'^ # IDoT cf\6 HANDBOOK OF FLOWER POLLINATION BASED UPON HERMANN MULLER'S WORK 'THE FERTILISATION OF FLOWERS BY INSECTS' BY DR. PAUl'^KNUTH^ FORMERLY PROFESSOR IN THE OBER-REALSCHULE IN KIEL, AND CORRESPONDING MEMBER OF THE BOTANICAL SOCIETY DODONAEA IN GHENT TRANSLATED BY J. R. AINSWORTH DAVIS, M.A. TRINITY COLLEGE, CAMBRIDGE VOLUME III r::- (II. BAND, II. TEIL OF THE GERMAN EDITION) OBSERVATIONS ON FLOWER POLLINATION MADE IN EUROPE AND THE ARCTIC REGIONS ON SPECIES BELONGING TO THE NATURAL ORDERS GOODENOVIEAE TO CYCADEAE WITH 208 FIGURES IN THE TEXT, AND A SYSTEMATIC LIST OF INSECT VISITORS WITH THE NAMES OF THE PLANTS VISITED ;■) OXFORD AT THE CLARENDON PRESS 1909 ^^'^^^ Gray Mer'^.arlum rlarY«r(< University! (m) HENRY FROWDE, M.A. PUBLISHER TO THE UNIVERSITY OF OXFORD LONDON, EDINBURGH, NEW YORK TORONTO AND MELBOURNE CONTENTS ANGIOSPERMAE Class I, Dicotyledones Natural Order LVII. Goodenovieae R. Br. . LVIII. Campanulaceae y«jj. . LIX. Vacciniaceae Lindl. . LX. Ericaceae Lindl. LXI. Epacrideae R. Br. LXII. Diapensiaceae Lindl. . LXIII. Plumbagineae yaw. LXIV. Primulaceae Vent. LXV. Oleaceae Lindl. . LXVL Apocynaceae R. Br. . LXVIL Asclepiadeae R. Br. . LXVIII. Gentizneze fuss. Polemoniaceae Lindl. Hydrophyllaceae DC. Boragineae Desv. Convolvulaceaey«w. . Solanaceae /uss. Scrophularineae R. Br. LXXV. Orobanchaceae Ric/i. . LXXVI. Lentibulariaceae RicA. Gesneriaceae L^ndl. Bignoniaceae R. Br. . Acanthaceae R. Br. . Selagineae DC. . Verbenaceae /uss. Labiatae_/«w. LXXXIII. Plantaginaceae y«j-j. . LXXXIV. Nyctagineaeyi^jj. LXXXV. Illecebraceae R. Br. . LXXXVI. Amarantaceaey«jj. . LXXXVII. Cheitopodiaceae Venl. LXXXVIII. Polygonaceae yaw. LXXXIX. Cytinaceae Brogn. XC. Aristolochiaceae Juss. XCI. Laurineae Vent. XCII. Proteaceae y«w. XCIII. Thymelaeaceae yaw. . XCIV. Elaeagnaceae R. Br. . XCV. Loranthaceae Don XCVI. Santalaceae R. Br. XCVII. Euphorbiaceaeyaw. . LXIX. LXX. LXXI. LXXII. LXXIII. LXXIV. LXXVII. LXXVIII. LXXIX. LXXX. LXXXI. LXXXII. PAGE I I 27 32 54 54 55 58 81 86 90 96 no 114 115 142 150 160 232 233 237 237 237 240 241 243 321 328 329 331 332 337 350 350 356 356 356 359 360 362 364 IV CONTENTS Natural Order XCyill. Urticaceae Endl. XCIX. Platanaceae Leslib. C. Juglandaceae DC. CI. Myricaceae Rich. CII. Cupuliferae Rich. cm. Salicineae Rich. CIV. Empetraceae Nuit. CV. Ceratophyllaceae Gray PAGE 371 374 375 375 376 379 389 390 i Class II. Monocotyledones CVI. Hydrocharideae DC. . . . . .. . . . • 392 CVII. Orchideae /uss. .......... 393 CVIII. Scitamineae 7?. i?r 422 CIX. Haemodoraceae Ren/h. ei J/ook. . . . . . . .423 ex. Irideae/«w 423 CXI. Amaryllideae R. Br. ^ . . 430 CXII. Taccaceae Benlh. et Hook . 436 CXIII. Dioscoreaceae R, Br. » 437 CXIV. Liliaceae DC -437 CXV. Y^r. 5; 31. H. levis jS". S; 32. H. punctulatus ^. } and J; 33. H. rubicundus Chr. 5 and 5; 34. H. tumulorum Z. 5; 35. H. zonulus Sm. 5; 36. Megachile centuncularis Z. J; 37. Nomada brevicornis Mocs. $; 38. N. flavoguttata K. 5, 2nd gen. ; 39. N. fuscicornis Nyl. 5 ; 40. N. jacobaeae Pz. 5 and S ; 41. N. obtusifrons Nyl. 5 and S; 42. N. similis Mor. 5 and $; 43. N. solidaginis Z*z. 5 and J, skg. ; 44. N. roberjeotiana Pz. $ and S ; 45. Podalirius bimaculatus Pz. 5 and $ ; 46. P. furcatus /*2. J ; 47. P. vulpinus Pz. 5 ; 48. Prosopis communis Nyl. 5 and J ; 49. P. confusa Nyl. 5 and $ ; 50. P. genalis Ths. 5 and J ; 51. P. pictipes iVy/. 5 and J; 52. Psithyrus quadricolor Lep. $. ((5) Sphegidae: 53. Ammophila cam- pestris Z/r. J; 54. Crabro subterraneus Z'. 5 and J. In Juist. — A. Diptera. Syrphidae: i. Eristalis tenax Z., very common. B. Hymenoptera. Apidae: 2. Bombus lapidarius Z. ^ and $, very common, skg. ; 3. B. muscorum F. C. Lepi- doptera. (a) Lycaenidae : 4. Polyommatus phlaeas Z. (<5) Satyridae : 5. Satyrus semele Z. (f) Nociuidae : 6. Plusia gamma Z. VerhoefF records the following for Norderney. — A. Diptera. (a) Muscidae : i. Echinomyia tessellata Z'. 5 ; 2. Lucilia latifrons Schin. $ and J, very common. (^) Syrphidae: 3. Helophilus trivittatus Z'. 5; 4. Melithreptus scriptus Z. 5 ; 5. M. strigatus Staeg. i ; 6. Platycheirus sp. ; 7. Syrphus corollae F. J, freq. ; 8. Syritta pipiens Z. S. B. Hymenoptera. (c) Apidae: 9. Bombus lapidarius Z. 5 and $, very common; 10. Coelioxys sp. ; II. Prosopis communis Nyl. ?. (^) Sphegidae: 12. Ammophila lutaria Z'. (=A. affinis ^.) $, skg. (Q^ VerhoefF, Nova Acta Leop., Halle, Ixi, 1894, p. 160.) C. Lepidoptera. (a) Nymphalidae: 13. Argynnis latonia Z. (b) Satyridae: 14. Pararge megaera Z., one. Loevv noticed the following in Silesia ('Beitrage,' p. 32). — A. Coleoptera. Cerambycidae : i. Leptura maculicornis Deg., nect-Ikg. B. Diptera. Conopidae : 2. Physocephala nigra Deg. 5, skg. C. Lepidoptera. Rhopalocera: 3. Polyommatus hipponoe Esp., skg.; also (op. cit., p. 25), — A. Coleoptera. i, Cryptocephalus sericeus Z., nect-lkg. B. Hymenoptera. (a) Apidae : 2. Megachile argentata F. J, skg. ; 3. Saropoda rotundata Panz. $, skg. and po-cltg. {6) Sphegidae : 4. Ammophila sabulosa Z., skg. ; 5. Bembex rostrata Z., 5 and J, skg. Burkill and Willis record the following for Central Wales (' Fls. and Insects in Gt. Britain,' Part I). — A. Coleoptera. Nilidulidae : i . Meligethes viridescens F., po-dvg. B. Diptera. {a) Muscidae: 2. Anthomyia radicum Z., freq., po-dvg.; 3. A. sp., do.; 4. Lucilia cornicina F. ; 5. Oscinis sp. ; 6. Scatophaga stercoraria Z., skg. (/5) Syrphidae : 7. Eristalis tenax Z., skg.; 8. Helophilus pendulus Z. ; 9. Melanostoma scalare F., skg. ; 10. Platycheirus manicatus Mg. C. Hymenoptera. {a) Apidae : 1 1 . Bombus agrorum F., skg. ; 12. B. terrester Z., do. {b) Formicidae: 13. Formica fusca Z., skg. D. Lepidoptera. Rhopalocera: 14. Pieri rapae Z. ; 15. Polyommatus phlaeas Z. CAMPANULACEAE 25 Herm. Muller (H. M.) for Westphalia (W.), Thuringia (T.), and the Bavarian Oberpfalz (O.), and Buddeberg (Budd.) for Nassau, give the following list. — A. Coleoptera. {a) Ceramhycidae: i. Leptura livida L., in large numbers, nect-lkg. (H. M.) ; 2. Strangalia melanura Z., freq., skg. (H. M,, T.). ((5) Chryso- melidae: 3. Cryptocephalus sericeus Z, (H. M.). {c) Oedemeridae \ 4. Oedemera virescens Z. (H. M.). B. Diptera. (a) Bombyliidae : 5. Exoprosopa capucina F., not infrequent, skg. (H. M.). {V) Conopidae: 6, Myopa fasciata Mg., skg. (H. M.) ; 7. Physocephala rufipes F., numerous, skg. (H. M.) ; 8. P. vittata F., skg. (H. M.) ; 9. Sicus ferrugineus Z., do. (H. M.) ; 10. Zodion notatum Mg., do. (H. M.). (f) Empidae: 11. Empis livida Z., very common, skg. (H. M.). ( * Alpenblumen,' p. 381; Lindmann, 'Bidrag till Kanned. 6m Fjellvaxt. Blomn. o. Befrukt.'; MacLeod, Bot. Jaarb. Dodonaea, Ghent, ii, 1891, p. 374, v, 1893, pp. 447-8; Loew, ' Bliitenbiol. Floristik,' p. 395; Knuth, ' Bloemenbiol. Bijdragen.') — This species bears feebly protandrous bee flowers. These are bright-green in colour, with a reddish tinge, and odourless ; but in spite of their inconspicuousness they are very rich in nectar. Sprengel says that this is secreted by a white annular sweUing on the ovary, surrounding the base of the style. The pendulous corolla is strongly ventricose, and its mouth is so contracted that only bees with a proboscis sufficiently long to reach the base of the flower are able to act as pollinating agents. The capitate stigma projects a little from the opening of the flower, and the head of an insect visitor therefore touches it before the anthers, which are hidden within the bell. The latter lie above the stigma and surround the style. They dehisce apically, and each of them possesses two long Fig. 215. Vaccinium, L. (after Herm. Mailer). (1) Flower of V. Myrtillus Z., slightly enlarged and seen from the side. (2) Do. of V. uliginosum L., seen from the side after removal of half the corolla (X 7). ' 28 ANGIOSPERMAE—DICOTYLEDONES diverging processes stretching as far as the corolla. When the proboscis of a bee is inserted into the bell it strikes against one of these processes, causing the dry powdery pollen to fall out of the opening of the corolla on to the visitor's head. Should insect-visits fail, the pollen ultimately falls of its own accord on the edge of the stigma, effecting automatic self-pollination. Visitors. — Herm. Miiller saw the following bees in Westphalia. — I. Andrena nigroaenea K. t> (proboscis 3^ mm. long), vainly trying to suck; 2. Apis mellifica Z. 5, very freq., skg. ; 3. Bombus agrorum F. 5, freq., skg., persistently visiting and holding on to the under-sides of the bells ; 4. B. lapidarius L. 5, do., but not so freq. ; 5. B. scrimshiranus K. $, do. ; 6. B. terrester Z. 5, do. Alfken and Hoppner (H.) observed the following at Bremen. — A. Diptera. {a) Asilidae: i. Laphria flava Z. 5, skg. (H.). (3) Conopidae\ 2. Conops vesicularis Z. 5 and J, freq., skg. (H.); 3. Physocephala nigra Deg. J, skg. (H.); 4. P. rufipes Z'. (c) Syrphidae: S-EristalisalpinusPz. 5, skg.(H.). {d) Musctdae: 6. Sarcophaga carnaria Z. B. Hymenoptera. Apidae: 7. Andrena albicans iI/«7/. $ (H.) ; 8. A. convexiuscula K.t)-, 9. A. gwynana K. $; 10. A. lapponica Zett. $ skg. and po-cltg. S skg.; 11. A. nigroaenea K. (H.); 12. A. parvula .^. $; 13. A. varians K. $ and J ; 14. Apis mellifica Z. 5 ; i5- Bombus agrorum F. j and J ; 16. B. der- hamellus K. 9 and S ; 17. B. hortorum Z. $ ; 18. B. jonellus K. 5 very common, skg. and po-cltg. 5 ; 1 9. B. lapidarius Z. 5 and 5 ; 20. B. muscorum F.<^', 2 1 . B. pratorum Z. 5 and 5, skg. ; 22. B. proleus Gerst. 5 ; 23. B. terrester Z. 5 and 5, skg. and po- cltg. ; 24. Halictus calceatus Scop. 5; 25. H. flavipes F. 5 (H.); 26. Nomada bifida Ths. 5; 27. N. borealis Zeti. 5 (H.), skg.; 28. N. lineola Pz. (H.), skg.; 29. N. ruficornis Z. (=N. flava Pz. 5) ; 30. N. succincta Pz. 5 (H.), skg. ; 31. Osmia rufa Z. ; 32.0. uncinata Gerst. $, skg. ; 33. Psithyrus campestris Pz. 5, skg. ; 34. P. vestalis Fourcr. 5, skg. The following were recorded by the observers, and for the localities stated. — Knuth (Sachsenwalde), the honey-bee, and 3 humble-bees — i. Bombus agrorum Z'. $; 2. B. lapidarius Z.J ; 3. B. terrester Z. $, freq., skg. Loew (Silesia) (' Beitrage,' P- 54)> 3 bees — i. Bombus latreillellus K. S, skg. ; 2. B. pratorum Z. ^i skg. ; 3. B. variabilis Schmiedekn. l^, skg. Schmiedeknecht (Thuringia), 4 bees — i. Andrena lapponica ZeU.\ 2. Bombus jonellus K. 5; 3. B. mastrucatus Gerst. 5; 4. Osmia corticalis Gerst. Rossler (Wiesbaden), the Geometrid moth Halia brunneata Thunbg. Friese in Alsace (A.), Baden (B.), and Thuringia (T.), 4 bees — i. Andrena lapponica Zett. not infreq. (B.) ; 2. Bombus mastrucatus Gerst, 5 occasional (B.), 5 do. (A.); 3. Osmia corticalis Gerst. {^.^\ 4. O.vulpecula Gerst.{T.). Frey-Gessner (Switzerland), the bee Osmia nigriventris Zett. (=0. corticalis Gerst.). Schletterer and von Dalla Torre (Tyrol), and Hoffer (Steiermark), the humble-bee Bombus mastrucatus Gerst. Morawitz (St. Petersburg), the bee Andrena fucata Sm. McLeod (Flanders), the humble- bee Bombus agrorum F. $ (Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 448) ; (Pyrenees), 3 humble-bees (op. cit., iii, 1891, p. 374). WiUis and Burkill (Central Wales), 2 humble-bees — Bombus agrorum F., freq., skg., and B. terrester Z., do. (' Fls. and Insects in Gt. Britain,' Part I). Scott-Elliot (Dumfriesshire), 2 humble-bees (' Flora of Dumfriesshire,' p. no). Schneider (Arctic Norway), 3 humble-bees — i. Bombus lapponicus F.; 2. B. pratorum Z. ; 3. B. scrimshiranus IC. (Tromse Mus. Aarsh., 1894). Lindmann (Dovrefjeld), a humble-bee. 1752. V. uliginosum L. (Herm. Muller, 'Fertilisation,' pp. 373-5, 'Weit. Beob.,' Ill, p. 67, ' Alpenblumen,' p. 381 ; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 100, 113; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 107, 526; Loew, ' Blutenbiol. Floristik,' p. 399.) — Hermann Muller says that the flower mechanism of this species agrees with that of the last, except as regards the following points. — VACCINIA CEAE 29 The flowers are borne on taller bushes, are more numerous, and coloured red on the side next the sun, so that they are much more conspicuous than those of V. Myrtillus. As the opening of the flower is 3 mm. broad, small insects can push their heads and the front part of their bodies into the corolla. The stigma does not project from the flower as in V. myrtillus, but is situated a little way inside the corolla, so that the smaller bees (sp. of Andrena, Halictus, and Nomada) are obliged to touch it before their heads are dusted with pollen. {€/. Fig. 215.) V. Myrtillus, therefore, is adapted to the visits of a select number of the more industrious long-tongued bees, and V. uliginosum to those of a much larger set of insects, some with a long and others with a short proboscis. This has been confirmed by direct observation, as Hermann Miiller emphasizes. Warming describes the flowers of the Arctic va.nety mi'crophynum Lange (Fig. 216) as first feebly protandrous and then homogamous : they are rather smaller than in the type form (Bot.Tids.,Kjoben- havn, 1895, pp. 47-9). Both cross- and self-pollination are possible, and it is probable that the latter may even take place pseudo-cleistogamously in the bud. Numerous fruits are set, even when insect- visits fail. Lindman says that the flowers of plants growing on the Dovrefjeld possess a strong aromatic odour, re- sembling that of pepper. The corolla varies in length from 5 to 7 mm. Although the anthers develop rather before the stigma, their pollen is not ripe until the latter has become receptive and nectary are larger in the small flowers than in those of greater size. Ekstam says that the flowers are feebly protandrous, indeed almost homogamous, in the Swedish Highlands. In Greenland this variety is a low small-leaved shrub in habit, often with its branches running close to the ground, and with flowers usually only 3 mm. (rarely 6 mm.) long. Wormskjold says that it smells like woodruff", but Warming and Vanhoffen were unable to confirm this. The latter botanist collected ripe fruits on Storo as early as the beginning of July (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' pp. 59-62). Visitors. — Verhoeff observed the following in Norderney. — A. Diptera. Muscidae: i. Lucilia caesar Z., a 5, skg. B. Hymenoptera. (a) Apidae: 2. Bombus hortorum Z., a 5, skg. ; 3. B. lapidarius Z., 2 j, skg. ; 4. B. proteus Gerst., a 5, skg. ; 5. B. terrester Z., a 5, skg. ; 6. Psithyrus rupestris F., a j, skg. ; 7. P. vestalis Fourcr. 5, freq., skg. (3) Formicidae : 8. Formica fusca Z. (= Rasse fusca Forel) g, skg. Fig. 216. Vaccinium uliginosum^ Z., var. microphyllum, Lange (after E. Wanning). A. Flower seen from the side. B. Do. from below. C. Do. with part of corolla removed. D. Do. from below. £■. Do. in longitudinal section. .^ and C Stamens. //. End of style with stigma, (A-E X4J ; F, G, H x 12.) The Stigma 30 AN GOISPERM AE— DICOTYLEDON ES Herm. Miiller saw 3 humble-bees in the Alps, and gives the following list for Westphalia. — A. Diptera. {a) Empidae: i. Empis opaca F., skg., extraordinarily numerous. {b) Muscidae: 2. Echinomyia fera Z., repeatedly, skg. {c) Syrphidae: 3. Eristalis arbustorum Z., in very great numbers, skg. ; 4. E. horticola Deg., one, skg. ; 5. E. intricarius Z., do. ; 6. Rhingia rostrata Z., freq., skg. B. Hymenoptera. Apidae: 7. Andrena atriceps K. S, skg. ; 8. A. fulva Schr. j, skg. ; 9. A. gwynana K. $, skg.; 10. A. nigroaenea K. 5 and $, skg. ; 11. A. pilipes F. J, skg. ; 12. Apis mellifica Z. 5, freq., skg.; 13. Bombus agrorum F. 5, skg. ; 14. B. confusus Schenck 5, skg.; 15. B. hortorum Z. 5, skg.; 16. B. sylvarum Z. $, skg.; 17. B. pratorum Z. 5, skg.; 18. B. terrester Z. 5, in large numbers, skg.; 19, CoUetes cunicularius Z. 5, skg.; 20. Halictus cylindricus F. 5, skg.; 21. H. flavipes F. 5, skg.; 22. H. rubicundus Chr. 5, skg.; 23. H. sexnotatus K. 5, skg.; 24. H. sexstrigatus Schenck 5, skg.; 25. H. zonulus Sm. 5, one, skg. ; 26. Nomada ferruginata K. 5, skg. ; 27. N. ruficornis Z. 5, skg. ; 28. N. sexcincta K. J, skg. ; 29. N. succincta Pz. 5, one, skg. ; 30. Osmia rufa Z. $, skg. ; 31. Psithyrus campestris Pz. 5, skg.; 32. P. vestalis Fourcr. 5, do. C. Lepidoptera. Rhopalocera-. 33. LycaenaargiolusZ., skg. ; 34. Thecla rubi Z,, do. The following were recorded by the observers, and for the localities stated. — Knuth (North Frisian Islands), Apis, a humble-bee, and a hover-fly. Loew (on the Albula, in the Alps), 2 humble-bees (Bombus alpinus Z. 5, and B. alticola Krchb. 5) and a hover-fly (Sericomyia lappona Z.). Frey (canton Graubiinden), the Tortricid moth Phoxopteryx myrtillana Tr. Schneider (Arctic Norway), 3 humble-bees — I. Bombus lapponicus F.', 2. B. pratorum Z.; 3. B. scrimshiranus K. (Tromso^ Mus. Aarsh., 1894). Lindman (Dovrefjeld), a humble-bee. 1753. V. Vitis-Idaea L. (Herm. Muller, * Alpenblumen,' pp. 380-1 ; Warming, ' Bestovningsmaade,' p. 7 ; Warnstorf, Verh. bot. Ver., Berlin, xxxviii, 1896; Ricca, Atti Soc. ital. sc. nat., Milano, xiv, 3, 1 87 1.) — This species is homogamous. The flowers are white in colour, often with a reddish tinge, widely open, and oblique. Nectar is secreted as in the last species, and the passage to it is covered by the stamens, of which the filaments are clothed with hairs externally and laterally. The anthers closely surround the style, are produced into tubes, and dehisce apically, allowing some pollen to escape when insect visitors strike against them. The stigma matures at the same time as the anthers, and are first touched by visitors, which then press the latter apart and get dusted with pollen. Crossing is therefore ensured by insect-visits. Warnstorf describes the flowers as protogynous, with a style which may be only as long as the stamens, equal in length to the corolla, or exserted. The flowers are not infrequently male by suppression of the pistil. The white filaments are covered with hairs externally as well as marginally, and such of these hairs as are situated in the base of the flower serve as nectar-covers. The pollen-grains are white in colour, Fig. 217. Vaccinium Vt'ft's-ltiaea, L. (aSter Htrm. Muller). A. Flower in longitudinal section (x 5). B. Stamen seen from the inner side (x 7). C. Do. from the outer side, a, anther ; «, nectary ; ov, ovary ; fi, corolla; s, calyx: st, stigma. VACCINIA CEAE 31 irregularly tetrahedral or of indeterminate shape, tuberculate, up to 44 /u, in diameter. Visitors. — The following were recorded by the observers, and for the localities stated. — Knuth (Usedom, where the plant covers large tracts), Apis and 3 humble-bees (i. Bombus hortorum Z. 5; 2. B. lapidarius Z. ^ ; 3. B. terrester Z. 5), all freq., skg. A. Rose (Thuringia), two humble-bees — Bombus hortorum Z., and B. terrester Z. Alfken (Bremen), 4 humble-bees — i. Bombus jonellus -A', 5 ; 2. B. muscorum Jf". 5; 3. B. proteus Gersf. 5; 4. B. terrester Z. 5. Friese (Thuringia), the bee Osmia nigriventris Zg//. Herm. Miiller (Alps), Apis and 3 humble-bees. Scott-Elliot (Dumfriesshire), an Empid and a Muscid ('Flora of Dumfriesshire,' p. 11 1). The arctic variety pu- milum Hornem. (Green- land, Labrador) has been investigated by Warming, who describes it as follows (Bot. Tids., Kjobenhavn, 1895, pp. 44-6).— The flowers vary in size, sometimes being only half as large as those of the type form, though re- latively broader. In these small flowers the style only reaches to the mouth of the corolla, where the anthers are situated, so that self-pollination can easily take place. But in the larger ones the style projects from the corolla, as in the type form (Fig. 2 1 8). Fruits are only set in warm years. Ekstam describes the flowers as feebly protandrous, odourless, and 4-8 mm. in diameter. 1754. V. Oxycoccos L. (=Oxycoccos palustris Pers.). (Sprengel, 'Entd. Geh.,' pp. 228-9; Herm. Miiller, 'Weit. Beob.,' Ill, pp. 67-9; Warming, ' Bestovnings- maade'; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 107; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896.) — Although Kerner gives an admirable account of the flower mechanism of this species, he failed to observe that the visits of bees inevitably effect crossing. The red wheel-shaped corolla is reflexed, and Sprengel says that the anthesis of individual flowers lasts for eighteen days. As in other species, the nectar is sheltered from rain by the pendulous position of the flower, and Kerner says it is protected against unbidden guests by the stamens, which closely surround the style. Hermann Muller points out that the stamens are also the means by which bees of suitable size are forced to eff'ect crossing. They are so greatly broadened as to form a tube round the style, their outer surface is rough with short hairs, and their closely apposed edges are beset with longer curly hairs, so closely interwoven that a nectar-seeking insect is unable to succeed in penetrating between them. The anthers are borne on the inner sides of the filaments, and each Fig. 218. yacciniuftt Viit'S'/daea, Z,. (sLher K-WaLTming). A-G. Var. pumilum, from Greenland. A, B. Larger flowers. C, D. Smaller flowers. E, F. A stamen from A. G. Nectary. H. Type- form, from Stockholm. (A-D, H x 4.) 32 ANGIOSPERMAE—DICOTYLEDONES of them is produced into a pair of tubes as long as itself, open at the tip, and closely embracing the style. In order to get at the nectar, bees must climb on to the flowers from below, and thrust their proboscis between the tubular prolongation of the anthers, from which pollen falls upon their heads. Since the stigma is the part projecting furthest from the corolla, it is first touched by the pollen-covered heads of bee visitors, so that crossing must necessarily take place. Lindman says that automatic self- pollination is not assured in the var. /»««//« Rupr., owing to the great distance between stigma and anthers, but Warming is of opinion that in Greenland it may take place in the bud, for very numerous fruits are set there. Warnstorf describes the pollen-grains as white in colour, and up to 50 fi in diameter. Visitors. — In spite of long and careful watching I have never been able to observe any, nor was Herm. Miiller more successful. The latter adds that though honey-bees quench their thirst with the water which permeates the masses of Sphagnum in the immediate neighbourhood of the flowers, they do not trouble about these. He also correlates the very long time for which anthesis lasts with the sparsity of insect-visits. Scott-Elliot observed 2 Muscids, which were obviously useless guests ('Flora of Dumfriesshire,' p. iii). LX. ORDER ERICACEAE LINDL. (including Rhodoraceae Kloisch, and Pyrolaceae Ltndl.). Literature, — Knuth, ' Grundriss d. Blutenbiol.,' p. 70 ; Drude, in Engler u. Prantl,, ' D. nat. Pflanzenfam.,' IV, i, p, 25. Flowers usually in racemes, rarely (Andromeda) in umbels : nectar concealed in the base of the corolla. The anthers generally possess two processes which reach the corolla, are struck by insect visitors, and serve as levers for scattering the pollen, which consists in many species of loosely connected tetrads. 1. Tribe Arbuteae. 519. Arctostaphylos Adans. Homogamous or feebly protogynous humble-bee flowers, with nectar secreted by a fleshy ring surrounding the ovary. Kerner states that automatic self-pollination can ultimately take place as in Vaccinium. I755« A. Uva-ursi Spreng. (=A. officinalis Wimm. et Grab., and Arbutus Uva-ursi Z.). (Herm. MuUer, ' Alpenblumen,' pp. 385-8.)— The pendulous flowers of this species are arranged in short terminal racemes, and the corollas are almost conical bells. The nectar does not remain adhering to the nectary, but is sheltered in ten pits which surround it at the base of the corolla. It is prevented from running away by the dense hairy covering of the filaments and inner surface of the corolla. It is also protected against unbidden guests by long erect hairs at the opening of the corolla. The ten filaments are narrow at their bases, and then enlarge very quickly to form a ring surrounding the ovary, afterwards narrowing again, but continuing to remain apposed to the ovary for some distance. Their ends project beyond ERICACEAE 33 the ovary, running parallel to the style, and each of them bears two inwardly directed anther-lobes, which open by pores below, and are produced into tail-like appendages extending to the corolla. Only the most skilful insects, humble-bees and bees, are able to get at the nectar quickly and easily, by hanging on to the flower from below and probing for it through the small opening of the corolla. In doing this the proboscis is almost certain to touch, and if previously dusted with pollen to pollinate the stigma, which lies a little distance within the opening of the corolla and is covered with a thick sticky fluid. It next strikes against one or more of the 20 tail-like anther-appendages, causing some of the smooth pollen-grains (loosely aggregated into te- 11 A trads) to fall upon it. Cross- ing is thus ensured by insect- visits. Kerner states that the flowers are very feebly pro- togynous. Towards the end of anthesis, should insect- visits fail, pollen falls upon the stigma, which is at a lower level than the anthers, so that automatic self-pollina- tion is possible as a last resort. In plants observed by Lindman on the Dovrefjeld the flowers were strongly fragrant. The appendages of the anthers are much shorter in this locality than in the Alps, but the edge of the stigma is produced into a rim, so that automatic self-pollination can more easily be effected. Warming states ('Arkt. Vaxt. Biol.,' pp. 18-21) that autogamy is also easily possible in Green- land, and is effective. In that country the flowers are homogamous, while the anthers dehisce and the stigma becomes receptive in the bud. Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. Miiller (Alps), 3 humble-bees skg. legitimately and one perforating the flowers, a Lepidopterid (as an unbidden guest), and Thrips (do.). Lindman, 2 humble-bees. MacLeod (Pyrenees), a humble-bee (Bot. Jaarb. Dodonaea, Ghent, iii, 1 89 1, p. 374). Hoppner (Bremen), the humble-bee Bombus agrorum F. 5, skg. Fig. 219. Arctostaphylos Uva-tirsi, Spreng. (after Herm. Miiller). A. Flower seen from the side ( x 3). B. Do. from below. C. Sketch of interior of bud shortly before opening ( x 7). D. Stamen ( x 15). E. Flower cut through transversely under the anthers, seen from below (x 7). F. Calyx, ovary, and nectary, seen from below (x 7). G. Ovary and nectary turned up, and seen from the side (X 7). H. A flower perforated by Bombus mastrucatus. a, anthers ; gr, style ; w, nectary; ov^ ovary; /, petals; s, sepals; st, stigma. 34 ANGIOSPERMAE—DICOTYLEDONES 1756. A. alpina Spreng. (= Arbutus alpina Z.). (Warming, 'Arkt. Vaxt. Biol.,' pp. 13-18.) — This species has so far been investigated in northern habitats, but not in alpine ones. The pendulous ovoid flowers are 5-6 mm. long, and arranged in short terminal racemes. Warming says that in Greenland they are either homogamous or feebly protogynous. In that country the plant blossoms very early in the neigh- bourhood of snow- and ice-fields, and sets fruit abundantly. There is a strong autogamous tendency, for the pollen falls very easily on the large sticky stigma which lies below the anthers, and this is found to be dusted with it soon after the flower opens. The fall of pollen is checked, how- ever, by the narrow opening of the corolla and the hairs which line it. The • appen- dages of the anthers are less well developed than in A. Uva-ursi, and in specimens from Greenland may be en- tirely absent. {C/. Fig. 220.) 530. Arbutus L. 1757. A. Unedo L. (Sprengel, 'Entd. Geh.,' pp. 240-1.) — Visitors. — Schletterer observed at Pola — i. The beautiful humble-bee Bombus argillaceus Scop., on fine days in November and Fig. 220. Arciostaphylos alpina, Spreng. (after E. Warming). A, B. External view and longitudinal section of a flower ; though only just opened, the pollen has fallen from the anthers (x 4). C. An anther from the same flower ; there are no appendages. D. Longi- tudinal section through a flower with a tolerably short style (x 8). E, F, G. Anthers and filaments in various positions and of different ages (X 20). //", /. Anthers from a bud (x 20). K. Longitudinal section through a flower with a long style. L. Limb and opening of a corolla, from below; the stigma can be seen within the latter (limb about 2J mm. and aperture i mm. in diameter). M. Tetrad of pollen-grains. December; 2. Bombus ter- rester Z., freq., in September, October, and November. — ' On sunny days when there was no wind it was also occasionally seen in January. I noticed it frequently during the Christmas season up to the end of January on the late blossoms of the strawberry-tree.' 1758. A. Andrachne L. (Entleutner, Ost. bot. Zs., Wien, xxxix, 1889.) — Visitors. — In some of the flowers of this species at Meran, Entleutner noticed small Muscids held fast by the tangled hairs, suffering the penalty of death for their greediness. He also mentions that some insects had ' bitten through the flower-urn close to the calyx.' ERICACEAE ^ 2. Tribe Andromedeae. 521. Andromeda L. Flowers usually homogamous, with concealed nectar secreted at the base of the ovary. 