: ISSN 0968-0446 BM foto Bulletin of The Natural History Museum Tre RATURAL MESTORY LSUSEUM -7 JUN 2001 POS Sante Botany Series S\2 NATURAL HISTORY MUSEUM VOLUME 31 NUMBER 1 28 JUNE 2001 The Bulletin of The Natural History Museum (formerly: Bulletin of the British Museum (Natural History) ), instituted in 1949, is issued in four scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology. The Botany Series is edited in the Museum’s Department of Botany Keeper of Botany: Dr R. Bateman Editor of Bulletin: Ms M.J. Short 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 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. All papers submitted for publication are subjected to external peer review for acceptance. 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(Bot.) © The Natural History Museum, 2001 Botany Series ISSN 0968-0446 Vol. 31, No. 1, pp. 1-35 The Natural History Museum Cromwell Road London SW7 5BD Issued 28 June 2001 Typeset by Ann Buchan (Typesetters), Middlesex Printed in Great Britain by Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset me ea) Bull. nat. Hist. Mus. Lond. (Bot.) 31(1): 1-4 pommenssued 28 June 2001 j ; ; MESTORY E“USSUN New synonymy in some Asian species of ee Ss h d (C | -M . -7 JUN 2001 yrrhopodon (Calymperaceae: Musci) PSS MTED CEPA USRAR\ LEN T. ELLIS Department of Botany, The Natural History Museum, Cromwell Road, London SW7 5BD SYNOPSIS. Calymperes dixoconstrictum B.C. Tan & Mohamed is placed in synonymy with Syrrhopodon croceus Mitt., and Calymperes mussuriense Dixon in synonymy with Syrrhopodon gardneri (Hook.) Schwiagr. Syrrhopodon subelimbatus Dixon, hitherto erroneously regarded as a synonym of Syrrhopodon trachyphyllus Mont., is conspecific with Syrrhopodon armatus Mitt. Syrrhopodon croceus Mitt. in J. Linn. Soc., Bot. Suppl. 1: 41 (1859). Fig. 1. Calymperes constrictum Dixon in Bull. Torrey Bot. Club 51: 233 (1924), hom. illeg. Calymperes dixoconstrictum B.C. Tan & Mohamed in Mohamed & B.C. Tan, Bryologist 91: 29 (1988), syn. nov. Type: Peninsular Malaysia, Selangor, Klang Watercatchment Forest, 12 March 1922, Burkill 6836 (BM!-holotype). DISCUSSION. Mohamed & Tan (1988) proposed ‘Calymperes dixoconstrictum’ to replace the illegitimate Calymperes constrictum Dixon, a combination already published for a different species, i.e. Calymperes constrictum Sull. [= Mitthyridium constrictum (Sull.) H. Rob.]. Eddy (1990), without mention of Tan & Mohamed’s new name, placed C. constrictum Dixon in synonymy with Syrrhopodon loreus (Sande Lac.) W.D. Reese. However, the holotype of C. constrictum (Burkill 6836), in Dixon’s herbarium (BM), represents an extreme form of Syrrhopodon croceus Mitt. that possesses unusu- ally poorly developed shoots and leaves. In typical material of Syrrhopodon croceus Mitt. the leaves are < 5-10 mm long and consist of a narrowly subelliptical base, with entire margins, extending into a linear chlorophyllose limb with a blunt apex (Fig. 1a, c, e) and toothed margins. The hyaline lamina is confined to the proximal region of the base and has a truncate to broadly acute apex. Distally, the lamina in the leaf base is largely composed of thick-walled, porose, orange-red cells (Fig. 1j, k). For a short distance beyond the leaf base the margin usually possesses a row of long, acute teeth; above these, it thickens to form a prominent rib that extends to near the leaf apex. This is composed of stereids enclosed within a unistratose layer of subrectangular cells (Fig. 11, m). Subtriangular teeth occur at intervals along the rib. The holotype of Calymperes constrictum Dixon (Burkill 6836) has leaves which are mostly linear (reaching 5-6 mm long), but some are relatively broad and short with broadly acute apices (Fig. 1b, d), as illustrated by Dixon in the protologue. The hyaline lamina occupies the entire length of the leaf base and possesses an acute apex (Fig. lh, i). Thick-walled, porose, orange-red cells are all but absent or occur in reduced patches on either side of the hyaline lamina in the upper leaf base (Fig. 11). In the leaf limb marginal teeth are sometimes obscure or absent, and the layer of subrectangular cells enclosing the thick marginal rib is sometimes missing or poorly developed. All of these features are consistent with those occurring in depauperate, aberrant or juvenile forms of Syrrhopodon croceus Mitt. collected elsewhere in southeast Asia. Collections similar to Burkill 6836 have been made in the Philippines (Jan & Tandang 82- 376, FH) and South Kalimantan (Ellis 252 pro parte, BO). The latter © The Natural History Museum, 2001 specimen occurred within a few meters of populations of S. croceus with the typical form. SPECIMENS EXAMINED. Malay Peninsula. Negri Sembilan, Pasoh For- est Reserve, Smithsonian 50 Hectare Plot, tree number 62866, March 1995, Ellis s.n. (BM). Philippines. Luzon Island, Laguna Province, Cavinti, Bo. Lumot, Ubali River, near Sitio Ubali, 24 October 1982, Tan & Tandang 82- 376 (FH). Indonesia. South Kalimantan, Panaan, 01° 36' 44" S, 115° 30' 00.5" E, 29 March 2000, Ellis 252 pro parte (BO). Sarawak. Fourth/Fifth Division, Gunong Mulu National Park, W. of Sungei Berar Camp, 150 m, 16 March 1978, Jermy 13664:13 (BM). Syrrhopodon gardneri (Hook.) Schwagr., Sp. musc. frond. suppl. 2(1): 110 (1824). Calymperes mussuriense Dixon, The 150th anniversary volume of the Royal Botanic Garden, Calcutta, 1, 2: 178 (1942), syn. nov. Type: India, Mussooree, Landour, near Woodstock School, 2 July 1922, Dudgeon 64 (BM!-holotype). Syrrhopodon mussuriense Broth. in R.S. Chopra, Taxonomy of Indian mosses: 103 (1975), nom. nud. Original specimen: India, below Mussooree, 10 September 1895, Duthie s.n. (BM!, BM- K!). DISCUSSION. Dixon labelled the type specimen of Calymperes mussuriense Dixon (Dudgeon 64, BM) as ‘Syrrhopodon mussooriensis Dixon, sp. nov.’