trinidadian representative examined belonging to this genus, C. aff. linearifolium, gave rather poor quality preparations in which the chromosome number was determined as being n = 33 or 34, there being doubt at one point in particular where a bivalent had despiralized, obscuring details of the outline of nearby members. However, the number is in general agreement with that reported by Wagner in C. rostratum. This Trinidad plant requires further investigation in that its characters do not fit in a number of details with those of C. linearifolium as enumerated by Bishop (1978). Some of the characters are those of C. rostratum, but again there is not complete accord. Meiosis in the specimen examined is regular and there is no suggestion that the plant may be a hybrid between these two species. 204 FERNS OF TRINIDAD 3. Xiphopteris Kaulf. In his revision of Cochlidium, Bishop (1978) included Xiphopteris serrulata as one of the 16 species he recognised as belonging to the same genus, pointing out that its characters are at variance with some members of Xiphopteris of which it was the type species. However, Bishop draws attention to the ways in which it also differs from the other species of Cochlidium and, although preferring to include X. serrulata within Cochlidium, he acknowledges that in view of its distinctness it might reasonably be retained in its own monotypic genus. Until a full investigation of the group is completed, I prefer to consider X. serrulata the sole member of the genus. Previous chromosome counts for this widespread species have been recorded as n = c. 74 bivalents, whilst most cells showed c. 148 univalents (Walker, 1966a) in Jamaican specimens, whilst Araujo (1976) quoted n = 74 for Brazilian material, all these being tentatively based on x = 37, although Jamaican counts were quoted as approximations only. However, Trinidadian plants gave clear preparations in which 105 univalents were clearly present (Fig. 31A & B) and several cells gave the same result. This seemingly anomalous result caused me to thoroughly search again through my permanent Jamaican preparations and a hitherto unrecorded plant of X. serrulata (T5077 from Lawrence Bottom, Portland), also showed 105 univalents (Fig. 31C & D). Some better cells were discovered on a slide of plant number T1733, originally quoted as having approximately 148 univalents. These cells showed 140 univalents (Fig. 31E & F). Thus in Jamaica there are plants with 105 and 140 univalents which represent the triploid and tetraploid Fig. 31 Xiphopteris serrulata. A, T10976 (Trinidad; 3x), ‘n’ = 105, x 1000. B, explanatory diagram of A, 105 univalents, x 1000. C, T5077 (Jamaica; 3x), ‘n’ = 105, x 1000. D, explanatory diagram of C, 105 univalents, X 1000. E, T1733 (Jamaica; 4x), ‘n’ = 140, x 1000. F, explanatory diagram of E, 140 univalents, No of = OO a OO nN © © 6.2 Bio 2 BS 8 9 0 1112 8 14 «15 6 17 BS DW 21 Chromosome length 2 Fig. 39 A, Hemidictyum marginatum, J11161, histogram of chromosome lengths. B, H. marginatum, T6410, spore, x 1500. C, Diplazium cristatum, spore, X 1500. In his survey of the stomata of ferns van Cotthem (1970) examined those of several species of Diplazium and found they were all polocytic, but he did not report on Hemidictyum. Here the stomata are also mainly polocytic, although occasional individual stomata may be encountered which are diacytic. Whilst the chromosome number (n = 31) of Hemidictyum lies well within the range shown by Thelyteridaceae (x = 27 to 36), the simple entire pinnae found in Hemidictyum are only to be found in the thelypteroids in those genera which are based on x = 36. Holttum (pers. comm.) has pointed out the uniqueness of the venation in the thelypteroids and that anastomosis in this group always relates to the sinus-membrane. He further points out that the scales are very different from those of Asplenium, and nearer the ones found in Diplazium as regards the marginal cells. Proctor (1966) reduced H. marginatum to a species of Diplazium, namely D. limbatum (Willd.) Proctor, stating that there were no distinctive characters by which Hemidictyum could be maintained as distinct from Diplazium, and he continued this practice in his account of the ferns of the Lesser Antilles (1977). Latterly (1980) he has had a change of opinion and recognises Hemidictyum as a genus in its own right. However, whilst there is general agreement that Hemidictyum is more closely related to Diplazium than to other genera most recent authors, e.g. Copeland (1947), Crabbe, Jermy & Mickel (1975), Pichi Sermolli (1977), Lovis (1977) and Kramer (1978), have maintained it as a distinct genus, the last three authors specifically mentioning the anomalous chromosome number as an important character. Such a large difference in chromosome number (x = 31 versus x = 41) must inevitably isolate the two genera from one another, effectively preventing any genetic interchange. The balance of evidence therefore strongly suggests that Hemidictyum has developed from a CYTOLOGY 221 diplazioid ancestry and involving a reduction in chromosome number from x = 41 tox = 31. This exactly parallels the numerical situation reported by Roy & Manton (1966) in Lomariopsis, where there is a reduction from 2n = 82 in L. cochinchinensis Fée to 2n = 62 in L. rossii Holttum (plus other numbers; see under Lomariopsis). An examination of the centromere positions of Hemidictyum (Table 16) shows relatively little significant differences between these and those found in a species of Diplazium (D. caracasa- num). However, an inspection of the karyogram (Fig. 38D) of Hemidictyum shows a very different situation when compared with that of D. caracasanum (Fig. 37C), especially if attention is focused on chromosome length as expressed in the histograms (Figs 37B & 39A). In the case of Diplazium the distribution of chromosome lengths is normal, showing a single well-marked peak. This contrasts strikingly with the situation in Hemidictyum in which there are at least three well-defined peaks. As we are dealing here with a diploid plant (and not an allopolyploid with parents having three different chromosome size ranges) it is evident that there has been a considerable redistribution of the chromosomal material in the form of translocations. Other evidence (Walker, unpub.) suggests that distortion of the normal mono- modal distribution is a common characteristic of ferns which have undergone drastic changes in basic chromosome numbers. Table 16 Number of chromosomes in each centromere position in Diplazium caracasanum and Hemidictyum marginatum. (For ex- plantation of symbols see p. 152.) Position Diplazium caracasanum Hemidictyum marginatum M 2 0 m 4 4 sm 10 7 st 12 12 t 26 14 fi 28 25 Totals 82 62 4, Ctenitis (C.Chr.) C.Chr. ex Tardieu & C.Chr. Ctenitis ampla (Humb. & Bonpl. ex Willd.) Copel. is a name which has been commonly applied to two morphologically similar species with partially overlapping ranges which together stretch from Florida to Central and tropical South America, including the Caribbean Islands. Morton (1968) showed that it was to the species called Dryopteris nemophila (Kunze) C.Chr. in Christensen’s monograph of Dryopteris (1920) that the name C. ampla should be correctly applied, the other member of the duo being C. sloanei, and he drew attention to some of the features distinguishing the two taxa. These contrasting characters were as follows, those of C. ampla being placed first: pinnae short-stalked and pinnules nearly sessile versus pinnae long-stalked and pinnules obviously stalked, pinnule apices obtuse versus attenuate, rhizome scales larger and dark brown versus light brown, and the veins underneath usually lacking glands versus bearing minute glandular hairs. A plant from Jamaica was reported, under the name of C. ampla, to be diploid with n = 41 (Walker, 1966a). This specimen must now be attributed to C. sloanei. In Trinidad a plant from Aripo valley agreed very closely with Morton’s diagnosis of C. sloanei and with Jamaican specimens of this taxon but proved to be tetraploid with n = 82 in contrast to the diploid state of the Jamaican plants. It is evident that here two different cytotypes exist in C. sloanei which are very similar to one another morphologically and that these in turn form part of a complex which also incorporates C. ampla. Two other counts are on record for C. amplas.1., 227, FERNS OF TRINIDAD both being diploid, one from the U.S.A. (Wagner, 1963) and the other from Galapagos (Jarrett, Manton & Roy, 1968). C. protensa was originally described from African material and this species is also a common plant in Trinidad and Guyana. Christensen (1920) considered that although the American form cannot be separated from the African one at the specific level there are nevertheless small differences which he states are worthy of varietal recognition. Chief among these differences are soral characters — the sori being small, near the margin and having persistent indusia in the American variety funesta as opposed to the larger, more medial sori which have smaller, deciduous indusia in the African var. protensa. Cytologically the African and American varieties appear to be similar, a count of n = 82 being reported by Manton in Alston (1959) for a plant from Ghana and the same number is also recorded here for a specimen from the Valencia Forest Reserve in Trinidad. It is interesting to note the very small difference existing between two such widely geographically separated representatives of a species and it may be no accident in this respect that they are found in West Africa on the one hand and the Guyanan region on the other, two areas that were in intimate contact before the drifting apart of the continents. A plant of C. aripensis which came from the type locality (Aripo Heights) was diploid with n = 41. An additional diploid which showed some similarities to C. aripensis but differed in a number of important characters was found on the slopes of El Tucuche and has been described as a new species C. kallooi (Jermy & Walker, 1985). A number of taxa originally reported on cytologically under the name Ctenitis have been transferred to Lastreopsis and these are detailed in Love, Léve & Pichi Sermolli (1977). Despite these transferences, cytological records of more than 25 taxa of Ctenitis s.str. are available from many countries, approximately 80% of them being at the diploid level, the remainder being tetraploid with the exception of a single triploid. All are based on x = 41. 