1759. A. Polifolia L. (Loew, 'Bliitenbiol. Floristik,' p. 270 ; Warming, 'Arkt. Vaxt. Biol.,' pp. 19-21.) — In this species five or more delicate pendent flowers are arranged in an almost umbellate inflorescence at the end of the stem. The bright- red peduncles are about three times as long as the flowers, which are 5 mm. in length and of about the same breadth. The bell-shaped corolla-tube is red in colour, while the teeth are white with five reddish longitudinal streaks. Loew describes the bell as pos- sessing a pentagonal opening about i^ mm. broad, formed entirely by the short reflexed corolla-lobes. The inside of the corolla is clothed with hairs, and the filaments are also hairy. In this way the nectar secreted by ten swell- ings at the base of the ovary is protected, and pollen is prevented from falling out of the flower. The stigma is receptive when the flower opens, is situated in the opening of the corolla, and pro- jects beyond the dark-brown anthers, which Loew says mature simultaneously in the March of Brandenburg. In normal flowers the anther-pores are directed inwards, and the appendages outwards. The nectar can be reached by a proboscis of 4-4^ mm. long. Warming states that in the arctic plants he examined automatic self-pollination could be eff'ected, should insect-visits fail, by fall of pollen on to the stigma, which completely fills the narrow opening of the corolla. Lindman, whose observations were made on the Dovrefjeld, says that the stigma becomes receptive in the bud, and he sometimes found pollen-grains on its edge, which is beset with five small rounded projections. In other cases he noticed pollen on the under-side of the stigma, suggesting insect-visits. Visitors. — Alfken (Bremen) noticed 2 humble-bees (Bombus lapidarius Z. $, not freq., skg., and B. muscorum F. 5, freq., skg., persistently visiting this species, but avoiding other nectar-yielding plants, e.g. Ajuga, growing close by) and a butter- fly (Thecla rubi Z., very freq., skg.). D 2 Fig. 221. Androineda Polifolia^ L. (after E. Warming). A. Dia- gram of a flower with its bract and bracteoles. B. The end of a flowering branch ; below are two foliage-leaves with small leaf-buds in their axils; above these a third foliage-leaf has been removed to show the further developed leaf-bud in its axil. Above this again are two bracts respectively subtending a flower-bud {f) and a fully developed flower; between these are closely apposed bracteoles (x 3). C. Longitudinal section through a mature flower. D. A flower seen from above (x 4). E. An anther (x 20). F. Pollen. G. Ovary with nectary and 2 stamens (x 8). H^ I. End of the style, and stigma. 36 ANGIOSPERMAE—DICOTYLEDONES Fig. 222. Cassiope tetragona^ D. Don (after E. Warming). A . Diagram of a flower seen from the side ( X 4). B. A stamen. C. Diagrammatic plan of the same. D. Longitudinal section of a flower (x 4). E. Stamens and stigma seen from below (x 10). 522. Cassiope D. Don. Bell-shaped pendulous flowers, with nectar secreted by yellow nectaries at the base of the ovary. 1760. C. tetragona D. Don. (Warming, Bot. Tids., Kjobenhavn, xv, 1885, pp. 25-9.) — Warming thinks this arctic species possibly belongs to flower class Lm. The yellowish-white flowers exhale an odour of hawthorn, especially towards evening. The pollen is scattered by the impact of the proboscis of insect visitors against the diverging appendages of the anthers. Crossing by insects is possible, but in Greenland automatic self- pollination generally takes place while the flowers are closed. The species is abundant on heaths in Spitzbergen, and Ekstam says that its pendulous flowers erect themselves when anthesis is over (' Blutenbiol. Beob. a. Spitzbergen,' p. 9). It blossoms in that island from the end of June to the middle of September, and sets abundant fruits (Andersson and Hesselman, ' Bidrag till Kanned. om Spetsbergens o. Beeren Eil. Karlvaxtflora,' p. 18). Vanhoffen was unable to perceive the odour of hawthorn described by Warming (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 49). Visitors. — ^Ekstam observed numerous small insects in Spitzbergen. 1761. C. hypnoides D, Don (= Andromeda hypnoides Z.). (Warming, op. cit.. pp. 29-31.) — Warming describes the flowers of this species as white with purple-red corolla-lobes. They are more widely open than those of the last species, and Lindman says that they possess a tolerably strong odour. Warming found the species to be homogamous in Greenland, but on the Dovre- fjeld Lindman observed that the flowers were at first pro- togynous, afterwards becoming homogamous. Autogamy result- ing in the setting of numerous fruits apparently takes place before the flowers open, by fall of pollen upon the clearly defined stigma, which is covered with a sticky resinous fluid. {C/. Fig. 223.) Yanhoff"en compares the species to a Polytrichum in habit, and he found it in Greenland with numerous (.-* last year's) fruits, collected together under the delicate Fig. 223. Cassiope hypnoides, D. Don (after E. Warming). A, Flower in longitudinal section, seen from the side ( X 4). B. Do., seen from below (x 4). C. Style (x 5). D. A stamen, seen from the side. E. An anther. F. A stamen, seen from the inner side. ERICACEAE 37 white flowers, the corolla-lobes of which are of a purple-red colour (op. cit., p. 49). Nathorst found it in full bloom in Spitzbergen (i. 8. '68) (Andersson and Hesselman, op. cit., p. 12). 3. Tribe Ericeae. 523. Calluna Salisb. Feebly protandrous, pinkish-red, rarely white flowers, aggregated into racemes ; with concealed nectar, secreted in the base of the flower by eight little swellings alternating with the filaments. 1762. C. vulgaris Salisb. (=Erica vulgaris Z.), (Sprengel, 'Entd. Geh.,' p. 230; Herm. Miiller, 'Fertilisation,' pp. 377-80, ' Alpenblumen,' p. 382, 'Weit. Beob.,' Ill, p. 67 ; Lindman, ' Bidrag till Kanned. om Skandin. Fjellvaxt. Blomn. o. Befrukt.' ; Verhoeff, 'Bl. u. Insekt. a. d. Ins. Norderney'; de Vries, Ned. Kruidk. Arch., Nijmegen, 2. Ser., 2. Deel, 1875 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, iii, 1891, V, 1893; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins./ pp. loi, 163, 'Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins./ pp. 227, 238; Kerner, 'Nat. Hist. PI./ Eng. Ed. i, II, p. 139; Loew, 'Bliitenbiol. Floristik,' p. 390; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896.) — The attraction of insects effecting cross-pollination is brought about by the enlarged red, rarely white calyx, the aggregation of the flowers into dense unilateral racemes, and last, but not least, by the asso- . . 1 r u ^'*^- ^^+- Calluna vulgaris, Salisb. (after Herm. MuUer). CiatlOn together of vast numbers (1) older flower, seen almost directly from below. (2) Younger f>f nlant<; '^''•' ^'^'" removal of half the calyx and corolla, seen from the side. r °' (3) A stamen. a, sepals ; d, petals ; /. J; 34. Nomada brevicornis Macs. S, skg. ; 35. N. jacobaeae Pz. $, skg.; 36. N. obtusi- frons Nyl. $, skg.; 37. N. roberjeotiana Pz. ?, skg.; 38. N. solidaginis Pz. $ and I, skg.; 39. Prosopis pictipes Nyl. J; 40. Psithyrus campestris Pz. ? and $ (H.); 41. P. rupestris F. J. ((5) Sphegidae: 42. Cerceris arenaria Z. $ and S skg.; 43. Melhnus arvensis Z. $ and J, do. (r) Tenthredinidae : 44. Athalia lugens Ths. ; 45. A. rosae Z. Willis and Burkill record the following for Central Wales (' Fls. and Insects in Gt. Britain,' Part I).— ^ A. Diptera. (a) Muscidae: 1. Calliphora erythrocephala Mg.; 2. Onesia cognata Mg. ; 3. O. sepulcralis Mg. ; 4. Lucilia cornicina F, freq. ; 5. Pollenia rudisZ: {b) Syrphtdae: 6. Eristalis tenax Z., freq., skg.; 7. Melanostoma scalare ERICACEAE 39 F., skg. ; 8. Platycheirus manicatus Mg. ; 9. Sericomyia borealis Flor. B. Hy- menoptera. {a) Apidae: 10. Bombus agrorum F., skg.; 11. B. hortorum Z., do.; 12. B. lapidarius L., do. ; 13. B. lapponicus F., do. ; 14. B. scrimshiranus K., do.; 15. B. terrester Z., freq., skg. {U) Formicidae: 16. Formica fusca Z., skg. (f) Vesptdae: 17. Vespa vulgaris Z., skg. C. Lepidoptera. All skg.: {a) Rho- palocera: 18. Coenonympha pamphilus Z. ; 19. Lycaena icarus i?(?//. ; 20. Poly om- matus phlaeas Z. ; 21. Vanessa urticae Z. {V) Microlepidoptera: 22. Undetermined species. Willis saw the following in the neighbourhood of the south coast of Scotland (* Fls. and Insects in Gt. Britain,' Part I). — A. Diptera. (a) Muscidae: i. Anthomyia radicum Z., skg.; 2. A. sp., po- dvg. ; 3. Limnophora sp., do.; 4. Scatophaga stercoraria Z., freq., po-dvg. ; 5. Themira minor Hal., freq., skg. ((5) Syrphidae : 6. Platycheirus albimanus F., freq., skg. and po-dvg. ; 7. P. manicatus Mg., freq., skg. ; 8. Sericomyia borealis Flor., freq., po-dvg. B. Hymenoptera. Apidae : 9. Apis mellifica Z., very common, skg.; 10. Bombus agrorum F., freq., skg.; 11. B. pratorum Z., skg. ; 12. B. scrim- shiranus J^., do.; 13. B. terrester Z., freq., skg. C. Lepidoptera. (a) Rhopa- locera: 14. Polyommatus phlaeas Z., skg. (3) Tortricidae : 15. Teras aspersana Hub., skg. The following were recorded by the observers, and for the localities stated. — Sickmann (Osnabriick), the fossorial wasp Mellinus arvensis Z. (Hollingsholt- hausen), the fossorial wasp M. sabulosus Z. Verhoeff (Norderney). — A. Diptera. (a) Bibionidae '. i. Dilophus vulgaris Mg., freq. (3) Muscidae: 2. Calliphora erythro- cephala J^., freq.; 3. Lucilia latifrons Schin., do. B. Hymenoptera. Apidae: 4. Bombus lapidarius Z. 5, ^ and 5, freq., skg.; 5. B. terrester Z. 5, not infrequent, skg.; 6. Psithyrus rupestris F. S, skg. Loew (Brandenburg), the humble-bee Bombus agrorum F. 5, skg. (' Beitrage,' p. 41). Krieger (Leipzig), 7 bees — i. Andrena fiiscipes K. 5 and J; 2. Bombus hypnorum Z. J; 3- B. soroensis F. ^ and J; 4. B. terrester Z. ^J and S; 5. B. variabilis Schmiedekn. S; 6. Nomada solidaginis Pz. ; 7. Psithyrus vestalis Fourcr. 5 and $. Schmiedeknecht (Thuringia), 4 bees — i. Andrena argentata Sm. ; 2. A. pubescens K. (= A. fuscipes ^.) ; 3. Bombus terrester Z. S ; 4. Nomada solidaginis Pz. Rossler (Wiesbaden), the moth Agrotis castanea Esp., and remarks, ' This moth confirms the often quoted axiom that Lepidoptera appear to pay attention to their food-plant mostly at the time when it comes into bloom.' Friese, in Baden (B.), Hungary (H.), Fiume (F.), and Mecklenburg (M.), 4 bees — I. Andrena fuscipes K. (B., not infreq. ; M., freq.); 2. Colletes succinctus Z. (F. and I\I., freq. ; H., occasional) ; 3. Epeolus variegatus Z. (B. and M., occa- sional) ; 4. Nomada jacobaeae Pz. (B., one 5), Schiner (Austria), the Muscid Siphona geniculata Mg. Frey (Switzerland), 4 moths — i. Grapholitha mendiculana Tr.; 2. Pholopteryx unguicella Z. ; 3. Gelechia ericetella Hb. ; 4. Plemota bicostella CI. Schletterer and von Dalla Torre (Tyrol), 7 bees — i. Bombus alticola Krchb.; 2. B. confusus Schefick ; 3. B. mastrucatus Gersi. ; 4. B. sylvarum Z. ; 5. B. variabilis Schmiedekn.', 6. Colletes succinctus Z. ; 7. Sphecodes ephippius Z. Ducke (Austrian Silesia), the bee Andrena simillima Sm. Hoffer (Steiermark), the bee Andrena argentata Sm., po-cltg. Gerstacker (Upper Bavaria), the alpine humble-bee Bombus alticola Krchb. t and 5. MacLeod (Flanders), Apis, 3 humble-bees, 3 other Hymeno- ptera, 9 hover-flies, 5 other flies, and 7 Lepidoptera (Bot. Jaarb. Dodonaea, Ghent, v> i893> PP- 449-50); (Pyrenees), only a hover-fly (Syritta sp.) (op. cit., iii, 1891, p. 373). H. de Vries (Netherlands), 3 bees — i. Apis mellifica Z. $; 2. Bombus subterraneus Z. 5; 3. B. terrester Z., J and 5 (Ned. Kruidk. Arch., Nijmegen, 2. Sen, 2. Deel, 1875). Lindman (Dovrefjeld), a humble-bee. Morawitz (St. Petersburg), 2 bees — I. Andrena argentata Sm. ; 2. A. nigriceps K. Smith (England), the bee Colletes succinctus Z. Scott-Elliot (Dumfriesshire), Apis, 4 humble-bees, several flies and Lepidoptera (' Flora of Dumfriesshire,' p. 112). 40 ANGIOSPERMAE—DICOTYLEDONES 524. Erica L. The species of this genus belong to flower classes H, L, LH, C, and An. 1763. E. Tetralix L. (Herm. Miiller, 'Fertilisation,' pp. 376-7, ' Weit. Beob.,' Ill, p. 67; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, PP- 45°-! > Schulz, ' Beitrage'; Knuth, 'Bl. u. Insekt. a, d. nordfr. Ins.,' p. 161, 'Weit. Beob. u. Bl. u. Insekt. a. d. nordfr. Ins.,' 238.) — This species belongs to the class of bee flowers. The pendulous red flower bells, aggregated into capitulo-umbellate inflorescences, make the plant very conspicuous. Hermann Miiller says that their mechanism agrees with those of Vaccinium Myrtillus and V. uliginosum. The flower bell is 7 mm. long, and its central part 4 mm. broad. The ovary is sessile in the bottom of the flower, and its base is surrounded by a blackish annular nectary, the secretion of which accumulates where it is formed. The blackish sticky stigma occupies the narrow (only 2 mm.) opening of the corolla, or even projects from it, so that an insect visitor hanging on to the blossom and probing for nectar must first touch this, effecting cross-pollination if another flower has previously been visited. At the same time the insect's proboscis is moistened with the sticky stigmatic fluid, and made ready to receive a fresh supply of pollen. The down- wardly directed anther-pores are situated some- what above the stigma, and the pairs of long pointed thorn-like anther-processes stretch as far as the wall of the bell. Immediately after the proboscis of a nectar-seeking insect has touched the stigma, it strikes against some of these pro- cesses, and some of the dry powdery pollen falls from the anther-pores upon the front part of its head, adhering to the part previously made sticky with stigmatic fluid. When the next flower is visited crossing must take place, the head of the insect being at the same time sprinkled with more pollen. Failing insect-visits, automatic self-pollination is eff'ected by fall of pollen on the edge of the stigma. I have not myself determined whether the flowers become anemophilous towards the end of anthesis. A proboscis 7 mm. long is required to obtain the nectar, and as that of the honey-bee is only 6 mm. in length, this zealous visitor is unable to suck legitimately. It therefore perforates the bell somewhere about the middle, and steals the nectar through the aperture. Hermann Muller, however, observed it sucking autumn flowers in the normal fashion, and he thinks that these are perhaps a little smaller than those developed in the warmer part of the year, so that the proboscis of the honey-bee may be long enough to get at the nectar legitimately {c/. my remark below). Fig. 225. Erica Tetralix, L. (after Herm. Miiller). A flower from which the front half of the corolla has been removed, a, calyx ; i, corolla ; r, reflexed limb of the same ; d, stamens (partly displaced) ; «, the downwardly directed openings of the an- thers ; f, appendages of the anthers, which are [struck against by the proboscis of in- sects probing the flower; g, nectary; h, ovary ; i, style ; k, stigma. ERICACEAE 41 Visitors.— Herm. Miiller gives the following list for Westphalia. — A. Diptera. Syrphidae: i. Rhingia rostrata Z., very common, skg. ; 2. Volu- cella bombylans Z., freq., skg. ; 3. V, haemorrhoidalis Zett., one, skg. ; 4. V. plumata L., repeatedly, skg. B. Hymenoptera. Apidae : 5. Apis mellifica Z. ^, its pro- boscis being only 6 mm. long, it is unable to suck legitimately, and therefore it bites through the middle of the bell from outside and steals nectar through the hole ; once skg. normally ; 6. Bombus agrorum F. 5 and 5, very freq., skg., hanging on the bell from below and inserting its proboscis into the opening ; 7. B. muscorum F. J, 5 and 5, do.; 8. B. rajellus K. |^, do.; 9. B. sylvarum Z. 5 and 5, do.; 10. B. terrester L. % do., small 5 alternately perforate the bells and steal nectar, and suck legitimately ; II. Nomada solidaginis Pz. $, once, apparently vainly skg. C. Lepidoptera. Noctm'dae: 12. Plusia gamma Z., in enormous numbers, skg. D. Thysanoptera. 13. Thrips, freq. Knuth observed the following in Schleswig-Holstein. — A. Diptera. Syrphidae: i. Eristalis sp. ; 2. Helophilus pendulus Z. ; 3. Vo- lucella bombylans Z. B. Hymenoptera. Apidae : 4. Andrena pubescens K. 5 ; 5. Apis mellifica Z. ; 6. Bombus agrorum F. ; 7. B. cognatus Sieph. ; 8. B, derha- mellus K.) 9. B. distinguendus Mor.; 10. B. lapidarius Z. ; 11. B. terrester Z. C. Lepidoptera. {a) Noduidae: 12. Plusia gamma Z. (J)) Rhopalocera: 13. Epinephele janira Z. ic) Sphingidae : 14. Zygaena filipendulae Z. On July 26, 1897, Knuth observed many honey-bees, skg. legitimately near Norddorf in the island of Amrum. Although their proboscis is only 6 mm. long, while the bells were 7 mm. in length, they must have obtained plenty of nectar, for they flew steadily from flower to flower, remaining several seconds on each. Some of them now and then examined the bases of the flowers, obviously for the purpose of biting a hole through which to steal nectar, but few actually did this, as for the most part they went back to the mouth of the corolla and continued to suck normally. Alfken records the following for Bremen. — A. Diptera. Muscidae: i. Echinomyia grossa Z. B. Hymenoptera. [a) Apidae: 2. Bombus derhamellus -ff'. 5; 3- ^- distinguendus J/ijr. 5; 4. B. jonellus K.'<^\ 5. B. lucorum Z, 5 ; 6. B. muscorum Z". 5 ; 7- B. terrester Z. 5 ; 8. B. varia- bilis Schmiedekn. 5; 9- Halictus lineolatus Lep. (=H. canescens Schenck) 5; 10. Megachile analis Nyl. 5 and J; 11. M. circumcincta K. 5 and $; 12. Psithyrus campestris Pz. 5. {b) Sphegidae: 13. Mellinus arvensis Z. 5 and S, skg. The following were recorded by the observers, and for the localities stated. — Wiistnei (Sylt), the bee Andrena nigriceps K. Smith (England), the bee Poda- lirius bimaculatus Pz. Willis and Burkill (Central Wales), a butterfly (Coenonympha pamphilus Z., skg.) and 3 humble-bees — i. Bombus agrorum F., skg.; 2. B. lapida- rius Z., skg.; 3. B. terrester Z., skg. (' Fls. and Insects in Gt. Britain,' Part I). Willis (op. cit.) (neighbourhood of south coast of Scotland), 3 bees — i. Apis mellifica Z., freq., skg. ; 2. Bombus agrorum F., very common, skg. ; 3. B. hortorum Z., freq., skg. Scott-Elliot (Dumfriesshire), Apis, 3 humble-bees, a IVIuscid, and a hover-fly (' Flora of Dumfriesshire,' p. 113). 1764. E. cinerea L. (Ogle, Pop. Sci. Rev., London, ix, 1870, p. 170; Powell, J. Bot., London, xxii, 1884, pp. 278-9; Schulz, ' Beitrage.') — Ogle says that the flower mechanism of this species entirely agrees with that of E. Tetralix. Powell and Schulz both state that the bells are sometimes perforated by humble-bees. Visitors. — Willis observed the following in the neighbourhood of the south coast of Scotland (' Fls. and Insects in Gt. Britain,' Part I). — 42 ANGIOSPERMAE— DICOTYLEDON ES A. Diptera. {a) Muscidae : i. Trichophticus cunctans Mg., po-dvg. (3) Syrphidae : 2. Platycheirus albimanus F., skg. B. Hymenoptera. Apidae : 3. Apis mellifica Z., very common, skg. ; 4. Bombus agrorum jF., do. ; 5. B. lapidarius Z., do,; 6. B. latreillellus J^. (=B. distinguendus Mot:), skg.; 7. B. pratorum Z., freq., skg. ; 8. B. terrester Z., do. ; 9. Psithyrus campestris Pz., skg. C. Lepi- doptera. Rhopalocera : 10. Epinephele janira Z., freq., skg. The following were recorded by the observers, and for the localities stated. — Willis (Central Wales) (op. cit.), 2 humble-bees (Bombus agrorum F., skg., and B. terrester Z., do.) and 2 butterflies (Polyommatus phlaeas Z., skg., and Vanessa urticae Z., do.). Scott-Elliot (Dumfriesshire), Apis, 7 humble-bees, a short-tongued bee, and 2 hover-flies (' Flora of Dumfriesshire,' p. 1 1 2). Fig. 226. Erica caruea, L. (after Herm. Miiller). A. A next year's flower-bud (X 7). B. Do., after removal of two sepals. C. Do., after removal of the calj'x and front part of the corolla, and forcible bending back of three stamens (x 7). D. Pollen-tetrads from a bud (greatly enlarged). £. A flower, seen from the side ( x 7). E. Do., after removal of part of the calyx and corolla and some of the stamens. G. Flower seen from below. /f. Reproductive organs and nectaries. y. Anthers seen from the side, from within, and from without ( x 7). a, anthers ; co, corolla ; m, nectaries ; S, sepals ; si, stigma. 1765. E. scoparia L. (Malpighia, Genova, iv, 1890.) — Delpino describes this species, native to South Europe, Dalmatia and France, as anemophilous. 1766. E. arborea L. (Knuth, 'Blutenbiol. Beob. a. d. Ins. Capri,' p. 11.) — I have not seen fruits set by this species in Capri. In April the sticky stigmas still projected from the flowers, though the anthers had all shed their pollen. ERICACEAE 43 Visitors. — Schletterer (Pola), 2 bees (Andrena carbonaria Z., numerous, and A. morio BrulL, freq.) and a wasp (Polistes gallica Z.). 1767. E. carnea L. (Herm. Muller, ' Alpenblumen/ pp. 382-5.) — Although the flowers of this species possess a bell-shaped corolla with its opening directed downward, Hermann Muller says they are adapted to the visits of butterflies and not to those of bees. That they belong to class Lb is shown by their beautiful red colour, and the narrow mouth of the corolla, which is so completely fifled up by the stamens that only the thin proboscis of a Lepidopterid can make its way past or between them. By summer or autumn the next year's flowers are developed as green buds, and Linnaeus even described plants in this condition as a distinct species E. herbacea. When the snow has melted, therefore, blossoming can at once take place. The flowers are rendered conspicuous, not only by the bright-red calyx and corolla, but also by the still more vividly coloured flower-stalks and the strongly exserted red style. The dark-brown anthers, devoid of appendages, are also exserted, so that insects flying to the flowers first touch the stigma, and then strike against the anthers, which dust them with pollen tetrads. Automatic self-pollination is excluded, for the stigmatic tip of the style is not capitate but truncate. Kerner says that as in Calluna the flowers are pollinated by the wind towards the end of anthesis. Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. Muller (Alps), almost exclusively a butterfly (Vanessa cardui Z.), but humble-bees very occasionally. A. Schulz (Tyrol) noticed the latter more frequently (' Beitrage '). Friese (Innsbruck), the bee Osmia bicolor Schr. J and $, skg. ; (Fiume), the bee Andrena extricata Sm. Knuth (Kiel Botanic Garden), the humble-bee Bombus hortorum Z., skg. 525. Bruckenthalia Reichb. Bell-shaped nectarless flowers ; entomophilous and anemophilous. 1768. B. spiculifolia Reichb. (= Erica Bruckenthalii Spreng.). (Loew, ' Blii- tenbiol. Floristik,' p. 269.) — This species is native to Greece, the Siebengebirge, and Hungary. Loew investigated plants cultivated in the Berlin Botanic Garden, and gives the following account. — The small pink flowers possess rounded bells about 3 mm. long and 2 mm. broad, which are arranged in small racemes i^ cm. in length. The style projects for about 2 mm. from the throat of the corolla, which is completely filled by the brown anthers. These are devoid of appendages, and borne on slender filaments, the bases of which are connected into a narrow ring. The anther-pores are downwardly directed, and the pollen is extremely powdery, while its grains are not united into tetrads. The round red stigma becomes receptive before the anthers dehisce, and its surface bears four secretory punctiform projections. It is protected against falling pollen-grains by its position. Pollination seems to be largely effected by the wind, as well as by insects. 44 ANGIOSPERMAE—DICOTYLEDONES 4. Tribe Rhodoreae. Homogamous or protogynous flowers, belong to the classes E, EC, and H. 526. Phyllodoce Salisb. | Ovoid, usually pendulous, blue or red bee flowers ; concealed nectar, secreted by a yellow crenate ring at the base of the ovary. 1769. P. taxifolia Salisb. (=P. caerulea Bab., Erica caerulea Willd., E. arctica Wattz and Bryanthus taxifolius A. Gray). (Warming, Bot. Tids., Kjobenhavn, XV, 1885, pp. 20-5.)— Warming describes this northern species as feebly protogynous in Greenland. The length of the style is variable, and the stigma becomes sticky in the bud. In short-styled flowers the stigma and anthers are at the same level, so that automatic self- pollination is inevitable. The generally pendulous position of the flowers, and the narrow opening of the corolla, suggest adaptation to pollination by bees, but these have not so far been observed. Bessel only saw a butter- fly (Colias boothii H.-Sch. = C. hecla Le/.). {€/. Fig. 227.) The mechanism of the flowers examined by Lindman on theDovrefjeld agreed essentially with that of Greenland speci- mens, but a form was observed with a style only 2 mm. long, so that the anthers projected beyond the stigma, excluding the possibility of self-pollination. Ekstam found the species to be protogynous-homogamous in the Swedish Highlands. The specimens collected by Vanh6ff"en in Greenland mostly possessed homo- stylous flowers, and fruits were set there at the end of July or the beginning of August (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 48). Fig. 227. Phyllodoce taxifolia, Salisb. (after E. Warming). Drawn from Greenland specimens (.<4, B, C, D. X aj). A. A young flower, just opened ; there are already some pollen-grains on the stigma. The hairs on the flower and pedicel are omitted. B. Another flower, in which anthers and stigma are at the same level. Most of the stamens have been removed. C. A third young flower, in which the anther-pores and stigma are at the same level, approximately between the upper and middle thirds of the corolla. D. Do., seen from the mouth of the bell. E. Pistil and nectary, seen en/ace. F. A stamen, seen from the ront. G. A pollen-tetrad. H. Base of the pedicel, with bracteoles. 527. Ledum Rupp. Flowers white or rose-red in colour, homogamous or feebly protogynous, arranged in umbels ; nectar half-concealed, secreted at the base of the ovary. 1770. L. palustre L. (Warming, Bot. Tids., Kjobenhavn, xv, 1885, pp. 39-44 ; Loew, 'Blutenbiol. Floristik,' p. 271 ; Knuth, ' Bloemenbiol. Bijdragen.') — ERICACEAE 45 In this species the entire plant possesses a strong aromatic odour. The white or rose-red petals are expanded to form a flat surface. Nectar is secreted by a ten- lobed swelling at the base of the ovary, and is easily accessible, although it is protected by hairs situated above the bases of the stamens. Warming describes the species as feebly protogynous in Greenland and Norsvay, though automatic self- pollination appears to be effected in the bud. The anthers are borne on long filaments, and are strongly exserted at a later stage. Unfortunately I did not carefully investigate the plants of this species I saw on Wollin I., but have frequently watched for visitors there, and noticed a Muscid (Sarcophaga carnaria L.). I have, however, examined the mechanism of specimens growing in the Kiel Botanic Garden, and this is as follows. — The flowers are homogamous, but the stigmas are persistent, remaining receptive after all the pollen has been shed. The diverging filaments are 6 mm. long, and the stigma is placed about a mm. lower. Automatic self-pollination by the fall of pollen is therefore possible in lateral flowers. Abromeit gives the following description of the var. ^ decumhens Ait., for West Greenland (' Bot. Ergeb. von Drygalski's Gronlandsexped.,' pp. 58-9). — The inflo- rescences are covered with woolly white or brown hairs, and bear 12-15 white flowers, which differ essentially from those of Rhododendron in the absence of a corolla-tube, and have pedicels as much as 14 mm. long. The petals are about 5 mm. long and 3 mm. broad. The ten long filaments are broadened at their bases, and pollen falls very easily from the small white anthers upon the glutinous stigma which is placed at a lower level. Visitors. — The following were recorded by the observers, and for the localities stated.- - Warming (Jakobshavn) on the var. /? decumbens, a butterfly (Argynnis chariclea Schneid.). Knuth (Wollin L), the Muscid Sarcophaga carnariaZ. : (Kiel Botanic Garden), the hover-fly Syritta pipiens Z., po-dvg., and only occasionally touching the stigma — also in many flowers sticking to the style and ovary, 15-20 of these were often found in the some 20 flowers of an umbel, adhering so closely that they could not be separated without tearing ; they would almost seem to have been digested by the plant, for their shape ultimately became unrecognizable, and only blackish chitinous masses remained. 1771. L. latifolium Jacq. (=L. groenlandicum Relz.). (Warming, Bot. Tids., Kjobenhavn, xv, 1885, pp. 39-44.) — This reputed species is perhaps only a variety of L. palustre, and Warming says that its flower mechanism is the same, though homogamy undoubtedly obtains. The anthers dehisce in the bud. Both self- and cross-pollination are possible, and may be effected not only by insects, but also by the wind, which is able to transfer pollen to the stigma of the same or adjacent flowers. 528. Azalea L. Flowers protogynous, rose-red in colour, arranged in umbels containing only a few blossoms ; exposed nectar, secreted by a ring at the base of the ovary, 1772. A. procumbens L. (=Loiseleuria procumbens Z^^jt'.). (Ricca, Atti Soc. ital. sc. nat., Milano, xiv, 1871 ; Kerner, 'Nat. Hist. PL,' Eng. Ed., i, II, p. 337; 46 ANGIOSPERMAE—DICOTYLEDONES Lindman, •' Bidrag till Kanned. om Skandin. Fjellvaxt. Blomn. o. Befrukt.' ; Warming, ' Bestovningsmaade,' pp. 6-7, Bot. Tids., Kjobenhavn, xv, 1885; Herm. Miiller ' Alpenblumen,' pp. 17 1-2, 377-8.) — In this species an insect, when inserting its head or proboscis between the ovary and stamens in order to reach the nectar, will touch the pollen-covered inner surfaces of the anthers with one side and the stigma with the other side, and flying from flower to flower will effect crossing, which is also favoured by the slight protogyny of the species. Automatic self- pollination can also no doubt take place, during bad weather, in flowers which close or have not yet opened. Kerner states that the stamens bend towards the stigma and bring this about, also that the plant may be pseudo-cleistogamous in bad weather. Lindman on the Dovrefjeld. also noticed self-pollination by bending of the stamens towards the stigma. There, as in Greenland, Finmark, and Nordland, the flowers are at first feebly proto- gynous, and then homo- gamous. Warming noticed that in the three localities mentioned the anthers are situated nearer the stigma than in alpine habitats, and are frequently in actual contact with it. Automatic self-pollination consequently predomi- nates, and appears to be effective. Ekstam de- scribes the flowers as homogamous in the Swedish Highlands. Ricca, on the other hand, in the Val Camonica, found the flowers to be so strongly protogynous that the stigmas were usually completely dried up before the anthers dehisced. Greenland specimens collected by Vanhoff'en and von Drygalski possessed extremely small flowers only 5-6 mm. in diameter, and feebly protandrous (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 49). Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. Miiller (Alps), 3 flies, 2 humble-bees, and 5 Lepidoptera ('Alpenblumen,' p. 378); also 7 flies, 2 humble-bees, an ant, and 5 Lepidoptera (op. cit., p. 172). Warming (Greenland), small flies. Wormskjold (Greenland), Lepidoptera. 1 Fig. 228. Azalea procumbens, L. (after Henn. Miiller). A. A flower in the first (female) stage. B. Do., partly dissected. C. A flower in the second (hermaphrodite) stage. D. Do., in the third (male) stage, a, an- thers ; «, nectaries ; ov, ovary ; />, petals ; s, sepals. ERICACEAE 529. Rhododendron L. 47 Protandrous humble-bee flowers, usually brightly coloured ; nectar secreted by an annular swelling at the base of the ovary. Kerner states that in many species the pollen-tetrads are bound together by threads of viscin. 1773. R. ferrugineum L. (Ricca, Atti Soc. ital. sc. nat., Milano, xiii ; Herm. Muller, ' Alpenblumen/ pp. 378-9.) — In this species the abundant nectar collects in the base of the almost horizontal corolla-tube, especially in a slight pouch on the upper side of this. The erect hairs on the filaments serve as nectar-covers. In Fig. 229. Rhododendron, L. (after Herm. Muller). A. A just-opened flower of/?, ferrugineum, L. (natural size). B. A rather older flower of the same species. C. A young flower of R. hirsutiiin, L. (in the male stage), after removal of the perianth and some of the stamens (x 7). D. An older flower of the same species (in the female stage), treated similarly ( x 7). A, nectar ; w, nectary ; st, stigma. order to get at the nectar-bees and humble-bees must creep over the stamens and stigma into the base of the flower, and if this is in the first stage their under-side is dusted with pollen, which will be transferred to the stigmas of flowers in the second stage. As the longest stamens project beyond the stigma, automatic self-pollination is possible if insect-visits fail. Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. Muller (Alps), the honey-bee and 7 humble-bees, skg. legitimately and eff"ecting cross-pollination ; also, as unbidden guests, a beetle, 4 flies, an ant, and 9 Lepidoptera. Ricca (Alps), humble-bees up to a height of 2,200 m. MacLeod (Pyrenees), 3 humble-bees, Halictus, and a Muscid (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, P- 373)- 1774. R. hirsutum L. (Herm. IMUller, op. cit.) — Hermann Muller says that the flower mechanism of this species completely agrees with that of R. ferrugineum. Hansgirg noticed the occurrence of pseudo-cleistogamy. 48 ANGIOSPERMAE—DICOTYLEDONES Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. MuUer (Alps), almost the same insects as for R. ferrugineum. Frey- Gessner (Switzerland), 5 bees — i. Bombus alpinus L.^; 2. B. mastrucatus Gerst.; 3. B. mendax Gerst. ; 4. B. -montanus Lep. ; 5. Osmia nigriventris Zett. ( = O. criticalis Gerst). Schletterer (Tyrol), the humble-bee Bombus pratorum L. 1775. R. lapponicum Wahlenb. (Warming, Bot. Tids., Kjobenhavn, xv, 1885, pp. 35-9.) — Warming says that in the homogamous Hymenopterid flowers of this species the stamens diverge so much laterally that the anthers are scarcely likely to touch the stigma, so that self-pollination is rendered very difficult, and crossing is usually necessary. He noticed many ripe fruits. The flowers of the specimens collected by Vanhoffen (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' pp. 49-51) in Greenland were situated in groups of 2-4 at the ends of the branches, and surrounded in the bud by glandular scale- leaves covered with a felt of woolly hairs. When the flowers open their stalks are very short (5 mm.) and beset with numerous yellow glands, but subsequently elongate to 10-14 "^"i- The calyx is purple-red in colour, also glandular, and the edges of its teeth fringed with long hairs. The total length of the corolla is 8-8-5 mm., of which about half is taken up by the tube ; it is dark purple-red or sometimes bright pink in colour, and its throat is lined with small hairs. There are five to nine stamens, equal in length to the pistil, and usually widely separate from one another. The bases of the filaments are broadened and covered with small hairs, and the brown-red anthers dehisce by means of two rounded apertures. The style is 8-11 mm. long, and the dark purple-red stigma is extremely glutinous. Nectar is secreted by a hypogynous ring. 1776. R. praecox. — This species is native to the Himalayas. Visitors. — Knuth (Kiel Botanic Garden) saw 2 bees, skg. (Apis mellifica Z. 5, and Bombus terrester L. 5). 1777. R. Chamaecistus L. (=Rodothamnus Chamaecistus Rekhb.). — The rose-red corolla of this species is not funnel-shaped as in the preceding ones, but wheel-shaped. Kerner states that the protogynous flowers are inevitably cross- pollinated in the first stage of anthesis. The filaments can be twisted round, and are used as alighting-rods by insects, which transfer pollen to the stigmas of blossoms in the first stage, while in those in the second-stage they rub off" the pollen-tetrads which are united together by threads of viscin. Ultimately the flower sinks down till the stigma is brought into the line of fall of the pollen, rendering automatic self-pollination possible. 1778. R. Vanhoeffeni Abrom. — Vanhoffen found only a single plant of this species in Greenland, which was growing between thick clumps of Vaccinium uliginosum and Betula nana. In some respects it appears to be closely related to R. lapponicum, in others to Ledum palustre L., var. jB decumhens Ait., so that it is possibly a hybrid between them. It is distinguished from R. lapponicum by more numerous flowers in the inflorescence, longer pedicels, a smaller corolla less deeply cleft and with a tube only 1-2-5 "^"i- lo"gj as well as by a series of vegetative ERICACEAE 49 characters. The pollen-grains are smaller, and their walls often shrivelled (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped./ pp. 51-8). The stamens are usually ten in number, and project a little beyond the style. Some of the brownish or yellowish anthers appear to be reduced. 530. Rhodora L. Flowers homogamous, with concealed nectar ; the stigma is at first covered as with a cap by the middle lobe of the upper lip. 1779. R. canadensis L. (= Rhododendron Rhodora/. F. Gmel). (Hilde- brand, Flora, Marburg, xxxix, 1881.) — Hildebrand gives the following account of this species. — The corolla possesses two lower lobes separate almost to the base, and a three- lobed upper lip, the central division of which covers the opening of the flower like a cap, holding fast the elongating style so that it is bent sharply downwards at its centre. There are ten stamens, of which the upper ones are shorter with tips bent downwards, while the longer lower stamens are bent upwards. The anthers are so placed that their apical pores surround the opening of the flower, so that an insect visitor must dust itself with the pollen by which these are covered. The continued elongation of the style causes it to spring out of the cap at a later stage, and it now projects beyond the anthers so that an insect visiting the flower must first touch it, securing cross-pollination if already dusted in another flower. Autogamy is not absolutely excluded, but as visitors have usually removed all the pollen before the stigma emerges, it is generally impossible. 531. Kalmia L. The anthers are situated in pouches of the corolla, and the elasticity of the filaments causes them to spring out when insects visit the flower. Drude gives the following description of the mechanism (in Engler and Prantl, * D. nat. Pflanzenfam.,' IV, I, p. 25).— The anthers are enclosed in pits of the wheel-shaped corolla, the margins of which prevent them springing out prematurely, though the filaments are strongly bent inwards and in a state of elastic tension. In warm sunshine the elasticity of the filaments increases, and they perhaps become shorter, so that the slightest touch causes them to spring out and scatter a cloud of pollen from their dehisced anthers. Drude's observations were made in the Dresden Botanic Garden, where he never saw the liberation effected by insects, which curiously did not appear to visit the bright red flowers. In favourable weather it took place spontaneously, and was followed in due course by the formation of seeds. The pollen reaches the stigmas of neighbouring flowers much more easily than that of the one in which it is produced, but autogamy is not excluded. 1780. K. glauca Ait. ( = K. polifolia Wangen.). (Sprengel, *Entd. Geh.,' pp. 238-40; Delpino, 'Ult. oss.,' p. 169; Hildebrand, Bot. Ztg., Leipzig, xxviii, 1870, p. 669; W. J. Beal, Amer. Nat., Boston (Mass.), i, 1868.)— Sprengel supposed the flower mechanism of this species to be adapted to self-pollination. Delpino and DAVIS. Ill 50 ANGIOSPERMAE— DICOTYLEDON ES Hildebrand think that insects are driven away by the explosion of the stamens, and transfer the pollen to other flowers. W, J. Beal says that the flowers are self-sterile. Visitors. — W. J. Beal observed the honey-bee, bringing about the explosion, and eifecting crossing. 5. Tribe Pyroleae. Flowers usually homogamous, with or without nectar. 532. Pyrola L. Flowers generally white in colour ; nectar abundantly secreted in their bases, or absent. Pollen-grains in tetrads. Anthers dehisce by pores. Flowers arranged in radial racemes, or rarely solitary. 1781. P. minor L. (Ricca, Atti Soc. ital. sc. nat., Milano, xiii, 1870; Warming, Bot. Tids., Kjobenhavn, ii, 1877, pp. 122-4; Herm. MuUer, 'Alpenblumen,' pp. 376-7; MacLeod, Bot. Jaarb. Dodonaea, Ghent,v,i893,p.452 .) — Ricca describes the nectarless flowers of this species as protandrous, but Warming, MacLeod and myself found them to be homogamous. The five stigmatic lobes abundantly secrete a sticky fluid, which in the absence of nectar appears to be licked by insect visitors before they search for Fig. (X 3J). 330. Pyrola rotiindifolia L. (after Herm. Miiller). A. Flower, seen immediately from the front B. Pistil, seen from the side. C Stamens (X 7). gr^ style : ov, ovary ; s, calyx ; j/, stigma. pollen, so that their visits effect crossing. The anthers are erect in the bud, but afterwards turn over, so that their basal pores, of which the margins are orange-red, are directed downwards. Automatic self-pollination regularly takes place, should insect-visits fail, by fall of pollen on the reflexed margin of the stigma. Warming observed flowers of different size and breadth: — in some the petals come together to form a globular bell with narrow aperture, and the stamens are relatively long ; in others the corolla is more widely open, and the stamens are shorter. Warnstorf describes the pollen-tetrads as four-sided, and 30-44 fx. in diameter. Visitors. — Very few. The following were recorded by the observers, and for the localities stated. — Herm. Muller (Westphalia), a beetle (Dasytes flavipes F!), constantly present in large numbers, first visiting the stigma, then the stamens, and thus effecting crossing ; I ERICACEAE 5T also some small flower-beetles (Meligethes sp.) and 2 Muscids (Anthomyia sp., and Opomyza germinationis L.). Scott-Elliot (Dumfriesshire), a humble-bee, a INIuscid, a micro-Lepidopterid, and a beetle (' Flora of Dumfriesshire,' p. 113). 1782. P. rotundifolia L. (Warming, op. cit., p. 124 ; Herm. Miiller, op. cit., p. 376; Lindman, 'Bidrag till Kanned. om Skandin. Fjellvaxt. Blomn. o. Befrukt.' ; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.' pp. 102-3 5 Warnstorf, Schr. natw. Ver., Wernigerode, xi, 1896, p. 7.) — The flowers of this species examined by me at Kiel were white in colour with an open bell-shaped corolla, devoid of nectar, feebly odorous, and homogamous (strongly protandrous according to Warnstorf. Their mechanism is at first adapted to crossing, and subsequently, as a rule, to automatic self-pollination. This change is brought about by a gradual alteration in the direction of growth of the style, which is at first directed almost vertically downwards, sometimes with a slight upward curve, so that the line of fall of the pollen is about 8 mm. in front of the stigma. The end of the style subsequently bends upwards, bringing the stigma vertically below the opening of the anthers, so that autogamy follows automatically by the fall of pollen (Fig. 231). Lindman says that in plants growing on the Dovrefjeld automatic self-pollination finally becomes possible, for the anther-pores, at first basal, are brought into a suitable position. In this species again the stigma secretes a large amount of sticky fluid, from which five conical elevations pro- ject, and the pores of the yellow anthers are surrounded by an orange- ^ „ , ,..--,. ^ „ . ^ •' ° Fig. 231. Pyrola rotundtjoha, L. (from nature). yellow band. Warnstorf states that the (0 stamens and pistil in the first condition of the ,, , . J -J" . (lower; the stigma is not in the line of fall of the pollen. pollen-tetrads are 37 /* m diameter. (2) Do., in the second stage of anthesis; the stigma Visitors ■ ^These are Verv few in ''^^ vertically below the tips of the anthers, from which ■' the pollen is distributed. number. On the Meimersdorfer Moor near Kiel, where this plant grows in association with Parnassia palustris, I observed large numbers of insects visiting the latter (11 and 14. 9.'92), but, though I watched for a long time, was unable to see a single insect visiting the Pyrola, though it was quite as conspicuous. On flowers taken into my study I noticed several house-flies, touching the stigmas, anthers, and petals with their proboscis, but after a few vain attempts to find nectar they quickly went away again. Alfken observed no visitors in Norderney. Warming has examined herbarium specimens of the var. arenaria Koch in which the stigma and anthers are closer together than in the type-form, so that automatic self-pollination would appear to be effected more easily. Visitors. — Verhoeff observed none in Norderney. 1783. P. grandiflora Rad. (Kolderup Rosenvinge, Meddel. om Gronland, xv, 1896, p. 68; Abromeit, 'Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 48.) — Rosenvinge states that there are transitions between this arctic species and P. rotundi- folia. The Greenland specimens described by Abromeit possess an external annular swelling at the base of the calyx which is absent in the latter, while the calyx-teeth are shorter (usually less than half that of the petals), broader, and often dentate at their ends. E 2 52 ANGIOSPERMAE—DICOTYLEDONES 1784. P. media Sw. (Kemer, 'Nat. Hist. PI.,' Eng. Ed. i, II.) — Kerner says that automatic self-pollination is brought about in the white flowers of this species by a bending of the style, by which the stigma is brought into contact with pollen lying in depressions of the petals. 1785. P. secunda L. (Kemer, op. cit., p. 274 ; Ricca, Atti Soc. ital. sc. nat., Milano, xiv, 187 1 ; Warnstorf, Schr. natw. Ver., Wernigerode, xi, pp. 7-8.) — Kerner says that in this species nectar is secreted at the base of the corolla in the pendulous flowers. The anther-pores face upwards, and the S-shaped filaments are kept in place by the petals. When a nectar-seeking insect touches the stamens the anthers tip over, so that the pollen falls upon and dusts it. This pollen is then transferred to the stigma of the next flower visited. Ricca describes the flowers as feebly protogynous, and Warnstorf also says they are protogynous. During the first (female) stage of anthesis the thick glutinous stigma projects about 2 mm. from the flower-bell, while the white pubescent anthers, borne on S-shaped fila- ments, are first closed, but afterwards dehisce on the side turned inwards. If the proboscis of an insect is inserted into the flower at this stage, the anthers tip over and dis- charge their mealy white pollen on the head of the visitor, to be trans- ferred to the projecting stigma of the next flower visited. Should insect- visits fail, the filaments straighten themselves, and the anthers project from the flower, the opening of which is widened by the pressing back of the petals. The anthers now tip over of their own accord, and the pollen is able to fall on the stigmas of lower flowers. The pollen-grains are smooth, ellipsoidal, about 25 /A long and 12 /* broad. 1786. P. uniflora L. (=Moneses grandiflora ^. F. Gray). (Ricca, Atti Soc. ital. sc. nat., Milano, xiv, 1871 ; Herm. Muller, ' Alpenblumen,' pp. 375-6 ; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, p. 383 ; Warming, Bot. Tids., Kjobenhavn, xv, 1895, pp. 15-18 ; Lindman, ' Bidrag till Kanned. om Skandin. Fjellvaxt. Blomn. o. Befrukt.') — The large white nectarless flowers of this species are turned downwards, and as they expand to a breadth of 20 mm. are tolerably conspicuous, though only one is situated at the end of each peduncle. The lowest part of the flower is the most con- venient alighting-platform, and this is constituted by the five sharp lobes of the] Fig. 232. Pyrola uniflora, L. (after Herm. Muller). A. Flower seen directly from below (x 3). B. Pistil of same, seen from the side (x 3). C. An anther ( x 7). gr, style ; ov, ovary ; st, stigma. ERICACEAE 53 stigma, upon which are damp glistening spots (considered as nectar by Ricca), that visitors lick, at the same time depositing any pollen adhering to their proboscis. Finding no nectar they climb up the style, attracted by the orange-yellow horns of the anthers, and busy themselves with the pollen, so that the proboscis is again dusted. Crossing is therefore easily eifected by insects, but Hermann Miiller says that the projecting position of the stigma usually prevents automatic self-pollination. Kemer gives a different account. He says that at first the peduncle is bent in such a way that the style projects vertically downwards, while the anther-pores face upwards, autogamy being therefore impossible. Insect visitors first touch the stigma, and then tip over the anthers, which sprinkle them with pollen. Later on the peduncle becomes less bent, so that the flower is brought into a nodding position, while the style is directed obliquely downwards and the stigma now lies directly below the anthers. At the same time the fila- ments have bent round, so that the anther-pores face downwards, and pol- len can easily fall from them upon the stigma, automatically effecting self- pollination. Warming says that in plants growing in Greenland the distance between the stigma and anthers is less than in P. rotundifolia, so that automatic self-pollination is more easily effected. (Cf. Fig. 233.) According to Lindman, the flowers on the Dovrefjeld have a smaller diameter (13 mm.) than those of the Alps. Ekstam says that the diameter varies from 12 to 20 mm. in the Swedish Highlands, while that of the faintly odorous flowers of Nova ZemHa is 10-20 mm. The mechanism in the latter locality agrees with the description given by Warming, and sometimes suggests that of P. rotundifolia. No nectar is secreted. Fig. 233. Pyrola unijlora, L. (after E. Warming). A. Flower seen from the side. A Do. from the front (x 2). C. Flower-bud sheltered by a bract. ZJ, £", F. Stamens of an older flower (x 8). G. Stigma seen from above. H^ I. Stamens of a bud, before they have turned round (X 8). K. Flower of P. roiundi/olia, L. (x 2). 533. HjHpopitys Dill. Homogamous flowers with concealed nectar, secreted, according to Kerner, by the fleshy base of the corolla. 1787. H. multiflora Scop. (=Monotropa hypopitys Z.). (Kirchner, 'Flora v. Stuttgart,' p. 530; Warnstorf, Verb. bot. Ver., Berlin, xxxvii, 1896.)— The flowers of this species, which like the whole of the plant are pale-yellow in colour, are homo- gamous and arranged in racemes. The terminal one is pentamerous, and the lateral 54 ANGIOSPERMAE—DICOTYLEDONES ones tetramerous. Kirchner states that the former has ten, while the latter have eight small narrow nectaries at the base of the ovary, which project into gibbosities of the petals that serve as nectar-receptacles. The erect dentated petals are about 15 mm. long, and closely apposed laterally, so as to contract the opening of the flower to 4-5 mm. This is almost blocked up by the large capitate stigma, which is 3-3^ mm. broad. A proboscis at least 10 mm. long is required to reach the nectar. There is a central pit in the stigma, surrounded by a wall of very sticky papillae and the lower side of the stigma is surrounded by whitish hairs which help to prevent self-pollination. The anthers are situated rather below the stigma at the level of these hairs, and dehisce extrorsely. Insect visitors must first touch the stigma with their heads, dusting it with pollen if they have previously visited another flower, and at the same time making their head or proboscis sticky with stigmatic fluid, so that the white pollen against which they at once brush will adhere to them. Crossing is thus ensured, while automatic self-pollination would seem to be excluded. Warns- torf describes the pollen-grains as white in colour, spheroidal, smooth, and about 25 /A in diameter. Visitors. — I observed the humble-bee Bombus agrorum F. 5, skg. (length of proboscis 10-15 mm.) on Wollin Island. LXI. ORDER EPACRIDEAE R. BR. Delpino ('Ult. oss.') says that some of the species of the genus Epacris are protogynous. 534. Richea R. Br. 1788. R. sprengelioides F. Muell. ( = Cystanthe sprengelioides R. Br.). (Borzi, 'Contrib. alia biol. veget.,' II, Fasc. i, Palermo, 1897.) — Borzi says that this species is anemophilous. LXII. ORDER DIAPENSIACEAE LINDL. 535. Diapensia L. 1789. D. lapponica L. (Warming, ' Bestovningsmaade,' pp. 34-6.) — This species, native to high latitudes, is said by Warming to be feebly protogynous in Greenland. The stigma and anthers are tolerably far apart, so that automatic self- pollination is rendered difficult, but sometimes the anthers dehisce in the bud, so that autogamy can take place when the flower opens. Nectar is abundantly secreted at the base of the ovary, and is completely concealed. Lindman states that the flowers are protogynous on the Dovrefjeld. The stamens are at first curved inwards, but afterwards become erect, though autogamy is excluded, for the flowers always remain erect, and the anthers project beyond the stigma. Vanhoff'en noticed (27. 6. '93) fruiting plants in Greenland (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 47). Visitors. — Ekstam observed flies in the Swedish Highlands. PLUMBAGINEAE 55 LXIII. ORDER PLUMBAGINEAE JUSS. Literature. — Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' p. 122. Flowers small but brightly coloured, and arranged in heads or corymbs. Nectar secreted and concealed in the bases of the flowers, which therefore belong to class C or S. Fritz Mijller states that many species of Plumbago and Statice are dimor- phous (Bot. Ztg., Leipzig, xxvi, 1868, p. 113). 536. Armeria L. 1790. A. elongata Hoffm. ( = A. vulgaris WiUd., Statice Armeria Z., and S. elongata Hoffm.). (Sprengel, ' Entd. Geh.,' pp. 174-5; Treviranus, Bot. Ztg., Leipzig, xxi, 1863; MacLeod, Bot. Centralbl., Cassel, xxix, 1887; Knuth, op. cit., xlviii, 1891, 'Vergl. Beob.,' 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 122-3, ' Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins,' p. 239, 'Bl. u. Insekt. a. d. Halligen ' ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. I, II, p. 358; Schulz, ' Beitrage,' I, pp. 89-90.) — The plants of this species which I have investi- gated in the North Frisian Islands belong to a variety often reckoned as a distinct species (A. maritima Willd.). The flowers smell of cumarin, and the conical calyx, about 5 mm. in length, possesses a membranous limb of bright-violet colour like the corolla, and strengthened by five stiff teeth, the reddish tips of which enhance conspicuousness. The five corolla-lobes alternate with these teeth, are 8 mm. long and 5 mm. broad, and only connected at their bases. Each of them is traversed by a strong median vein of darker colour, and two weaker lateral ones. These lobes are held together by the calyx so as to constitute a funnel-shaped tube about 7 mm. deep. The stamens are 4-5 mm. long and opposed to the petals. Upon the top of the ovary there is a green five-rayed nectary, from the middle of which spring five styles equalling the stamens in length. The lower third of these is beset with erect white hairs, which are particularly long and numerous above, making up a dense feltwork serving as an effective protection to the nectar. The terminal third of the styles is beset with papillae giving a velvety surface. MacLeod says there is a nectary at the base of each petal. In the island of Sylt the flowers are feebly protandrous, indeed almost homo- gamous. The erect stamens dehisce as soon as the flowers open, so that insects Fig. 234. Diapensia lappontca, L. (after E. Warming). Drawn from material collected in Greenland. A. A widely open flower, seen from above, showing that the anthers are remote from the stigma. B. Corolla and stamens, seen from the side. C. Pistil and petal from the same flower. D, E. Pollen-grains. F. A young flower with corolla only partly expanded ; the anthers have dehisced and there are some pollen-grains upon the stigma, which is already receptive ; anthers and stigma are so close together that autogamy is probably easj-. G. A young flower partly dissected ; the anthers have opened and the stigma is receptive. H. Trifid style. {A, B, C x 2^; G X 3i.) 56 ANGIOSPERMAE—DICOTYLEDONES probing for nectar dust themselves with pollen. But as at the same time they touch the stigmas, automatic self-pollination necessarily takes place. According to Mac- Leod, however, the anthers have lost so much of their pollen as to render this difficult. Up to this time the outwardly bent styles alternate with the stamens, so that insect- visits are still able to effect crossing. MacLeod states that the stamens and styles ultimately become so intertangled that automatic self-pollination is inevitable. Insect visitors dust their upper sides with pollen if they probe for nectar between the corolla and stamens, but get covered all over with it should they creep into the base of the flower between the stamens. The description of the method of pollination given by Schulz for the main form A. elongata does not entirely agree with the above account, possibly because it is sometimes difficult to distinguish between younger and older flowers. At first the styles bend outwards so as to Kz touch the anthers, and as the flowers are homogamous n autogamy is thus effected. The stamens first move inwards and then outwards. Towards the end of an thesis the styles and stamens become closely intertangled, but this does not lead to autogamy, for at this time there is Fig. 235- Armeria, L. (from often no pollcn left, bcsidcs which the tips of the styles aftw^coroita, stamtns, and TtyS frequently projcct from the tangled mass. Kerner asserts, have fallen off seen from above, howcvcr, that automatic sclf-pollination does take place AV, calyx-teeth; «, five-radiate ' r r nectary. at this Stage, stylcs and stamens being thrown into intertwining spirals. Visitors. — Knuih observed the following. — North Frisian Is. — A. Coleoptera. i. Cantharis fusca Z. (with its head in the flowers). B. Diptera. All skg. or po-dvg. (c) Muscidae : 2. Aricia lardaria F. ; 3. A. vagans Fall. ; 4. Lucilia caesar Z. ; 5. Sarcophaga carnaria Z. ; 6. S. sp. ; 7. Scatophaga stercoraria Z. ; 8. Trypeta sp. ; 9. 4 sps. of smaller Muscidae. {d) Syrphidae: 10. Eristalis intricarius Z.; 11. E. tenax Z.; 12. Helophilus pendulus Z.; 13. H. trivittatus F.; 14. Volucella bombylans Z. C. Hymenoptera. Apidae: all skg. or po-cltg. : 15. Apis mellificaZ. ; 16. Bombus agrorumZ". ; 17. B. distin- gucndus Mor.; 18. B. lapidarius Z. ; 19. B. terrester Z. ; 20. Dasypoda plumipes Pz.; 21. Panurgus aterPz. ; 22. P. lobatus F. D. Lepidoptera. {a) Rhopalocera : all skg. : 23. Argynnis aglaja Z. ; 24. Epinephele janira Z. ; 25. Lycaena semiargus Rott.; 26. Pieris sp. ; 27. Satyrus semele Z. (3) Sphingidae : 28. Ino statices Z.; 29. Zygaena filipendulae Z. Helgoland. — A. Diptera. (a) Muscidae: i. Lucilia caesar Z. {b) Syrphidae : 2. Eristalis sp. ; 3. E. tenax Z. ; 4. Syritta pipiens Z. B. Lepidoptera. Noctuidae : 5. Plusia gamma Z. (Bot. Jaarb. Dodonaea, Ghent, viii, 1896, p. 41). On May 6, 1897, I observed (Helgoland) the characteristic pollinator of this species, i. e. Andrena carbonaria Z., skg. The proportions of the bee exactly corre- spond to the dimensions of the flowers when the insect inserts its head. Also (occasional), Pieris brassicae Z. J, skg., Lucilia caesar Z., do., and Scatophaga sp., do. The following were recorded by the observers, and for the localities stated. — Leege (Juist), the Noctuid moth Hydroecia nictitans Z. Verhoeff in Norderney and Juist (J.). — A. Coleoptera. Scarabaeidae : i. Phyllopertha horticola Z., po-dvg. (J.). B. Diptera. (a) Bibionidae : 2. Dilophus femoratus Mg. 5, skg. ; 3. D. vulgaris Mg. 5 and $, skg. (3) Empidae : 4. Hilara quadrivittata Mg. 5 and $, very common, skg. (r) Muscidae : 5. Aricia incana Wiedem. $ and J, skg. ; 6. Cyno- PLUMBAGINEAE 57 myia mortuorum L. i. {d) Syrphidae: 7. Eristalis intricarius L.\ 8. Platycheirus sp. J, skg. C. Hymenoptera. 9. Colletes cunicularius Z. 5, po-cltg. (J.). Hein- sius (Holland), various flies (Ceratopogon sp. 5 ; Dilophus vulgaris Mg. J ; Hilara chorica Fall. (?) ; Rhamphomyia sp. 5), a short-tongued bee (Prosopis communis Nyl. J), and a butterfly (Coenonympha pamphilus Z.) (Bot. Jaarb. Dodonaea, Ghent, iv, 1892, pp. 84-5). Scott-Elliot (Dumfriesshire), a humble-bee, an Empid, a Muscid, A hover-fly, and several Dolichopodids ('Flora of Dumfriesshire,' p. 142). 