. The material was never annotated with the published combination. Consequently, Dudgeon 64 and two paratypes of C. mussuriense (Sawhney 236, 250, BM) have hitherto remained unrecognized, and were filed in BM under the unpublished herbarium name. An undated pencilled note on Dudg- eon 64 by R.S. Chopra correctly identifies it as a form of Syrrhopodon gardneri (Hook.) Schwagr. Syrrhopodon mussuriensis Broth., nom. nud. is apparently based on another collection from Mussooree (Duthie s.n.). Coincidentally, the two duplicates of this specimen in BM are also Syrrhopodon gardneri. SPECIMENS EXAMINED. _ India. Kumaon, Thall to Dindihat, June 1926, Sawhney 236 (BM), 250 (BM). Syrrhopodon armatus Mitt. in J. Linn. Soc., Bot. 7: 151 (1863). Fig. 2. Syrrhopodon subelimbatus Dixon in J. Siam Soc., Nat. Hist. Suppl. 9(1): 12 (1932), syn. nov. Type: Thailand, Kaw Tao, 300 m, September 1928, Kerr 338 (BM!-holotype). DISCUSSION. Mohamed & Reese (1985) and Menzel & Schultze- Motel (1990) place Syrrhopodon subelimbatus Dixon in synonymy L.T. ELLIS ‘(NE) C199] Kumar Wosy UMvI | “8 “(Og) ed o1d 7CZ SI] Wor uMeIG Y ‘9 ‘p SIN) “U's Sq Wo UMBIG f ‘J ‘9 SIAN) 9E89 /YNg Wo UMeIG WT *y ‘q ‘eB “(JRoy JURLIOGe ‘UU ‘Jeo] [PULIOU *]) QUIT] Jeo] UT QU pee pue eae PBA aioe “$09 2 ‘] :(Jeay JuBLIOge 2 ‘Jeoy [euLIOU :f) aseq JeIT [eISIP WOIJ S][9d pos-oSuvIo :y ‘f ‘(s]]ao pos-asuv1O Jo sdnois were 0} PIONPal YIM SIABIT steane ‘ Yq alee aheny ne : e Ppa . eer: juouTUIOId YIM Soave] [BdIdA] :3 ‘J) MOTA [eIOIL] Ul SOARI] JO SUOTSOI [eseq :I—-J ‘(SOARO] JURLIOGR :P ‘q ‘SARI [BUIOU :d ‘Dd ‘B) MOIA [P.UDA UT SOAR] JO SadIde :a-v “WI sna podoysixg [ ‘31 win (¢ | Wu | WU C0) foe) NEW SYNONYMY IN SYRRHOPODON ‘WA ‘8Ee€ “lay Woy UMvig J—e “(avifided ajdunts yum eururey asop[Aydosoyyp : ‘Jeo] [eISIp UI BUTLER] asoj]AYdosO[YO puke vISOO :d) JR] JO SUOTIDES-SSOID +f ‘9 {(RUTUE] ouiye dy ay) Jo xodv ay) 0} Jude/pe UrSreU Ie :p ‘eUTUTe] aso][AYdosO]YD :9) MATA BdEJANS UT JLI] JO S][2d :p ‘d souids [eISOd SUIMOYS MOIA [e.UDA UT Xade yea] :q ‘SaARa] 7B “NI SsMYULLY UopodoyLiKs “J-V-Z ii | 4 with Syrrhopodon trachyphyllus Mont. However, the holotype material in Dixon’s herbarium (Kerr 338, BM) represents a form of Syrrhopodon armatus Mitt. Tixier (1978) was correct to include S. subelimbatus in synonymy with Syrrhopodon larminatii Broth. & Paris, the latter now recognized as conspecific with S. armatus. Leaves of specimens of Syrrhopodon armatus Mitt. usually pos- sess costae with a partial to continuous superficial layer of chlorophyllose cells, many of which are drawn out as long spines. The cells forming the chlorophyllose lamina are very slightly ven- trally protuberant and usually possess a simple papilla on the dorsal and ventral surfaces. In contrast, the leaves of Syrrhopodon trachyphyllus Mont. have the surface of the costa smooth and usually formed by stereids. Each cell of the chlorophyllose lamina possesses a crown of papillae on the dorsal and ventral surfaces. Kerr 338 possesses leaves that more closely resemble those of Syrrhopodon armatus (Fig. 2a). Chlorophyllose cells, some drawn out as spines, form the ventral surface of the costa (Fig. 2b, e). However, in most leaves, the dorsal surface of the costa is formed by L.T. ELLIS stereids, a few spines sometimes occurring towards the leaf apex. The cells of the chlorophyllose lamina are unipapillose (Fig. 2f) on the dorsal and ventral surfaces or lack papillae (Fig. 2e). These and all other features of Kerr 338 fall within the range of variation found in specimens of Syrrhopodon armatus. REFERENCES Eddy, A. 1990. A handbook of Malesian mosses, 2. London. Menzel, M. & Schultze-Motel, W. 1990. The bryophytes of Sabah (North Borneo) with special reference to the BRYOTROP transect of Mount Kinabalu. XI. Calymperaceae (Bryopsida). Willdenowia 19: 475-542. Mohamed, H. & Reese W.D. 1985. Syrrhopodon (Musci: Calymperaceae) in Malaysia and adjacent regions. Bryologist 88: 223-254. —— & Tan, B.C. 1988. A checklist of mosses of Peninsular Malaya and Singapore. Bryologist 91: 24-44. Tixier, P. 1978. Le genre Syrrhopodon Schwaegr. (Calymperaceae) en Indo Malaisie. Nova Hedwigia 29: 957-1022. Bull. nat. Hist. Mus. Lond. (Bot.) 31(1):5—7 xX 0236 13\.\) Issued 28 June 2001 Two new species of Pilea (Urticaceae) from Panama ALEX K. MONRO Department of Botany, The Natural History Museum, Cromwell Road, London SW7 5BD; alm@nhm.ac.uk SYNOPSIS. Two new species of Pilea from Panama are described and illustrated: Pilea corona A.K. Monro, which most closely resembles P. acuminata Liebm., and P. digitata A.K. Monro, which most closely resembles P. fasciata Wedd. The affinities of these species are discussed and their position within Weddell’s subdivisions of the genus indicated. INTRODUCTION Pilea Lindl. is the largest genus in the Urticaceae and comprises over 600 species (Burger, 1977), distributed throughout the tropics, subtropics, and temperate regions (with the exception of Australia, New Zealand, and Europe). It is easily distinguished from other neotropical Urticaceae by the combination of opposite leaves and a single, ligulate, intrapetiolar stipule in each leaf axil. In the course of preparing a revisionary account for Flora Mesoamericana, ten new species have already been described by the author (Monro, 1999, 2000) and a further two new species are described here. Their affinities are discussed and their position within Weddell’s (1869) subdivisions of the genus indicated, which although not phylogenetic, are based on the most comprehensive worldwide treatment of the genus. Pilea corona A.K. Monro, sp. nov. Type: Panama, Veraguas, 3 miles from Escuela de Agricultura Alto Piedra on road to Rio Calovébra, along stream, 2400 ft, 7 October 1979, Antonio 2043 (PMA!-holotype; MO!