5. Lastreopsis Ching Lastreopsis was split off from Ctenitis by Ching, the distinguishing feature being the nature of the ridging on the upper surface of the frond axes — the ridges being continuous in Lastreopsis from one order of branching to another, and being either discontinuous or absent in Ctenitis. Tindale (1965) in her monograph of the genus recognises four subspecies of the widely distributed and variable American L. effusa. Jamaican material, reported under the name of Ctenitis effusa (Walker, 1966a, 1973b), was shown to be diploid with n = 41. These plants have abundant yellow glandular hairs on the lower surface of the lamina and are referable to subsp. effusa. By contrast, Trinidadian specimens are assigned to subsp. divergens, having darker green fronds which for the most part lack the glandular hairs of ssp. effusa, although this feature is variable. Cytologically they also contrast with Jamaican material in being sexual tetraploids with n = 82, 2n = 164. It would appear at first sight that there is a good case for raising these subspecies to specific levels, but it is a very polymorphic group and much further study is necessary to delimit specific boundaries. A photograph of the habit of subsp. divergens collected by Fendler may be seen in Tindale (1965). Almost half the species in this genus have been cytologically examined from Australia, Africa, and the Caribbean and all are consistent in having a base number of x = 41 with only the diploid and tetraploid levels being known. 6. Tectaria Cav. In terms of number of individual plants the various species of Tectaria form a conspicuous part of the fern flora of Trinidad and the range of variation is such that some specimens present problems of identification. The most distinctive and isolated of all the species is the small, simple-fronded T. plantaginea, with a relatively thin creeping rhizome, which is diploid, as is also T. trifoliata, the latter having also been reported as diploid in Mexico (Wagner, 1963). It should be pointed out that the taxonomy and nomenclature of this group is far from clear (Jermy, pers. comm.). There appears a complete range from the more simple ternate leaf with CYTOLOGY 223 an entire margin (T. trifoliata) to the pentaphyllous leaf-form in which the basiscopic lobe is well developed, and with often deeply cut lobes (T. heracleifolia - more common in the Greater Antilles) and, according to Proctor (1985), often incorrectly named T. trifoliata. Pinnate forms with 2-3 pairs of pinnae are found and Jenman (1909: 202) named Trinidad plants Tectaria purdiei (Jenman) Maxon (sub Aspidium). Whilst Christensen (1934: 183) equates this with T. trifoliata, we believe it is distinct and prefer to maintain it as a separate species. A population found in dense montane forest on limestone on Aripo Heights (Jermy 3002, Walker T 7088) was distinct in being of plants of a substantial size and with a glaucous cast to the leaves. This was due to the lamina being covered with short light-reflecting hairs. It is reminiscent of T. heracleifolia in colour and leaf margin cutting, but has 5—7 pinnae on a broadly lanceolate frond, and has been named T. ramkissoonii (Jermy & Walker, 1985) in recognition of the help and friendship of Roodal Ramkissoon, whose field knowledge of the flora of Trinidad was invaluable. It approaches T. trinitensis Maxon in its abundant covering of hairs on both surfaces of the frond although not as dissected as the latter. T. trinitensis was not collected during this survey and its cytology is unknown, but it is tempting to suggest a genetic connection between the two species. T. ramkissoonii has n = 80 chromosomes and hence is tetraploid as is the case with T. heracleifolia in Trinidad and also in Jamaica (Walker, 1966a, 19735). This latter species has also been noted as tetraploid from Florida (Wagner, 1963) but diploid cytotypes have been reported as occurring in Mexico (Mickel, Wagner & Chen, 1966) and Costa Rica (Gomez-Pignataro, 1971). The most complex group is that centred on T. incisa, where there is not only a range of morphological variation which at the extremes approach other species, but where there are also cytological differences. Sorsa (in Fabbri, 1965) recorded T. incisa as being diploid in Peru and as tetraploid (under the synonym T. martinicensis (Sprengel) Copel.) from Puerto Rico. Both diploid and tetraploid forms occur in typical T. incisa from Jamaica (Walker, 1966a), but in Trinidad all the specimens examined were uniformly tetraploid. Smith & Mickel (1977) noted, under the name T. incisa, a specimen sent from Trinidad by Dr Fay as being diploid. As no voucher specimen can be found (Mickel, in litt.) the true identity of this record is in doubt. However, here the situation is complicated further by the presence of a morphologically distinctive diploid entity, sometimes known as T. incisa var. vivipara, which differs from the diploid Jamaican form mentioned above. The former tends to have narrow pinnae (c. 2-5 cm wide) and the bulbils produced in the axils of the upper pinnae are a prominent feature of the plant when well-developed, especially when seen growing in wet situations. Even where the bulbils on a particular frond are not well-developed, the position of the young initials may be detected by the presence of small clusters of dark scales. Trinidadian material of this diploid is further distinct in having on the underside of the leaf numerous, short (2-3-celled) hairs on the costae and larger veins (and occasionally on the lamina itself in the region of the costa). Viviparous forms from Central and South America however lack these hairs, and have also a gross morphology resembling tetraploid T. incisa. Tetraploid T. incisa, common throughout Trinidad in a typical and easily recognisable form, is rarely pilose beneath and, if so, then only at the very base of the pinna. T. incisa var. vivipara has been redefined at specific rank under a new type of which the cytology is known (Jermy & Walker, 1985). T. vivipara has been found in the Brickfield population to hybridize with tetraploid T. incisa to give a triploid (Walker T6175) which forms up to c. 40 bivalents and 40 univalents at meiosis in some cells, others showing virtually all univalents. It has been named Tectaria xbulbifera (Jermy & Walker, 1985), is very vigorous and is larger than T. vivipara, with broader pinnae and lacking the short hairs on the underside of the costae, more characteristic of T. incisa. It inherits the viviparous habit and as a consequence can increase in numbers despite the irregular meiosis leading to inviability of the spores. Silhouettes of the hybrid and two parents are given in Fig. 40A-C. A fourth entity of the Tectaria incisa complex collected near Brasso Secco by A. C. Jermy (J 10941), and grown to maturity at Kew, proved to be a diploid with 2n = c. 80. The lamina of the fronds is as broad as it is long, with usually only two pairs of pinnae, giving an overall orbicular 224 FERNS OF TRINIDAD A B re Fig.40 Tectaria. A, T. vivipara, T6173 (2x), silhouette, x 1/8. B, T. x bulbifera, T6175 (3x) silhouette, x 1/8. C, T. incisa, T6972 (4x), silhouette, x 1/8. outline, in contrast to the ovate-laceolate fronds with several pinnae seen in other members of the complex. The taxon has been named T. orbicularis (Jermy & Walker, 1985). 7. Hypoderris R.Br. ex Hooker All our specimens of this monotypic genus were gathered in very damp, deeply shaded situations and had a somewhat fleshy texture in all parts, including the creeping rhizome. The simple fronds with sagenoid venation vary from being only slightly lobed at the base to being prominently hastate. In some cases this lobing almost takes the form of a pair of pinnae. The sori are scattered on the under surface of the frond and each is protected in the early stages by a fimbriate indusium which is soon hidden by the developing sporangia and requires careful searching to find in fully mature specimens. Although Hypoderris has been considered as being closely related to Woodsia (Bower, 1928) on account of its indusial characters, in nearly all other respects it is tectarioid, and modern opinion is virtually unanimous in placing this genus close to Tectaria. The chromosome numbers of n = 40, 2n = 80 (Walker, 1973a) are in complete agreement with a tectarioid origin (Fig. 41A—D). The spores are furnished with prominent toothed spines (Fig. 41E) similar to those found in some species of Tectaria. 