1791. A. alpina Willd. (Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, H, p. 358; MacLeod, Bot. Jaarb. Dodonaea, Ghent, iii, 1891, p. 373.) — The flower mechanism of this species agrees entirely with that of A. elongata. MacLeod says that crossing and automatic self-pollination are successively ensured. According to Kerner, the stamens of the homogamous flowers are so situated in the first stage of anthesis that insects probing for the abundant nectar are obliged to rub against the pollen-covered anthers, while the five styles with their stigmas are erect in the centre. Anthers and stigmas then change places, the former turning towards the middle of the flower, and the latter moving to its periphery. Should insect-visits fail, the styles ultimately twist up spirally, move back to the centre, and become intertwined with the similarly twisted stamens, so that the stigmas are brought into contact with any pollen that may remain clinging to the latter. 537. Statice 1 ourn. Flowers blue-violet in colour, and arranged in conspicuous corymbs ; the con- cealed nectar secreted and stored up in the bases of the flowers. Sometimes hetero- styly. 1792. S. Limonium L. ( = S. Behen Drejer, and S. scanica Fries). (Mac- Leod, Bot. Centralbl., Cassel, xxix, 1887; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 124-5, *Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,' p. 239, ' Bloemenbiol. Bijdragen.') — The plants of this species I examined in the North Frisian Islands were protandrous. The lobes of the corolla, as in Armeria, are held together by the calyx during the first stage of anthesis, and the pollen-covered anthers project 1-2 mm. from them. After these have withered, the styles, which are glabrous at the base, elongate so that the receptive stigmas project from the entrance of the flower. Crossing is therefore ensured by insect-visits, but should these fail, automatic self- pollination is possible by means of the pollen which has fallen out of the anthers and remains in the flowers. Geitonogamy appears to be brought about by the wind, for masses of pollen are not infrequently seen on and near the flowers. I observed only one type in the North Frisian Islands, but MacLeod describes the following three varieties for the coast of Belgium (near Ter Neuzen and Nieuw- port) : — (a) macrostyla n. var. : style 7-8 mm. long ; stigmatic papillae occupying 2-2^ mm. of the tip of the style, not prominent ; stamens short ; extine with polygonal markings. (b) brachystyla n. var.: style 4-5 mm. long; stigmatic papillae occupying only f-i mm. of the end of the style, small but more prominent; stamens long; extine without polygonal markings. (c) isostyla n. var. : stamens and style about the same length. 58 ANGIOSPERMAE— DICOTYLEDON ES Automatic self-pollination is almost unavoidable in (c) ; pollen can easily fall from the anthers on the stigma in (b) ; autogamy sometimes takes place in (a) by bending down of the style. MacLeod also observed numerous flowers with sterile stamens, so that there is a tendency to gynodioecism. Visitors. — The following were recorded by the observers, and for the localities stated. — Knuth (Amrum), only a few minute Muscids, and a bug (Lygus pratensis i^.) obviously not adapted to the size and mechanism of the flowers, for a proboscis 5-6 mm. long is required to reach the nectar: (Sylt), the honey-bee, in enormous numbers, skg., the humble-bee Bombus terrester Z., do., and the hover-fly Meli- threptus nitidicollis Zett., do. : (Langeness in the Hallige), medium-sized Diptera. Willis (neighbourhood of the south coast of Scotland), a beetle (Meligethes sp., po- dvg.) and a humble-bee (Bombus hortorum Z., skg.) ('Fls. and Insects in Gt. Britain,' Part I). Scott-Elliot (Dumfriesshire), a humble-bee and the beetle Meligethes (' Flora of Dumfriesshire,' p. 142). LXIV. ORDER PRIMULACEAE VENT. Literature. — Herm. Miiller, 'Alpenblumen,' pp. 373-4; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' p. 120, 'Grundriss d. Bliitenbiol.,' p. 86. The brightly coloured corolla serves to attract insects. Numerous gradations are found between open nectarless flowers and such as are adapted by the way in which nectar is concealed and their entire mechanism to a restricted circle of long-tongued and industrious insects (bees, Lepidoptera). The flowers belong to the following classes : — Po : Trientalis, Lysimachia, Anagallis, Centunculus, Samolus (with pseudo- nectaries). C : Glaux (?), Hottonia, Androsace, Soldanella pusilla Bawng., var. inclmata Hb. : Soldanella pusilla Bamng., var. pendula, S. alpina. HbLb : Primula elatior Hill, P. officinalis Jacq., P. vulgaris Huds. Lb : Primula integrifolia Z., P. farinosa Z., P. viscosa AIL, P. longifolia All. (diurnal hawk-moth flowers). The species of Hottonia and Primula are usually dimorphous. 538. Trientalis Rupp. Open protogynous pollen flowers, sometimes, according to Schulz, varying to homogamous. The thick fleshy ring which bears the stamens and surrounds the ovary is, however, so juicy that Hermann Muller suggests many visitors may bore it to get the sap. 1793. T. europaea L. (Herm. Muller, ' Weit. Beob.,' Ill, pp. 65-6 ; Schulz, 'Beitrage,' I, p. 88.) — Hermann Muller says that the white petals of this species spread out into a flat star 12-15 ni"i' broad. The stamens are directed obliquely upwards and outwards, and their anthers as a rule at first remain closed, while the stigma is at the same level and receptive when the flower opens. The flowers examined by Schulz in the Riesengebirge were either homogamous or very feebly protogynous. The anthers dehisce above and internally, so that an insect when pushing its head into the base of the flower must touch the pollen with one side PRIMULACEAE 59 of this and the stigma with the other. When several blossoms are visited successively crossing must regularly be brought about. In the course of anthesis the style elongates to some extent, so that the stigma, at first on the same level as the anthers, ultimately projects beyond them. The flower closes again when it withers, pressing the stamens against the style, so that some pollen can now easily fall on the stigma, or this may come into contact with some of the grains that have dropped on the petals. The species is represented in the Arctic regions by a variety different in some respects, i. e. arcHca Fisch. Visitors. — Herm. Miiller only observed the beetle Meligethes. 539- Lysimachia L. Homogamous yellow pollen flowers. 1794. L. vulgaris L. (Herm. Miiller, ' Fertilisation,' pp. 389-90, ' Weit. Beob.,' Ill, p. 65; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 443-4; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 120-1, ' Weit. Beob. u. Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 229-30, ' Bloemenbiol. Bijdragen ' ; Kirchner, 'Flora v. Stuttgart,' pp. 531-2.) — The golden-yellow flowers of this species exist in three different oecological forms. — (a) aprica Knuth: corolla-lobes about 12 mm. long and 6 mm. broad, golden- yellow in colour with red bases, tips reflexed ; filaments red towards their tips ; style projecting a few millimetres beyond the two longest stamens, thus ensuring crossing by insect visitors, and rendering automatic self-pollination difficult. Grows in sunny stations on the mainland (but not in the North Frisian Islands). (3) tmihrosa Knuth : corolla-lobes about 10 mm. long and 6 mm. broad, bright-yellow in colour, directed obliquely upwards, tips not reflexed ; filaments greenish-yellow; style as long as the two longer stamens, so that automatic self- pollination is inevitable failing insect-visits. Grows in shady stations. (c) intermedia Knuth : corolla-lobes 10 mm. long and 5 mm. broad, distant, bright-yellow in colour, sometimes reddish at the base ; filaments usually reddish ; style somewhat longer than the two longest stamens, so that automatic self- pollination takes place more easily than in (a), and with greater difficulty than in (b). Grows in stations of intermediate character, e. g. the sunny edges of ditches. Approximates sometimes to one, sometimes to the other of the well-defined varieties (a) and (b). Warnstorf describes the pollen-grains as yellow in colour, ellipsoidal, coarsely tuberculate, about 37 /* long and 23 /x broad. Visitors. — The most important is the bee Macropis labiata Pz., the presence of which in a district appears to be related to that of this species (Ducke also observed at Trieste the rare species IMacropis frivaldskyi Mocs.). In the North Frisian Islands, which are otherwise rather poor in insects, I found considerable numbers of this bee on the flowers, its hind-legs laden with enormous balls of pollen. In the East Frisian Islands, on the other hand, where this plant is absent, the bee has not been observed, although a pretty complete entomological survey has been made. The same bee has 6o ANGIOSPERMAE—DICOTYLEDONES been seen by me on the flowers in East Holstein, Mecklenburg, Riigen, and Thuringia ; by MacLeod in Belgium, Buddeberg in Nassau, Herm. MuUer in Westphalia, Krieger at Leipzig, Alfken at Bremen; Friese in Mecklenburg, Baden, Alsace, and Hungary, also at Fiume and Trieste ; Nylander in Finland, Morawitz at St. Petersburg, and Delpino in Tuscany ('Ult. oss.,' Atti Soc. ital. sc. nat., IVIilano, xvi, 1873). Herm. Miiller adds that he found the bee in tolerable numbers on flowers growing in sunny stations, the females (which he only saw on this species) industriously brushing off the pollen and heaping it up in thick moistened balls on their hind-legs. How the necessary moisture is obtained is doubtful, but probably the bee bores into the juicy cellular tissues of the flowers. The blades of its maxillae, however, are blunt and clothed with long hairs, so that the function they usually perform may perhaps be carried out by the spines with which the short thick ligula is beset. The following were recorded by the observers, and for the localities stated. — Herm. IMiiller. — A. Diptera. Syrphidae : i . Syritta pipiens Z., po-dvg. on var. (b), effecting both self- and cross-pollination; 2. Syrphus balteatus Deg., po-dvg. B. Hymenoptera. (a) Apidae : 3. Andrena denticulata I^. J, one, vainly searching for nectar ; 4. Halictus zonulus Sm. S, one, do.; 5. Macropis labiata Fz., var. fulvipes J^. $ (Bavarian Oberpfalz). (d) Vespidae : 6. Odynerus parietum L. 5, one, po-cltg. and vainly searching for nectar. Knuth (Riigen), the fossorial wasp Crabro palmarius Schreb. Alfken (Bremen), the bees Halictus calceatus Scop., and H. morio F. Friese for Fiume (F.) and Trieste (T.), 2 bees — i. Andrena korleviciana Friese (F., T.), not rare (Korlevic); 2. iVIacropis frivaldskyi il/i'f.r. (Hungary), occasional (F.), freq. (Korlevic). 1795. L. nemorum L. (Kirchner, 'Flora v. Stuttgart,' p. 532; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 444; Knuth, ' Bloemenbiol. Bijdragen.') — In the egg-yellow flowers of this species the diverging stamens are of equal length, and remote from the siigma, which is situated at a somewhat lower level. Kerner states, however, that automatic self-pollination takes place by contact of anthers and stigma. Visitors. — The following were recorded by the observers, and for the localities stated. — Knuth, the po-dvg. hover-fly Syrphus balteatus Deg. Scott-Elliot (Dumfriesshire), a Muscid and several Dolichopodids (' Flora of Dumfriesshire,' p. 115). 1796. L. Nummularia L. (Darwin, 'Variation,' II, p. 154; Kirchner, 'Flora v. Stuttgart,' p. 532; jNIacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 444; Warnstorf, Verh. bot. Ver., Berlin, xxxviii, 1896 ; Knuth, ' Bloemenbiol. Bijdragen.') — The large golden-yellow flowers of this species are marked internally with glandular brown points. Their stamens are of unequal length. Although owing to the size of the flowers crossing by insect visitors appears to take place pretty frequently, auto- matic self-pollination can also be easily effected, as was pointed out by Darwin, though this rarely results in the formation of seeds. Warming suggests that this is because all the plants of a particular station have been derived from the same original stock. Warnstorf states that the flowers are protogynous at Ruppin. At the time when the pollen is ripe the anthers are usually at the same level as the stigma, so that autogamy is inevitable. The pollen-grains are yellow in colour, very irregular PRIMULACEAE 6i (ellipsoidal, or ovoid to tetrahedral), beset with a network of papillae, variable in size (25-30 /a in diameter). Visitors. — I observed the honey-bee, po-cltg. 1797. L. thyrsifolia L. (Warming, Bot. Tids., Kjobenhavn, ii, 1877 ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 326; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896.) — The flowers of this species are protogynous. The ovary is covered with small papillae, which Kerner says serve as food to visitors. Warnstorff states that the receptive stigma projects from the flowers before they open. After they have done so, the stamens become erect and are remote from the stigma, sometimes attaining the same level and sometimes being a little shorter. The pollen-grains are yellow in colour, ellipsoidal, finely luberculate, up to 31 /a long and 19 /x broad. Kerner states that geitonogamy takes place should insect-visits fail, for the filaments elongate and bend in such a way as to transfer the pollen to the stigmas of adjacent flowers. Visitors. — I saw the po-dvg. hover-fly Syritta pipiens L. 1798. L. ciliata L. (=Steironema ciliatum Rafin.). — Kerner says that in this species also there are litde papillae on the ovary which are devoured by insect visitors. 540. Anagallis L. Homogamous pollen flowers. 1799. A. arvensis L. ( = A. phoenicea Scop.). (Delpino, 'Ale. app.' ; Herm. Miiller, 'Fertilisation,' pp. 390-2 ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 217; ^ty Fig. 236. Anagallis arvensis, L.\ and ^. (rjgr«/^(7, 3'c/jr«5. (after Herm. Miiller). (i) Fully open ^o\i^r oi A. arvensis. (2) Half-open flower of do. (3) Fully open flower of -(4. ca^r/^/^a. (4) Do., seen from the side, after removal of part of the cal3-x and corolla, a, anthers ; /, petals ; j, sepals ; St, stigma. MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 442-3; Kirchner, 'Flora v. Stuttgart,' p. 535; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' p. 121.) — The red flowers of this species expand in sunny weather from 9 (7) a.m. to 3 (2) p.m., to form a disk 1 0-12 mm. in diameter. The anthers of the five diverging stamens are covered with pollen all round, and the style bends down between them in such a way that the simultaneously mature stigma must first be touched by an insect visitor alighting on the lower part of the corolla. Crossing will thus be effected if the visitor is already dusted with pollen. The corolla closes in the afternoon, bringing the stigma into contact with the 62 ANGIOSPERMAE—DICOTYLEDONES anthers of the three lowest stamens, so that automatic self-pollination regularly takes place, and this is largely made use of by the plant, for scarcely any insect visitors have so far been observed. Kerner states that each flower opens and closes three times, after which it does not open again. During the periodic closing of the corolla, the pollen which clings to it is brought into contact with the stigma and autogamy consequently effected. During unfavourable weather the flowers remain closed and self-pollination takes place pseudo-cleistogamously. {C/. Fig. 236.) It is possible that the delicate clavate hairs covering the filaments may be used by visitors as food, in addition to the pollen. Visitors. — Smith (England) saw the bee Halictus morio F. 1800. A. caerulea Lam. ( = A. arvensis L., according to the Index Krcvensts). (Herm. jMiiller, loc. cit.) — The flower mechanism of this species is exactly the same as that of A. arvensis. It must, however, be regarded as a distinct species, for Clos states that when crossed with the latter no seeds capable of germination are produced. 1801. A. tenella L.— The plants of this species observed by MacLeod on the dunes of Flanders bore white or reddish pollen flowers, with red-violet longitudinal streaks on the corolla-lobes. The corolla-tube is deeper than in the two last species, and is quite filled up by the hairs covering the filaments. The stigma projects 2-3 mm. beyond the anthers, so that automatic self-pollination cannot take place. 541. Centunculus Dill. Inconspicuous homogamous pollen flowers. 1802. C. minimus L. (Ascherson, Bot. Ztg., Leipzig, xxix, 1871, p., 553 ; Herm. Muller, 'Fertilisation,' p. 390; Kirchner, 'Flora v. Stuttgart,' p. 535; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, pp. 170, 213, 332 ; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 121, ' Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,' p. 230.) — In this species the very small white or reddish flowers are regularly self-pollinated, for in unfavourable weather they remain closed and pseudo-cleistogamy obtains. Crossing is now and then possible, however, for Kerner says that the flowers open for a short time in bright sunshine between 10 and 11 a.m. In the island of Fohr I noticed numerous purely cleistogamous flowers. 542. Androsace L. Literature. — Herm. ]\Iuller, ' Alpenblumen,' pp. 357-8. Homogamous (also protogynous according to Kerner) flowers, with concealed nectar secreted in favourable weather only by the surface of the ovary and hidden in the shallow (1^-2 mm.) corolla-tube. This narrows above, leaving only a very small aperture, so that although the nectar is not deeply concealed, it can only be found by the more intelligent insects, an orange-coloured nectar-guide indicating its position. When Lepidoptera, bees, or the more skilful flies insert their proboscis into the narrow opening of the flower, one side of this touches the stigma and the other side the anthers, so that crossing is ensured. Should insect-visits fail, self-pollination is secured by the nearness of the anthers to the stigma in the homogamous flowers. I PRIMULACEAE 63 The narrowness of the corolla-tube protects the nectar from rain-drops, which are unable to displace the air. Kerner states that many species are heterostylous. 1803. A. septentrionalis L. (Herm. Miiller, ' Alpenblumen,' p. 358 ; Kerner, *Nat. Hist. PI.,' Eng. Ed. i, II, p. 341.) — The white flowers of this species are only 6 mm. in diameter, {C/. Fig. 237.) Kerner says that automatic self- pollination is ultimately ef- fected by contact of the anthers and stigma. Visitors. — Herm. Miiller observed anEmpid, aSyrphid, and 3 Muscids. 1804. A.Chamaejasme WiUd. (Herm. Muller, 'Al- penblumen,' pp. 358-9.) — In this species the flowers are 7-8 mm. in diameter. The nectar-guide is at first yellow in colour, but becomes car- mine-red after pollination has been effected. Should insect- visits fail, the latter takes place automatically by the fall of pollen. {C/. Fig. 238.) Visitors. — Herm. Muller observed 15 flies, 4 Lepidoptera, and a bee. Fig. 237. Androsau septentrionalis, L. (after Herm. Muller). A. Flower seen directly from above. B. Do. in longitudinal section. C. Pistil seen obliquely from above (x 7). Fig. 238. Androsace Chamaejasme, Witld. (after Herm. Muller). A. Flower seen directly from above. B. Do. in longitudinal section. C. Older pistil seen obliquely from above (x 7). D. Younger pistil. 1805. A. obtusifolia All. (Herm. Muller, 'Alpenblumen,' p. 360.) — The white flowers of this species are more than 8 mm. in diameter. Autogamy is easily effected. Visitors. — Herm. Miiller observed 10 flies and 3 Lepidoptera. 1806. A. alpina Lam. (=A. glacialis Hoppe). (Herm. Miiller, 'Alpenblumen,' p. 360.) — The white or rose-red flowers of this species are 5 mm. broad, and possess nectar-guides. They are homogamous, and autogamy takes place should insect- visits fail. 64 ANGIOSPERMAE—DfCOTYLEDONES 1807. A. bryoides DC. (=A. helvetica AIL); 1808. A. imbricata Lam,; and 1809. A. alpina Lam. (=A. pubescens DC). (Herm. Mtiller, loc. cit.) — These species are homogamous, and self-pollination takes place should insect-visits fail. 1810. A. lactea L. (Briquet, ' £tudes de biol. flor. dans les Alpes Occident.') — Briquet states that the flowers of this species are white with a yellow throat. The limb of the corolla is 11-12 mm. in diameter, while the corolla-tube is 2 mm. broad with an entrance of \ mm. As the flowers are homogamous, and the five anthers almost touch the capitate stigma and project beyond it, automatic self-pollination regularly takes place, and this is also eff'ected by Diptera and small Lepidoptera. Briquet was unable to confirm the statement of Kerner that nectar is secreted on the upper surface of the ovary. Kirchner, however, found little drops of nectar on the flat upper side of the ovary, both in this species and also in A. villosa, while Kerner made similar observations for the species of Androsace in general. The flowers of A. lactea possess an agreeable odour. 1811. A. villosa L. (Briquet, op. cit.) — Briquet says that the flowers of this species agree with those of A. lactea, except that the corolla is somewhat larger, and its throat at first flesh-coloured and afterwards white. He observed no visitors. In flowers examined by Kirchner the diameter was only 8-9 mm., and the throat of the corolla golden-yellow at the beginning of anthesis, afterwards changing to a peach- blossom red. MacLeod (' Pyreneenbl./ p. 372) describes the flowers as white or rose in colour, with purple or yellowish nectar-guides, and a somewhat venlricose corolla-tube 3-3^ mm. long and constricted at the throat. Visitors. — MacLeod observed 3 flies and a Lepidopterid. 1812. A. Vitaliana Lap. (=Douglasia Vitaliana). — Treviranus describes this species as dimorphous (Bot. Ztg., Leipzig, xxi, 1863, p. 6). 543. Primula L. Literature. — Charles Darwin, J. Linn. Soc. Bot., London, vi, 1862, pp. 77-96; Treviranus, Bot. Ztg., Leipzig, xxi, 1863; Hildebrand, op. cit., xxii, 1864; Scott, J. Linn. Soc. Bot, London, viii, 1865; Pax, ' Primulaceae,* in Engler and Prantl, 'D. nat. Pflanzenfam.,' IV, i. Flowers mostly homogamous and heterostylous-dimorphous, sometimes homo- stylous ; rarely protandrous and belonging to classes L or Hh (or Hb) ; sometimes belonging to both KUi and L. Nectar is secreted by the base of the ovary, and sheltered in the corolla-tube. The pollen-grains of the long stamens are larger than those of the short ones, and the stigmatic papillae of the long styles are longer than those of the short styles. Darwin's researches showed that ' legitimate ' pollination, in which the stigma of the long (or short) style receives pollen produced at the same level by the anthers of the long (or short) stamens, results in a much higher degree of fertility than 'illegitimate' pollination, {C/. Vol. I, pp. 47-8.) He also found Primula officinalis, P, sinensis, and P. Auricula very infertile when insect-visits were prevented, but completely fertile when such visits were permitted or artificial pollination effected. Legitimate unions were about i^ times as fertile as illegitimate ones. i PRIMULACEAE 65 Fig. 239. Diagram of the Legitimate and Illegitimate Unions possible in Primula (after Charles Darwin). The legitimate unions are indicated by horizontal dotted lines, and the illegitimate ones by curved ditto. These results were confirmed by the investigations of Hildebrand, who further proved that when flowers were artificially self-pollinated fertility was at a minimum. By sowing separately the seeds resulting from the different kinds of union, Hildebrand found that when both parents were long-styled the offspring were predominatingly so, and similarly for short-styled stocks. Crosses between the two kinds of stock resulted in off- spring which were long- and short- ^~\ ^. .^ styled in approximately equal pro- portions. The researches of Darwin and Hildebrand threw entirely new light on the significance of crossing and sexuality in general. 1813. P. elatior Hill. (Herm. Miiller, 'Fertilisation/ pp. 384-5, 'Al- penblumen,' p. 369, ' Weit. Beob.,' HI, pp. 64-5 ; Schulz, ' Beitrage,' II, pp. 145-6; Kirchner, 'Flora v. Stutt- gart,' pp. 533-4 ; Knuth, ' Bloemen- biol. Bijdragen '; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 444-6.) — This species bears hetero- stylous flowers belonging to class HhL, which do not attain their full size till towards the end of anthesis. The corolla is of pale-yellow colour with a yolk-yellow throat, and its tube differs in length and shape in the long- and short- styled forms. (a) brachystyla: corolla-tube 15-17 mm. long, gradually narrowing to a little distance (3-5 mm.) below the horizontally expanded limb, and then at a level of 12-13 mm. from its base enlarging again. The five anthers, borne on filaments with wider bases, are situated in this enlarged region, and they extend to the opening of the tube, where their tips converge. The pollen-grains are about twice as large as in (b). The relatively thick style is about half the length of the corolla-tube ; the stigma is broader than deep, and beset with short papillae. (b) macrostylai corolla-tube 12-14 n^"^- long, widening somewhat in the middle where the stamens are inserted, and then gradually narrowing again. The pollen-grains are only about half as large as in (a). The style is tolerably thin in its upper part, and so long that the spheroidal stigma is situated in the entrance of the flower. The stigmatic papillae are about five times as long as those of (a). The two kinds of flowers are about equally frequent, and borne on separate stocks. Humble-bees probing for nectar in the legitimate way touch the organs in the entrance of the flower with their heads, and those in the middle of the corolla-tube with their laciniae. The regions in question consequently get dusted with pollen, which is transferred to stigmas situated at the same level in the other kinds of stocky DAVIS. Ill F 66 ANGIOSPERMAE—DICOTYLEDONES so that ' legitimate ' union is regularly effected. As the head of a humble-bee, about 5 mm. in length, can be entirely thrust into the corolla-tube of either sort of flower, a proboscis 1 2 mm. long is able to probe the longest tubes, while one not less than 7 mm. can suck all the nectar from flowers with the shortest tubes. Legitimate crossing is regularly effected, not only by humble-bees, but also by the brimstone butterfly (Rhodocera rhamni Z.). The first observation regarding it was made by A. Mfilberger, of which Hermann MuUer says : ' In my Black Forest valley (Herrenalb) Primula elatior is the first, and for a long time the only hunting- ground, where it can disport itself. It visits the long- and short-styled forms apparently without discrimination. The flower and the butterfly are usually of precisely the same yellow colour. In a short-styled flower it is generally easy to see if it has or has not been visited by a butterfly. In the former case a small hole formed by the proboscis is seen between the anthers which exactly fill the mouth of the corolla-tube.' Miiller has seen this butterfly as a visitor at Lippstadt and at Kiel (21. 3. '96). I have noticed it flying industriously from flower to flower. The mark left by the inserted proboscis is always easily detected. As an equally frequent visitor I saw Bombus hortorum L. 5. Both the insects visited with equal zeal the three associated species (P. elatior, P. ofiicinalis, P. vulgaris), so that they effected hybridization as well as crossing. Flowers which have been perforated by humble-bees (Bombus terrester Z.) just above the calyx are not infrequently to be seen. Visitors. — Vide supra. Herm. Miiller observed a humble-bee and a hover-fly in the Alps, and gives the following list for Lippstadt. — A. Coleoptera. Staphylinidae : i. Omalium florale Payk., freq., creeping about in the flowers. B. Diptera. Bombyliidae : 2. Bombylius discolor Mg., freq., skg. ; 3. B. major Z., much rarer, not as a rule getting at the nectar. C. Hymenoptera. Apidae: 4. Andrena gwynana ^. 5, freq., po-cltg. on the short-styled flowers, but leaving the long-styled ones at once ; 5. Anthophora pilipes F. 5 and $, very numerous, skg. legitimately and po-cltg.; 6. Apis mellifica Z. 5. casually skg.; 7. Bombus confusus Schenck 5, skg. legitimately; 8. B. hortorum Z. 5 and 5> very numerous, skg. legitimately, and po-cltg.; 9. B. lapidarius Z. $, skg. legitimately; 10. B. sylvarum Z. $, do. ; 11. B. terrester Z., perforating the corolla-tubes and stealing nectar; 12. Osmia rufa Z. J, casually skg. The following were recorded by the observers, and for the localities stated. — MacLeod (Belgium), 2 long-tongued bees, skg. legitimately (Anthophora pilipesZ^., and Bombus hortorum Z.), a short-tongued bee (Andrena gwynana K. 5, po-cltg.), and the honey-bee, skg. for a short time; also the humble-bee Bombus terrester Z., perforating the flowers. Alfken (Bremen), 6 bees — i. Andrena cineraria Z. $; 2. Bombus agrorum Z'. 5; 3. B. hortorum Z. 5; 4. B. pratorum Z. 5; 5. Osmia rufa Z. J ; 6. Podalirius acervorum Z. S. 1814. P. officinalis Jacq. (=P. veris, var. officinalis). (Darwin, 'Forms of Flowers,' p. 14; Hildebrand, 'D. Geschlechts-Vert. b. d. Pfl.,' p. 34; Herm. MuUer, 'Fertilisation,' p. 385, 'Weit. Beob.,' Ill, p. 65; Kirchner, 'Flora v. Stuttgart,' p. 534, 'Beitrage,' p. 51 ; Schulz, 'Beitrage,' II, pp. 14 1-2 ; Ljungstrom, 'Fine Primula-Exkursion nach Moen' ; Loew, 'Blutenbiol. Floristik,' p. 392 ; Knuth, 'Bloemenbiol. Bijdragen'; Weiss, New Phytol., London, iii, i904,p. 168.) — This species bears heterostylous flowers belonging to class HhL. Their mechanism is the same as I PRIMULACEAE 67 that of P. elatior and they are yellow in colour, usually with an orange-red patch in the throat that serves as a nectar-guide. Flowers devoid of this patch have, however, been observed by Kirchner in Wurtemburg and Appel (as he tells me in a letter) at Wiirzburg. Schulz has measured the flowers and finds that they do not attain their full size till towards the end of anthesis. In long-styled flowers the style usually elongates during this process of growth, but sometimes its development is arrested, so that the anthers and stigma are ultimately at the same level. Breitenbach and Schulz noticed such equal-styled (isostylous) flowers. The latter states that the short-styled form is somewhat smaller than the long-styled one, and that its style is always of approximately the same length. Kirchner noticed large- and small-flowered forms in Wurtem- berg. In the island of Moen E. Ljung- strom observed two forms in which the calyx was markedly short or long, respectively, as compared with the corolla-tube, and he gave them the varietal names of brevicalyx and longicalyx. He also found variations as regards the breadth of the limb of the corolla, and distinguished between two forms, laiiloba and angiistiloba, respectively possessing a broad and a narrow limb. In flowers with a short calyx the corolla was often very large, elegantly saucer-shaped, and of a beautiful yellow colour. On the other hand, a long calyx was not infrequently associated with a smaller and paler corolla. The corolla-tube is fairly often perforated by humble-bees. Visitors. — The following were recorded by the observers, and for the localities istated. — Herm. Miiller. — A. Coleoptera. Nitidulidae : i. Meligethes, po-dvg. B. Diptera. BombylUdae : 2. Bombylius discolor Mg., skg. C. Hymenoptera. 