-isotype). Fig. 1A-C. Species P. acuminata Liebmann similis, sed inflorescentiis staminalis non ramosus, stipulis minimis, differt. Herb to 30 cm; epiphytic or epipetric. Stems erect or prostrate, drying dark brown, pubescent, the hairs to 1 mm, appressed, curved; cystoliths fusiform; internodes 7-31 x 14 mm, angulate or circular in cross-section. Stipules 3-5 mm, obovate or oblong, drying grey- brown. Leaves petiolate, petioles at the same node equal or unequal by ratio 1:1.5—-4.0, major petiole 3-34 mm, pubescent, the hairs to | mm, appressed, curved or straight; laminas of leaves at the same node equal to subequal, 25-130 x 11-45 mm, elliptic, narrowly elliptic or lanceolate, chartaceous; upper surface drying dark brown to dark green, pubescent, the hairs to c. 0.8 mm, appressed, weakly curved, the cystoliths fusiform, ‘V’- and “Y’-shaped; lower surface drying grey-green to grey-brown, pubescent on veins only, the hairs to 1 mm, upright, curved or occasionally straight, glandular-punc- tate; primary venation 3-nerved, lateral nerves visible for '/3 to 7/3 of the lamina length, secondary veins (4)8—16 pairs, 45—60° to the midrib, straight; base asymmetrical or symmetrical, cuneate, attenu- ate or decurrent; margins coarsely dentate, basal '/i0 to '/s entire; apex acute. Inflorescences 2-4 per stem, unisexual, occasionally bisexual, where bisexual dominated by a single sex; peduncular bracts 1.0-1.5 mm; bracts c. 0.5 mm. Staminate inflorescences solitary, 25-47 mm, bearing 15-50 flowers in a compact head; peduncle 2/3 to 3/s inflorescence length, pubescent, the hairs to © The Natural History Museum, 2001 1.5 mm, appressed, straight; pedicels 2.5-4.0 mm, glabrous or pubescent, the hairs to c. 0.5 mm, erect, crisped; flowers 3.0—3.5 x 1.0-1.3 mm immediately prior to anthesis, cream to brown; tepals 4, 1.0-1.3 mm, glabrous, occasionally pubescent, the hairs to c. 0.5 mm, erect, crisped, the subapical appendage 1.8—3.3 mm, linear, pubescent, the hairs to 1 mm, erect, crisped; stamens 4. Pistillate inflorescences solitary per axil, 3-10 mm, bearing 20—60 flowers in a compact head; peduncle '/3 to '/2 inflorescence length, glabrous or sparsely pubescent, the hairs to c. 0.8 mm, appressed, curved; pedicels 0.4—-0.7 mm, glabrous; dorsal tepal 0.5—0.7 mm, oblong to obovate, the dorsal tepal appendage c. 0.3 mm, scale-shaped; lateral tepals 0.5—0.7 mm, asymmetrically ovate. Infructescences 14-27 mm; fruit 1.0-1.4 mm, compressed, asymmetrically elliptic, the margin narrow. DISTRIBUTION. This species is endemic to the provinces of Chiriqui and Veraguas in western Panama. It is found at elevations of 700- 1200 m in wet forest. MATERIAL EXAMINED. PANAMA. Chiriqui: SE of Fortuna Lake, near mouth of Rio Hornito, 8°45'N 82°13'W, 1150 m, Hampshire & Whitefoord 318 (BM). Veraguas: above Santa Fe beyond Escuela Agricola Interamericana, |.8 miles beyond fork in road on Pacific slope, above rocky ravine on side of Cerro Tute, Croat 34207 (MO); Rio Segundo Brazo, 700 m, Maas & Dressler 1621 (F, MO); vicinity of Escuela de Agricultura Alto Piedra near Santa Fe, c. | hour walk along road beyond school, 900 m, Antonio 2984 (MO); vicinity of Escuela de Agricultura Alto Piedra near Santa Fe, 3 miles beyond fork in road near the school toward Atlantic coast, near trail to top of Cerro Tute, 700 m, Antonio 3537 (MO); vicinity of Escuela de Agricultura Alto Piedra near Santa Fe, along trail to top of Cerro Tute, 700 m, Antonio 4043 (MO); mountains W. of Alto de Piedras, Siclo Basico school N. of Santa Fe, 700 m, Hammel 4648 (MO, NY); forest at base of Cerro Tute, 6.5 km outside Santa Fe, Folsom 3057 (MO); N. of Santa Fe on property of Escuela Agricola Alto de Piedra, Mori & Kallunki 2521 (NY); NW of Santa Fe, 8.8 km from Escuela Agricola Alto de Piedra, Pacific slope, Mori et al. 3911 (NY). Pilea corona falls into Weddell’s Dentatae species group (Weddell, 1869) in having equal-sized, toothed leaves at each node. Material of this species has previously been determined as P. acuminata Liebm., which it closely resembles, but although both species occur in Panama, P. acuminata is known only from Coclé Province which lies to the east of the area from which P. corona is known. The two taxa may be distinguished on staminate inflorescence arrangement and stipule size, as summarized below. Pilea acuminata: stipules 7-20 mm; staminate inflorescences with (15—25)50-200 flowers borne in 5S—30 compact heads arranged in a loose panicle, peduncle (!/s)!/3 to '/2(3/4) inflorescence length. Pilea corona: stipules 3—S mm; staminate inflorescences with 15—50 6 A.K. MONRO oe) Fig. 1 A-C. Pilea corona (Antonio 2043, MO). A. Fertile branch with staminate inflorescence and infructescence; B. Staminate flower at anthesis; C. Pistillate inflorescence and stipule. D-F. Pilea digitata (Hampshire & Whitefoord 694, BM). D. Fertile branch; E. Staminate flower immediately prior to anthesis; F. Pistillate inflorescence. NEW SPECIES OF PILEA flowers borne in a single compact head, peduncle 2/3 to 3/4 inflores- cence length. The species epiphet refers to the staminate flowers immediately prior to anthesis, at which time the tepal appendages give the flower the appearance of a crowned head. Pilea digitata A.K. Monro, sp. nov. Type: Panama, Chiriqui, trail W. from Fortuna Dam camp to La Fortuna, 8°43'N 82°14'W, 1300 m, 28 February 1985, Hampshire & Whitefoord 189 (PMA!- holotype; BM!-isotype). Fig. 1D-F. Species P. fasciata Weddell similis, sed inflorescentiis staminalis non ramosus, floribus staminalibus majoribus, differt. Herb to 50 cm; terrestrial. Stems erect, prostrate at base, drying dark brown, densely pubescent, the hairs to 1.5 mm, erect or weakly appressed, curved; cystoliths fusiform; internodes 10-85 x 2.5-6.0 mm, angulate in cross-section. Stipules 3.0-10.5 mm, obovate to oblong, drying dark brown. Leaves petiolate, petioles at the same node unequal by ratio 1:1.5—3.5, the major petioles 6-30 mm, densely pubescent, the hairs to 1.3 mm, weakly appressed or erect, curved or straight, the minor petioles 5—20 mm; laminas of leaves at the same node equal, 40-130 x 17-70 mm, obovate to rhomboid to broadly elliptic, chartaceous, occasionally bullate; upper surface drying dark brown to dark green, pubescent, the hairs to 2 mm, erect or appressed, weakly curved, the cystoliths fusiform and ‘V’-shaped, occasionally ‘Y’-shaped; lower surface drying grey-green, densely pubescent on veins only, the hairs to 1 mm, erect, curved or occasionally straight, glandular-punctate; primary venation 3-nerved, lateral nerves visible for !