8. Cyclopeltis J. Smith This genus was typified on Jamaican material collected by Swartz. It has a disjunct distribution throughout the tropics, being absent from Africa and southern India (Holttum, 1954) and is variously treated as being either monotypic or comprising a small number of species. Trinida- dian material is morphologically identical with that from Jamaica and also agrees (Walker, 1966a) in being diploid with n = 41. 9. Didymochlaena Desv. This pantropical genus is usually regarded as monotypic, although Christensen (1934) recog- CYTOLOGY Pde & Fig. 41 Hypoderris brownii. A, T6205, meiosis, x 1000. B, explanatory diagram of A, 40 bivalents, x 1000. C, T6205, tapetal mitosis, 2n = 80, x 1000. D, explanatory diagram of C, x 1000. E, spore, x 1500. nised two species in Madagascar, and Holttum (1954) considers that more local species may be recognised wherever the genus has been more intensively studied. The basic chromosome number is x = 41 and previous counts have been established on material from Malaysia (Manton in Holttum, 1954), Costa Rica (Gomez-Pignataro, 1971) and Mexico (Smith & Mickel, 1977). All proved to be diploid and the same is true of the Trinidadian material reported here. A further count, extending the geographical range, has proved to ben = 41 (and therefore also diploid) for a plant from Papua New Guinea (Walker, unpublished). 10. Polybotrya Humb. & Bonpl. ex Willd. This tropical American genus comprises some 25 species of which four occur in Trinidad. All are 226 FERNS OF TRINIDAD conspicuously dimorphic, the fertile pinnae being almost devoid of lamina and covered, at least on their lower side, by naked sporangia. Polybotrya cervina is anomalous in a number of features, such as in being completely terrestrial normally with a thick, short, creeping rhizome. The other species pass through an initial terrestrial stage in which the rhizomes are thin (c. 8 mm diameter) and the fronds relatively small and sterile. After making contact with a tree trunk the rhizomes thicken considerably (to c. 25 mm diameter), become scandent and produce large fronds, some of which may be fertile. A further distinction is that the veins of P. cervina are joined by an inframarginal commissure in contrast to the entirely free state found in some of the other species. Most authors consider these characters to be insufficient to justify generic recognition, but Pichi Sermolli (1977) upholds the separation of this species as the sole member of the genus Olfersia of Raddi. It should be noted that the distinction between the typically terrestrial habit of P. cervina and the scandent habit of the other members of the genus may occasionally break down. My field notes for a specimen of P. osmundacea (T6426) state ‘this specimen unusual in that it was fertile whilst still terrestrial in deep leaf mould’. Anatomically, P. cervina is similar to P. osmundacea (Walker, unpub.); it is very easy to cultivate in pans and readily becomes fertile grown in this manner, unlike the other species which require the stimulus of climbing. Eight specimens of P. cervina have been cytologically examined from several localities in Trinidad and agree with Jamaican representatives in being sexual diploids with n = 41, 2n = 82 (Walker, 1966a; fig. 40). Smith & Mickel (1977) also noted an unlocalised specimen from Trinidad as being diploid. Similarly, P. osmundacea, also examined from Jamaica (Walker, 1966a; fig. 41) was diploid with n = 41. In this species there is also a certain amount of instability in the expression of frond dimorphism, in which occasionally fertile parts appear on vegetative- type fronds. In one specimen, of an otherwise typically vegetative frond, the lowest pinna was completely fertile and the basal half of the adjacent pinna was sterile whilst its upper half was fertile. A specimen behaving in a similar way was also collected in Jamaica. The third species examined, P. caudata, was also sampled from several localities and likewise proved to be diploid. Nearly all modern systems agree in placing Polybotrya among the dryopteroid ferns next to the monotypic Maxonia to which it is morphologically similar in a number of features, including the separate and distinctive terrestrial and scandent phases. They also have the basic chromo- some number of x = 41 incommon. The two genera differ in soral characters, Polybotrya having naked acrostichoid sporangia as compared with the discrete sori of Maxonia which are protected by reniform or rounded indusia. Glands which are present on the sporangial stalks of Polybotrya appear to be absent from Maxonia. Anatomically (Walker, 1972, and unpub.) there are great similarities between the two genera for example in the structure of stipe and lamina. In particular, transverse sections of the rhizome of Polybotrya cervina and the scandent form of the rhizome of Maxonia are virtually identical, even to the presence of numerous small groups of exceptionally thick-walled cells with conspicuous pitting and which are randomly scattered in the ground tissue. In both genera the spores are very densely and minutely spinulose. 11. Bolbitis Schott Although chromosome counts are available for some 19 species of Bolbitis (including some which were formerly ascribed to Eganolfia), together with a number of additional cytotypes and interspecific hybrids (see summary in Hennipman, 1977) only two have been recorded from the New World tropics. These are for B. pergamentacea and B. aliena from Jamaica (Walker, 1966a) which proved to be diploid and tetraploid respectively. To this very short list two more species, together with a further cytotype may be added. Two plants of B. portoricensis from the same locality showed 2n = 82 at mitosis and are therefore diploid. However, B. hemiotis collected by both A. C. Jermy and T. G. Walker on different occasions from the same small area in a gully in Aripo Valley showed cytological differences. Two specimens were diploid, whilst the third was tetraploid. In gross morphology CYTOLOGY 227 this tetraploid differs in no way from the diploid, and even at low magnification the differences between the cytotypes are relatively slight. The rhizome scales are light brown and measure approximately 1-5 mm Xx 4mmin the diploid, as compared with the dark brown and rather larger scales (c. 1-5 mm X 7 mm) of the tetraploid. In addition small glandular hairs c. 3 cells long are very evident on the under surface of the frond of the tetraploid, whilst being much less evident or even lacking in the diploid. However, stomatal lengths are conspicuously different in the two cytotypes, those of the diploid having a mean of 67-5 wm (56-5 to 76-0 wm) compared with a mean of 79-0 wm in the tetraploid (60-0 to 90-0 ~m). Measurements of stomatal lengths of four other plants from the same population suggests that the diploid state is the normal and that the tetraploid may be an individual plant, possibly of very recent origin. The almost identical superficial appearance of the two cytotypes suggests that here one may be dealing with an autotetraploid, and this view is strengthened by the lack of any other species in the vicinity which is remotely like B. hemiotis with which it may have contributed to an alloploid origin. It is of interest to note that Hennipman (1977: 54) comments that, in the case of the Asiatic triploids, the morphological differences are trifling as compared with the diploids and he considers these to be of an autoploid nature. Some further support for this theory may be seen in some of my preparations of triploid plants of B. quoyana from Papua New Guinea, where trivalents are present in addition to the univalents and bivalents, which form the bulk of the chromosome associations. The same is also true of preparations of B. sinuata (C. Presl) Hennipman from Sarawak (Walker, unpub.). The sporangia of the Trinidad tetraploid B. hemiotis were fixed in the field and proved to be too young to be undergoing meiosis, and the presence or absence of multivalents which may have provided more direct evidence of the type of polyploidy involved could not therefore be determined. Some of the tapetal or archesporial cells were undergoing mitotic divisions and it is upon these cells that the cytological record is based. All records to date for Bolbitis throughout the world have been at the diploid, triploid, or tetraploid levels and without any evidence of agamospory. The strong tendency for the genus to produce bulbils (three quarters of the species according to Hennipman, 1977) may help to account for the persistence of large numbers of otherwise sterile triploid plants in local populations in different parts of the world, and may be a contributory factor in the maintenance of autopolyploids. 