3. Andrena gwynana J^. 5, in large numbers, po-cltg. on short-styled flowers, but leaving long-styled ones after a brief visit ; 4. Anthophora pilipes i^. 5 and $, freq., skg. ; 5. Bombus agrorum JF". 5, skg. ; 6. Halictus albipes F. $, as 3 ; 7. H. •cylindricus F. 5, do. Knuth, the butterfly Rhodocera rhamni Z., and the humble-bee Bombus hortorum Z. (c/. P. elatior). Loew (Brandenburg), the humble-bee Bombus hortorum Z., skg. ('Beitrage,' p. 45); (Berlin Botanic Garden), the bee Anthophora pilipes F, skg., on the var. colorata. MacLeod (Pyrenees), the humble-bee Bombus rajellus K. (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, p. 372). F. E. Weiss (England), 2 humble-bees — Bombus muscorum F., and B. terrester Z. 1815. P. vulgaris Huds. (=P. acaulis Hill). (Darwin, 'Forms of Flowers,' PP- 34-5. 37, 266; Lange, Bot. Tids., Kjobenhavn, xiv, 1885, pp. 147-58; Correns, Ber. D. bot. Ges., BerHn, vii, 1889, pp. 265-72 ; Focke, Abh. natw. Ver., Bremen, ix, 1887, pp. 75-6; Cobelli,Abh. Zool. Bot. Ges., Wien, xliii, 1892, pp. 73-8; Ljungstrom, -■Eine Primula-Exkursion nach Moen'; Knuth, Bot. Centralbl., Cassel, Iv, 1893, F 2 Fig. 240. Primula officinalis, /acq. (after Hildebrand). (a) Long-styled and (5) short-styled flowers, partly dissected from the side. 68 ANGIOSPERMAE— DICOTYLEDON ES I pp. 225-7; Ixiii, 1895, pp. 97-8; F. E. Weiss, New Phytol., London, ii, 1903, p. 99, iii, 1904, p. 168.) — This species bears heterostylous flowers belonging to class HhL. Those examined by me in Schleswig-Holstein were of sulphur-yellow colour, with a Fig. 241. Primula vttlgarts, Huds. (i) and (2) Short- and long-styled flowers, in longitudinal section (X 2). 3 0 5 6 Relative size of the pollen-grains (3) of the short-styled, and (4) of the long-styled flower. Relative size of the stigmatic papillae (5) of the long-styled, and (6) of the short-styled flower. darker nectar-guide at the base of each corolla-lobe. Their diameter varied from 2^ to 4 cm., but was usually about 3 cm. Similarly the length of the corolla- tube was i^ai cm., mostly, however, about 2 cm. In the long-styled form the stigma is situated in the opening of the flower, while the anthers are inserted into the corolla-tube about its middle. In the short-styled form the opening of the corolla -tube, which widens somewhat like a funnel, is, of course, occupied by the five anthers, while the style with its stigma is about half as long as the tube. There are microscopic diff"erences between the two forms as regards the length of the anthers and the shape of the stigma. In short-styled flowers the anthers are generally rather more than 2 mm. long, in long-styled ones usually a little less. The stigma in the latter is spheroidal as a rule with a diameter of i-i mm., but in short-styled flowers it is mostly somewhat flattened, about 1-2 mm. broad and 0-9 mm. deep. With the aid of a lens the stigmatic papillae of the long-styled form are clearly visible, but those of the short-styled one scarcely perceptible. The former are 0-07 mm. long and CGI mm. broad, the latter 0-02 mm. long and about the same in breadth. The pollen-grains are of an angular ovoid shape, those of the long-styled form 0-025 ^^' long and 0-02 mm. broad, and those of the short-styled one almost 0-04 mm. long and 0-025 mm. broad. As in the case of the last species, Ljungstrom observed four varieties in the island of Moen, i. e. brevicalyx, longicalyx, laiiloba, and angustiloba. He also noticed a form {laciea) with an almost milk-white corolla, and another {colorata)i PRIMULACEAE 69 in Avhich this was purple - violet, except for its star -shaped yellow centre and sometimes whitish margin. Visitors. — I saw at Kiel (25. 4. '95) several individuals of Bombus hortorumZ. 5, flying busily from flower to flower, and sinking their proboscis into the corolla-tube, so that in long-styled flowers the laciniae, and in short-styled ones the head became dusted with pollen. This was then transferred to stigmas at corresponding levels, and legitimate crossing regularly effected. These humble-bees, however, not only visited this species, but also P. officinalis and P. elatior, which were growing near, so that a great deal of hybridization as well as crossing must have been brought about. In some cases the bee Anthophora pilipes F. } behaved in the same way as Bombus hortorum, though it preferred the flowers of Pulmonaria officinalis, which grew close by. In the two last-named insects the proboscis is 18-21 mm. long, so that it can easily reach the nectar concealed in the bases of the flowers of this and the last two species. The average length of the corolla-tube is here 20 mm., but in P. officinalis and P. elatior it is considerably shorter. As a bee when sucking can completely thrust its head (about 5 mm. long) into the opening of the corolla- tube, it follows that other species with shorter tongues are able to legitimately pollinate P. officinalis and P. elatior. Hermann Miiller actually observed humble-bees of the kind doing this. The three species of Primula in question can also be pollinated by the brimstone butterfly (Rhodocera rhamni Z.). Cobelli saw it on P. vulgaris, Miilberger and Hermann Miiller on P. elatior, and myself on all three (26. ^.'gd). Cobelli also observed Bombylius medius Z. on P. vulgaris, and the other two species of Primula are also visited by Bombyliids, though only those with a par- ticularly long proboscis are able to get at the nectar. On March 21, 1896, I saw Vanessa urticae Z. flying persistently from flower to flower of this species (eighteen were successively visited). This butterfly sucked very vigorously, and evidently succeeded in getting a part of the nectar. Though useless to the short-styled flowers, it undoubtedly transferred their pollen to the stigmas of long-styled ones. I also saw the honey-bee visit several flowers in succession, and as it sucked with equal zeal it perhaps succeeded in reaching the uppermost layer of nectar. Wustnei noticed the bee Anthophora acervorum Z. in the island of Alsen, and Cobelli saw small beetles, though these could only effect crossing by accident. We may say of Primula vulgaris, P. elatior, and P. officinalis, that all three are chiefly pollinated by long-tongued Hymenoptera and the brimstone butterfly, while Bombyliids, Vanessa urticae, and the honey-bee are visitors of secondary importance. I was able to observe directly the transfer of pollen by visitors for the short distance of a few metres, but Focke has seen a hybrid between P. vulgaris and P. officinalis, for the development of which it must have been carried a kilometre. Gibson (' Flora of St. Kilda ') states that in St. Kilda, the most westerly island of Scotland (except the barren Rockall), where bees, wasps, and Lepidoptera are absent, the primrose appears to be pollinated by flies, for fruits are now and then set. Archer Briggs (Rep. Inst., Plymouth, iv, 187 1-2) did hot notice the larger humble-bees in England, but only Anthophora acervorum Z., freq., smaller bees ^o ANGIOSPERMAE'-DICOTYLEDONES (Andrena gwynana K.), the brimstone butterfly (Rhodocera rhamni Z.), and a Bombyliid (Bombylins medius Z., freq.). The following were recorded by the observers, and for the localities stated. — Burkill (Yorkshire coast) ('Fertlsn. of Spring Fls.'). — A. Coleoptera. i. An- thobium (Eusphalerum) primulae Fauv. (=A. triviale Er), dvg. the anthers; 2. Meligethes picipes Sturm., skg. B. Hymenoptera. Apidae : 3. Andrena gwynana K. $, searching for nectar, but unable to reach it, C. Thysanoptera. 4. Thripn sp., freq. Burkill elsewhere remarks that 'the fertilization of this plant is yet unexplained. None of the insects seen on it through many hours of watching are sufiicient for its fertilization.' Darwin, only Thrips: he says 'the primrose is never visited (and I speak after many years' observation) by the larger humble- bees and rarely by the smaller kinds.' Scott-Elliot (Dumfriesshire), the humble-bee Bombus hortorum Z. Miller- Christy (Essex), 2 bees (Apis mellifica Z,, and Anthophora acervorum Z.), humble-bees (Bombus sp.), a hover- fly (Syrphus sp.), 2 butterflies (Rhodocera rhamni Z., and Pieris rapi Z.), and a beetle (Meligethes picipes Sturm.). Loew (Berlin Botanic Garden), the bee Anthophora pilipes F., steadily skg. and po-cltg., and settling repeatedly. E. Bell (England) only noticed 4 visitors ' after seeing and examining thousands and thousands, we might say millions of the flowers ' : he adds that ' the primrose gives unimpeachable evidence that self-fertilization of heterostyled plants is the natural and legitimate fertilization as being fully productive ' (' The Primrose and Darwinism '). F. E. Weiss (Shropshire), the Bombyliid Bombylius major Z., freq. (also in North Staffordshire), the humble- bee Bombus terrester Z., and 3 bees — i. Andrena gwynana^., freq.; 2. Anthophora pilipes F. ; 3. Apis mellifica Z. Miss M. L. Armitt (Westmoreland, teste Weiss), Bombylius, eff"ecting crossing. Weiss endeavours to reconcile conflicting views: ' The fact that many observers have been unable to detect such insect visitors I attributed to their observations having been made either in cold or dull weather, or in exposed and windy situations. For even on sunny days I could not observe the usual insect visitors on primroses in wind-swept localities, while, at the same time, in sheltered positions some larger humble-bees might occasionally be met with on the primroses, and Anthophora, Bombylius, and pollen-gathering Andrenae fairly regularly.' He'finally concludes : ' From the observations I have made on the primrose, I feel convinced that it is both regularly visited and cross-pollinated by insects under favourable climatic conditions, but that like most flowers adapted to the visits of insects, it is provided with efficient means for self-poUination, and these are important to a plant flowering at so early a period of the year when the visits of insects may be precarious.' Ljungstrom graphically represents the relationship between the three species of Primula just considered by means of a scalene triangle, of which the angles represent the species, and in which the shortest side is between P. vulgaris and P. elatior, and the longest between P. vulgaris and P. officinalis. P. elatior P. vulgaris ^^— -~- P. officinalis This diagram also indicates the degree of fertility of the hybrids, for the (pollen) sterility of these increases as the affinity of the stocks crossed becomes more remote. Ljungstrom examined the pollen of various hybrids and obtained the following results. — P. vulgaris x P. officinalis : 26-5-33 % normal pollen-grains, 73-5-67 % shrivelled and useless. a I PRIMULACEAE 71 P. elatior x P. officinalis : 31-6 % good, 69-63 % shrivelled and useless. P. elatior (average of flowers from Schonen) : 33 % normal, 67 % shrivelled and useless. P. elatior X P. per-officinalis (from Schonen): 45% normal, the rest shrivelled and useless. P. vulgaris x P. elatior : 66-9 % normal. P. vulgaris (per-acaulis) x P. elatior 178% normal. These results appear to be confirmed by the number of seeds developed in the diflferent cases. Fig. 242. PriTHula integrifolia, L. (after Herm. M&ller). A, B. Short- and long-styled plants (natural size). C, D. Short- and long-styled flowers, partly dissected (natural size). E. Stigmatic papillae of the short-styled, i% G, do. of the long-styled flowers. H, J. Stigmas of the short- and long- styled flowers (x 7). A", L. Moistened pollen-grains of short- and long-styled flowers. 1816. P. integrifolia L. (Herm. Miiller, ' Alpenblumen,' pp. 350-62,) — This species bears dimorphous heterostylous butterfly flowers. The tube of the purple-red corolla is 10-14 nnni- lo"gj and as a rule is of noticeably greater length in the short-styled form, where also the limb of the corolla is broader. {Cf. Fig. 242.) Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. MuUer (Alps), 7 Lepidoptera, a Bombyliid, and a beetle. Redtenbacher (Austria), the Staphylinid beetle Anthobium robustum Heer. 1817. P. villosa Jacq. (?) (Herm. Miiller, ' Alpenblumen,' pp. 362-3.) — This species bears dimorphous heterostylous butterfly flowers. According to Pax (Bot. Jahrb., Leipzig, x, 1888, p. 227), the species described by Hermann Muller as 72 ANGIOSPERMAE— DICOTYLEDON ES P. villosa Jacq. is apparently P. hirsuta All, for the former is only to be found in Steiermark. Gremli (' Exkursionsflora fur die Schweiz,' 6. Aufl., 1889, p. 359) says that P. hirsuta All is identical with P. viscosa Vill, but not with P. villosa Koch^ nor with P. villosa /of^. [P. villosa Jacq. — P. villosa Wulf., according to the Index Kewensis7[ The flowers are of a dark violet-red colour, with a tube 10-13 mm. long, but hardly i^ mm. wide, so that only Lepidoptera can get at the nectar. {Cf. Fig. 243.) Visitors. — Herm. Mai- ler observed 3 butterflies ; also a beetle as an unbidden Fig. 243. Primula villosa, Jacq. (?) (after Herm. MuUer). Short- and long-styled flowers, seen from the side (natural size). Do., seen from above. E, F. Do. in longitudinal section. A, B. C,D. guest. 1818. P. viscosa All. ( = P. latifolia Koch, and P. graveolens Heg.). (Herm. Miiller, ' Alpenblumen/ pp. 367-9.) — This species bears dimorphous heterostylous butterfly flowers. The corolla-tube is so narrow, that between it and the stigma the distance is scarcely \ mm., and consequently the K. 0 o^ Fig. 244. Primula viscosa, L. (after Herm. Muller). A, B. Short- and long-styled flowers, partly dissected (X 2). C, Z?. Stigmas of do. ( X 7). £■, /^ Stigmatic papillae of do. C, .^. Dry pollen- grains of do. y, K. The same, moistened. L. Cross-section of a long-styled flower fast above the stigma (X 7). nectar can only legitimately be sucked by the proboscis of a lepidopterous insect, which must at the same time touch the anthers and stigma. The requisite length of proboscis is 12-14 J^™- {Qf- Fig- 244.) Visitors. — Herm. Muller only observed useless (Rhingia campestris Mg^ and injurious (Bombus mastrucatus Gersl, stealing nectar) guests. PRIMULACEAE 73 1819. P. farinosa L. (Darwin, 'Forms of Flowers,' pp. 45, 224, 273 ; Herm. Miiller, ' Alpenblumen,' pp. 363-7 ; IVIacLeod, ' Pyreneenbl.,' p. 372.) — This species bears dimorphous heierostylous butterfly or humble-bee flowers. It is of particular interest because in the Alps, where Lepidoptera abound, it is adapted to butterflies, while in North Pomerania, where Lepidoptera are relatively few and bees abundant, it is adapted to the latter. Herm. Miiller gives the following differences between flowers from the two regions. — (i) Alpine plants bear flowers which are usually larger and more brightly coloured than in Pomerania. (2) In Pomeranian plants, on the other hand, the corolla-lobes are on the average somewhat broader. (3) In Pomeranian plants, as a rule, the opening of the corolla and its tube are markedly wider. {Cf. Fig. 245.) In Greenland, according to Abro- meit ('Bot. Ergeb. von Drygalski's Gronlandsexped.,' pp. 39-40), the var. mtstassinica (Mchx.) Pax occupies a middle position between P. farinosa, var. typtca, and P. stricta Hornem. The flowers are homostylous, an oeco- logical peculiarity shared with Meny- anthes trifoliata in the same country, for the European type-forms of both plants are heterostylous. Visitors. — Herm. Miiller ob- served 42 Lepidoptera, 3 Bombyliids, 2 Syrphids, a humble-bee, and a wasp in the Alps. MacLeod saw 2 Lepi- doptera, and a Bombyliid in the Pyrenees. 1820. P. minima L. (Herm. Miiller,' Alpenblumen,' p. 369 ; Schulz, 'Beitrage,' II, pp. 148, 223; Kerner, ' Nat. Hist. Pi.,' Eng. Ed. i, II, p. 396.) — This species bears dimorphous heterostylous butterfly flowers. The tube of the rose-red corolla is lined with hairs, and is 10-12 mm. long with a contracted opening, so that only the proboscis of a lepidopterous insect can conveniently reach the base of the flower. Kerner says that automatic self-pollination is possible in the short-styled flowers by fall of pollen. Visitors. — Schulz observed Lepidoptera. 1821. P. longiflora All. (Darwin, ' Forms of Flowers,' p. 50 ; Herm. Muller, 'Alpenblumen,' p. 369; Schulz, ' Beitrage,' II, pp. 146-7, 223; Pax, Bot. Jahrb., Leipzig, X, 1888, p. 227 ; Ricca, Atti Soc. ital. sc. nat., Milano, xiii, p. 260; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, pp. 396-7.) — This species bears diurnal hawk-moth flowers, described by Darwin as homostylous, and by Ricca and Pax as protandrous. The corolla-tubes are 16-24 mni- long, so that only diurnal hawk-moths are able to suck all the nectar from the longest of them. Fig. 245. Primula farinosa, L. (after Herm. Muller). A. A short-styled flower from the Alps, seen from above. B. Do., partly dissected, and the limb of the corolla bent upwards. C. A long-styled flower, partly dissected (X 2J). D. Average width of the entrance of long-styled flowers from North Germany. E. Do. of short-styled flowers. F. Do. of long-styled Alpine flowers. G. Do. of short- styled Alpine flowers, a, anthers; st, stigma. I 74 ANGIOSPERMAE—DICOTYLEDONES Kerner, however, states that this species is heterostylous, and that the short- styled stocks flower before the long-styled ones. Autogamy by the fall of pollen is possible in the former. Visitors. — Schulz observed the diurnal hawk-moth Macroglossa stellatarum L. (proboscis 25-8 mm. long). 1822. P. Allionii Loisel. (?) (Schulz, ' Beilrage,' II, pp. 148-9, 223.) — Pax (Bot. Jahrb., Leipzig, x, 1888, p. 230) says that the plant observed by Schulz at San Martino Castrozza, and named as above, is probably P. tirolensis Schott, for P. Allionii Loisel. does not grow there. The flowers are heterostylous. Visitors. — Schulz observed Lepidoptera. 1823. P. Auricula L. (Sprengel, 'Entd. Geh.,' p. 102 ; Schulz, ' Beitrage,' II, p. 148; Kerner, 'Nat. Hist. Pi.,' Eng. Ed. i, II, pp. 396-7; Knuth, ' Bloemenbiol. | Bijdragen.') — The stocks of this species which bear long-styled flowers come into bloom earlier than those bearing short-styled ones. In the former autogamy takes place towards the end of anthesis, for the corolla falls off and the stigma is self- i pollinated by being drawn through the whorl of anthers. Visitors. — I observed the brimstone butterfly (Rhodocera rhamni Z.), skg., and Schulz also saw butterflies. 1824. P. glutinosa Wulf. (Kerner, op. cit.) — Autogamy is brought about in the long-styled flowers as in the last species. 1825. P. scotica Hook. ( = P. farinosa Z., according to the Index Kewensis). — This species bears homostylous butterfly (.?) flowers. The stigma and anthers are usually at the same level and close together, both on the Dovrefjeld (Lindman) and at Tromse (Warming). In rare cases the anthers are a little higher than the stigma. Automatic self-pollination is therefore unavoidable, and this is eflfective, for the setting of fruits has been observed, but only casual insect-visits (from Lepidoptera). Scott, on the contrary, describes the species as self-sterile. Visitors. — Vide supra. 1826. P. stricta Hornem. (Warming, * Bestovningsmaade,' p. 7, * Arkt. Vaxt, Biol.,' pp. 21-5.) — This species bears lepidopterid flowers. Warming examined it in Greenland, where he says stigma and anthers are at the same level, so that as the flowers are homogamous, automatic self-pollination is inevitable. In Norway the plant is feebly protandrous, and the stigma is situated at a variable height a little above the anthers. Short-styled flowers have not been noticed. Autogamy is thus rendered more difficult. On the Dovrefjeld only one form has been observed, in which the stigma is somewhat higher than the anthers. Scott describes the species- as heterostylous. 1827. P. sibirica Jacq. (Warming, 'Arkt. Vaxt. Biol.,' pp. 25-7.) — Thi species bears heterostylous or homostylous lepidopterid (?) flowers. Warming ob- served markedly heterostylous blossoms by the Altenfjord, and a homostylous one by the KSfjord, in which the stigma and anthers were at the same level, so that automatic self-pollination was inevitable. 1828. P. egaliksensis Wormsk. — Warming describes this species as homo- stylous. ^ J I PRIMULACEAE 75 1829. P. saccharata Mill. — Visitors. — Loew observed the bee Anthophora pilipes F. $, skg., in the Berlin Botanic Garden. 1830. P. sinensis Sabine. (Ljungstrom, Bot. Not., Lund, 1884, pp. 171-4.) — Ljungstrom observed cleistogamous flowers on plants of this species cultivated under glass. These possessed a bell-shaped calyx, and a short closed tubular corolla, with faint indications of lobes, and of a pale yellowish green colour. The anthers were very small, and also the pollen-grains, these being only 14 /a long, while those of the long- and short-styled chasmogamous flowers were respectively 32 /x and 24 /x in length. One plant was long-styled, with the style bent in the middle and enclosed in the corolla. In short-styled flowers the style was straight. Fruits and seeds were not observed. 544. Hottonia Boerh. Flowers heterostylous dimorphous, with concealed nectar, secreted at the base of the ovary and stored up in the corolla-tube. Sometimes cleistogamy. 1831. H. palustris L. (Darwin, ' Forms of Flowers,' pp. 50, 52, 252, 254 ; Sprengel, ' Entd. Geh.,' p. 103; John Scott, J. Linn. Soc, Bot., London, viii, 1865; Herm. Muller, ' Fertilisation,' pp. 386-9, ' Weit. Beob.,' Ill, p. 65 ; Knuth, ' Bloe- FiG. 246. Hottonia palustris, L. (after Herm. Muller). (i) Long-styled flower. (2) Stigmatic papillae of do. (3) Short-styled flower. (4) Stigmatic papillae of do., enlarged to same scale as (2). menbiol. Bijdragen ' ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 446-7.) — Sprengel discovered heterostyly in this species, about which he makes the following remarks (loc. cit.) : ' Some plants only bear flowers with stamens inside the corolla-tube but the style projecting from it, and others only flowers with the style shorter and the stamens longer than the tube. I do not believe that this is accidental, but an arrangement of Nature, though I am unable to explain its meaning.' The corolla-tube of the white or reddish flowers is 4-5 mm. long, and the shorter reproductive organs are placed in its opening, while the longer ones project 3-4 mm. from it. Insect visitors when probing for nectar touch the two kinds of organ with different parts of their bodies, and thus regularly eff"ect legitimate crossing. lat 1 76 ANGIOSPERMAE—DICOTYLEDONES Visitors which collect or devour pollen touch only the anthers and not the stigma in the short-styled flowers, though this may cause pollen to fall down on the latter, while when they push their heads into the long-styled flowers they touch the stigma and may bring about illegitimate union. John Scott and Hermann Miiller repeated on this species the crossing experi- ments carried out by Darwin on Primula, and they both came to the same conclusion as he did, i. e. that legitimate unions are most fertile. MuUer further found that autogamy and crosses between flowers on the same stock gave still worse results th; illegitimate unions, but that, on the contrary, illegitimate union between differeni stocks of long-styled flowers resulted in fertility as high as that produced by legitimat unions. O. Appel tells me in a letter that he found a number of plants living in com" paratively deep water in swampy ground near Schweinfurt which did not reach to the surface, but nevertheless had set normal fruits. In this case it is clear that pollination took place before the flowers opened, after which the petals expanded. These flowers were smaller and paler than normal ones. Visitors. — The following were observed by Herm. MuUer. — A. Diptera. {a) Empidae-. i. Empis chioptera Fall. 5, skg. ; 2. E, livida Z., freq. ; 3. E. pennipes Z., freq., skg.; 4. E. rustica Fall., skg. ; 5. E. vernalis Mg., freq. ((5) Muscidae : 6. Anthomyia sp., skg. ; 7. Aricia incana Wt'edem., skg. ; 8. Siphona geniculata Deg., skg. (c) Syrphidae : 9. Eristalis arbustorum L., not infrequent, skg. and po-dvg. ; 10. E. nemorum Z., do.; 11. Rhingia rostrataZ., freq., skg. B. Hymenoptera. Sphegidae\ 12. Pompilus viaticus Z., skg. The following were recorded by the observers, and for the localities stated. — MacLeod (Belgium), the honey-bee, an Eristalis, a butterfly (Pieris sp.), and a beetle. Knuth, the hover-fly Eristalis tenax Z., skg. and effecting legitimate crossing ; (between Plon and Eutin), the butterfly Anthocharis cardamines Z. $, skg., and 4 hover-flies, skg., and po-dvg. in short-styled flowers — i. Eristalis intricarius Z. ; 2. E. tenax Z.; 3. Rhingia rostrata Z. ; 4. Syrphus sp. 545. Cortusa L. 1832. C. Matthioli L. — Kerner describes this species as protogynous. The stigma matures in the bud, and projects from the pendulous flowers before they open. According to Scott this plant is undoubtedly self-sterile, but Treviranus states (Bot. Ztg., Leipzig, xxi, 1863) that other species of the genus are autogamous, the style bending back towards the anthers. 546. Dionysia. According to Kuhn (Bot. Ztg., Leipzig, xxv, 1867), species of this genus are dimorphous. • 547. Gregoria. 1833. G. vitaliana L. — Kuhn and Kirchner describe this species as hetero- stylous. PRIMULACEAE 77 548. Dodecatheon L. Undoubtedly pollen flowers with pollen guides. Kerner states that the same kind of autogamy takes place as in Soldanella (' Nat. Hist. PI.,' Eng. Ed. i, II, p. 333. Vide infra). 1834. D. Meadia L. (=D. frigidum Cham, et Schlecht., and D. integrifolium Michx.). (Loew, ' Bliitenbiol. Beitrage,' I, pp. 17-19.) — The flower mechanism of this North American species resembles that of Cyclamen {cf. p. 79). As the flowers wither they become erect and the anthers separate so that pollen can fall upon the stigma, allogamy being thus replaced by autogamy. K. Brandegee (Zoe, San Diego (Cal.), i, 1890, pp. 17-20) says that D. JefTreyi Moore, described by Loew (op. cit., p. 463), is a variety of this species. In D. frigidum Cham, et Schlecht. the filaments are so short that they are completely enclosed in the throat of the corolla, from which they project for about 3 mm. in the main type. This difference results in an important modification in the flower mechanism, for in the former case visitors cannot cling to the staminal cone. Visitors. — Loew saw a small bee (Andrena fulva Schr.) alight on the staminal cone and fly away again after a short lime without obtaining any booty. 549. Soldanella L. Bee-flowers, usually homogamous, rarely protogynous, sometimes with concealed nectar (S. pusilla Baumg., var. inclinata). This is secreted by a ring below the ovary, and stored in the base of the corolla-tube. 1835. S. alpina L. (Kerner, ' Schutzmittel d. Bl.,' p. 232, 'Nat. Hist. PI.,' Eng. Ed. I, II, p. 368; Ricca, Atti Soc. ital. sc. nat., Milano, xiv, 187 1 ; Herm. Miiller, ' Alpenblumen,' pp. 369-71 ; Schulz, 'Beitrage,' II, pp. 149-50.) — This species bears bee - flowers. The stigma projects a little from the violet corolla, so that it is first touched by humble-bee visitors, which consequently effect crossing. Miiller de- scribes the flowers as homo- gamous, Ricca and Kerner as protogynous. Should in- sect-visits fail, "Miiller says that automatic self-pollination may be effected by the fall of pollen in the vertical flowers, while Kerner states that it is brought about when the corolla drops off, for the stigma is then drawn through the anthers. i^Cf. Fig. 247.) Fig. 247. Soldanella alpina, L. (after Herm. Muller). A. Pisti! and half the calyx, seen from the side (x 3J). S. Partly dissected flower ( X 3J). C. Flower cut through immediately below the nectar- covers (as indicated hy ab m B), seen from below (X 7). co, corolla; _/?, filaments ; gr, style ; », nectary ; s, sepal ; sd, nectar-cover ; sk, nectar. 78 ANGIOSPERMAE—DICOTYLEDONES Visitors. — The following were recorded by the observers, and for the localities stated. — Herm, Miiller (Alps), 4 humble-bees, 4 Lepidoptera, and a Syrphid. Kemer (Alps), Apis and 4 humble-bees. MacLeod (Pyrenees), only a Muscid (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, p. 373). Fig. 248. Soldanella pusilla, Bautng. (after Herm. M&ller). A. Flower seen immediately from below (X 3). B. Do. in longitudinal section (X 3). C. Part of the same further enlarged (X 7). D. Flower cut through immediately below the nectar-covers and seen from below ( x 7). E. A stamen of .S". fninitna. a, anthers ; co, corolla ; _/f, filament ; gr^ style ; ov, ovary ; s, sepal ; sd, nectar-cover. 