/2 to 7/3 of the lamina length, secondary veins 8-26 pairs, 60—75° to the midrib, straight to weakly curved; base asymmetrical or symmetrical, cuneate or obtuse, occasionally decurrent; margins serrate, basal '/io to '/s entire; apex cuspidate. Inflorescences 2-6 per stem, unisexual; peduncular bracts 1.8—3.0 mm; bracts 1.0—-1.5 mm. Staminate inflorescences solitary, 20-60 mm, bearing 30—200 flowers in a compact head; peduncle '/2 to 3/4 inflorescence length, densely pubescent, the hairs to 1.5 mm, appressed or erect, curved or occasionally crisped; pedicels 2.5—7.0 mm, glabrous, occasionally pubescent, the hairs to c. 0.5 mm, erect, crisped; flowers 2.5—3.5 x 1.0—1.3 mm immediately prior to anthesis, cream and green; tepals 4, 1.3—1.8 mm, glabrous, occasionally pubescent, the hairs as for pedicel, the subapical appendage 1-2 mm, linear, frequently reflexed, pubescent, the hairs to 1.5 mm, erect or appressed, curved, occasionally straight; stamens 4. Pistil- late inflorescences solitary, 12-24 mm, bearing 45—100 flowers in a loose panicle; peduncle '/2 to 2/3 inflorescence length, glabrous or pubescent, the hairs to c. 0.5 mm, erect, crisped or curved; pedicels c. 0.5 mm, glabrous; dorsal tepal 0.7—1.0 mm, oblong, the dorsal tepal appendage 0.4—0.5 mm, obovate to oblong; lateral tepals 0.5— 0.7 mm, asymmetrically ovate. Infructescences 13-35 mm; fruit 1.5 mm, compressed, asymmetrically elliptic, the margin narrow. DISTRIBUTION. This species is endemic to the provinces of Bocas del Toro, Chiriqui, Coclé, and Darien in Panama. It is found at elevations of 700-1700 m in wet forest. MATERIAL EXAMINED. PANAMA. Bocas del Toro: along Continental Divide from road branching north off main Fortuna-Chiriqui Grande high- way near Continental Divide, 1.1 miles from main highway, 8°44'N 82°17'W, 1200 m, Croat & Grayum 60315 (BM, MO); vicinity of Fortuna Dam, 8°40'04"N 79°50'04"W, 850-900 m, McPherson 10550 (MO). Bocas del Toro/Chiriqui border: Continental Divide above Quebrada Arena, carretera del Oleoducta, IRHE Fortuna Hydroelectric Project, 1150-1200 m, Knapp & Vodicka 5639 (MO). Chiriqui: road between Fortuna Lake and Chiriqui 7 Grande, 4.5—5 km N. of dam over Fortuna Lake, 8°43'N 82°17'W, 1100-1135 m, Croat & Grayum 60041 (MO); road between Gualaca and Fortuna Dam site, 8.3 miles NW of Los Planes de Hornito, 8°44'N 82°16'W, 1260 m, Croat 49935 (BM, MO); Distrito Boquete, Fortuna Dam site, along trail following Continental Divide, 1100 m, van der Werff & van Hardeveld 6721 (MO); Distrito Boquete, Fortuna Dam site, Continental Divide, 1100 m, van der Werff & van Hardeveld 6798 (MO); La Fortuna Dam site, 9.4 miles beyond entrance to Finca Linares, 20.9 miles from bridge to Rio Esti, 1400 m, Antonio 2833 (MO); road between Gualaca and Fortuna Dam site, 8.3 miles NW of Los Planes de Hornito, 1260 m, Antonio 4162 (MO); road between Gualaca and Fortuna Dam site, 8.3 miles NW of Los Planes de Hornito, 1260 m, Antonio 4163 (BM, MO); La Fortuna Hydroelectric project, ridge top N. side of river, c. 1200 m, Hammel 2191 (MO); E. del campamento Bijao- Fortuna, Mendoza et al. 264 (US); between Los Planes de Hornito and Fortuna Lake, trail to Zarzo, 8°41'N 82°13'W, 1200 m, Hampshire & Whitefoord 694 (BM, PMA); Fortuna Dam, above Gualaca, 8°45'N 82°15'W, 1200 m, McPherson 6710 (MO). Coclé: E. of El Copé sawmill along small stream, 700 m, Hammel 3578 (MO). Darien: Pirre Massif, Alturas de Nique, above Cana mine, 7°45'N 77°40'W, 1250-1500 m, McPherson 12205 (MO); Cana-Cuasi trail, Chipigana District, 1700 m, Terry & Terry 1563a (F, GH, MO); N. slopes of Cerro Pirre, 700-950 m, Mori & Kallunki 5478 (MO); Cerro Campamento (S. of Cerro Pirre), Duke 15671(2) (MO); Cerro Pirre, 800-1400 m, Duke & Elias 13698 (MO); Cerro Pirre, ridge top and slope from Rancho Frio to Rancho Plastico, 800-1200 m, Folsom 4204 (MO); Coasi-Cana trail, between Cerro Campamento and La Escalera to ‘Paramo’, E. of Tres Bocas, Kirkbride & Duke 1336 (MO, NY); summit of Cerro Pirre, 1000-1400 m, Gentry & Clewell 7112 (MO); vicinity of Cerro Tacarcuna summit camp, along stream N. of camp, 1550-1650 m, Gentry & Mori 14056 (F, MO). This species falls into Weddell’s (1869) Dentatae species group in having equal-sized, toothed leaves at each node. Material of Pilea digitata has previously been determined as P. fasciata Wedd., P. latifolia Wedd., and P.rugosissima Killip, all of which occur in Chiriqui Province. Of these it resembles only P. Jatifolia and P. fasciata, the latter closely. Pilea digitata is easily distinguished from P. latifolia by the pubescent upper surface of the leaf lamina. It may be distinguished from P. fasciata on staminate inflorescence arrange- ment and flower size, and pistillate inflorescence flower number, as summarized below. Pilea fasciata: staminate inflorescences with flowers borne in a loose panicle, flowers 1.3—1.8 mm; pistillate inflorescences bearing 100-280 flowers. Pilea digitata: staminate inflorescences with flowers borne in a single compact head, flowers 2.5—3.5 mm; pistillate inflorescences bearing 45—100 flowers. The species epiphet refers to the tepal appendages of the staminate flowers which, because of their rounded apex, resemble fingers. ACKNOWLEDGEMENTS. _I thank the curators at C, F, GH, MO, and NY for the loan of herbarium material, Helen Greenop for providing the botanical illustrations, and Sandy Knapp and Bob Press for help with the preparation of the manuscript. REFERENCES Burger, W. 1977. Pilea. In W. Burger (Ed.), Flora Costaricensis. Fieldiana, Botany 40: 246-272. Monro, A.K. 1999. Seven new species of Pilea Lindley (Urticaceae) from Mesoamerica. Novon 9: 390-400. 