12. Lomariopsis Fée This genus of large scandent ferns is widespread in the tropics including the Pacific, Asia, Africa, and the New World. Copeland (1947) expressed doubts as to whether or not the American group was properly included with the Old World species, but he did not elaborate on this brief comment. The general morphology, habit, and anatomy do not appear to me to indicate any major discontinuity. Chromosome counts have been recorded for only five species (Manton, 1959; Roy & Manton, 1966), four of which are African in origin and are quite clearly anomalous in showing a reduction series from the base number of x = 41 shown by the Asiatic L. cochinchinensis. Here there is a reduction in chromosome number from 2n = 82 in diploid members of the family via L. guineensis (L. Underw.) Alston with 2n = 78, to 2n = 62 in L. rossii Holttum and to 2n = 32 in L. hederacea Alston. In the case of Lomariopsis the two lowest numbered species show striking differences in chromosome size and shape, due, in Lovis’ (1977: 295-297) opinion, to translocations leading to a refashioning of the karyotype and a reduction in number. No chromosome counts have previously been available for American material, and the two specimens of L. marginata which were examined from widely separated localities in Trinidad proved to be diploid with n = 41. This is in agreement with the Asiatic L. cochinchinensis and a cell is illustrated in Fig. 42A & B. The confirmation of x = 41 as the primary base number in Lomariopsis helps to underline the affinity of the genus with other members of the subfamily Lomariopsidoideae sensu Holttum or with Lomariopsidaceae of other authors. 228 FERNS OF TRINIDAD A Fig.42 Lomariopsis marginata, T6214. A, meiosis, n = 41, x 1000. B, explanatory diagram, 41 bivalents, x 1000. 13. Elaphoglossum Schott ex J. Smith The chromosome numbers of the majority of the species of Elaphoglossum in Trinidad have been determined and all have proved to be at the diploid level. Six of these are new records and the two that have been counted from elsewhere also agree in being diploid, namely E. crinitum from Puerto Rico (Sorsa, 1966) and Jamaica (Walker, 1966a, 1973b) and E. rigidum (under the name E. flaccidum (Fée) T. Moore) from Puerto Rico (Sorsa, 1966, 1970). This absence of polyploidy contrasts markedly with the situation in Jamaica where four of the 11 species examined were tetraploid (Walker, 1966a, 1973b). The members of this genus, despite a high proportion of them being epiphytes, are very amenable to pot culture provided that adequate drainage is provided. Over the course of many years it has been noted that their behaviour in cultivation closely parallels that seen in the wild. Thus, species which are frequently collected in the fertile state in the wild normally produce fertile fronds freely in cultivation, e.g. E. rigidum; conversely E. herminieri as a pot plant only becomes fertile at infrequent intervals, sometimes several years elapsing between one crop of fertile fronds and another, a type of behaviour which doubtless accounts for the fact that it is most commonly found in the sterile state in nature. This type of behaviour is common to many species, an appreciable number of which have been described from sterile material. Their amenability to cultivation, coupled with the retention of their wild characteristics, suggests that here is a group which may form admirable material for investigating the factors which affect or induce fertility. Fée created the genus Hymenodium, of which H. crinitum (L.) Fée was the sole representa- tive, on the basis of the anastomosing veins present, in contrast to the free ones of Elaphoglos- sum. However, the venation is the only distinguishing feature, and in all other respects such as spore morphology, gametophyte development, cytology, etc., H. crinitum is a true Elaphoglos- sum and is considered as such here. One of the most conspicuous features of E. crinitum is the presence of conspicuous, shiny, black scales, somewhat like eyelashes, which clothe the stipe and fronds. Two plants growing side by side on El Tucuche behaved rather differently in respect of scales. One was quite typical in having scales present on the frond surfaces in addition to the margins, rachis, and stipe (T10990), whilst the other plant differed only in lacking scales on the frond surfaces (T10989). Both plants were sent alive to Newcastle in 1966 and have retained this habit even since, the striking difference in appearance being due to a simple developmental event. The young fronds produced by both plants are at first identical with abundant scales being present on all parts. However, the scales of T10989 soon drop off the upper and lower surfaces of the lamina, whilst persisting elsewhere, including the margins. This is in contrast to those of T10990 which persist throughout the life of the frond. This suggests that scale distribution may be under relatively simple physiological/genetical control, and it is tempting to speculate whether or not in the evolutionary history of the species of Elaphoglossum which characteristi- cally have scales more or less confined to the margins of their fronds, the scales had been present CYTOLOGY 229 on the frond surfaces and then later were lost except at the margins, rather than having been produced only in this highly specialized marginal position from the very beginning. Elaphoglossum produces few aberrations in cultivation, a simple forking of the frond being the most common form. In one instance E. crinitum produced a frond which was intermediate between a fertile and sterile one, with the sporangia spreading along a broad marginal band for about 2/3 of the way up, leaving a broad, sterile, central and upper area. 14. Oleandra Cav. Oleandra has the bulk of its 40 or so species in the Asiatic and Pacific areas, with only a very few representatives extending to Africa and America. O. articulata is the only American species which has been cytologically examined and is diploid with n = 41 in Jamaica (Walker, 1966a) and Puerto Rico (Sorsa in Fabbri, 1965; Sorsa, 1970). A specimen which was scandent on a palm trunk at the edge of Aripo Savanna was also diploid. This species lacks the somewhat soft hairy nature and characteristic odour possessed by many other members of the genus. 15. Nephrolepis Schott All 14 species of Nephrolepis which have been cytologically examined from various parts of the world have been diploid, although two, namely N. hirsutula (G. Forster) C. Presl and N. pectinata (Willd.) Schott, also have tetraploid cytotypes as reported by Walker (1966a) and Kuriachin (in Fabbri, 1965) respectively. The Trinidadian specimens of the pantropical N. biserrata were also diploid as has been shown to be the case in three continents viz. Asia (Ghatak, 1962, 1963; Abraham, Ninan & Mathew, 1962), Africa (Manton, 1959) and America (Sorsa, in Fabbri, 1965; Sorsa, 1970; Walker, 1966b). Similarly, the purely American N. rivularis showed n = 41. XII. BLECHNACEAE 1. Blechnum L. The most numerous members of Blechnum in Trinidad in terms of species are those belonging to the B. occidentale affinity, all of which have a basic chromosome number of x = 31. This places them cytologically approximately in a mid-position in the genus which shows a series of base numbers from x = 28 to x = 36. B. occidentale often occurs in large stands which are at least partially a consequence of the stoloniferous habit of the species. All plants examined from a number of different localities in Trinidad and Tobago were sexual tetraploids with n = 62, 2n = 124 (Fig. 44A & G). This is also the case in Jamaica (Walker, 1966a, 1973b; Smith & Mickel, 1977), Mexico (Smith & Mickel, 1977), Galapagos (Jarrett, Manton & Roy, 1968) and in Texas, U.S.A. (Walker, unpub.). Sorsa’s report (1970) shows a slight discrepancy in that he records n = 64 instead of 62 for this species from Puerto Rico; nevertheless, it is clearly still at tetraploid level. A further member of the complex is B. fraxineum, which has two cytotypes in Trinidad, both of which are sexual, one being diploid with n = 31, 2n = 62 (Fig. 44B & H), and the other tetraploid with n = 62, 2n = 124 (Fig. 45A). Comparing the morphology of the limited amount of cytologically investigated material, there seems to be a tendency for the fronds of the tetraploid to be rather narrower and to have somewhat more pinnae (c. 3 pairs) than in the diploid with only one or two pairs. A further tendency is for the stipe and rachis of the diploid to be deeper red than in the tetraploid. How far these are reliable features needs further investigation, but silhouettes of living material are shown in Fig. 43A & B. Spore length differences may be a more reliable character, as they gave consistent results in the five samples measured, the spores of the tetraploid being approximately one third as long again as those of the diploid (Table 17). This contrasts with the situation as regards stomatal length which is virtually the same in the two cytotypes, as are also rhizome scale characters. The very close morphological similarities existing between the diploid and tetraploid forms of B. fraxineum immediately raises the suspicion that the tetraploid may be autopolyploid in 230 FERNS OF TRINIDAD at Fig.43 Blechnum, silhouettes of fertile fronds, x 1/4. A, B. fraxineum, NY6 (4x). B, B. fraxineum, T6243 (2x). C, B. X caudatum, T7232 (3x). D, B. occidentale, J11359 (4x). D origin. If