1836. S. pusilla Baumg. (Herm. Muller, ' Alpenblumen,' pp. 371-3; Schulz, 'Beitrage,' II, pp. 150-1.) — Hermann Muller says that this homogamous species occurs in the Alps in two varieties which diflfer both morphologically and oecolo- gically. The variety pendula bears bee -flowers, while in the variety inclinata (Fig. 249) the nectar is accessible to less intelligent short-tongued in- sects. In the former the bell is pendulous and relatively long and narrow, while in the latter it is wider and directed obliquely down- wards. In both varieties automatic self- pollination by fall of pollen is possible. Visitors. — The foUow- FiG. 249. Muller). A. from the side. Soldanella pusilla, Baumg., var. inclinata (after Herm. Entire plant, natural size. B. A flower, partly dissected ing were recorded by the observers stated.- PRIMULACEAE 79 Herm. Miiller (on pendula), a humble-bee and a beetle ; (on inclinaid) 3 INIuscids and a moth. Schulz, 20 bees (including Bombus alticola Krchb) and various flies and beetles. 1837. S. minima Hoppe. (Schulz, 'Beitrage/ II, p. 191.) — The conical flowers of this species are 8-15 mm. long, and project almost at right angles from the main axis, so that automatic self-pollination is rendered difficult in spite of the homogamy. Visitors. — Schulz saw 2 bees and 7 flies. / \e / / / ■^ B 550. Cyclamen L. Protandrous pollen flowers, from which visitors perhaps obtain sap by boring the delicate tissue of the corolla-tube. The anthers make up a sprinkling arrange- ment, as in Borago. Their lobes dehisce by terminal pores, and are produced into stiff appendages against which visitors strike. Automatic self-pollina- tion is ultimately ef- fected by strong down- ward inclination of the peduncle, bringing the stigma into the line of fall of the pollen {cf. Fig. 250). According to Hil- debrand (Ber. D. bot. Ges., Berlin, xv, 1897, pp. 292-8), the species of Cyclamen are at first entomophilous and afterwards anemophi- lous, as in the cases of Calluna vulgaris. Erica camea, and Bartsia alpina described by Kerner('Nat.Hist.Pl.,' Eng. Ed. I, II, p. 129). The pollen-grains are at first covered by sticky oil, but later on cease to be adhesive and become pulverulent. Although the anthers usually dehisce in the bud autogamy cannot take place, partly owing to the initial stickiness of the pollen and partly 0 Fig. 250. Cyclamen lali/olium, Sibth. et Sm. (from Kerner, after Ascher- son). A. Diagram of the parts of the flower at the beginning of anthesis. The direction in which the pollen falls is far removed from the stigma. B. Do. at time of complete development. By further bending of the peduncle the line of fall of the pollen is brought nearer the stigma. C. Do. at the end of anthesis. The stigma is now in the line of fall of the pollen, a, peduncle ; 6, cone of anthers : c, line of fall of the pollen ; d, e, direction of basal and terminal parts of the peduncle (and of the style). 8o ANGIOSPERMAE—DICOTYLEDONES because of the position of the stigma. In C. ibericum Goldte and C. Coum Mill. the dehisced pollen is held fast by a protective circlet above the stigma. Club- shaped hairs at the base of the ovary appear to serve as food for insects. 1838. C. europaeum L. (Kerner, 'Nat. Hist. PI./ Eng. Ed, i, II, pp. 379.) — On the first day of anthesis the peduncle of this species is bent almost at right angles. The angle subsequently increases about 10° a day, so that towards the end of anthesis the short downwardly bent terminal part of the peduncle and the! long upright basal part are nearly parallel. It follows that autogamy is at first impossible, but crossing can be brought about by insect visitors, for the stigma projects to some extent beyond the anthers. The bending of the peduncle at last renders automatic self-pollination possible by bringing the stigma into the line of fall of the pollen. Coulter observed cleistogamous flowers (Bot. Gaz., Chicago (III), viii, 1883, pp. 211-12). 1839. C. latifolium Sibth. et Sm. ( = C. persicum Mill.). (Ascherson, Ber. D. bot. Ges., Berlin, x, 1892, pp. 226-35.) — The flower mechanism of this species agrees entirely with that of C. europaeum. Darwin describes the flowers as self-sterile. Visitors. — Hildebrand observed numerous honey-bees in the Freiburg Botanic Garden, po-cltg. and apparently skg. ; also a small humble-bee, po-cltg., and Xylocopa violacea Z., as a casual visitor. 1840. C. hederaefolium Ait.(=:C. repandum Sibth. el Sm.). (Knuth,'Blutenbiol. Beob. a. d. Ins. Capri,' pp. 10-13.) — The flower mechanism of this species agrees with that of C. europaeum. The reflexed corolla-lobes surround the opening of the flower (5 mm. wide), from which the style with its small stigma projects 2-3 mm. The five stamens are enclosed in the almost hemispherical corolla- tube, and converge to form a cone which closely surrounds the base of the style. Visitors. — Hildebrand observed Apis and Bombus sp,, skg., in the Freiburg Botanic Garden. This conspicuous species is common below Monte St. Michele on the east coast of Capri, but I observed no visitors on its faintly fragrant flowers. 1841. C. ibericum Goldie.— Visitors. — Hildebrand observed Apis, po-cltg., in the Freiburg Botanic Garden. 1842. C. neapolitanum Tenore (Knuth, op. cit.). — The flower mechanism of this species is the same as that of C. europaeum. 551. Samolus L. 1843. S. Valerandi L. (MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 447; Schulz, 'Beitrage,' I, p. 89; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 341 ; Knuth, ' Bloemenbiol. Bijdragen.') — Plants of this species which I examined in Schleswig-Holstein agreed as to their flower mechanism with others examined by MacLeod in Belgium. The corolla-tube is only 1^ mm. deep and encloses the ovary, which bears a ring resembling a nectary in shape and position, but secreting no nectar. The anthers are at the same level in the corolla-tube as the stigma, which matures simultaneously. As they converge towards the latter and dehisce PRIMULACEAE 8i introrsely automatic self-pollination is inevitable. This is effective, for the flowers are completely fertile, although insect -visits are extremely rare. The throat of the corolla bears five white appendages, which perhaps enhance conspicuousness. Visitors. — I once observed a small hover-fly (Syritta pipiens Z.), po-dvg. Owing to the small distance between anthers and stigma it could effect cross- and self-pollination with equal facility. 552. Glanx L. VerhoeflF states that concealed nectar is secreted in very small quantities and stored in the bases of the small flowers, which are of a pale rose colour ^ 1844. G. maritima L. (Knuth, 'BI. u. Insekt. a. d. nordfr. Ins.,' p. 120; Francke, ' Beitrage zur Kennt. d. Bestaubungseinricht. d. Pfl.,' Halle, 1883.) — I find this species to be homogamous in Schleswig-Holstein. The anthers and stigma mature immediately after the small flowers have opened. As they are at the same level, and the pollen-covered surfaces of the anthers are turned towards the stigma, automatic self-pollination is inevitable. This is effective, for all the flowers without exception set fruits, although insect-visits are extremely few. Francke, however, describes the flowers as protandrous with anthers remote from the stigma, so that autogamy is impossible. He says nothing about the way in which pollination is effected. Visitors. — The following were recorded by the observers, and for the localities stated. — Knuth (Nordstrand, 31. 5. '93), a minute Muscid (Siphonella palposa Fall.) with its head deeply sunk in the flowers. Verhoeff (Norderney). — Diptera. {a) Empidae : I. Hilara quadrivittata Mg., skg. (d) Muscidae : all skg. : 2. Anthomyia sp. ; 3. Aricia incana Wiedem. : 4. Cynomyia mortuorum Z. 2 J ; 5. Lucilia caesar Z. ; 6. Onesia floralis R.-D. a ?. LXV. ORDER OLE ACE AE LINDL. Flowers entomophilous, attracting insects by the corolla, an odour which is often powerful, and aggregation into cymose inflorescences. Nectar secreted by the ovary, and concealed in a more or less elongated corolla -tube. Some species are anemophilous (Fraxinus excelsior). 553. Ligustrum L. Flowers homogamous, in crowded cymes; with concealed nectar secreted by the ovary. 1845. L- vulgare L. (Herm. MuUer, * Fertilisation,' pp. 393-4, ' Weit. Beob.,' Ill, pp. 62-3; Knuth, *B1, u. Insekt. a. d. nordfr. Ins.,' pp. 103, 163-4.) — Hermann ^ I was unable to detect free nectar in the flowers of plants from Kiel (June, 1892), Nordstrand (May, 1893), and Sylt (July, 1898). But when treated with orthonitrophenylpropionic acid they assumed a bright violet colour, especially in the central part of the perianth leaves where these abut upon the ovary. Sugar-containing tissue must therefore be present there. (C/. the note on Leucojum aestivum Z.) 82 ANGIOSPERMAE—DICOTYLEDONES Mailer describes the strongly odorous white flowers of this species as possessing a corolla-tube scarcely 3 mm. long and expanding above into a four- or rarely five-lobed limb. The bilobed stigma is situated in the entrance to the flower, while the two or rarely three stamens project freely from it. The anthers dehisce laterally, but so widely that their inner surfaces are entirely covered with pollen. The position of the anthers as regards the stigma is variable. Sometimes they diverge widely, so that an insect visitor usually touches an anther with one side of its body and the stigma with the other, thus eff"ecting crossing : sometimes they bend over the stigma, so that insect-visits can easily bring about autogamy, which can also readily take place automatically. Fig. 351. Ligtistrum vulgare, L. (after Herm. Mailer). (i) Flower seen obliqnely from above. (2) A flower less widely open, seen directly from above. (3) and (4) Flowers seen from the side after removal of half the corolla, (x 3J.) I Visitors. — Herm. Miiller (H. M.) in Westphalia and Thuringia (T.), and Buddeberg (Budd.) in Nassau, observed the following. — A. Coleoptera. (a) Cerambycidae: i. Cerambyx cerdo Z. (should be Scop.), often creeping in the flowers, but taking nothing from them (Budd.). {b) Cleridae: 2. Trichodes apiarius Z., burying its head among the flowers (Budd.). (r) Nitidulidae : 3. Cercus pedicularius Z., skg. (H. M.). {d) Scarabaetdae : 4. Cetonia aurata Z., gnawing the flowers (H, M., T., Budd.). B. Diptera. {a) Empidae : 5. Empis livida Z., freq., skg. (H.M.). (<5) Syrphidae: 6. Eristalis arbustorum Z., skg. (H. M., T.); 7. E. nemorum Z., do. (H. M.). C. Hjrmenoptera. Apidae: 8. Apis mellifica Z. 5, skg. (H. M., T.); 9. Heriades truncorum Z., do. (H. M.); 10. Nomada succincta Pz. 5, do. (H. M., T.). D. Lepidoptera. All skg. {a) Pyralidae : 1 1. Scoparia ambigualis Tr. (Budd.). (b) Rhopalocera : 12. Coenonympha arcania Z. (H. M., T.) ; 13. C. pamphilus Z. (H. M., T.) ; 14. Epinephele janira Z. (H. M., T.) ; 15. Melitaea athalia Esp. (H. M., T.); 16. Thecla pruni Z. (H. M., T., Budd.). \c) Sphtngidae: 17. Sesia asiliformis Rott. ? (H. M., T.). The following were recorded by the observers, and for the localities stated. — Knuth (Fohr), 6 hover-flies, 2 Lepidoptera, and 2 Muscids: (Riigen), the humble-bee Bombus terrester Z. 5> skg. Rossler (Wiesbaden), 3 Lepidoptera — I. Limenitis Camilla S.V.; 2. Doloploca punctulana S.V.; 3. Aedia funesta Esp. Schletterer (Tyrol), the bee Andrena carbonaria Z. MacLeod (Flanders), small flies and the beetle Meligethes (Bot. Jaarb. Dodonaea, Ghent, vi, 1894, p. 372). Loew (Berlin Botanic Garden), a Syrphid (Eristalis nemorum Z.) and a bee (Apis mellifica L. 5, skg.). 554. Phillyrea L. Kerner states that the species of this genus are protogynous. 1846. P. latifolia L. — Visitors. — Schletterer observed the carpenter-bee Xylocopa violacea Z. at Pola. OLE ACE AE 83 555. Syringa L. Flowers homogamous, rarely protandrous or protogynous; aggregated into large conspicuous inflorescences; with concealed nectar, secreted in the base of the corolla-tube by the ovary. 1847. S. vulgaris L. (Sprengel, *Entd. Geh./ pp. 47-8; Herm. Muller, 'Fertilisation,' pp. 392-3, *Weit. Beob.,' Ill, p. 62; Kirchner, 'Flora v. Stuttgart,' p. 537; Warnstorf, Schr. natw. Ver., Wemigerode, xi, 1896; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 103, 164.) — The flowers of this species, and also those of the two following ones, are bluish-lilac, rarely white in colour, fragrant, and aggregated into large conspicuous inflorescences. They are usually homogamous, more rarely protandrous or protogynous ac- cording to Batalin (Bot. Ztg., Leipzig, xxviii, 1870, pp. 54-5)- The corolla-tube is 8-10 mm. long and about 2 mm. in diameter. Its lower part is filled for 2-4 mm. by the nectar which the ovary secretes abundantly. The anthers are situated in the entrance of the flower at a higher level than the stigma, so that the proboscis of an insect-visitor will first touch the former and then the latter. This does not result, however, in self-pollination of the homogamous flowers, the reason being that pollen dops not adhere to the proboscis when it is pushed in, but only during withdrawal, after it has been moistened with nectar. Insects which suck nectar will therefore regularly eff"ect crossing, but those which devour pollen always bring about autogamy. Should insect-visits fail, the latter takes place automatically by fall of pollen upon the stigma. Kemer says that during the early days of anthesis autogamy is rendered difficult because the anthers are turned outwards, but when they shrivel later on it can easily take place. Warnstorf describes the pollen-grains as yellow in colour, more or less ellip- soidal, longitudinally fiu-rowed, closely beset with a network of tubercles, up to 50 /x long and 30 yx broad. Visitors. — Herm. Miiller gives the following list for Westphalia. — A. Diptera. {a) Bombyliidae: i. Bombylius major Z., skg. {b) Syrphidae: 2. Eristalis arbustorum Z., po-dvg. ; 3. E. sepulcralis Z., po-dvg. ; 4. Rhingia rostrata Z., extremely frequent, skg. and po-dvg. ; 5. Syritta pipiens Z., po-dvg. ; 6. Xylota segnis Z., vainly trying to suck, and then po-dvg. B. Hymenoptera. {a) Apidae : 7. Anthophora pilipes F. $ and S, freq., skg. ; 8, Apis mellifica Z. 5, numerous, skg. and po-dvg. ; it pauses in its flight, without settling, before diff"erent flowers, until one in a suitable condition is found. 9. Bombus hortorum Z. 5 and 5, very numerous, skg. ; 10. B. lapidarius Z. '^ and 5, numerous, skg.; 11. B. terrester Z. 5 ^^^ ?> skg.; 12. Eucera longicornis Z. J, do. ; 13. Halictus albipes F. j, do.; 14. Osmia rufa Z. Fig. 252. Syringa vulgaris, L. (after Herm. Muller). (I) Flower after removal of half the corolla. (a) Flower seen from above. (3) Entrance of a flower immediately after opening. (4) Do., rather later, a, anthers; _fi, fila- ments ; ov, ovary ; /, petals ; po, pollen j s, sepals ; si, stigma. 84 ANGIOSPERMAE—DICOTYLEDONES 5, freq., skg. {b) Vespidae: 15. Odynerus sp., vainly searching for nectar and going away at once. C. Lepidoptera. {a) Rhopalocera: 16. Anthocharis cardamines Z. ; 17. Papilio machaon Z. ; 18. P. podalirius Z. ; 19. Pieris brassicae Z., freq. ; 20. P. napi Z., freq.; 21. P. rapae Z,, freq. ; 22. Vanessa io Z., skg. ; 23. V. urticae Z., freq. {b) Sphiftgidae: 24. Macroglossa fuciformis Z., in large numbers, skg.; 25. M. stellatarum Z., do. The following were recorded by the observers, and for the localities stated. — Knuth (North Frisian Islands and Kiel), the honey-bee, 2 humble-bees, 3 butter- flies (Pieris sp.), and 4 hover-flies. C. Schroder (Rendsburg), 3 species of hawk-moth, freq. (i. Sphinx ligustri Z. ; 2. Deilephila elpenor Z. ; 3. D. porcellus Z.), and numerous Noctuids : all skg. Alfken (Bremen). — A. Coleoptera. Elateridae : I. Corymbites pectinicornis Z. B. Hymenoptera. {a) Api'dae: 2. Apis mellifica Z. ; 3. Bombus hortorum Z. 5 ; 4. B. sylvarum Z. 5 ; 5. B. terrester Z. 5 ; 6. Po- dalirius retusus Z. 5 ; 7. Psithyrus barbutellus ^. $ ; 8. P. vestalis Fourcr. $. (3) Tenthredinidae : 9. Trichiosoma betuleti Klg. {c) Vespidae: 10. Vespa germanica F. 5. Schenck (Nassau), the parasitic bee Melecta armata Pz. Friese (Strasburg), the carpenter-bee Xylocopa violacea Z. 5 and J, freq. 1848. S. chinensis Willd. (Kirchner, ' Flora v. Stuttgart,' p. 538.) — Kirchner states that this species, like S. vulgaris, is homogamous or feebly protandrous or protogynous, and that its flower mechanism is similar. It is never fertile in Germany. Visitors. — F. F. Kohl observed the true wasp Leionotus nigripes H.-Sch. in the fl Tyrol. 1849. S. persica L. (Herm. Muller, 'Weit. Beob.,' Ill, p. 62; Kirchner, * Flora v. Stuttgart,' p. 538 ; Knuth, ' Bloemenbiol. Bijdragen.') — The flowers of this species are gynomonoecious. Hermann Muller observed hermaphrodite and female flowers in the same inflorescence. The former are more numerous and of greater size, homogamous, with the stigma in the middle of the corolla-tube and the anthers at its entrance. The anthers of the smaller female flowers are reduced, and generally situated at the same level as the stigma, though sometimes they may be either higher or lower than this, Some of these flowers possess only three corolla-lobes, and others but a single stamen. In addition to the large hermaphrodite flowers Kirchner noticed here and there smaller ones with non-dehiscing anthers. Visitors. — Knuth observed the butterfly Pieris napi Z., skg. ; Herm. Mailer the bee Osmia rufa Z. $, do. ; and Loew (Berlin Botanic Garden), the humble-bee Bombus hortorum Z. 5, do. 556. Forsythia Vahl. Flowers yellow, homogamous, appearing before the leaves; with concealed nectar. Darwin (' Forms of Flowers ') describes the species as heterostylous, but Hildebrand states (Bot. Ztg., Leipzig, lii, 1894) that our gardens contain only the short-styled form of F. suspensa and the long-styled one of F. viridissima. The seeds obtained from the former always grow up into the hybrid F. intermedia (=F. suspensa x F. viridissima). 1850. F. viridissima Lindl. (Herm. Muller, ' Weit. Beob.,' Ill, p. 63.)— The flower mechanism of this species agrees essentially with that of Ligustrum. The OLE ACE AE 8$' style usually projects beyond the stamens by about the length of the latter, so that insect visitors must first touch the stigma and then the simultaneously mature anthers, thus eifecting cross-poUination. In some flowers, however, the style is so short that the stigma is touched by the anthers, and self-pollination consequently takes place. Visitors. — The following were recorded by the observers, and for the localities stated. — Herm, Miiller (Lippstadt), 2 bees (Andrena fulva Ckr. $, skg., and Bombus pratorum L. 5) and the beetle Meligethes (penetrating deeply into the flowers). Alfken (Bremen), the honey-bee, not infrequent. 1851. F. suspensa Vahl. (Knuth, ' Bloemenbiol. Bijdragen.')— Visitors. — I observed the honey-bee, skg. 557. Fraxinus Toum. Flowers polygamous. Petals two, four, or absent. Partly anemophilous, partly entomophilous. 1852. F. excelsior L. (Kirchner, ' Flora v. Stuttgart,' pp. 538-9 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 381; Schulz, 'Beitrage'; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 312 ; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 104.) — The blossoms of this species are pollinated by the wind, and develop before the leaves. Kirchner states that the female flowers possess stamens, but these soon drop off, and their anthers neither dehisce nor contain mature pollen-grains. Many of the hermaphrodite flowers are infertile. Schulz describes this species as andromonoecious, gynodioecious, gynomonoe- cious, and also trioecious. In nearly all cases hermaphrodite flowers are present, so that in Central Germany the sexes are distributed in at least ten different ways. Kerner asserts that this species is protogynous. The large fleshy stigma matures 2-4 days before the anthers, which are borne on short thick filaments and produce mealy pollen that is scattered by the wind. 1853. F. Omus L. — The flowers of this species smell like hawthorn, and Kerner states that some of them are pseudo-hermaphrodite. Visitors. — Delpino saw the beetle Melolontha farinosa (no doubt = Hoplia argentea Poda) in large numbers (' Ult. oss.,' Atti Soc. ital. sc. nat., Milano, xvi, 1873). 558. Jasminum L. Treviranus states (Bot. Ztg., Leipzig, xxi, 1863) that autogamy takes place by bending back of the style to the anthers. Kuhn says that some of the species are dimorphous (Bot. Ztg., Leipzig, xxv, 1867). 1854. J. humile L. (=J. revolutum Sivis). (Pirotta, Rend. 1st. Lomb., Milano, Ser. 2, xviii, 1885.) — Pirotta describes this species as heterostylous dimorphous. Both forms are protandrous in the Rome Botanic Garden. Visitors. — Small beetles and flies, together with bees and other Hymenoptera, have been observed. 86 ANGIOSPERMAE—DICOTYLEDONES 1855. J. Sambae Ait. — This species is especially fragrant after sunset. 1856. J. noctiflorum Afzel. — Visitors. — These appear to be nocturnal Lepidoptera. 559. Nyctanthes L. 1857. N. Arbor-tristis L. — This species bears large fragrant flowers with long corolla-tubes, and most of them are shed at sunrise. Visitors. — These appear to be nocturnal Lepidoptera. 560. Monodora Dun. 1858. M. longiflora Eng., and 1859. M. pubens A. Gray. — The large fragrant flowers of these species are of a bright-yellow colour and possess long corolla-tubes. They open in the evening. Visitors. — These are apparently nocturnal Lepidoptera. 561. Schrebera Roxb. The flowers are particularly fragrant in the evening. Visitors. — ^Judging from the above these would appear to be nocturnal Lepi- doptera. LXVL ORDER APOCFNACEAE R.BR. Literature. — K. Schumann, ' Apocynaceae,' in Engler and Prantl's *D. nat. Pflanzenfam.', IV, 2, pp. 115-17. 562. Vinca L. Flowers herkogamous, with concealed nectar secreted at the base of the ovary. i860. V. minor L. (Sprengel, 'Entd. Geh.,' pp. 135-7; Herm. Miiller, ' Fertilisation,' pp. 394-6, ' Weit. Beob.,' Ill, p. 62 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 384-5 ; Kirchner, ' Flora v. Stuttgart,' p. 544 ; Baillon, Bull. soc. linn., Paris, i, 1882, pp. 323-5; Darwin, Gard. Chron., London, 1861, pp. 552, 831; Crocker, Bull. R. Bot. Gard, Kew, 1861, Gard. Chron., London, i86i, p. 669; F. A. P., op. cit., p. 736 ; Delpino, ' Sugli appar. d. fecondaz. nelle piante autocarp.,' pp. 15-17 ; Hildebrand, Bot. Ztg., Leipzig, xxv, 1867, p. 274 ; Humphrey, Bot. Gaz., Chicago (111.), x, 1885, p. 296.) — The flower mechanism of this species was long since described by Sprengel, but he supposed it to be adapted for self- pollination. Darwin and Delpino have both given correct independent accounts of it. — Nectar is secreted by two yellow glands near the ovary, and stored up in the corolla-tube (11 mm. long), the entrance of which is lined by hairs serving as a pro- tection against rain. About the middle of this tube the style thickens conically and terminates in a short cylindrical horizontal plate, the edge of which functions as a stigma and is covered with a sticky secretion. The plate bears a tuft of hairs, which takes up the pollen as it is shed from the anthers. The filaments spring from the middle of the corolla-tube, are bent in a knee-like fashion, and beset with hairs internally. The anthers are situated immediately above the stigmatic disk, and I APOCYNACEAE 87 dehisce introrsely. Their margins are hairy, so that the pollen can only fall upon the terminal brush of the disk. Nectar-seeking insects can insert their heads for several millimetres into the corolla tube, as far as the brush, so that a proboscis 8 mm. long is able to reach the nectar. When this is inserted it gets covered with viscid matter, which takes up pollen on withdrawal, and can therefore effect crossing in the next flower visited. Auto- matic self-pollination is excluded. Visitors, — Herm. MuUer gives the following list. — A. Diptera. Bombyliidae : i . Bombylius discolor Mih., very common, skg. legitimately ; 2. B. major Z., do. B. Hymenoptera. Apidae : 3. Anthophora pilipes F. 5 and S, very common, skg. ; 4. Apis mellifica Z. 5. tolerably freq., taking all the nectar from the smaller flowers, and part of it from the larger ones; 5. Bombus agrorum F. {, very common, skg.; 6. B. hortorum Z., do. ; 7. B. hypnorum Z. $, one, skg. ; 8. B. lapidarius Z. 5, very common, skg. ; 9. B. pratorum Z. % do. (H. M. ; Borgstette, Tecklenburg) ; 10. B. terrester Z. $, skg. ; 1 1 . B. vestalis Fourcr. 5, one, skg. ; 12. Osmia fusca Chr. 5, persistently skg.; 13. O. rufa Z. S, skg. C. Thysanoptera. 14. Thrips, freq. The following were recorded by the observers, and for the localities stated. — Fig. 253. Vinca minora L. (after Herm. Miiller). Flower after removal of half the corolla, a, ovary ; i, yellow nectaries ; c, style ; rf, place where a filament diverges from the corolla, visible externally as a depression; de^ filament with its inward knee-like bend; ef, introrse anther; g, thickening of the style; A, disk- like process of the style, covered all round with sticky secretion, and with a stig^atic lower edge ; ky brush of hairs upon the stigmatic disk, which takes up the pollen as it is shed. Sprengel, only Thrips. Knuth (Kiel churchyard, 26. 4. '96), the humble-bee Bombus hortorum Z. 5, occasional, skg., visiting several flowers in succession. Alfken (Bremen), 2 bees — i. Osmia rufa Z. 5 and $; 2. Podalirius acervorum Z. S. Schletterer (Pola), the bee Andrena deceptoria Schmiedekn. 1861. V. major L. (Sprengel, ' Entd. Geh.,' pp. 136-7 ; Darwin, Gard. Chron., London, 1861, p. 552; Herm. Muller, * Fertilisation,' p. 396; Knuth, ' Bloemenbiol. Bijdragen' ; Baillon, Bull. soc. linn., Paris, i, 1882.) — The flower mechanism of this species agrees with that of V. minor. The corolla-tube is 15-16 mm. long, and a proboscis of 11 mm. can secure all the nectar. The flowers are self-sterile. Darwin was able to cause the production of good fruits by effecting artificial pollination with a small brush. Baillon gives a detailed account of the flower mechanism. Visitors. — The following were recorded by the observers, and for the localities stated. — Knuth, the humble-bee Bombus hortorum Z. 5, skg., repeatedly. Herm. Muller, the humble-bee Bombus agrorum F. 5, skg. numerous flowers. Schletterer (Pola), an Ichneumonid (Bassus laetatorius F^ and 6 bees — i. Bombus argillaceus Scop., skg. ; 2. B. terrester Z. ; 3. Eucera clypeata Er. ; 4. E. longicornis Z. ; 5. Poda- lirius acervorum Z. ; 6. P. crinipes Sm. 1862. V. rosea L. (=Lochnera rosea Reichb.). — The flower mechanism of this species is the same as that of V. minor. 1863. V. herbacea Waldst. et Kit. — The flower mechanism of this species is the same as that of V. minor. 88_ ANGIOSPERMAE—DICOTYLEDONES 563. Trachelospermiim L. 1864. T. jasminoides Lem. — Hildebrand states that the flower mechanism of this species is the same as that of Vinca. 564. Tabemaemontana Plum. 1865. T. echinata Aubl. — Fritz Miiller says that this species is only fertile with the pollen from other stocks (Bot. Ztg., Leipzig, xxviii, 1870, p. 274). 565. Apocynum L. Flowers homogamous, with concealed nectar, secreted and stored in their bases. 1866. A. androsaemifolium L. (Ludwig, Bot. Centralbl., Cassel, viii, 1881, pp. 184-5.) — Ludwig says that this species bears campanulate whitish flowers with internal red streaks serving as nectar-guides, and five basal nectaries of which the secretion possesses an unpleasant sweetish odour. The short filaments are beset with hairs playing the part of nectar-covers. The five anthers make up a cone surrounding the capitate end of the style. This is divided by a ring into upper and lower parts, the latter serving as a stigma. The inner sides of the stamens, somewhat above the centre of their length, are fused with this ring, so that a chamber is formed into which the pollen falls without touching the stigma. The backs of the anthers are thick angular woody plates, which prevent insects from gnawing away the upper part of the stamens and style so as to make a more convenient way to the nectar. The chinks between the anthers narrow above, and serve as clips to hold fast unbidden guests. The actual pollinators (bees, and the larger hover-flies and Muscids) after sucking nectar are obliged to withdraw their proboscis between the anthers, i.e. through these clips, and it can only be freed by the exercise of considerable force. During this withdrawal the proboscis passes over the stigma, and its sticky upper edge through the pollen-chamber, from which it takes up some of the adhesive granular pollen, to be transferred to the next flower visited. The smaller and weaker insects, which are unable to penetrate the pollen-chamber and are therefore useless guests, remain held fast by the clips to perish miserably. Among these Ludwig observed numerous Muscids (Spilogaster carbonella Zeti., Scatophaga merdaria F., Anthomyia pluvialis Z.), sometimes small Hymenoptera, and occasionally Lepi- doptera. The presence of numerous dead flies (and proboscides and limbs of these) in the flowers shows that there must be a large number of these unskilled visitors. Visitors. — Loew observed the following in the Berlin Botanic Garden. — A. Coleoptera. {a) Cocdnellidae : i. Coccinella quattuordecimpunctata L., resting in the flowers, {b) Nitidulidae : 2. Meligethes sp., nect-lkg. in the bases of the flowers, (c) Ptinidae : 3. Anobium striatum OL, in the bases of the flowers. B. Diptera. {a) Muscidae : 4. Anthomyia sp., caught by the proboscis in the flowers ; 5. Onesia floralis R. D., do. ((5) Syrphidae : 6. IMelanostoma mellina Z., caught by the proboscis in the flowers ; 7. Platycheirus scutatus Mg., do. ; 8. Syritta pipiens, Z., do. 1867. A. cannabinum L. (= A. hypericifolium Ait^. (Ludwig, op. cit.) — Ludwig describes this species as bearing much smaller, more inconspicuous, greenish or yellowish-white flowers, devoid of nectar-guides, and possessing a still more APOCYNACEAE 89 disagreeable odour. In other respects their mechanism agrees with that of A. andro- saemifolium. In correlation with the duller colouring we find that the only visitors are flies, among which large numbers of the smaller Syrphids and Muscids are im- prisoned by the clips. Ludwig (Kosmos, Stuttgart, viii, 1881) observed that 56 flowers caught and killed 88 small Muscids and Syrphids between early morning and 3 p.m. Visitors. — Vide supra. 1868. A. venetum L. — This species is doubtfully arachnophilous {cf. Vince- toxicum officinale, p. 90). 