2000. Three new species of Pilea (Urticaceae) from Costa Rica and Panama. Bulletin of The Natural History Museum, Botany series 30: 7-11. Weddell, H.A. 1869. Pilea. In A. De Candolle, Prodromus systematis naturalis regni vegetabilis 16(1): 104-163. Paris. Bull. nat. Hist. Mus. Lond. (Bot.) 31(1): 9-25 ‘\ \ KX CB3SI32.\ ) Synopsis of Mesoamerican Pilea (Urticaceae), including eighteen typifications and a key to the species ALEX K. MONRO Department of Botany, The Natural History Museum, Cromwell Road, London SW7 5BD; alm@nhm.ac.uk CONTENTS MADE OCUICEN OM asc Ss acess ae ceectas saaece cscs oes ca uAaceioee seas Seanad Satin ca Sessa canes to nst a Say Suse gosh sass aocesesatet eased eat cbasustees ees sas btan tops taebeus tucbeasvaeetearee 9 Materials andimethodsts sents cccced cas cecucecoccessesdecss cise cvecaaate ccetl scccess cgaseci sas vlatssuassseccucaes tovdsecdsadatuasesvsesosuceeteeeoscaeepesgeee eaissaceseanigseeoes 9 TaxOnomic:treatmenmt vcs yes oes ce cost acesacccccasccs sxcstosccs sucsd ceetasetvace sucess cesses dces cocatoatuacenpeestacsbeccs ndeess ace S20iasutseckesuccotcceecensuses 10 Rey tothe Species ates. cacisvcrececcns totes gace caucetect vs cocseus vouecavareest sat cesee tude svousatcrees eccuewatses sons sua stuonatonscons dus curseesssausesten canis tund teasenctae 10 FRETETONCES is siy cess couss sea csthe iouecconkcshencdvacsusecstcs couse cous sueegsantovoresete wae swetevsegueacouvietber tar cucustes saoasseteska¥cshoseus stat ssueabuaa caneenveioveisnsatsne 17 Material examined s¢c23s0te ssc: dec tans baasecazsetoccs suctcastives cae «eel ootsdesetcauecquotsanttates Sesttets sdnelatesseseianscaccesseced aos sectasbevagetasetadutessersenttegee ss 17 SyStematic INGOXs-cic.iseciceccsstevcd csscpese beset. tieeiataccaartaeretace, cach: fastateeysducesansmeneeseeeasspeatesteatidnets ctesostiess eda slaasauecbagasssansseasetnicoasetortesy 25 Synopsis. A key to the Mesoamerican taxa of Pilea is presented together with a nomenclatural revision of 85 names, of which 18 are typified here: P. brittoniae Urb., P. centradenoides Seem., P. cornuto-cucullata Cufod., P. forgeti N.E. Br., P. hyalina Fenzl, P. imparifolia Wedd., P. involucrata (Sims) Urb., P. latifolia Wedd., P. lundii Liebm., P. microphylla var. peregrina (Griseb.) Urb., P. nummulariifolia (Sw.) Wedd., P. ovalis Griseb., P. ptericlada Donn. Sm., P. pubescens Liebm., P. rubiifolia Blume, P. rupicola Issued 28 June 2001 Wedd., P. trianaeana Wedd., and P. vulcanica Liebm. A list of material examined with determinations is appended. INTRODUCTION With over 600 species (Burger, 1977), Pilea Lindl. is the largest genus in the Urticaceae and one of the larger genera in the Urticales. It is distributed throughout the tropics, subtropics and temperate regions (with the exception of Australia, New Zealand and Europe) and easily distinguished from other neotropical Urticaceae by the combination of opposite leaves and a single ligulate intrapetiolar stipule in each leaf axil. Pilea was first described by Lindley in 1821 using Pilea muscosa Lindl., a superfluous name for P. microphylla (L.) Liebm., as its type. This species was introduced as a greenhouse exotic in the early nineteenth century. Prior to Lindley’s description there had been disagreement as to where it should be placed, with Linnaeus (1759) placing it in Parietaria L. and Swartz (1797) and Willdenow (1805) placing it in Urtica L. Little more than 30 years later Weddell, in his comprehensive revisions of the genus in 1856-1857 and 1869, had identified 159 taxa in three major subgeneric groupings, many of these taxa having been originally placed in Urtica by their authors. Pilea has attracted little monographic attention since Weddell’s monographs but the genus has attracted significant contributions from localized treatments (Killip, 1939; Standley & Steyermark, 1952; Adams, 1972; Burger, 1977 and Chen, 1982) and by 1997 a further 562 names and 17 major subgeneric groupings had been published (Anon., 1997). For the purpose of this synopsis, the definition of Mesoamerica is that used in Flora Mesoamericana (Davidse et al., 1994), a region bounded to its north by the Mexican states of Yucatan, Campeche, Tabasco, Quintana Roo and Chiapas, and to its south by Panama. This represents the closest geopolitical delimitation of the Mesoamerican phytogeographical region. Within Mesoamerica there are 85 names for 56 recognized taxa of Pilea and there is significant © The Natural History Museum, 2001 confusion over the application of many names. Combined with a lack of regional keys, and the similarity of form and habit within the genus, the determination of collections can be very difficult and has resulted in a significant proportion of herbarium material from Mesoamerica being misidentified. As more names are published (there are currently over 800 (Index Kewensis, 1997)) so the logistical problems of undertaking a monographic revision grow, and the classification of the genus has become more problematic. Whether or not Pilea is the subject of a global monographic revision in the near future, it is felt that the preparation of an identification key and nomenclatural review for Mesoamerican Pilea would be a useful first step in addressing some of the problems encountered whilst dealing with this genus for Flora Mesoamericana and would help provide a foundation for future work on neotropical Pilea. In this treatment types are cited with the country of origin, collector name and number and the