this is indeed the case, then its karyotype would be expected to show each type of chromosome found in the diploid to be represented four times. As may be seen from Table 18 the pattern of distribution of centromere positions is quite differerent overall, the corresponding figures for the diploid and tetraploid plants not being in a two:four relationship. A closer inspection of the karyograms (Figs 46B & 47B) reinforces this impression and hence it is highly probable that, in the case of Blechnum fraxineum, we are dealing with an allo- rather than an auto-tetraploid. If the assumption is made that the close similarity in morphology between the diploid and tetraploid forms is a consequence of the former being part-parental to the latter, then it should be possible to make some predictions concerning the other, as yet unknown, diploid parent involved in the ancestry of the allotetraploid. Although little can be said about the morphology of the unknown parent because of the dominance of the characters in the diploid, except to suggest that its frond may have more numerous pinnae and be narrower than those of the known diploid, it should possess a characteristic karyotype. A close approximation to what this is may be arrived at by subtracting the figures in each centromere group of the known diploid from the corresponding figures of the tetraploid. When this is done (Table 18) it will be seen that the two diploid karyotypes, the known and the unknown, differ markedly one from another and are quite distinctive. This prediction should also help to provide a test for the validity of the method if and when the second diploid is found. In some areas of the Maracas river valley B. occidentale occurs in quite large patches, with diploid B. fraxineum growing in close proximity. Intermingled with B. occidentale are plants which at first sight may be taken for this species, but which have many fewer pairs of pinnae and whose fronds abruptly terminate in a large entire pinna (Fig. 43C). These plants have been taxonomically recognised as B. caudatum or B. occidentale var. caudatum. However, all the plants examined cytologically proved to be sterile triploids, with 2n = 93 (Fig. 45B) and with CYTOLOGY 231 5, "* et #, Meee | fst " : ma -* a =! 7 o Reehal B E vo ey 8,9 Po ae ee Pe o8, eg *. & 06 ° 2 a goo Plo & oP, ge H° v< % FB 0 a4 — om: 6 820 o eGo os 0,98 Bad o eo, fo) ee | abe : YS es Pal eae P Pen, See aD Se \ a a a Pad _ ™“ ”~ ee ~ —“s MIF MN ¢ y ly ; es ea f.,, Vina H Fig. 44 Blechnum. A, B. occidentale, T6137 (4x), meiosis, n = 62, X 1000. B, B. fraxineum, T6243 (2x), meiosis, n = 31, X 1000. C, B. X caudatum, T10717 (3x), meiosis irregular, x 1000. D, explanatory diagram of C, 19 bivalents (solid) + 55 univalents (outlined), x 1000. E, B. x caudatum, T10717 (3x), meiosis irregular, x 1000. F, explanatory diagram of E, 22 bivalents (solid) + 49 univalents (outlined), x 1000. G, B. occidentale, J11283 (4x), mitosis, 2n = 124, x 1000. H, B. fraxineum, J10981 (2x), mitosis, 2n = 62, x 1000. 232 FERNS OF TRINIDAD Fig. 45 Blechnum. A, B. fraxineum, NY6 (4x), mitosis, 2n = 124, x 1000. B, B. antillanum (= xX caudatum), T4136 (Jamaica; 3x), mitosis, 2n = 93, x 1000. C, B. unilaterale, T4439 (Jamaica; 4x), mitosis, 2n = 124, x 1000. D, B. serrulatum, J11215 (2x), mitosis, 2n = 72, x 1000. irregular meiosis resulting from the formation of a mixture of univalents and bivalents (Fig. 44C-F). As may be seen in Table 19 the number of bivalents ranges widely but nowhere reaches that of a full genome (x = 31). The cytological and gross morphological evidence, together with the fact of association, overwhelmingly indicates that B. caudatum is not a species but is a triploid hybrid formed between the tetraploid B. occidentale and the diploid cytotype of B. fraxineum. The plant is also intermediate in respect of scale characters, those of diploid B. fraxineum being narrow and dark brown with thickened cell walls in the centre which become Table 17 Length of spores in Blechnum fraxineum in wm. Collection no. Mean Min. Max. 4x cytotype NY6 47-0 41-0 56-0 NY3 49-0 41-0 59-0 2x cytotype Fay s.n. 36-0 33-0 44-0 T6243 36:0 33-0 44-0 ACJ 10981 31:5 33-0 44-0 CYTOLOGY 233 ATH ei HTL a TOLL 4 Bb 1 2 12 J TA UL 11 TAO sound il g > Fig.46 Karyograms of Blechnum. A, B. occidentale, J11283 (4x). B, B. fraxineum, J10981 (2x). Each unit of length = 0-33 wm. thinner towards the edge, unlike those of B. occidentale which are broad, very light brown in colour, and uniformly thin-walled. The triploid has light-coloured scales of intermediate shape and, whilst some of the scales have a central dark streak, others lack it. Plants collected in Jamaica (under T4313—T4316, T4318) in the company of G. R. Proctor from the type population of B. antillanum Proctor were also found to be triploids with irregular chromosomal pairing (Walker, 1966a, 1973b). Two cells were analysed precisely and were found 234 FERNS OF TRINIDAD Table 18 Number of chromosomes in each centromere position in Blechnum frax- ineum (4x) and its assumed diploid parents, B. fraxineum (2x) and B. ‘unknown’ (2x). The centromere data for B. ‘unknown’ have been obtained by subtracting the figures in the second column from those in the first column. (For explanation of symbols see p.ls2.) B. fraxineum (4x) B. fraxineum (2x) B. ‘unknown’ (2x) M 4 zn 2 m 16 12 4 sm 2 4 8 st Ze 12 10 t 37 4 33 5g 33 28 5 Totals 124 62 62 to have 16 bivalents plus 61 univalents in one instance, and 21 bivalents plus 51 univalents in the other. These results lie within the range of chromosome pairing shown by B. Xcaudatum in Trinidad (Table 19). I am unable to find any distinguishing features, either in herbarium specimens or in plants grown side by side in cultivation, which would separate Jamaican B. antillanum from Trinidadian B. X caudatum, and must conclude that they represent the same taxon, being of hybrid origin from the same parental species. A morphologically similar plant from Belize was also found to be triploid with 2n = 93. B. x caudatum is widespread among the islands of the Caribbean and adjacent territory, and, because of its hybrid sterility, the implication is that it must have arisen independently in different areas and localities and also probably at different times. Once established, as a consequence of its stoloniferous habit this hybrid can rapidly build up large local populations which are similar in appearance to populations of normally reproducing gregarious species. The evidence from karyotypes helps to confirm the deduction made on morphological grounds and on chromosome numbers that B. x caudatum is in fact the hybrid between tetraploid B. occidentale and diploid B. fraxineum. The karyograms of all three taxa are shown in Figs 46A, B & 47A, together with the summaries of centromere positions (Table 20). It will be noted that B. occidentale has an exceptionally large number of chromosomes having their centromeres at the median point M, and that these are distributed more or less evenly through the size classes of the chromosomes. In addition, two chromosomes are satellited. By contrast, diploid B. fraxineum has only a single pair of chromosomes with median point centromeres, and these belong to the smallest size class. No satellites are present. If the centromere classes are set out in tabular form (Table 20), and the half-number for each parental species is given in parentheses as representing the gametic complement, it will be seen that there is remarkable agreement in that the somatic complement of B. Xcaudatum is the sum of the gametic Table 19 Pairing at meiosis of the 93 chromosomes in Blechnum X caudatum. Nos. of cells No. of bivalents No. of univalents RPrRNNNNRFNFE = ON loa) — 235 CYTOLOGY —— co rene o_o {ees aT ee oe Ames Pei a eres a ae BSE Dae ES petra ee eae RS me O fee ted 1 SRG, SReabei St See eres, (Sear RASTA — —— o_o — en OS, eam =a, aera aed menu esses i eee! =a aaaet: om = CO | Sa 1s ee Se i) tee sa nee ee Ee Si eee: = hay > aOR | eae — = ES iT LlUd Pe ea ee: jee = ces SE i ee, area i NY aman © sean Se ws SaSeorma A mens , DP] sa ead Ce een eae oma) : eam Nearer eo ey mare, ey eee see Komen, a, Rie see WSS pees) exes: ee PaRRS SE Seis ee ese Sens ro) paeeae —— (ea ee al 4 eases ae ee eet] ae eee, ae ee ao tana mn SeBCoRIOR: eR ees waa oe eS fe aoe - ea rae ee: hs 2 TS ed rio Camas: ccaieas aes Rey i Sey EA? ce peewee: maomar . Ds ea seal a Baas: a Raa es ‘Raat ‘smaseresi on ca Se oS eRe eens se Kearse ce ERED 1 ABB = a s- ee 35 cramees Se ai ED Y mEeaSe Naa meee = on Leta ese a Rae ema gare, 2 a. as wa eave, — ames, Pees 15 a —— 2 as aneese SP ee a Rees nad oma anaes oe a aot man eens lee Teen Bova Sead KX. eae Aone me | eee me ee = ih SPE EES, = ‘ete ROR) | ceseerres: + eR: iS PER, 5 ENE. ie ea Saree aa SO eam een ‘eae GERSON PeaeM ReT . eee mR eR ae See 5 CN, 15 cm) lanceolate-narrowly triangular, pinnate becoming pinnatisect-pinnatifid at apex; lowermost pinnae sessile, inflexed, 90 x 23 mm, lanceolate, attenuate at apex, pinnatifid, other pinnae sessile, with occasional adventitious buds in axils of upper pairs, 80 X 18 mm decreasing upwards, linear-lanceolate, apex attenuate, pinnatifid, margins entire with short stiff hairs; rachis, costae and costules stramineous with sparse short crisp hairs which are also seen on the lamina and veins of the abaxial side, first and second pairs of veins joining below or at the sinus. Sori nearer margin than costa; indusium with few long hairs; sporangia glabrous; spores abortive. Chromosome number n = 108 (triploid), meiosis irregular. Type: TRINIDAD, Charuma Ward, Central Ranges, near Forest Resthouse at Tabaquite, 4 miles N. of Brickfield, c. 45 m alt., in partially disturbed seasonal forest, 9 July 1963, T. G. Walker T6192 (BM — holotype). Paratypes: TRINIDAD, Charuma Ward, same locality and date, A. C. Jermy 2167 (UC); 2168 (TRIN); T. G. Walker T6191, T6193-6 (herb. Walker). A plant intermediate between the parents, differing from Goniopteris paucijuga in having shortly stalked pinnae with hairs on the margins and in being more hairy on costae, costules, and veins. From G. tetragonait differsin having a pinnatifid frond apex witha proliferous bud there orin the axils of the upper pinnae, a hairy indusium, and glabrous sporangia. The cytology and comparative morphology are discussed by Walker (1985: figs 34C & D and table 15). 