566. Lyonsia R. Br. According to Loew (Bot. Centralbl., Cassel, xxviii, 1886), the flower mechanism resembles that of Apocynum androsaemifolium. Schumann (op. cit.) noticed that flies were killed by the flowers of species of this genus. 567. Nerium L. Homogamous Lepidopterid flowers. 1869. N. odorum Ait. (Ludwig, Bot. Centralbl., Cassel, viii, i88r, pp. 185-8.) — The large fragrant flowers of this species possess a large funnel-shaped corolla, which becomes rotate above, and is provided with an incised corona. There are nectar-guides in the form of dark-red streaks converging to the nectar-containing "base of the flower. As in Apocynum the corolla-tube encloses a cone of anthers covered externally by woody plates, and fused internally with the dilated end of the «tyle to form a pollen-chamber, beneath which is the stigmatic surface. The anther- plates are produced into points below, and covered with hairs dorsally. Each stamen is drawn out into a long terminal appendage, which is filiform at its base and then becomes broader and feather-like. These five appendages are twisted together into a loose, woolly, whitish ball, 8-9 mm. long and 4 mm. broad, which (with the corona) blocks the entrance of the flower in such a way that only long-tongued Lepidoptera are able to penetrate to the nectar. Within the flowers Lepidoptera have to overcome the same difficulties as those presented by Apocynum to pollinating agents. Their proboscis can only reach to the base of the flower (about 10 mm. deep) by being inserted into the narrow glabrous fissures between the stamens, and has to be withdrawn between the anthers, through a cleft which narrows above. In the latter operation the stigma is first touched, and gets pollinated if another flower has previously been visited, after which the proboscis is smeared with the viscid secretion of the upper edge of the stigma, and takes up fresh clumps of pollen from the pollen-chamber. All visitors do not possess the necessary strength and endurance for this, so that here again unbidden guests are caught and killed. The observation of two cases of the kind first called the attention of Ludwig to the mechanism of oleander flowers. Visitors. — The larger Lepidoptera, especially the hawk-moth Sphinx nerii L. 1870. N. Oleander L. ; 1871. N. cupreum L. ; 1872. N. Grangeanum ; and 1873. N. Ricciardianum. — Ludwig (op. cit.) says that these species possess the same flower mechanism as N. odorum. 90 ANGIOSPERMAE—DICOTYLEDONES LXVIL ORDER ASCLEPIADEAE R.BR. In the sub-order Cynanchoideae the five filaments are broadened, generally fused into a tube, and provided with external appendages which make up a corona ; anthers usually with terminal membranous appendages; pollen aggregated into- poUinia, attached in pairs to the clip-glands of the large capitate stigma. The clips grasp the legs of insect-visitors when the nectar-secreting spots are on the same radii as the stamens (Asclepias), or the proboscis if these spots alternate with the stamens (Vincetoxicum, Stapelia, Bucerosia, Araujia). The clips are thus drawn out of their recesses by the legs or proboscis of visitors, and transferred to other flowers. (Pinch-trap flowers.) The extremely specialized flower mechanisms are adapted to insect visitors in a very perfect manner, so that a comparison may be made with orchids, though in this case there is nothing like the same variety. According to K. Schumann (' Asclepiadaceae,' in Engler and Prantl's ' D. nat. Pflanzenfam.,' IV, 2), the flower mechanism of the sub-order Periplocoideae exhibits an undoubted analogy to that of the Ophryoideae. 568. Vincetoxicum Rupp. Yellowish-white pinch-trap flowers, arranged in axillary stalked umbels, and pollinated by means of the proboscis of insect visitors. 1874. V. officinale Moench (= Asclepias Vincetoxicum Z., and Cynanchum Vincetoxicum Pers.). (Sprengel, 'Entd. Geh.,' pp. 139-50; Delpino, 'Ult. oss.,*^ pp. 224-8; Hildebrand, Bot. Ztg., Leipzig, xxviii, 1870, pp. 604-5 '> Herm. Mtiller, 'Alpenblumen,' pp. 350-2; Kirchner, 'Flora v. Stuttgart,' p. 546.) — The flowers of this species smell of honey. The ovaries are surrounded by a fleshy column formed by fusion of the stamens, and covered by a fleshy disk, under which are five entrances to the stigmas. The staminal column bears the five anthers at its end, and also, externally, five appendages (cuculli) fused together to form a domed corona. The anthers are closely apposed to the terminal knob of the style, and each of them contains a pair of plate-like poUinia lodged in loculi opening on the side turned inwards. The connective is produced into a triangular membranous appendage which is closely applied to the top of the stylar knob. Each side of the anther is continued into a leaf-like wing, narrowing gradually above and vertical to the column of filaments. The adjoining wings of every two anthers bound between them a narrow slit that widens below. These slits open internally into a stigmatic chamber, which is partly bounded by the stigmatic surface on the under-side of the terminal expansion of the style. Lying in the upper part of each slit, and visible externally, is a dark, bilaterally symmetrical shining body (corpusculum), consisting of a hard, thin, homy plate. Its sides are bent forwards for their whole length so that their edges lie close together, and in the middle of its lower border there is a wedge-shaped slit. Two poUinia, lying in the adjacent loculi of two different anthers, are attached by bands to this 'clip.' If now a fly tries to suck the nectar contained in one of the coronal pits, situated immediately below a clip, its extended proboscis, beset with erect bristles, will be guided upwards in the slit between the adjacent anther-wings until it I ASCLEPIADEAE 9r inevitably held fast in the clip. The visitor will then draw back its proboscis with a jerk, pulling away the clip with the two connected poUinia, and carrying them oiF. When first extracted from their loculi the pollinia are wide apart, but the bands connecting them with the clip twist inwards as they dry, bringing the pollinia so close together that they can easily be introduced into a slit. Should the insect now visit another flower the pollinia are readily pushed into one of the slits, guided by which they will slip into the stigmatic chamber, there to effect crossing, for when the insect draws back its proboscis they are torn away from the bands connecting them with the clip. At the same time a new clip Fig. 254. Vincetoxicunt offidnak, Moench {lih^r iierca. 'iAxAle.r). A. Flower after removal of the five petals (X 7). B. Do. with calyx also removed, seen directly from above (x 14). C. The dilated end of the style, surrounded by the anthers. The pollinia lying hidden in the anthers, and the bands connecting them with the clips, are indicated by dotted lines. D. Inner side of a clip with attached pollinia ( X 80X E. Outer side of do. a, capitate end of the style ; b, membranous process of the connective, lying upon a ; c, outer side of loculns ; d, wing-like lateral margin of anther, which, with the corresponding wing of the adjacent anther, bounds the slit x that widens below ; «, nectar pit ; _f, clip, to which two pollinia {h) are attached by bands {g) ; /, nectar-secreting coronal appendages (cuculli). with its pollinia will be attached to the proboscis. It is only to the proboscis bristles of Muscids that the clips regularly get fixed. Other visitors (Empids, Syrphids, wasps, &c.) lack these bristles, and it is exceptional for an insect of the kind to carry off a clip on the end of its proboscis. F. Heim (Bull. soc. linn., Paris, ii, 1893) says that this species is pollinated by large Diptera, which usually do not succeed in getting nectar. Small flies are also found in the flowers, and these remain sticking in the clips, thus preventing the pollinia from being used for crossing. This is a case of insect-visits being not merely useless, but harmful. Heim believes that spiders protect the flowers against such unwelcome guests, and speaks of this as a case of * arachnophily. The same remark applies to Apocynum venetum L. Visitors. — Vide supra. The following were recorded by the observers and for the localities stated. — Sprengel, flies with clips attached to their proboscis. Herm. IMiiller (Alps), 12 Muscids, mostly with pollinia attached to their proboscis bristles: also, as 92 ANGIOSPERMAE—DICOTYLEDONES unbidden guests, an Empid, a hover-fly, 2 bees, a fossorial wasp, a true wasp, 2 Lepidoptera, and 4 beetles. MacLeod (Pyrenees), 4 short-tongued Hymenoptera, 3 beetles, and 3 Muscids : none of these bore pollinia (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, p. 344). Fig. 255. Asclepias syriaca, L. (after Herm. Mtiller). (i) Flower after removal of sepals and petals, seen from above (x ^i). (2) Do., from the side. (3) Do., after removal of the nectar-secreting organs (cucuUi) (x 7). (4) Do., after removal of a stamen. (5^ The detached stamen, seen from outside. (6) Inner side of do. (7) Nectar-secreting organ (cucuUus) ( x 3 J). (8) Do., in longitudinal section, to show the conical process apposed to an anther. (9) Freshly extracted pollinia, seen from the outside (X 7). (10) Do., when the torsion of the bands is half complete. (11) Do., when the torsion is complete. (12) Longitudinal section of flower, after removal of sepals, petals, and cuculli. a, cucnllns; by conical process of do. ; c, membranous process of connective ; d, outer side of locnius containing a pollinium ; e, lateral wing of an anther, which with the corresponding wing of the adjacent anther bounds a slit (y^, into which first the foot of an insect and then a pollinium is introduced; g, clip of the upper end of a slit, united by bands (h) to two pollinia (»"), from the adjacent loculi of different anthers ; k, empty loculus of anther ; /, connective ; tn, cylinder surrounding the ovary and bearing the cncnlli and stamens ; m, place of attachment of a cacullus ; o, stigmatic chamber ; p, fle^y stigmatic disk ; g, ovary. ASCLEPIADEAE 93 1875. V. medium Decne. (=V. latifolium C. Koch). — Visitors. — Plateau saw the hover-fly Melanostoma mellina L. in the Ghent Botanic Garden. 1876. V. purptirascens C. Morr. et Decne. — Visitors. — Plateau saw the house-fly Musca domestica Z. in the Ghent Botanic Garden. 569. Asclepias L. Pinch-trap flowers. Pollination eff"ected by the legs of insects. 1877. A. syriaca L. (=A. Cornuti Dectie.). (Delpino, ' Sugli appar. d. fecondaz. nelle piante autocarp.,' pp. 6-15; Hildebrand, Bot. Ztg., Leipzig, xxiv, 1866, p. 376, XXV, 1867, pp. 265, 273, 281 ; J. P. Mansel Weale, J. Linn. Soc, Bot., London, xiii, 1873, pp. 48-58 ; Herm. Miiller, ' Fertilisation,' pp. 396-400, ' Weit. Beob.,' Ill, p. 61 ; T. H. Corry, Trans. Linn. Soc, Bot., London, Ser. 2, ii, 1884, pp. 173-207, Proc. Phil. Soc, Cambridge, iv, 1883, pp. 5-6; Stadler, 'Beilrage.') — Hildebrand has given the most exhaustive account of the way in which this species is pollinated by insects, while Hermann Miiller was the first to publish drawings of the flower mechanism (Fig. 255), which agrees essentially wath that of Vincetoxicum officinale. Fig. 256. Asclepias syriaca, Decne. (from K. Schumann, after Payer). A. Flower seen from the side : ca, calyx ; co, corolla. B. Do., after removal of calyx and corolla, visited by a wasp, to the feet of which some pollinia are attached. C. Longitudinal section of flower : a, corolla ; anth, anthers ; /r, ovary ; na, stigmatic disk ; st, stamens. But while the latter is a pinch-trap flower adapted to nectar-seeking flies, to the proboscis bristles of which its minute clips become attached, Asclepias syriaca bears flowers of a kind adapted to bees, the claws of which become entangled in the clips and carry off" the pollinia to be introduced into the stigmatic chambers of other blossoms. As before, an odour of honey is exhaled. The petaloid appendages (cucuUi) of the anthers are in the form of five fleshy nectar-pockets, which alternate with the clips. From the bottom of each of these arises a curved horn-shaped process that bends inwards over the stigmatic disk. An insect searching for nectar slips about on the smooth flowers which make up the umbel until one of its feet gets a firm hold in the lower part of a slit. When it wishes to go on, and draws up the leg, the claws are guided upwards in the slit so that the clip becomes attached to the foot. During subsequent movements the 94 ANGIOSPERMAE—DICOTYLEDONES pollinia are introduced into one of the slits of another flower, and effect cross- pollination, while at the same time another clip affixes itself. The development of the pollinia was investigated by Corry. He also found that flowers are infertile not only with their own pollen, but also with that derived from plants raised vegetatively from the same stock. Pollination is fully eflfective only when it takes place between flowers belonging to plants grown from the seeds of different stocks. Stadler worked out the histological details of the secretion of nectar, and found that this is produced not only within the petaloid cucuUi, but also by internal nectaries on the inner wall of the stigmatic chamber. The approximated lower edges of the slits serve as nectar-covers for the latter. Visitors. — Sprengel observed a fly with clips attached to one of its legs. Herm. Miiller (' Fertilisation,' p. 399) gives the following list of insects observed by himself (H. M.) in Thuringia, Buddeberg (Budd.) in Nassau, Hildebrand (H.) at Freiburg, and Delpino (D.) at Florence, to which are added some others chiefly noticed by him in his garden at Lippstadt (op. cit., p. 400, ' Weit. Beob.,' Ill, p. 61). Those with clips attached to their claws are indicated by an asterisk (*). — A. Diptera. {a) Empidae: i. Empis livida Z., skg., drawing out the pollinia. (<5) Muscidae : 2. Lucilia sp., do. (H. M., Westphalia and T.) ; 3. Ocyptera brassicaria F. (H.). (f) Syrphidae: 4,* Eristalis arbustorumZ.(H. M., T.); 5.* E. nemorumZ. (H. M., T.); 6.* E. tenax Z. (H. M., T.); 7. Melithreptus scriptus Z., skg., without putting its feet in the slits (H. M., T.); 8. M. taeniatus Mg., do. (H. M., T.). B. Hymenoptera. (a) Apidae: 9.* Apis mellifica Z. 5 (H. M., T.; D.); 10. Bombus agrorum F. j, freq., skg. and pollinating (H. M., Wiirzburg); 11.* B. hypnorum Z. 5 (Budd.) ; 1 2.* B. italicus Z. (D.) ; 1 3.* B. terrester Z. 5 and $ (Budd.) ; 14.* Cpelioxys conoidea III. $ and $, freq., skg. and pollinating (H. M.) ; 15.* C. sp. 5 and j (Budd.); 16.* Halictus cylindricus F. S (Budd.); 17.* H. quadricinctus F. 5 (Budd.); 18.* H. scabiosae Rossi 5 (Budd.); 19. Several small sps. of HaHctus, which never put their feet in the slits (H. M.) ; 20.* Stelis aterrima Pz. 5 (Budd.). (V) Formicidae: 21. Different sps., caught in the slits (H. M., T.); 22. Myrmica levinodis Nyl. 5, do. (H. M.). (f) Sphegidae : 23.* Ammophila sabulosa Z. 5 (Budd.) ; 24.* Scolia hirta Schr. (D.); 25.* S. flavifrons F. (D.); 26.* S. quadripunctata F. 5 (Budd.); 27.* Psammophilaaffinis^. }(Budd.). {d) Vesptdae : 28.* Polistes diadema Ltr. (H. M., T.); 29.* P. gallica Z. ? (H. M., T.; Budd.). C. Lepidoptera. Nociuidae: 30. Hypena proboscidalis Z., skg., but not drawing out the pollinia (H. M.) ; 31. Plusia gamma Z., do., in the evening (H. M.). D. Neuroptera. 32. Panorpa communis Z., skg., and drawing out the pollinia (H. M.). 1878. A. fniticosa L. (=Gomphocarpus fruticosus R. Br.). (Sprengel, 'Entd. Geh.,' pp. 139-50.) — Sprengel gives a very thorough account of this species. The flowers smell like honey, and their mechanism agrees with that of A. syriaca. Visitors. — Sprengel observed a number of flies and wasps in the castle garden at Charlottenburg (22. 8. '89), with clips attached to their feet. 1879. A. curassavica L. — This species also was investigated by Sprengel. Fritz Miiller says that in South America, its native country, it is chiefly visited by butterflies, and Hermann Miiller depicts the foot of one of these to which 1 1 clips and 8 pollinia are attached (Fig. 568). 1880. A. tenuifolia L. — Visitors. — Hildebrand saw this species pollinated by a cabbage white, Pieris brassicae Z. (Bot. Ztg., Leipzig, xxix, 187 1, p. 746). ASCLEPIADEAE 95 570. Stapelia L. Pinch-trap flowers with a carrion odour, which attracts flies fond of putrefying substances. These effect cross-pollination by means of their proboscis. Kuhn observed cleistogamy. 1881. S. hirsuta L., and 1882. S. grandiflora Mass. — Both these species are native to the Cape. Visitors. — Delpino noticed two Muscids (Sarcophaga carnariaZ., and Calliphora vomitoria Z.) as pollinators. 571. Gomphocarpus R.Br. Flower mechanism similar to that of Stapelia. The clips attach themselves to the claws of hymeno- pterous visitors. (Delpino, ' Sugli appar. d. fecondaz. nelle piante autocarp.,' pp. 3-14 ; Hildebrand, Bot. Ztg., Leipzig, XXV, 1867, pp. 266-9.) 572. Araujia Brot. Fig. 357. Asclepias curassavica, L. (after Herm. Mttller). 1 1 clips 1883. A. Sericifera (-J) and 8 polHnia (j/) attached to a butterfly's foot. Brot. (=A. albens G. Don, and Physianthus albens Mart). (Delpino, op. cit. ; Hildebrand, op. cit. ; A. Rogen- hofer, SitzBer. ZoolBot. Ges., Wien, xl, 1890, pp. 67-8.) — In this species the poUinators are humble-bees, and the clips attach themselves to the proboscis. A. Rogenhofer saw a moth (Plusia gamma Z.) hanging dead from the flower, while strong humble-bees cannot be held fast, but tear away the clips. Visitors. — Vide supra. 573. Boucerosia Wight et Am. Delpino (op. cit.) states that the flower mechanism resembles that of Araujia. 574. Hoya R.Br. Delpino (op. cit.) states that the clips become attached to the legs of visitors. 1884. H. camosa R. Br. (Delpino, ' Sugli appar. d. fecondaz. nelle piante autocarp.,' p. 9; Darwin, 'Forms of Flowers,' p. 331.) — Delpino saw numerous bees visit this species at Florence, drawing out the pollinia upon their claws. From one plant which was carefully examined four-fifths of the pollinia had been removed from their loculi, and some with germinating pollen-grains were found upon the stigmas. This plant, however, and some from other ItaUan gardens, remained completely sterile. Delpino suggests as a reason that all the stocks had been vegetatively propagated from one and the same original plant. 96 ANGIOSPERMAE— DICOTYLEDON ES Darwin mentions cleistogamous flowers devoid of pollen one of which produced a capsule in which seeds were (? parthenogenetically) developed. These appeared normal, but were incapable of germination. Visitors. — Vide supra. 1885. H. globulosa Hook. f. (W. G. Smith, Gard. Chron., London, New Ser.,. xvii, 1882, p. 570.) — W. G. Smith observed flowers of this species in which flies had been caught by the legs. 575. Stephanotis Thou. The corolla-tube is long, so that only nocturnal Lepidoptera can effect pollination. The clips attach themselves to the proboscis (Delpino, op. cit.). 576. Ceropegia L. 1886. C. elegans Wall. (Delpino, ' Ult. oss.,' pp. 224-8 ; Hildebrand, Bot. Ztg., xxviii, 1870, pp. 604-5.) — Ij^ this species the visitors are small flies (e.g. Gymnopa opaca Rond.), which when they settle on the flower are held fast for a day by means of stiff' hairs. These then become limp and allow the flies to escape with clips holding on to their proboscis. Pollination is now effected of fresh flowers which may be visited. Visitors. — Vide supra. 577. Periploca Toum. 1887. P. graeca L. (Delpino, ' Sugli appar. d. fecondaz. nelle piante autocarp.,' pp. 14-15 ; Hildebrand, Bot. Ztg., Leipzig, xxv, 1867, p. 273.) — The flower mechanism of this species deviates from that of other Asclepiads. The five spoon-shaped bands (retinacula) are sunk in the five angles of the stigmatic disk in the direction of the long axis of the flower. The broadened part of each band lies under two loculi belonging to adjacent anthers, and becomes covered with a sticky mass shortly before the flower opens, taking up pollen when dehiscence takes place. When a fly visits a flower its proboscis sticks to the adhesive matter present on the stalk of the spoon, and this is carried off" with the pollen to be transferred to the stigma of another flower. LXVin. ORDER GENTIANEAE JUSS. Flowers homogamous, protandrous, or protogynous ; usually possessing a large, brightly coloured corolla. Some species are generally dimorphous (Menyanthes trifoliata Z., Limnanthemum nymphoides Hoffm. et Link, Erythraea Centaurium Pers.). The species of the genera Erythraea and Chlora appear to secrete no nectar; in other cases there is nectar, which is either accessible to all (Gentiana lutea Z.), or else concealed, in many cases so deeply that only humble-bees or Lepidoptera can reach it. The genera and species which have been investigated belong to the following flower classes. — Po (?) : Erythraea, Chlora ; E : Gentiana lutea Z. ; C : Menyanthes, Limnanthemum, Swertia ; I GENTIANEAE 97 Hh: Gentiana punctata Z., G. acaulis Z., G. asclepiadea L., G. ciliata Z., G. purpurea Z., G. Amarella Z. ; HhL : Gentiana tenella Roii., G. nana Wul/., G. campestris L., G. obtusifolia Willd., G. aurea Z. ; Lb : Gentiana nivalis Z. ; Lbdh-m (dh-m= diurnal hawk-moths) : Gentiana vema Z., G. bavarica Z. 578. Menyanthes Tourn. Flowers mostly dimorphous, with concealed nectar secreted at the base of the ovary. 1888. M. trifoliata L. (Sprengel, 'Entd. Geh.,' pp. 102-3; Warming, ' Bestovningsmaade/ pp. 13-15; Heinsius, Bot. Jaarb. Dodonaea, Ghent, iv, 1892, p. 71; MacLeod, op. cit., v, 1893, p. 383; Kemer, 'Nat. Hist. PI.,' Eng. Ed. I, II, pp. 310-n; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 104-5.) — The flesh-coloured flowers of this species are arranged in racemes, and are remarkable on account of the Fig. 258. MenyantJus trifoliata^ L. (from nature), (i) Short-styled flower, after removal of a petal and a stamen (natural size). (2) Long-styled do. (natural size). (3) Stigmatic papillae of long style (X 4). (4) Do. of short style (X 4). (5) Pollen-grain of a long stamen (x 70). (6) Da of a short stamen (x 70). fringed limbs of the petals. These not only enhance conspicuousness, but protect the nectar against rain and unbidden guests. Only the long-styled form was seen and depicted by Sprengel. The plant is not heterostylous everywhere, for Warming describes it as homostylous in West Greenland, between 6i° and 69° N. lat. The anthers and stigma are at the same level, or the latter a little higher. Automatic self-pollination is therefore easily possible. {Cf. Fig. 259.) Warnstorf found the long-styled form at Ruppin, with stamens of the same length, when the flowers opened, so that stigma and anthers were at the same level, thus facilitating autogamy. The pollen is of a beautiful orange-yellow colour in bulk: the individual grains are spheroidal to ovoid, and marked with closely approximated, very delicate streaks, parallel to a large extent, and gradually dis- appearing towards the poles. Curiously enough the cell-walls of the hairs on the inner surface of the limbs of the petals exhibit similar, but feebler streaks. Heinsius has measured the ovoid pollen-grains. Those of the long-styled form are on the I 98 AN GIOSPERMAE— DICOTYLEDON ES average 26 /a long and 50 /a broad, while those of the short-styled form are 120 ^l long and 63 /* broad. In the short-styled flowers I have examined at Kiel the stigma is situated in the throat of the corolla, while in long-styled ones it projects several millimetres from this. The anthers diverge in a swallow-tailed fashion, and their height is of course inversely proportional to that of the stigma. Their pollen-covered surfaces are directed inwards. Heinsius describes the extremely long stigmatic papillae of the two forms as pretty much the same, but it seems to me that there is a difference in size approximately proportional to that of the two kinds of pollen-grain. He also states that though plants of the same kind are associated in groups, legitimate crossing is frequent as indicated by the size of the pollen-grains adhering to the stigmas. Kerner and Warnstorf say that the flowers are not only dimorphous, but also feebly pro- togynous. According to the former, automatic self-pollination can take place pseudo-cleisto- gamously in the closed flowers. Fig. 259. Menyanihes trifoliata, L. (after VISITORS. — Sprcngcl obscrVCd humblc-bceS, Warming:) An isostyious flower from Julians- corresponding in size to the flowcrs. At Kiel haab, m Greenland, m longitudinal section r o . •»»■ i- .l l-i (X 3). I have only seen the beetle Meligethes, while Warnstorf only noticed small beetles and flies at Ruppin. Heinsius saw the butterfly Pieris rapae Z., skg., in Holland. In Dumfriesshire Apis and a humble-bee have been recorded (Scott-Elliot, ' Flora of Dumfriesshire/ p. 119). 579. Limnanthemum S. P. Gmel. '\ Flowers dimorphous, with concealed nectar, secreted at five places between the roots of the filaments. 1889. L. nymphoides Hoffmgg. et Link (=Menyanthes nymphoides Z., and Villarsia nymphoides Yent>j. (Kuhn, Bot. Ztg., Leipzig, xxv, 1867, p. 67; Heinsius, Bot. Jaarb. Dodonaea, Ghent, iv, 1892, pp. 72-6 ; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, p. 171.) — Kerner states that as the flowers of this species wither the petals become pulpy, the cell-sap exuding to form a thin surface layer which is particularly attractive to flies. These visitors effect cross-pollination. Heinsius describes the large, bright yellow, stellate corolla as possessing fringe-like appendages on the boundary between its tube and limb. These are directed obliquely upwards and extend to the ovary, completely closing the entrance of the flower. The long style is of the same breadth as the short one, but about half as long again. The proportion is 28 : 20, while the I relative length of the corresponding stamens is 20 i 27. The bluntly triangular pollen-grains are about 24-37 A^ i^^ diameter in the long-styled form, and 43-6 ^ in the short-styled one. fl The flower-buds are submerged, raising themselves above the surface before they open. When anthesis is over, the peduncle bends again, and the fruit ripens under water. Heinsius often found pollen-grains from the opposite form on the stigma, a proof that legitimate union takes place. GENTIANEAE . 99 Visitors. — Heinsius observed the following. — The bee Apis mellifica Z. ^, touching the anthers of the short stamens and the stigma of the short style with its thorax, and the corresponding parts of the long- styled form with its abdomen, 2 humble-bees (apparently Bombus agrorum I^., and B. scrimshiranus X.), 2 hover-flies (Platycheirus peltatus Mg. J, and Helophilus lunulatus Mg. $), and 2 Muscids (Anthomyia pratensis Mg. S, and A. sp. 5). 1890. L. Humboldtianum. (Fritz MuUer, Bot. Ztg., Leipzig, xxvi, 1868, p. 13.) — Fritz Miiller describes this species as dimorphous, like L. nymphoides. 580. Chlora L. Flowers devoid of nectar; arranged in sub-corymbose cymes. 1891. C. perfoliata L. (=G. perfoliata Z.). (Vaucher, 'Hist, physiol. des pi. d'Europe,' III, p. 404.) — Vaucher says that the yellow flowers of this species close at night. The corolla-tube is closely approximated to the ovary. The two bilobed, thickened, papillose stigmas are self-pollinated. 581, Swertia L. Flowers more or less protandrous; with nectar secreted by minute cups sur- rounded by interwoven fringes, and situated in pairs at the bases of the petals, one pair to each. 1892. S. perennis L. (Schulz, ' Beitrage ' ; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, pp. 241, 341; Francke, 'Beitrage.') — In the flowers of this species the corolla varies from steel-blue through grey-white to bright yellow in colour, and the petals are marked by numerous streaks. Schulz says that now and then the pistil or some of the stamens may be reduced, but complete gynodioecism or androdioecism is rare. The anthers of hermaphrodite flowers dehisce a longer or shorter time after the maturation of the stigma. Francke and Schulz state that the stamens are bent back so much that self-pollination is excluded. Kerner, however, observed that autogamy finally takes place, for before all the pollen is shed the stamens first straighten and then move towards and pollinate the stigma. But, on the other hand, Francke and Schulz assert that such autogamy is exceptional, for as a rule no pollen remains on the anthers by the time they reach the stigma. Visitors. — Schulz observed small flies and beetles in the Riesengebirge. 1893. S. punctata Baumg. — This species is native to Hungary and the Siebengebirge, and Kerner states that its flower mechanism is the same as that of S. perennis. 582. Gentiana Toum. Flowers blue, rarely red or yellow in colour; nectar as a rule so deeply concealed that only humble-bees or Lepidoptera can get at it, but exposed in rare cases {c/l pp. 96-7). Hermann Miiller divides the species into five groups, according to the position and mode of secretion of the nectar (' Alpenblumen/ pp. 329-49).— I. Species with exposed, freely accessible nectar : Gentiana lutea Z. lOO ANGIOSPERMAE—DICOTYLEDONES 2. Species with nectar secreted by the base of the ovary, and a bell-shaped corolla adapted to humble-bees (humble-bee flowers; sub -genus Coelanthe): G. purpurea Z., G. pannonica Scop., *G. punctata Z., G. cruciata Z., *G. ascle- piadea Z., G. Pneumonanthe Z., G. Froelichii Jan., G. frigida Haenke, G. acaulis Z. 3. Species with nectar secreted by the base of the ovary, and with the broad disk-shaped stigma so closely surrounded by the long tubular corolla that only long-tongued Lepidoptera can suck conveniently (Lepidopterid flowers ; sub-genus Cyclostigma) : *G. bavarica Z., *G. verna Z., G. imbricata Froel., G. pumila Jacq., G. utriculosa Z., *G. nivalis Z. 4. Flowers adapted to pollination by humble-bees, and with nectar secreted by the lowest part of the corolla (humble-bee flowers; sub-genus Crossopetalum) ; *G. ciliata. 