herbaria from which material has been seen. However, where types are designated here, all of the label locality information available, and the date of collection is included. Distributions for each species are given to country level within Mesoamerica, with the exception of Mexico and species which are only known from a single country, where they are given to state level. Global distributions are given to regional level e.g. South America, West Indies etc., following Flora Mesoamericana protocols (Davidse et al., 1994). MATERIALS AND METHODS The nomenclatural revision was based on the examination of the original published descriptions, type material for all 85 names, and all Mesoamerican material available on loan from BRU, C, F, GH, ITIC, K, LL, MEXU, MO, NY, P, PH, PMA, SCZ, TEX, and US. In 10 addition, material of related species from outside Mesoamerica, and from areas adjacent to Mesoamerica (e.g. Oaxaca and Veracruz in Mexico) was obtained, with the result that 2064 collections were examined and determined, 1748 of them from Mesoamerica. Of the 85 names included in this study, type material is known to have been destroyed for only one species (Pilea cornuto-cucullata Cufod.), and in this case a photograph of the holotype exists. Where it was felt that the existing type material was ambiguous, e.g. in the case of Pilea nummulariifolia (Sw.) Wedd. where the type element was an illustration, then an epitype was selected. As the number of species described in Pilea has grown, so have the characters used to delimit species in the genus. The most frequently used macromorphological characters used by previous authors have been: leaf isomorphy and margin morphology, staminate inflorescence arrangement, staminate flower division and staminate tepal appendage morphology, stipule morphology, cystolith arrange- ment in the leaves, and fruit size. In this study, emphasis was also placed on pistillate inflorescence arrangement, pistillate flower size and dorsal tepal morphology, and stem morphology. All material was examined using a stereo microscope at x64 to x400 magnifica- tion and up to 71 observations were made for each specimen sampled. These observations were then used as a guide to delimiting taxa and in the preparation of the identification key. The key to the species was prepared using herbarium specimens and the observ- ations made for each species; it was then tested in the herbarium on the loan material and collections at BM, and on the collections present at GH and P in 1999. Many of the characters used in this key are very small and it may be necessary to make measurements +/— 0.1 mm; a dissecting microscope (to x200) is therefore recommended. The terminology used for the description of leaf shape is based on that in Stearn (1992). Because of their small size and large number, it is usually fairly easy to find well preserved flowers on herbarium specimens. TAXONOMIC TREATMENT Key to the species lps) Leaves ‘pectinate 2) :4.00 tet ethan tasers eine 40. P. pteridophylla — Leaves entire, serrate, crenate or sinuate, but never pectinate ........... 2 Di PASC AVES! SINUAtEs. 5.2: 2c0c500 yes eeseecvece osseous beets 52. P. trichomanophylla - Leaves entire::semrate: Or Crenate).. ic. stern cs necessitated ences 3 3 Leaves 4—6 at each node, verticillate ............ccee 49. P. senarifolia 19) eaves 2 at-each node; opposite s.42- fast avectas ast terscrsesrt se cotncraeoke 4 4 Stipules generally more than 2 mm long, prominent (clearly visible to the naked eye), auriculate, cordiform, ovate, oblong or obovate, occasion- ally, CAGUCOUS Seek as foc ee eraenes aces sive oeseaani eee ears 5 — Stipules generally less than 2 mm long, evident to obscure (not clearly visible to the naked eye), deltate or broadly ovate ............c:.c:ecceeeees 42 Me we LCALIMALP IN CUTE oe ccases5sszaxesests 1:1.5 sb esebussbvicuuesus ¢ivossenssateutisatotescons uses susedcsbe es jtcsedssates pucetnesoeeceaceassicvevacte 11 Leaves of equal or subequal length in pair, if subequal then the ratio of Smaller to: larger< Del Sc 2 fscetsessncetenecctactsevesess tors cttocseiscethoovaeseed. 12 Petioles pubescent; leaf margin deeply serrate, the teeth weakly ascend- DISS oak cate en ssnacede eeotes tite Belen. vere esee ee eteeeaeet one 6. P. centradenoides Petioles glabrous; leaf margin weakly serrate, the teeth strongly ascend- DING cerca saves ya ataceecush sa schecechevcteis sae viaszccss ct conten sodacbeeh 12. P. costaricensis Lower surtaceof leaves: pubescent /2::sce.5 Secs sscsetscctadececacvteseeecssveee 13 Lower-surface of leaves 'plabrous.4c.:<. ctectesteseeesdesveestccalscsess fesestsoans: 20 Petioles glabrous <3 scsistisssssestscusscuseseaaseseses: 10. P. cornuto-cucullata Petiolespubescents 20/4. ssesistelt ci esscstvsssoretasnsacdaescsertnnetnatacdeottacsasets 4 Leaf margin entire from the base for = '/2 of the leaf length............ 15 Leaf margin entire from the base for < '/3 of the leaf length............ 16 Secondary leaf veins 5S—9 pairs, 30-65" to the midrib; stipules 2.5—5 mm long; staminate inflorescence < 10 mm long ......... 25. P. involucrata Secondary leaf veins 7-16 pairs, 60—75° to the midrib; stipules 5—14 mm long; staminate inflorescence > 30 mm long ................. 19. P. forgeti Secondary leaf veins 4-6 pairs; lower surface of leaves eglandular; staminate flowers 3-parted; fruit > 2 mm long........... 54. P. tripartita Secondary leaf veins 6—28 pairs; lower surface of leaves glandular- punctate; staminate flowers 4-parted; fruit < 1.5 mm long .............. 17 Leaves lanceolate or narrowly elliptic, or sometimes falcate; lateral veins visible for over 3/4 of the leaf length; staminate inflorescences < PE Simnnrn LOWS 2555s ss oeeeszck cee nddeesaaos ephetesee ces asta sasesaseresees 34. P. pallida Leaves ovate, elliptic, broadly elliptic, rhomboid, obovate, but never falcate; lateral veins visible for 2/3-3/4 of the leaf length; staminate inflorescences SU Simi long -e.