9. Diplazium X papyraceum Jermy & T. Walker, hybrida nova (Fig. 10) Rhizoma breviter repens, paleis paucis anguste triangularibus clathratis purpurascentibus obsitum. Frondes 30-50 cm, + erectae paucae; stipes 15-22 cm, paulo brevior lamina griseo-virescens alis angustis atris, mox glabrescens; /Jamina 25-30 x 12-17 cm, ovato-triangularis, pinnata pinna terminali; pinnae 70-85 xX 15-22 mm, breviter petiolatae; pinnae inferiores lineari-lanceolatae basi inaequales, latere acroscopico quadrato truncato, basiscopico acute cuneato, apicibus acutis vel attenuatis, marginibus grosse serratis; pinnae superiores basi quasi aequales utrinque cuneatae, apicibus plus attenuatis; pinna terminalis 70-90 mm, trullata vel hastata, infra margine profunde rotundeque lobato supra grosse serrato, apice acuto; rhachis stipiti similis paleis angustissimis triangularibus clathratis dentatis dispersis; costae paleis similibus vel filiformibus paucis et pilis ? glandulosis; venae pilis 2-3-cellularibus, glandulosis. Sori secus venam lineari-arcuati indusio angusto integro vel margine subtiliter fimbriato; sporae abortivae. Rhizome very shortly creeping with few clathrate purplish narrowly triangular scales. Fronds 30-50 cm, + erect, few; stipe 15-22 cm, slightly less than the blade length, grey-green with narrow black wings, soon glabrous; lamina 25-30 x 12-17 cm, ovate-triangular, pinnate with terminal pinna; pinnae 70-85 x 15-22 mm, shortly petiolate, lower pinnae linear lanceolate with NEW SPECIES & HYBRIDS 265 HERB. MUS. BRIT. TVP# SPECIMEN Gonieptaris « tmhagaikerss Tareas ® Toe OA CYTOLOGICAL VOUCHER SPEC DIMEN int “Te welke ““ OF Buu. Bat Mus (Nat Mut) Bele. or Tree i). Waa se TF OI9Z PLANTS OF TRINIDAD \ Fig.9 Holotype specimen of Goniopteris x tabaquitensis Jermy & T. Walker (BM). 266 FERNS OF TRINIDAD HERB. MLS BRIT a} 4 TYPE SPECIMEN of blatium « PAPYRALEEm Fe roy bh 7 & tledice : oe t YRINEBAD a ee rate | ane A. Carve foes We. PLANTS OF TRINIDAD ottectd wowker tae snipeons fe ae Cota Bagiantion Tet 2 ) Saas Lacalaty LeSond t} A. Cures Jews Fig. 10 Paratype specimen of Diplazium xpapyraceum Jermy & T. Walker (BM). NEW SPECIES & HYBRIDS 267 unequal base, that on acroscopic side squarely truncate, on the basiscopic side sharply cuneate, apices acute or attenuate, margins coarsely serrated; upper pinnae with more equal cuneate base and more attenuate apices; terminal pinna 70-90 mm long, trullate or hastate, with lower margin deeply and roundly lobed, coarsely serrate above, apex acute; rachis as stipe with occasional very narrow, triangular, toothed, clathrate scales, costae with few similar or filiform scales and ?glandular hairs, veins with 2-3-celled glandular hairs. Sori linear-arcuate along vein, indusiate with narrow entire or finely fimbriate indusium; spores abortive. Chromosome number n = 123 (triploid), meiosis irregular. Type: TRINIDAD, Charuma Ward, Central Range Forest Reserve, Brickfields Teak Planta- tion, 3 miles S. of Forest Resthouse, 60 m alt., in wet ground by stream, 9 July 1963, T. G. Walker T6179 (BM — holotype). Paratypes: TRINIDAD, Charuma Ward, same locality, population and date, T. G. Walker T6176 (TRIN), T6180 (herb. Walker); same locality and date, in aroid communities on floor of mixed forest in high shade, A. C. Jermy 2178 (BM). This specimen had all the appearance of an Asplenium, and its cytology alone gave the authors confidence in placing it in Diplazium. It is even more curious as, at the time of collection, no obvious close taxa were seen that could be putative parents. It has some similarities to D. trinitense Maxon (an endemic of the Northern Range) in rhizome, scales, stipe, rachis morphol- ogy, and in the simple pinnate frond, and that species may be one parent. 10. Ctenitis kallooi Jermy & T. Walker, species nova (Fig. 11) Rhizoma erectum, apice paleis triangulo-attenuatis usque ad 13 mm longis 0-5 mm latis, clathratis nitentibus spadiceo-purpurascentibus marginibus dentatis vestito. Frondes 50-56 cm; stipes c. 20 cm, vivus ferrugineo-purpurascens teresque murinus et sulcatus in sicco, paleis eis rhizomatis similibus et pilis brevibus in superficie adaxiali; lamina 37-41 x 23-28 cm, ovata basi bipinnata-pinnatisecta supra minus dissecta, apice + attenuata; pinnae infimae asymmetrico-triangulares pinnula basiscopica infima fere 2-plo acroscopica longiore; pinnae mediae superaeque lineari-lanceolatae apice acuto parum acuminato, seg- mentis ultimis linearibus apicibus truncatis vel rotundatis; rhachis supra griseo-virescens infra purpuras- cens, paleis angusto-triangularibus atro-violaceis et in superficie adaxiali pilis brevibus crispatis; costae paleis similaribus utrinque sparsis, in abaxiali pilis acicularibus 5-cellulis longis; costulae pilis similaribus utrinque; laminae textura tenuis hebes secus venas at super laminam sparse pubescens, margine integro pilis brevibus, stomatibus 37-0-(M42-5)-48-0 «um longis. Sori in vena acroscopica costulae proxima, exindusiati, paraphysibus absentibus; sporangia cellulis annularibus 13-14; sporae 37-5—(M40-5)—-44-5 um, cristatae cristis angustis serratis. Rhizome erect, apex covered with shiny purplish brown, triangular-attenuate, clathrate scales, up to 13 mm long, 0-5 mm wide, with toothed margins. Fronds 50-56 cm; stipe c. 20 cm long, purple-brown and terete when fresh becoming grey-brown and grooved on drying, with similar scales to those on rhizome and short hairs on the adaxial surface; lamina 37-41 x 23-28 cm, ovate, apex + attenuate, bipinnate-pinnatisect below, less compound above; lowermost pinnae asymmetric-triangular with lowest basiscopic pinnule almost twice as long as acroscopic; middle and upper pinnae linear-lanceolate, with acute or slightly tapered apex, ultimate segments linear with truncate or rounded apices; rachis greenish-grey above, purplish below, with narrow- triangular, purplish-black scales and short crisp hairs on adaxial side; costae with similar scattered scales beneath and with 5-celled acicular hairs on both surfaces, similar hairs on both underside and upperside of costules; laminar tissue thin, dull, sparsely hairy along veins and on blade above, margin entire, with short hairs; stoma length 37-0-(M42- 5)}-48- ‘0 wm. Sori on acroscopic vein closest to costule, exindusiate lacking paraphyses; sporangia with 13-14 annular cells; spores 37-5-(M40-5)-44- 5 yum, cristate, with narrow serrated ridges. Gametophytic chromosome number n = 41 (diploid). FERNS OF TRINIDAD 268 HERB. MUS. BRIT. TYPE SPECIMEN Saaremaa oy 2 rad ey ee — wer g # gee x 4 ‘ 3 : iM / ~ pot { { : 4 \ ; ee i : a Baal Hicennnecaainibsintceivmbiteiuaih A. Cégae Pear Se: e798 PLANTS OF TRINIDAD etinad wmder She cmitenes ot the Cems Kapecnnsizinn Legs * if g Lexabe hy Miitude Called $2 AT jouer, hat Ne. Holotype specimen of Ctenitis kallooi Jermy & T. Walker (BM). Fig. 11 NEW SPECIES & HYBRIDS 269 Type: TRINIDAD, Tacarigua Ward, El Tucuche massif, c. 750 alt., on grassy bank of path through montane forest, 7 August 1963, A. C. Jermy & T. G. Walker J2678 (cytol. ref. no. T6793) (BM — holotype; TRIN, herb. Walker — isotypes). Paratype: TRINIDAD, Tacarigua Ward, same locality and date, T. G. Walker T6794 (herb. Walker). Named after Bhorai Kalloo, Curator at the National Herbarium of Trinidad and Tobago, whose assistance in both the field and herbarium was greatly appreciated. 