< a2ts.0eceecsliscsoroetsestoeake ost yaseeneets 18 Leaf base cordate or occasionally subcordate; stipules widest at or below the midpoint; staminate flowers borne in 1-3 compact heads cisiasunsatdtvou louse steduecdiesdsta aisbessuoet cack jasoncdesazcscueseneeacSeseoesrs 37. P. pittieri Leaf base acute, cuneate, decurrent, obtuse, subcordate or cordate; stipules widest at or above the midpoint; staminate flowers borne in loose panicles, or in 5 or more compact heads borne in a loose panicle okuusessenesenen Sort uxseaseventaceyereesenteusosscs Venta oaeste wales Sonkau abe she ein atecsteanceeceets 19 Leaves oblanceolate, rhomboid or elliptic; stipules 3-6 mm long; secondary leaf veins 60-90" to the midrib; subapical appendage of staminate tepals 1.3-1.5 mm IONg ......... es eeeeeeseeeeeeeeeees 28. P. latifolia Leaves ovate to elliptic; stipules 7-20 mm long; secondary leaf veins 35-45 to the midrib; subapical appendage of staminate tepals 0.3-0.5 MAM ONG oi. oi cceitst Ste scsacesscenstastevactuguesta tase ia cenasseaiosesaass 1. P. acuminata Petioles pubescent, the hairs short, curved and appressed (frequently difficult.to:see with the naked eye) iiss a sssceck scceiees. stan ittccsessaserssscactes 21 Petioles Ola DrOUS 'atascccs cs wsktesb cteegetasdanakvoozscentsassessauassarsustbesteceradeastees 22 Leaves 63-235 mm long, with 13-28 pairs of secondary veins 60-80" to Le Teus rah (alg lo) Oper SRR re uOAeEe trap e NTEE: Ae Renin ee ery pore 34. P. pallida Leaves 6.5-47 mm long, with 3-7 pairs of secondary veins 30-45’ to the PTAA 3355 so fis saccvacctseeocecweaseesdscutnae cttesoatuevnad dogiseaseeveas 4. P. auriculata SYNOPSIS OF MESOAMERICAN PILEA 22 23 24 ZS 26 27 32 33 34 35 36 Upper surface of leaves variegated, the variegation visible when dry SPST DOs rere RSET nr ETT 5. P. cadierei Upper surface of leaves never variegated, or if so, the variegation not VISIDIE WHEN AGY. cao. hace 2s ccc cu sno fesancucnrsseyqesceouibeveen ou svsesettasvurecestecenats 23 Leaf margin entire from the base for = 2/3 of the leaf length, thereafter MEMOLELV: CLONAL sche ccreere sacs rvccecectyssnveseeoteoteent seenasessh ese 2. P. adamsiana Leaf margin entire from the base for = 2/3 of the leaf length, thereafter serrate: Crenate. Or Selrate-Cremate ois. sesisedccsecsosssesosscassbaatveucssisecsarssdss 24 TCAVES! ODOV ALE 0. eccscceesscccyteseonssccesccneceecesvcbsepevteteoeonyveers 19. P. forgeti Leaves ovate, lanceolate’ or elliptic... sicccciisessccscsessecsesovvevesesteazass 25 Upper surface of leaves drying bright green, yellow-green or occasion- Ally: Pale! BLOWIN sé 8 pairs on larger leaves; fruit < 2 mm long........ 37 Leaf margin entire from the base for !/10—!/s of its length; fruit 1.0-1.4 POM N OMG Soe os svi esse cssewesssccsstscbascssesssdteosseseasererssousentscesceeSens 1. P. corona VOD, siassasnsssciscrssasansnsescosesessaressonesssuvacensaanisngnosssootabescstssesdeiso@asbeneeseenns 36 Lateral veins visible for over 3/4 of the leaf length; upper surface of leaves sparsely pubescent, the hairs < 1 mm long; staminate flowers 3- REE 5, 5 czacctussaxtosncceseevasvadussioas tbvertanseasponsesiocssaanventy 54. P. tripartita 37 38 39 40 4] 42 43 45 49 11 Lateral veins visible for '/2/3 of the leaf length; upper surface of leaves pubescent, the hairs > | mm long; staminate flowers 4-parted ............ Sees teadeausvtn' suvceatydde~govsvobaysee usta sensor stgcasoneainestt stsasetseties 42. P. pubescens Staminate flowers borne in | or more compact heads ..............00 38 Staminate flowers borne in loose panicles, occasionally borne in clumps along pamicle “branches i. :3i.0scc.0sc0 "1: Oumim long ec 4s ciisecessseccesssescercteseoes 18. P. fasciata Stems pubescent, with hairs to 0.8 mm long; cystoliths on stem fusi- form; leaves ovate to ovate-lanceolate; fruit 0.5—1.0 mm long........ 41 Cystoliths on upper surface of leaves fusiform; apices of leaves acumi- nate to subcaudate; stipules 7-20 mm long; staminate inflorescences 30-90 mm long; fruit 1.0 mm long ............ceeeeeeeeeeee 1. P. acuminata Cystoliths on upper surface of leaves fusiform, *V’- and or “Y’-shaped; apices of leaves acute or subcuspidate; stipules 6-7 mm long; staminate inflorescences 12-18 mm long; fruit 0.7—0.8 mm long ..........::::e0 PET ee cea RUT EAS Maeda ate ouaah avid sea soaee sabes 21. P. gomeziana Upper'surface' of leaves pubescent -:sssscescs. cccsieesosesoesstsscneccctsseenceetae 43 Upper surface of leaves glabrous .............sccsccceseseeseeeeeeeseteeeeneeeeneenens 45 Margin serrate; staminate flowers 2-parted .................+- 23. P. hyalina Margin entire; staminate flowers 4-parted ..........ccccceceseeeseeeteeeteees 44 Leaves > 13 mm long, evenly spaced along the stem, occasionally clustered but never forming terminal rosettes, the lower surfaces pubes- cent: towards the base Wesc..6.5.t25. sei ecescesSecsssdencoesecteises 36. P. parietaria Leaves < 10 mm long, clustered towards the apex forming terminal rosettes, the lower surfaces glabrous.................. 22. P. herniarioides Leaves of equal or subequal length in pair, where subequal the ratio of Smaller tolarger << USUe5 wists ccccccsscssvesescvocsunsssancenssnteoenetsteccestecssrdes 46 Leaves of unequal length in pair, the ratio of smaller to larger 2 1:1.5 Se seac tee sa asta os ta Pe Sata tap doses anaes ec oeath vba eos sectzoas tat east tesceeeaas sesso weceeene® 56 Leaves pinnately-veined .............sc.ccscssssesssssscensssecersseusensansscneseeseesees 47 Wea VES 3=VEINed eer e oe sesee ecesectreeura cbastesecioescsttnoserssuegsutevstisnecsdeesstes 49 Teeaf margin entire c5c0. ited. wscsctt ee esostnassnsseetsessereéess 32. P. microphylla Leaf margin crenate or Cremate-Serrate ............cseeceseeeseeseeeeeeeeeeeeees 48 Leaves linear-lanceolate; staminate inflorescences borne at the base of an internode which is shorter than the adjacent leaves .............::0:008 Ana ge, tet Pe Ee act ae RUE TEs uae C cs auctvetactestte cores tokeeat ataes 39. P. plumulosa Leaves oblanceolate, narrowly rhomboid or narrowly obovate; staminate inflorescences borne at the base of an internode which is longer than, or rarely equal to, the adjacent leaves ...............: 38. P. pleuroneura Lateral primary veins visible for less than 3/s the leaf length ........... 