11. Tectaria X bulbifera Jermy & T. Walker, hybrida nova [T. incisa Cav. Xx T. vivipara Jermy & T. Walker] (Fig. 12) Hybrida sterilis ex affinitate specierum Tectariae incisae Cav. affinum, T. viviparae Jermy & T. Walker similis. Ab hac specie statura parum parviore, pinnis angustioribus, gemmis in axillis pinnarum saepe abortivis, costis costulisque in pagina abaxiali + glabris et indusio glabro differt. Plant with erect rhizome. Fronds up to 80 cm, + erect; stipe almost as long as the lamina, stramineous to yellow-brown, sparsely scaly at base with sparse glandular hairs on adaxial side, scales 3-6 X 1-5-3-0 mm, ovate-triangular; lamina up to 55 x 33 cm, mid to pale green, paper-like when dry, broadly ovate, pinnate, with often abortive buds in pinnae axils; pinnae c. 6 pairs, lowermost 12-0-25-5 x 3-5—-4-5 cm, shortly petiolate, with a basiscopic lobe 3-2 of pinna length, otherwise linear-lanceolate, margin undulate becoming more coarsely lobed towards the attenuate apex; middle and upper pinnae only slightly narrower decreasing to 11-5—17-5 cm in length, + sessile linear-lanceolate, rounded at the base, uppermost decurrent, margins as in lower pinnae; terminal pinna 22 cm long, broadly lanceolate with 2-3 deep lobes towards decurrent base; rachis similar to stipe in colour and indumentum, 2-3-celled glandular hairs abundant on abaxial side and in axils of pinnae and costae, with similar hairs on adaxial side of costae but + glabrous beneath, venation areolate with occasional included veins. Sori irregular- ly scattered over leaf surface but where denser, then more regularly on either side of secondary costule; indusium peltate, glabrous; spores abortive. Chromosome number n = 120 (triploid), meiosis irregular. Type: TRINIDAD, Charuma Ward, Central Range Forest Reserve, 3 miles S. of Forest Resthouse, Tabaquite, 4 miles N. of Brickfields, c. 45 m. alt., 3 July 1963, T. G. Walker 6175A (BM - holotype; herb. Walker — isotype). Paratypes: TRINIDAD, Charuma Ward, same locality and date, on clay bank of rivulet in seasonal forest, A. C. Jermy 2147 (BM, TRIN). This hybrid has been mistaken for Tectaria vivipara (v.i.) hitherto, and is indeed like a more robust form of that species, with somewhat wider pinnae. The axillary buds are often very small and abortive, the costae and costules are more or less glabrous on the (under) abaxial side, and the indusium is also glabrous in contrast to the hairy one of T. vivipara. The abortive sporangia are, of course, diagnostic. 12. Tectaria orbicularis Jermy & T. Walker, species nova (Fig. 13) Rhizoma breviter repens, ascendens. Frondes c. 50 cm longae, + erectae; stipes laminam longitudine aequans pallide aurantiaco-ferrugineus, basi fuscatus et leniter gibbus, paleis ovato-triangularibus, 2-4 x 0-75 mm sed plerumque glaber pilis brevibus ? glandulosis in sulco abaxiali ad laminam densioribus; lamina 25-32 X 21-25 cm, prasina tenuis glabra late ovata vel orbicularis, trifoliata vel pinnis duabus inferioribus; pinnae infimae 15-17 x 3-0-4-5 cm, lineari-lanceolatae, lobo basiscopico unico pinna 4 breviore, margine integro grosse undulato; pinnae mediae lineari-lanceolatae, sessiles vel adnatae; pinna terminalis c. 25 cm longa, basi duobus lobis binatis pinnatisectis aliter lanceolata ad apicem attenuata leniter et irregulariter lobata; rhachis stipiti similis; costae prominentes breviter pubescentes supra, infra glabrae, costulis prominentibus in superficiebus ambabus pubescentibus vel glandulosis, infra haud dense; nervatura areolata venulis inclusis. Sori in areolis ad costam costulasque proximis irregulares; indusium peltatum glabrum; sporae 62-69 ym, alis angustis rugosae peridermate verrucoso. 270 FERNS OF TRINIDAD HERB. MUS, BRIT, * ih X TYPE SPECIMEN ‘Tietenca, «tation jem. Taare, & oe were PLANTS OF TRINIDAD eo = TRINTHAL ee ‘ one wer HO Kays Lovalay: Gone : F : ? Alaprade » 4 nine ® _ _, CYTOLOGICAL VOUCHER SPECIMEN re ee ize Fe wate 1% BA é tot be Tex #& Warerm, N nen tnt Mas (Kat. best} Bar xe } ae oe — a ita Ties = Term ©. ® %» Térts & Fig. 12 Holotype specimen of Tectaria x bulbifera Jermy & T. Walker (BM). NEW SPECIES & HYBRIDS 271 HERB. MUS, BRIT, TYPE SPECIMEN TECTARIA ORBICULARIS ide 7G Watker j ; 4, a wen al Ate hor kw 1099 PLANTS OF TRINIDAD eEnitek smdes the emipess of te Gotmas Expiocge Tre dee! Altitude TS Fig. 13 Holotype specimen of Tectaria orbicularis Jermy & T. Walker (BM). 212 FERNS OF TRINIDAD Rhizome shortly creeping, ascending. Fronds c. 50cm long, + erect; stipe as long as lamina, pale orange-brown, base darker, slightly swollen, with few ovate triangular scales, 2-4 x 0-75 mm, otherwise glabrous but with short ? glandular hairs in abaxial groove increasing in density towards lamina; lamina 25-32 x 21-25 cm, mid-pale green, tissue thin, glabrous, broadly ovate to orbicular in outline, trifoliate or with two pinnae below; lowermost pinnae 15-17 x 3-0-4-5 cm, linear-lanceolate with single basiscopic lobe 4% length of pinna, margin entire, coarsely undulating; middle pinnae linear-lanceolate, sessile or adnate; terminal pinna c. 25 cm long, with 1 pair of pinnatisect lobes at base, otherwise lanceolate attenuate at apex, shallowly and irregularly lobed; rachis as stipe; costae prominent, shortly pubescent on the upper side, glabrous on the lower side, costules prominent, pubescent-glandular on both sides but less dense below, venation areolate with included veinlets. Sori produced irregularly on areola nearest to costa or costule; indusium peltate, glabrous; spores 62-69 wm, narrowly winged, rugose, periderm verrucose. Type: TRINIDAD, Blanchisseuse Ward, Brasso Seco Road just W. of village, 200 m alt., on gentle slope by roadside, area collecting storm water from plantation, 23 October 1974, A. C. Jermy 10941 (BM — holotype). Paratype: TRINIDAD, Blanchisseuse Ward, same locality and date, sent to Royal Botanic Gardens, Kew, as a sporeling Jermy 10941: 1 (TRIN). The paratype specimen was found to be diploid with n = 40 chromosomes, and in this respect it contrasts with Tectaria incisa Cav. which is tetraploid. In many respects it is similar to that species and has been included in it in the past. The frond outline is distinctive, T. incisa having 3 or 4 pairs of pinnae and therefore more elongate-ovate. 13. Tectaria ramkissoonii Jermy & T. Walker, species nova (Fig. 14) Rhizoma erectum. Frondes maximae 120 cm longae, + erectae vel leviter arcuatae, juvenes roseae paleis hyalinis et stomatophoris conspicuis basin versus stipitis; stipes fronde dimidio brevior aurantiaco- ferrugineus, basi paleis paucis ovatis fuscis integris, pilis brevibus glandulosis dense vestitus; lamina 45-65 x 25-50 cm, in superficiebus ambabus glanduloso-pubescens aeruginosa anguste ovata vel late lanceolata pinnata; pinnae 4~7, sessiles vel breviter petiolatae pinnatisecto-pinnatifidae; pinnae infimae c. 24 x 15cm, segmento basiscopico ad costam secto, quam pinna 3-plo breviore; pinnae mediae superaeque lineari- lanceolatae ad apicem attenuatae, lacerae, ad apicem frondis minus; pinna terminalis 22 x 11cm, rhombea basi lacerata lobis infimis et apice attenuatis; rhachis spadicea; costa costulaeque similares prominentes pilis glandulosis densis in superficiebus ambabus; nervatura areolata, venulis aliquando inclusis. Sori in vena primaria e costula divergente, praeter segmenta grandia basalia irregulariter biseriales; indusium peltatum; sporangia juvenia rosea, cellulis annularibus 14-16; paraphyses in receptaculo vel seta sporan- gifera exorientes, plerumque ad apicem cellulis glandulosis geminatis; sporae 37-5-(M52-5)-64-0 um, alis latis spinulosis. Rhizome erect. Fronds up to 120 cm long, + erect or gently arching, young fronds pink-red, with colourless scales and conspicuous stomatophores at swollen stipe base; stipe half the length of frond, rich orange-brown with few ovate, brown, entire scales at base, densely covered with short glandular hairs; lamina 45-65 x 25-50 cm, deep green, glandular pubescent on both surfaces, narrowly ovate to broadly lanceolate, pinnate; pinnae 4-7, sessile or shortly petiolate, pinnatisect-pinnatifid; lowest pinnae c. 24 x 15 cm with a basiscopic segment cut to costa and 4 length of pinna; middle and upper pinnae linear lanceolate with an attenuate apex, lacerate, becoming less cut towards apex of frond; terminal pinna 22 Xx 11 cm, rhomboid in outline, lacerate at its base, lowermost lobes and apex attenuate; rachis mid-brown, costae and costules similar and prominent, densely glandular hairy on both sides; venation areolate, sometimes with included veinlets. Sori arising on a primary vein from the costule and irregularly biseriate except in the larger basal segments; indusium peltate; sporangia bright pink when young, with 14-16 annular cells, paraphyses arising on receptacle or on sporangial stalk bearing usually pairs of glandular cells at apex; spores 37-5—(M52-5)-64:0 wm, with broad wing, finely echinate. Chromosome number n = 80 (tetraploid). NEW SPECIES & HYBRIDS 273 Fig. 14 Holotype specimen of Tectaria ramkissoonii Jermy & T. Walker (BM). Type: TRINIDAD, Arima Ward, Aripo Heights, along path to caves, in montane forest over limestone, c. 600 m alt., 26 August 1963, T. G. Walker T7088 (BM — holotype; TRIN, herb. Walker — isotypes). Paratypes: TRINIDAD, Arima Ward, same locality, population, and date, A. C. Jermy 3002 (BM, NY, CR, TRIN). Named after Roodal Ramkissoon, of the University of the West Indies, St Augustine, whose invaluable help in the field was greatly appreciated by the authors. Hitherto this species would have been included under Tectaria incisa Cav. (T. martinensis auct.). It differs in the more numerous, narrower pinnae, and the dense indumentum of the lamina, costules, and costae. 274 FERNS OF TRINIDAD 14. Tectaria vivipara Jermy & T. Walker, species nova [ Tectaria martinicense (Spreng.) Copel. var. vivipara auctores pl.]| (Fig. 15) Planta statura habituque Tectariae incisae Cav. similis. Rhizoma erectum. Frondes + erectae usque ad 105 cm longae in cultura, sylvestres c. 60 cm; stipes 2-3-plo fronde brevior stramineo-flavescens vel brunneo- rufus, basi paleis sparsis, pilis paucis in sulco adaxiali dispersis, meristemate paleis 3-4 xX c. 1 mm, + triangularibus apice longe attenuato, integris tecto; lamina 60 X 32 (in cultis) - 40 x 25 cm, prasina late lanceolata pinnata, ad axillas pinnarum vivipara; pinnae paribus 6-8, pinna basali 13-21 x 2-3 cm, petiolata lanceolata lobo basiscopico prominenti, acroscopico brevi sed conspicuo, margine irregulariter inciso vel undulato; pinnae superae 16-14 Xx 2-5-2-2 cm, ellipticae vel lanceolatae apice attenuato basi late cuneata vel decurrenti, margine leniter lobato vel sinuato (in holotypo) aut minus lobato (in paratypis); pinna terminalis late lanceolata + profunde lobata, lobis inferioribus in pinnas transientibus; rhachis colore stipiti similis sed densius in sulco adaxiali glanduloso-pubescens; costae in superficie adaxiali pubescentia similari in abaxiali minus densa; nervatura areolata, venulis aliquando inclusis. Sori uniseriales secus costulam, saepe irregulatim formati; indusium peltatum pilis brevibus glandulosis in pagina superiore; sporae 43-49 um, cristatae, sparse papillatae. Plant similar in stature and habit to T. incisa Cav.; rhizome erect. Fronds + erect, up to 105 cm long in cultivated material, in the wild c. 60 cm; stipe Y%3-'2 as long as frond, stramineous or yellowish to deep red-brown, very sparsely scaly at base and a few scattered hairs in adaxial groove, growing point covered in scales 3-4 X c. 1 mm + triangular with long attenuate apex, entire; lamina 60 X 32 (in cultivated plants) - 40 x 25 cm, mid-green, broadly lanceolate, pinnate, viviparous at the pinnae axils; pinnae 6-8 pairs, basal pinna 13-21 x 2-3 cm, petiolate, with a pronounced basiscopic lobe and with a small but distinct acroscopic basal lobe, lanceolate, margin irregularly cut to undulate; upper pinnae 16-14 X 2-5-2-2 cm elliptic to lanceolate, apex attenuate, broadly cuneate to decurrent at base, margin shallowly lobed to sinuate (in holotype), or less lobed (in paratype material); terminal pinna broadly lanceolate, + deeply lobed, lower lobes grading into pinnae; rachis similar in colour to stipe but more glandular-pubescent in adaxial groove, costae with similar covering on adaxial side, less dense on abaxial side; venation areolate with occasional included veinlet. Sori uniseriate along costule but frequently irregularly formed; indusium peltate with short glandular hairs on upper surface; spores 43-49 um, crested, sparsely finely papillate. Chromosome number n = 40 (diploid). Type: TRINIDAD, Charuma Ward, Central Range Forest Reserve, Brickfields Teak Planta- tion, 3 miles S. of Forest Resthouse, c. 60 m alt., on clay bank by rivulet with mixed population of viviparous and non-viviparous T. incisa, 9 July 1963, T. G. Walker T6173 (BM — holotype; herb. Walker — isotype). Paratypes: TRINIDAD, Charuma Ward, same locality and date, T. G. Walker T6171 (BM, TRIN); same locality and date, by stream in cut-over seasonal forest, A. C. Jermy 2145 (BM, TRIN), 2146 (NY, CR). Arima Ward, road from San Raphael—Cumuto, in cocoa just before iron bridge, 13 May 1927, Hombersley 243 (TRIN). Well known as a viviparous form of Tectaria incisa and its synonyms, and widespread throughout the Caribbean and Central America. T. incisa in Trinidad is, however, a tetraploid (Walker, 1985) and T. vivipara is based on a diploid of known origin and therefore a new type. It is distinguished from T. incisa by its vivipary, and hairs on the abaxial side of the costae. NEW SPECIES & HYBRIDS 275 HER, MUS. BRIT. i ; TYPE SPECIMEN Laxabee . Tackarin vivian Tarig & To. woe 40 1G Wallon Pee Bad Bal Mas (Nat Hust. | Boo car Pewee Wann, N Fig. 15 Holotype specimen of Tectaria vivipara Jermy & T. Walker (BM). 276 FERNS OF TRINIDAD New combination Meniscium nesioticum (Maxon & C. Morton) Jermy & T. Walker, comb. nov. Basionym: Dryopteris nesiotica Maxon & C. Morton in Bull. Torrey bot. Club 65: 362 (1938). Acknowledgements We are grateful to Professors Cope and Purseglove for putting their departments at our disposal during our various stays at the University of the West Indies, St Augustine, and we thank Roger Barnes, Borhai Kalloo, Roodal Ramkissoon, and David Wood, in particular, for help in the field. The Department of Forests of Trinidad and Tobago gave permission to visit Forest Reserves and stay in resthouses under their ownership, and Texaco Inc. allowed us to collect in their preserves with no restraint. At the Royal Botanic Gardens, Kew, we greatly appreciate the help of Curator John Simmons and Superintendent of the Ferneries (latterly Assistant Curator of the Tropical Department), John Woodhams, given to growing material sent in their care. At the British Museum (Natural History) we are grateful to Kathryn P. Kavanagh who has corrected our Latin descriptions and to Alison Paul for help with the Gleichenia descriptions, for taking the SEM electronmicrographs, and for her careful proof-reading throughout. Similarly we thank Alan Harrington and Jack Laundon for their careful editing of all three papers. References Fay, A. D. A. 1973. A natural Lygodium hybrid found in Trinidad. Amer. Fern J. 63: 165. Walker, T. G. 1985. Cytotaxonomic studies of the ferns of Trinidad 2. The cytology and taxonomic implications. Bull. Br. Mus. nat. Hist. (Bot.) 13: 149-249. British Museum (Natural History) Ferns of Jamaica A guide to the Pteridophytes G.R. Proctor This flora records and describes the 579 species and 30 varieties of ferns occurring in Jamaica. The succinct species descriptions include relevant synonymy and incorpo- rate distributional data both within and outside Jamaica. Special emphasis is given to the subtle distinctions between closely related species and all genera are illustrated. Keys to the genera and species facilitate a wider use of the flora in the West Indies and northern South America. The author, one time Senior Botanist in charge of the Herbarium of the Science Museum, Kingston, Jamaica is an outstanding field botanist and his expertise is reflected in the practicality of the flora and especially in the habitat and ecological information. This volume represents an important addition to our knowledge of the flora of the West Indies. 1985, 631pp, 135 line illustrations, 22 maps. Hardback. 0 565 00895 1 £50.00 Titles to be published in Volume 13 The lichen genus Usnea subgenus Neuropogon. By F. Joy Walker Cytotaxonomic studies of the ferns of Trinidad (3 papers). By A. C. Jermy & T. G. Walker Some genera of the Biddulphiaceae (diatoms) with interlocking linking spines. By Robert Ross & Patricia A. Sims Photoset by Rowland Phototypesetting Ltd, Bury St Edmunds, Suffolk Printed in Great Britain by Henry Ling Ltd, Dorchester Bulletin of the : British Museum (Natural History) Some genera of the Biddulphiaceae (diatoms) with interlocking linking spines Robert Ross & Patricia A. Sims Botany series Vol 13 No 3 27 June 1985 The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and an Historical series. Papers in the Bulletin are primarily the results of research carried out on the unique and ever-growing collections of the Museum, both by the scientific staff of the Museum and by specialists from elsewhere who make use of the Museum’s resources. Many of the papers are works of reference that will remain indispensable for years to come. Parts are published at irregular intervals as they become ready, each is complete in itself, available separately, and individually priced. Volumes contain about 300 pages and several volumes may appear within a calendar year. Subscriptions may be placed for one or more of the series on either an Annual or Per Volume basis. Prices vary according to the contents of the individual parts. Orders and enquiries should be sent to: Publications Sales, British Museum (Natural History), Cromwell Road, London SW7 5BD, England. World List abbreviation: Bull. Br. Mus. nat. Hist. (Bot.) © Trustees of the British Museum (Natural History), 1985 The Botany series is edited in the Museum’s Department of Botany Keeper of Botany: Mr J. F. M. Cannon Editor of Bulletin: Mr J. R. Laundon Assistant Editor: Dr A. J. Harrington Editor’s Assistant: Miss M. J. Short ISBN 0 565 08006 7 ISSN 0068-2292 Botany series Vol 13 No 3 pp 277-381 British Museum (Natural History) Cromwell Road London SW7 5BD Issued 27 June 1985 Some genera of the Biddulphiaceae interlocking linking spines Robert Ross and Patricia A. Sims Department of Botany, British Museum (Natural History), C © SW7 S5BD \ fied ae At jt “i r J Contents Son Bl eI ERA SEAR REA EaR UE RI ny FEC Oe ORR E MUR DEN aR ETT = aly) i 4 2 E ti rc cen nt Bea op A Rn ats ad Cee PRESSE ARP RE REAR ROTOR ee RI Wet DONC RT SOCIMIETIS GTA TECOTGS 5.5. 55.5 5.555005 cnc vtissececceterscedececserstisendeassenscascsas eee Tete et ee agt JUL 1985 MUNN ENE ye nul toh css cp vd oyncenan roar Veag arse veneacee sae vacete oateeks teense J095 . 2BRESENTED SD ae Ns FB 2s cnn Wes sees ven gree ries veacneesses sua vanuoceuaavuuai pe loasesooens 1s GERERAL LIBRAR' sR URE Re OE OEE POPE RPL VERT ET EET PELETIC CUe Ter eee ee vere dere en RENE MVR AD vos. cnvtcs = sods cetavouw yuak sass saxe corns smlodsaueu ans eaakec umansrs ieee daventon ts 282 My Pa oes cease tarp c ce areeet Sewoasume de vueeads set bdsopusieb neds qaeageeas sen iwaeesteeeuswendeass 282 Coe Crh A CERIN 4 Shei ocd canes a cenneseete tesa rors nade ean coe oas aasaaeesduneesensnreer