50 53 54 55 56 37 58 63 Lateral primary veins visible for 3/1 or more of the leaf length ........ Ss Pistillate inflorescences bearing 6—20 flowers; larger petiole in pair < LA ram NOM gy 355 ees secaees scat cesavcncaccovtnsstacevacsctacsdezeveess 14. P. dauciodora Pistillate inflorescences bearing 30-300 flowers; larger petiole in pair = D4 ram LOM Se ese iecstd cesecatecivacaccaesssvstetedacves si senssesenceure 56. P. vulcanica The majority of petioles equal or subequal at each node, where subequal thé ratio of shorter to longer:< 1.5 io ioF. eseiias cee ccsvccneccvesesesuesdounese 52 The majority of petioles unequal at each node, the ratio of the shorter to VOR Ber > LS aes cscecvececsscosescnvecssccsansevscseayobivassucsegnaqecstazsncnnasossaspatensssess 54 Leaves 2.5—7 mm wide; petioles < 4 mm long; staminate inflorescences bearing < 24 TOWNS vaca scisesctigts asks steh ss vacasecesvestonts ters .27. P. killipiana Leaves > 8 mm wide; petioles > 4 mm long; staminate inflorescences Dearing 724 TOWELS iis. csccecsauecsscaectaveaecastevacsooseteesstedsenzeetecventesses 53 Secondary leaf veins straight or weakly curved, 60-90" to the midrib; staminate inflorescences 8—25 mm long; staminate pedicels up to 1 mm JONG Sesiissctsdseenstlicsciusiace! snes tecsstheeetesheasrseevestecsasosevsessees@ 31. P. mexicana Secondary leaf veins strongly curved, 45-60" to the midrib; staminate inflorescences 15-75 mm long; staminate pedicels up to 3 mm long dees Gaeaansecaecdt dh sacueaa dBaasacdseea nah wag adagsanloaysdeen tag duecusiebeveease doses 20. P. glabra Leaves ovate, frequently falcate; staminate flowers 1.3—1.5 mm long Sosnscasabagtoadncct st eaote ct edeesaase as scstatonoscuss cosisoagaetsas .3S mimi assis cecescascsecescesessiceteeie kere 62 Stems angulate in cross-section, drying dark brown almost black; staminate inflorescences solitary, bearing | 1—50 flowers; pistillate inflor- escences bearing 4-30 floWefTS ...........cccccescesseesseees 30. P. magnicarpa Stems rounded or irregularly shaped in cross-section, not angulate, drying red-brown to dark brown; staminate inflorescences 1-4 per axil, bearing 15-200 flowers; pistillate inflorescences bearing 5—95(450) SIO WETS 5 ofecs3ee Sis letths cess cencesucsysacteccisseee cessativeenaeees 43. P. purulensis Lateral veins of leaves visible for 2/3 or less of the leaf length ........ 64 A.K. MONRO — Lateral veins of leaves visible for 3/4 or more of the leaf length ...... 65 64 Smaller leaf in pair <4 mm wide; major petiole in pair 1.0—1.5 mm long spe dees des cvaeesag states tags ttasss tina cacasceeeavusessseve Ceca se teats tated 44. P. quadrata — Smaller leaf in pair = 4 mm wide; major petiole in pair 1.5—2.5 mm long m cauab'bdab od sdeavsiscescasuses ans seussvossessas soavsessuaseovsscecnuCtre Naat 24. P. imparifolia 65 Lower surface of leaves pubescent, the hairs c. 0.5 mm long.............. abated Costecelaacaguversioss reach av oot evdoeesverisctotn ceeaeieen cot tise 13. P. daguensis = ‘Lower-surfaceiof leaves: glabrous) xi... .ccc.,.chececcesvvscss ens d-fastatteresttece 66 66 Stems with ‘V’- or ‘Y’-shaped cystoliths; minor leaves in pair 3-8 mm wide; pistillate inflorescences bearing 12—200 flowers ............:cc:000 GSehRceeaedecesitedoeasebsracet cx Seatusash pease teat ea tatea ta eeee ee tas 35. P. pansamalana — Stems lacking ‘V’- or ‘Y’-shaped cystoliths; minor leaves in pair 1.5— 2.5 mm wide; pistillate inflorescences bearing 6-25 flowers .............. Boe uadtatved St \eash este et utente tetetsieseeeeeeeeeees 16. P, ecboliophylla OT RARE SU PNM, en ccyassevae seach coy easczcnds Saosh peng Hast aeseouassaas Caparo p as trates .68 Sei) BEWUIE S 1S ah. 5 sob sczeeveecacecenavecserecessaze svat sctseessossisecraee tecnica tees 70 68 Smaller petioles in pair => 3 mm long. «2.0... eee 8. P. conjugalis — Smaller petioles in pair < 1.5 mm long, or leaves sessile ...............+ 69 69 Stems angulate in cross-section, drying dark brown almost black; staminate inflorescences solitary, bearing 11—50 flowers; pistillate inflor- escences bearing 4—30 flowefS .........:ceceeseeseeseeeeees 30. P. magnicarpa — Stems rounded or irregularly shaped in cross-section, not angulate, drying red-brown to dark brown; staminate inflorescences 1+ per axil, bearing 15-200 flowers; pistillate inflorescences bearing 5—95(450) PIO WETS ie ooo ie: eat Bes esees ohana toeadectreastons thee tee 43. P. purulensis 70 Smaller leaf in pair => 10 mm Wide. ............ceeeeseeseeees 50. P. skutchii =, _ Smaller: pair <9 mimi Wide is. 02s5 tah ct eeccscges. Sarees egieceal aestteneeeeice 71 71 Upper surface of leaves lacking ‘V’- or ‘Y’-shaped cystoliths; second- ary leaf veins inserted 45— 60° to the midrib; Costa Rica and Panama subpienasunass ind ccone ceuseddareygurcavonsste cuseVuueecobacitenessucsUangeates 12. P. costaricensis — Upper surface of leaves with some ‘V’- or ‘Y’-shaped cystoliths present; secondary leaf veins inserted 60—90° to the midrib; Tabasco, Chiapas; Guatemala and Belize: as vcstvcectscds. cassceh a cccsaeesatsssn oa eaavarserss 72 72 Smaller leaf in pair 1.0-1.8 mm wide; staminate inflorescences 16-54 mm, the flowers borne in a compact head..............:cce 46. P. riparia — Smaller leaf in pair => 3 mm wide; staminate inflorescences < 15 mm, the flowers borne ina loose: panicles