5. Species adapted to pollination by humble-bees and Lepidoptera, and with nectar secreted as in 4 (humble-bee and Lepidopterid flowers ; sub-genus Endotricha) ; *G. campestris Z., G. germanica Willd., G. AmarellaZ.,*G.obtusifolia Willd., *G.tenella Rotth., *G. nana Wulf. The species in the above list to which an asterisk (*) is prefixed have been de- scribed in a masterly way by Hermann Miiller in his ' Alpenblumen.' I would refer the student to his accounts, and in what follows add some of Mtiller's earlier observations, as well as those of other investigators. Kerner applies the term ' revolver flowers' to the blossoms of many species (e.g. G. acaulis Z., G. angustifolia Michx.. and G. Clusii Perr. et Song.) on account of their narrow tubular nectar-passages. {Cf. the note on Convolvulus.) 1894. G. lutea L. (Herm. Mailer, 'Alpenblumen,' pp. 329-30.) — The yellow homogamous flowers of this species secrete exposed nectar, and automatic self-pollination is possible. Visitors. —Herm. Mttller observed 3 beetles, 14 flies, 6 Hymenoptera, and 2 Lepidoptera. 1895. G. punctata L. (Herm. MOller, op. cit., pp. 330-2.) — This species bears protogynous humble-bee flowers, yellow in colour, with black punctations. Automatic self-pollination is generally excluded. Kerner describes the flowers as protandrous. Visitors. — Herm. Miiller observed 2 beetles, 2 flies, 7 Hymenoptera (including 5 humble-bees), and 3 Lepidoptera. Crossing is effected by humble-bees only. 1896. G. purpurea L. (Kirchner, 'Beitrdge,' pp. 47-9.) — Kirchner says that the flower mechanism of this species agrees essentially with that of G. punctata, the blossoms being feebly protogynous humble-bee flowers. They are strongly Fig. 260. Gentiana lutea, L. (from Herm. Mttller's 'Alpenblumen'). A. Oblique view of fully expanded flower. B. Bases of the pistil and two stamens, a, anther ; fi, filament ; «, nectary ; ov, ovary ; f, petal ; s; sepal ; st, stigma. GENTIANEAE loi aromatic, directed obliquely or vertically upwards, externally bright or dark purple in colour, and of whitish-yellow towards their bases both externally and internally. Longitudinal green veins on the inner surface serve as nectar-guides. The club- shaped corolla is thrown into internal longitudinal folds, and its length is 35 mm., of which 10 mm. are taken up by the six lobes. The filaments are free down to the place where the corolla narrows, but below this are fused with the longitudinal folds, to constitute high ridges extending to the ovary and leaving five narrow tubular nectar-passages. There are six green nectaries at the base of the ovary, between the bases of the filaments. The anthers are completely fused together and dehisce extrorsely. They surround the style, and the two stigmas project beyond them and mature somewhat earlier. Although the stigmas roll up later on into spirals of more than one turn, they do not come into contact with the anthers, and automatic self-pollination does not therefore take place. Visitors. — The size and structure of the flowers would indicate humble- bees as the pollinators, but Kirchner never saw them at Zermatt, though he observed numerous flies, which flew about inside the blossoms, and occasionally touched the anthers and stigmas. 1897. G. pannonica Scop. — Kerner describes this species as protandrous. 1898. G. cruciata L. — Kerner says that the protandrous flowers of this species open 8-9 a.m. and close again 7-8 p.m. Visitors. — Schulz observed flowers perforated by humble-bees in Central Germany. 1899. G. asclepiadea L. (Herm. Miiller, ' Alpenblumen,' pp. 356-7; Delpino, 'Ult. oss.,' pp. 166-7; Hildebrand, Bot. Ztg., Leipzig, xxviii, 1870, pp. 668-9.) — This species bears protandrous humble-bee flowers, in which automatic self-pollination is generally excluded. Hermann Miiller did not observe the true pollinators, but only Bombus mastrucatus perforating the flowers, and stealing the nectar. He convinced himself that the opening of the flowers is not dependent upon the action of light, but of warmth, for he picked a bunch of closed flowers and placed them in a dark, but warm room, where they began to open in 25 minutes. Kerner, on the contrary, believes that opening (which takes place 8-9 a. m.) is brought about by the stimulus of light. According to him self-pollination takes place when the corolla closes, in the same way as in the next species. Visitors. — Vide supra. HofFer (Steiermark) observed 2 humble-bees — Bombus gerstaeckeri Mor. 5, po-cltg., and B. latreillellus K. $, skg. 1900. G. Pnetunonanthe L. (Sprengel, 'Entd. Geh.,' pp. 150-2 ; Warming, ' Arkt. Vaxt. Biol.,' p. 10; Herm. Miiller, ' Fertilisation,' pp. 403-4; Schulz, ' Beitrage '; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 381-2 ; Kirchner, 'Flora v. Stuttgart,' p. 540; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 373; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' p. 105, ' Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,' p. 238.) — This species bears protandrous humble-bee flowers. The large deep-blue corolla is marked externally with five green streaks, and is 30 mm. long with an entrance 8-10 mm. broad. Nectar is secreted by the base of the ovary, and is I02 ANGIOSPERMAE—DICOTYLEDONES protected from rain by closure of the corolla during dull weather. This also takes place at night. The inner side of the corolla possesses nectar-guides in the form of small whitish circles with brownish centres, from which alternating blue and whitish longitudinal streaks turn to the base of the flower. At about its middle the corolla- tube suddenly contracts, and from this point downwards it, and the filaments fused with it, closely surround the ovary. Humble-bees can creep half-way into the flowers, dusting themselves in younger ones from the dehisced anthers which closely surround the still immature stigmas. In older flowers the style has elongated and its stigmatic branches have become bent back so that their papillose inner surfaces will be touched by those parts of humble-bee visitors which have taken up pollen. The arrange- ments, in fact, are such that insects of a size proportionate to the interior of the flower inevitably ef- fect crossing. Kerner states that automatic self-pollination is pos- sible in later stages of anthesis, for when the flower closes some of the pollen still clinging to the an- thers is transferred to the internally project- ing folds of the corolla, and is subsequently raised to the level of the stigma by elongation of the corolla-tube. Closure will then effect auto- gamy. Warnstorf de- scribes the pollen- grains as yellowish in colour, ellipsoidal, with a groove, delicately papillose, striated, on the average 60 fi long and 25 /a broad. Visitors. — E. Moller sent me the following from Sylt, of which only Nos. i, 2, and 5 were able to get at the nectar (' Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,' p. 238).- A. Hymenoptera. Apidae: 1. Bombus cognatus Steph. 5 and t>, skg. ; 2. B. derhamellus K. 5, do. ; 3. B. terrester Z., stealing nectar (up to beginning of October 1893) ; 4. Apis mellifica L. 5, do. ; 5. Psithyrus vestalis Fourcr. J, skg. B, Diptera. All only po-dvg. (a) Syrphidae : 6. Platycheirus scutatus Mg. 5 ; 7. P. manicatus Mg. 5. (<5) Muscidae: 8. Aricia incana Wied. 5; 9. Anthomyia sp. ; 10. Pollenia rudis F. Fig. 261. Gentiana acaulis, L, (from Herm. Mailer's 'Alpenblumen '). A. Entire plant. B. Longitudinal section of flower. C. Cross-section through base of do. (on the line ab). Jiy filaments ; w, nectary ; ov, ovary ; upper end of nectar-guides. a, anthers ; ca, calyx ; co, corolla ; J, nectar-passages; j/, stigma x^ GENTIANEAE 103 The following were recorded by the observers, and for the localities stated. — Herm. Miiller, 2 humble-bees — Bombus agrorum F. 5 (proboscis 12-15 mm.) and B. muscorum F. 5 (proboscis 11-15 mm.), both freq., skg., Schulz (Halle), numerous flowers perforated by humble-bees. Kerner, small beetles using the flowers as a refuge. Alfken (Bremen), the bee Halictus flavipes F. 5, po-cltg. H. de Vries (Netherlands), the humble-bee Bombus agrorum F. 5. 1901. G. acatilis L. (Herm. Miiller, ' Alpenblumen,' pp. 332-6; Ricca, Atti Soc. ital. sc. nat., Milano, xiv, 1871; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 163, 198, including G. excisa Presl.) — This species bears protandrous odourless humble-bee flowers (' revolver flowers ' of Kerner), in which self-pollination is usually excluded. Kerner says that they become pendulous in unfavourable weather, so that pollen which falls out of the anthers is guided to the stigma along the furrows between the folds of the corolla, thus eff'ecting automatic self-pollination. According to Hermann Miiller, opening and closing are not dependent upon increase and decrease of light, but of heat. Kerner states that the flowers open about 7-8 a. m., shutting again about 6-7 p. m , Fig. 262. Gentiatia verna^ L. (from Henn. Miiller's ' Alpenblumen '). A. Flower seen directly from above. B^ C. Upper and lower parts of longitudinal section of flower. D. Similar section through upper part of flower, with anthers at a higher level than in B. a, anthers ; co, corolla ; f, ligoles ; ^, filaments ; jfr, style ; «, nectary ; ov, ovary ; s/, stigma. Visitors. — The following were recorded by the observers stated. — Herm. Miiller, 8 bees (including 5 humble-bees), 3 Lepidoptera, a fly, and a beetle, though only the humble-bees are effective pollinators. Ricca, humble-bees effecting pollination. Herm. Miiller found 90 % of the flowers perforated by Bombus mastrucatus Gers/. Kerner saw small beetles using the flowers as a refuge. 1902. G. angustifolia Michx., and 1903. G. Clusii Perr. et Song. ( = G. acaulis Z., according to the Index Kewensis). — These species both bear 'revolver flowers ' in which, according to Kerner, autogamy can take place as in G. acaulis. 104 ANGIOSPERMAE—DICOTYLEDONES 1904. G. Froelichii Jan. — Kerner states that this species bears protandrous humble-bee flowers. 1905. G. bavarica L. (Herm. Miiller, * Alpenblumen,' pp. 341-2; Kemer, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 181-2, 209, 219, 282, 311.) — This species bears homogamous (according to Kerner protogynous) odourless Lepidopterid flowers, with nectar concealed at a depth of 20-2 mm. Visitors can effect self- as well as cross-pollination, but foreign pollen is prepotent. Kerner says that the flowers open very quickly, and that only the edge of the stigma is papillose. VisrroRS. — The most frequent pollinator observed by Herm. Miiller was the diurnal hawk-moth Macroglossa stellatarum Z. (proboscis 25-8 mm. long) visiting hundreds of flowers in a few minutes. 1906. G. vema L. (Herm. Miiller, op. cit., pp. 340-1 ; Kerner, op. cit, pp. 198, 209, 311; Delpino, 'Ult. oss.,' p. i68; MacLeod, ' PyreneSnbl.') — This species bears homogamous (according to Kemer protogynous) Lepidopterid flowers, with nectar concealed at a depth of 23 mm. Their mechanisiri agrees with that of G. bavarica. Kemer says that the flowers open very quickly. Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. Miiller (Alps) and MacLeod (Pyrenees), the diur- nal hawk-moth Macroglossa stellatarum L., as the actual pollinator. Hoffer (Steier- mark), the humble-bee Bombus mastmcatus Gersi. 5. 1907. G. prostrata Haenke. (Kemer, ' Nat. Hist. PL,' Eng. Ed. I, II, p. 391.)- Kemer states that in the pro- tandrous flowers of this species nectar is secreted at the base of the ovary. In unfavourable weather automatic self-pollination takes place pseudo-cleistogamously in the closed flowers. 1908. G. utriculosa L. — Kemer states that the flowers of this species open about 8-9 a. m. and close again about 3-4 p. m. 1909. G. nivalis L. (Herm. Miiller, ' Alpenblumen,' pp. 342-3 ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 116, 220; Warming, 'Arkt. Vaxt. Biol.,' pp. 8-9 ; Lindman, ' Bidrag till Kanned. om Fjellvaxt. Blomn. o. Befrukt.') — This species bears homogamous Lepidopterid flowers. Their conspicuousness is small, and Hermann Miiller saw no lepidopterous visitors capable of getting at the nectar. Automatic self-pollination is easily possible, for the anthers apply themselves to the stigma. In this respect Warming and Lindman state that flowers from Greenland and the Dovrefjeld agree with those from the Alps, and Warming even frequently Fig. 263. Gentiana tenella, Ro/i6.({rom Herm. Mailer's ' Alpen- blamen '). A. Flower partly dissected from the side. B. Part of the corolla-tube, seen from inside. C. Opening of corolla-tube, from above. », nectary ; o, & nectar-passage. GENTIANEAE 103 observed the anthers and stigma bound together by pollen-tubes. Kerner states that the flowers open and close several times in the course of an hour. 1910. G. tenella Rottb. (=G. glacialis VtlL). (Herm. Miiller, op. cit., p. 345 ; Kirchner, 'Beitrage,' p. 49; Warming, 'Arkt. Vaxt. Biol./ p. 9.) — This species bears feebly protogynous (according to Kirchner homogamous) humble-bee and Lepidopterid flowers, in which automatic self-pollination regularly takes place towards the end of anthesis. Kerner says that it may be effected pseudo-cleistogamously in unfavourable weather, when the flowers remain closed. He adds that the fringes of the valves projecting from the throat of the corolla-tube are beset with minute prickles, which prevent insects from inserting their proboscis except into the nectar- passages. Warming describes autogamy for plants from the DovreQeld. 1911. G. nana Wulf. (=G. tenella Rottb., according to the Index Kewensis). (Herm. Miiller, op. cit., pp. 345-6 ; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, II, p. 248.) — This species bears homogamous humble-bee and Lepidopterid flowers, in which automatic self-pollination regularly takes place towards the end of anthesis. Kerner describes the fringed valves of the throat of the corolla-tube as corresponding to those of G. tenella. Fig. 264. GenHana nana, W^«^ (from Herm. Mailer's 'Alpenblumen'). A. Flower seen directly from above. B. Do., partly dissected from the side. C. Part of corolla, seen from within, a, anthers ; CO, corolla;^, filaments; «, nectary; ov, ovary; st, stigma. 1912. G. aurea L. (=G. involucrata Rottb.). (Warming, 'Arkt. Vaxt. Biol.,' pp. IO-I2.) — This species bears humble-bee and Lepidopterid flowers. Warming describes it as protandrous in Finmark and at Troms0, though automatic self- pollination takes place in the second stage of anthesis by contact of the anthers (to which some pollen still clings) with the stigma. 1913. G. detorsa Rottb. (=G. serrata Gunner). — Aurivillius says that in Greenland the flowers of this species are adapted to Lepidoptera, and perhaps also to humble-bees. 1914. G. campestris L. (Herm. Miiller, • Alpenblumen,' pp. 346-8 ; Schulz, 'Beitrage,' II, pp. 107, 214; Lindman, 'Bidrag till Kanned. om skandin. Fjellvaxt. io6 ANGIOSPERMAE—DICOTYLEDONES Blomn. o. Befrukt.'; Warming, ' Arkt. Vaxt. Biol.,' p. 12 ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. I, II, pp. 366, 391 ; Warnstorf, Verb. bot. Ver., Berlin, xxxvii, 1896.) — This species bears humble-bee Lepidopterid flowers. Hermann Miiller (canton Graubiinden), Lindman (Norway), and Warming (Iceland) describe it as feebly protogynous, afterwards becoming homogamous, while Schulz (Westphalia and Thuringia) observed it to be strongly protandrous. In all cases automatic self- pollination is possible in the later part of anthesis. Kerner says that this autogamy is brought about by gradual elongation of the corolla, so that the anthers of the epipetalous stamens are brought into contact with the stigma ; and that during unfavourable weather it may take place pseudo-cleistogamously in the closed flowers. The flowers of plants from higher stations in Norway are of relatively large size, and the stigma is not above the anthers but at the same level or even lower, so that self-pollination is facilitated. It is otherwise in flowers from the Alps, for here the stigma at first projects beyond the anthers, and it is only in late anthesis that the stylar branches bend back far enough, according to Hermann Miiller, to effect autogamy. Schulz, on the other hand, says that this takes place very infrequently. ^^ m^HUi Mjj^^SB I Warnstorf describes ^B ^-fl^Hr ^Flvli 11 the pollen-grains as yellow- ^^B^H^^^ ^Hv il^Lli il^ ^^^ ^^ colour, ellipsoidal, ^^0^H^^^ ^Iw llllwl (1^ traversed by several longi- £ ^V J^V -^ In > Hw iflM tu^i"^^ furrows, densely ^ "^y ^'^ (^ Yi papillose, on the average 63 ;i long and 37.5 /* broad. Visitors. — The fol- lowing were recorded by the observers stated. — Lindman, humble-bees. Herm. Miiller, humble-bees and Lepidoptera, and also perforations made by Bombus mastrucatus Gerst. Schulz (Central Germany), humble- bees and Lepidoptera, and flowers perforated by the former. 1915. G. Amarella L. (Herm. Miiller, 'Fertilisation,' p. 404; Warming, * Arkt. Vaxt. Biol.,' p. 12; Schulz, ' Beitrage.') — This species bears homogamous ^ humble-bee flowers. The corolla-tube is 16-18 mm. long with an entrance 6 mm. wide, into which a humble-bee can easily thrust its head, so that a proboscis 10-12 mm. \ in length suffices to reach the nectar. This is secreted in the base of the flower by* five fleshy green spots alternating with the filaments. There are long inwardly] directed hairs at the junction between the tube and limb of the corolla, serving as] a protection against unbidden guests (flies), and the nectar is sheltered from rain by] closure of the corolla in dull weather. Fig. 265. Gentiana catnpestris, L. (from Herm. Mailer's ' Alpen- blumen '). A. Flower partly dissected from the side. B, C, F. Relations of stigmas and anthers at different stages. B. Stamen with dehiscing anther. D. Old pistil. E. Flower seen directly from above, a, anthers 7?, filaments ; «, nectaries ; ov, ovary ; si, stigma. GENTIANEAE 107 The anthers dehisce when the flower opens, their pollen-covered surfaces being directed upwards, so that if the head of a humble-bee is thrust into the corolla-tube it must touch them. The two stigmas simultaneously diverge, and as they project beyond the anthers cross-pollination is favoured, though autogamy is not excluded. In plants from the DovreQeld and Nordland, according to Lindman and Warming respectively, automatic self-pollination is easily possible, for the anthers generally touch the stigma. Wamstorf describes the pollen-grains as whitish in colour, ellipsoidal, densely papillose, about 56 /x long and 44 /x broad. Visitors. — Herm. MuUer observed a humble-bee (Bombus sylvarum Z., with a proboscis of 1 2-1 4 mm.), skg. 1916. G. germanica Willd. (Ricca, Atti Soc. ital. sc. nat., Milano, xiii, 1870; Schulz, 'Beitrage'; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 302, 311.) — The large flowers of this species attain an average length of 28-32 mm., and are violet in colour, often with a whitish tube ; rarely pure white, and still more rarely yellow. They are heterostylous humble- bee Lepidopterid flowers, de- scribed by Schulz as feebly or strongly protandrous, by Kerner as protogynous. The nectaries are situated as in G. Amarella. Schulz states that the anthers are at first directed inwards, but gradually twist themselves round till they face outwards. In the homogamous or feebly protandrous flowers automatic self-pollination is possible, owing to the stigma and anthers being at the same level, but the out- wardly directed position of the latter renders it difiicult. The flowers are homogamous in the Alps, but the stigma is at a higher level than the anthers, so that autogamy is impossible. Kerner describes the Alpine sub-species G. rhaetica Kerner as being hetero- stylous and protogynous. Visitors. — Ricca observed the honey-bee and humble-bees ; Schulz noticed flowers perforated by the latter. 1917. G. obtusifolia Willd. (Herm. Miiller, ' Alpenblumen,' p. 348 ; Schulz, ' Beitrage.') — This species bears protandrous humble-bee Lepidopterid flowers, which Schulz describes as gynomonoecious. As a rule the style projects beyond the anthers down to the point where it bifurcates. There are, however, some flowers with shorter styles, the branches of which roll back and take up the pollen still clinging to the anthers, thus effecting automatic self-pollination. Fig. 266. Gentiana ciliala, Z. (from Herm. Miiller's 'Alpen- blumen'). A. Exterior of flower, seen from the side, in first (male) stage. B. Do., partly dissected. C. Pistil of same. D. Flower in second (female) stage, partly dissected from the side, a, anthers; fit filaments ; n, nectary ; ov, ovary ; sd, nectar-cover ; si, stigma. io8 ANGIOSPERMAE—DICOTYLEDONES I Visitors. — Herm. Muller observed 3 humble-bees (including Bombus mastru- catus Gerst., and B. terrester Z., obtaining nectar by perforating the flowers), and a Lepidopterid. 1918. G. ciliata L. (Herm. Mflller, op. cit., pp. 343-4 ; Delpino, ' Ult. oss.,' pp. 166-7 j Hildebrand, Bot. Ztg., Leipzig, xxviii, 1870, pp. 668-9 ') Schulz, * Beitrage '; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, pp. 163, 300, 311.) — This species bears protandrous humble-bee flowers which smell like violets. Schulz states that they are sometimes homogamous, and Kerner describes them as trimonoecious. The anthers are at first directed inwards, but dehisce extrorsely in the first stage of anthesis and cover their outer sides with pollen. They are usually empty when the stigmatic lobes expand, and automatic self-pollination consequently only takes place occasionally. Nectar is secreted by five elongated raised patches of a shining green colour at the base of the corolla, and bees or Lepidoptera probing for this must regularly eflfect cross-pollination. Visitors. — Schulz observed bees, more rarely Lepidoptera. Herm. Muller and Schulz noticed flowers perforated by humble-bees. Kerner says that the flowers serve as a refuge to small beetles. 583. Erythraea Rich. I Flowers usually rose-red, rarely white in colour; homogamous, more rarely, feebly protandrous or protogynous ; nectarless, but possessing succulent basal tissue which insect visitors bore *. Heterostyly frequent. 1919. E. Centaurium Pers. (=Gentiana Centaurium Z.). (Sprengel, 'Entd. Geh.,' p. 152; Herm. Muller, 'Fertilisation,' p. 407, 'Weit. Beob.,' Ill, p. 61; Kirchner, ' Flora v. Stuttgart,' p. 543, ' Neue Beob.,' p. 63 ; Schulz, ' Beitrage,' I, p. 71 ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 213; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, PP- 382-3; A. Stephen Wilson, Rep. Brit. Ass., London, 1 1878, p. 568; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896; Knuth, *B1. u. Insekt. a. d. nordfr. Ins.,' pp. 105-6, 164.) — The plants of this species examined by me in the North Frisian Islands were homogamous. The stigmas are mature when the flower opens, at which time the anthers dehisce successively, but autogamy is at first prevented by bending of the style to one side, and the stamens, as their anthers dehisce, to the opposite side. Later on the stamens raise themselves to a height of 4 mm., and the somewhat shorter style also becomes erect, so that the anthers with some pollen still adherent are brought above the stigma, and automatic self-pollination results from the fall of pollen. Autogamy may also in many cases take place immediately after the flowers have opened, for not infrequently there is no lateral bending of style and stamens. During bad weather, and when the flowers begin to fade, this kind of pollination is inevitably brought about by convergence of the corolla-lobes. Wilson observed ' When flowers of Erythraea Centaurium were treated (i 7. 8. '98) with Fehling's solution and orthonitrophenylpropionic acid, only the former caused a small amount of copper oxide to be precipitated in the base of the flower, while the latter gave no indigo reaction. Only a small amount of sap can therefore be present. GENTIANEAE 109 heterostyly in England and associated dimorphism of the pollen-grains, but I was not able to confirm this in the North Frisian Islands, nor could Schulz and Kirchner do so in Central and South Germany. The two latter investigators, however, found the style to vary in length in different stocks, and even, in rare cases, on the same one. In long-styled forms the stigma may be at the level of the anthers, though usually lower; in short-styled ones it is situated in the opening of the corolla -tube. Schulz observed feeble protandry as well as homogamy, and Townsend records protogyny for the variety E. capitata Willd. The flowers close periodically, and Kerner states that anthesis lasts for five days. Schulz and Kirchner call attention to variations in their size. Hermann Miiller is of opinion that the spiral twisting of the anthers (resembling the screw- Jike torsion of the styles in Dianthus Carthusianorum and its allies) is probably an adaptation to the slender proboscis of butterflies, and that despite the absence of nectar these insects bore for sap in the bases of the flowers with the sharp processes on the tip of that organ. Wamstorf states that the flowers open between 6 and 7 a.m., closing again between 12 noon and i p.m. He describes the pollen-grains as yellow in colour, ellipsoidal, opaque, densely tuberculate, up to 44 IX long and 23 /it broad. Visitors. — Herm. Miiller gives the following list for Thuringia (T.) and Westphalia. — A. Diptera. Empidae: i. Empis livida Z., skg. B. Hymenoptera. Apidac. 2. Andrena aestiva Sm. $, po-cltg. ; 3. A. gwynana K. 5, do.; 4. Halictus morio F. $, do. C. Lepidoptera. All boring the tissue at the base of the flowers. (a) Noctuidae : 5. Agrotis pronuba Z., in large numbers, persistently skg. ; 6. Plusia gamma Z., do. (b) Rhopalocera : all skg. : 7. Hesperia lineola 0. ; 8. Lycaena damon S.-V.; 9. Melitaea athalia E!sp.; 10. Pieris rapae Z. {c) Sphingidae: II. Macroglossa stellatarum Z., skg. (T.); 12. Zygaena carniolica Scop.^ do. The following were recorded by the observers, and for the localities stated. — Knuth, the po-dvg. hover-fly Syrphus balteatus Deg. MacLeod (Flanders), the hover-fly Eristalis arbustorum Z. (Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 383). Handlirsch, the fossorial wasp Gorytes tumidus Pz. Scott-Elliot (Dumfriesshire), an Empid, a hover-fly, and 2 Muscids ('Flora of Dumfriesshire,' p. 118). 1920. E. linariifolia Pers. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 106.) — The flower mechanism of this species agrees with that of E. Centaurium, but the style does not bend away from the stamens to the same degree. 1921. E. ramosissima Pers. ( = E. pulchella Hornem.). (Knuth, loc. cit. ; Schulz, 'Beitrage;' Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 366.)— The flower mechanism agrees with that of E. linariifolia, and here again the divergence of the stigma from the anthers is not so marked as in E. Centaurium, but the stamens and style are almost always erect, so that, should insect-visits take place, cross- and self-pollination are equally possible, while the latter may also take place automatically. Schulz states that the short-styled form is particularly common in Central Germany. Kerner says that autogamy is effected by elongation of the corolla in the course of anthesis, the anthers being raised in this way to the level of the stigma. He adds that anthesis lasts for six days, and that the flowers open about lo-ii a.m., closing again 3-4 p.m. no ANGIOSPERMAE—DICOTYLEDONES 584. Hockinia Gardn. 1922. H. montana Gardn. (Gilg, Ber. D. bot. Ges., Berlin, xiii, 1895.) — Gil] describes the flowers of this species as pleomorphous. Knoblauch (op. cit, xiii 1895) refers all Gilg's forms to two only, so that it is only a case of dimorphism. 585. Halenia Borckh. 1923. H. Rothrockii A. Gray. (Gilg, op. cit.) — Gilg states that this speciei bears cleistogamous flowers of two kinds, in addition to the chasmogamous ones. 1924. H. multiflora Benth., and 1925. H. parviflora G. Don (=Exadenus viridiflorus Benth). — The relations are similar to those found in H. Rothrockii. 1926. H. elliptica D. Don ; 1927. H. sibirica Borckh. ; 1928. H. Perrottetii Griseb. ; 1929. H. deflexa Griseb. ; 1930. H. Schiedeana Griseb. ; 1931. H. brevicornis G. Don; and 1932. H. Pavoniana G. Don. (=H. asclepiadea Griseb.). — Gilg (op. cit.) found cleistogamous flowers in all these species. LXIX. ORDER POLEMONIACEAE LINDL. Literature. — A. Peter, ' Polemoniaceae,' in Engler and Prantl's 'D. nat. Pflanzenfam.,' IV, 3 a, p. 43. 586. Polemonium L. Flowers vary from class C to class Hb. Nectar secreted at the base of the ovary. Occasional gynomonoecism. 1933. P. caeruleum L. (Sprengel, ' Entd. Geh.,' p. 109 ; Axell, ' Om Anord for Fanerog. Vaxt. Be frukt.,* p. 33; Herm Muller, ' Alpenblumen,' pp. 257-9, ' Weit. Beob.,*' Ill, pp. 8-9; Kerner, 'Nat. Hist. PI.,' Eng. Ed. I, II, p. 175; Knuth ' Bloemenbiol. Bijdra< gen.') — In this species Fig. 267. Polemonium caeruleum^ L. (from nature). A. Flower in the abOUt twenty blue Or first (male) stage, seen directly from the front. B. Do., in the second i • a (hermaphrodite) stage, seen as before. «, anthers; j, stigmas. whltC flOWCrS, 30 mm. Or more in diameter, are borne in a terminal panicle, so that the plant is conspicuous from a distance. In garden plants examined by me at Kiel streaks in the base of the flower serve^ as nectar-guides, but these would not appear to be constant, for Hermann MiiUer only figures the whitish base of the corolla as serving this purpose in flowers cultivated at Lippstadt. Nectar is secreted at the base of the ovary by a green, fleshy, annular swelling with a wavy edge. It is stored up in the corolla-tube (about 2 mm. deep), and this is closed by woolly hairs, so that only the more intelligent guests, such as POLEMONIACEAE III bees, can easily find the way to the nectar. After settling on a flower, a visitor clings to the exserted stamens and style. In the first stage of anthesis the anthers are ripe, while in the second the three stigmas project beyond the stamens and their papillose inner surfaces are first touched by insect visitors. It follows that crossing always takes place, while automatic self-pollination appears to be excluded. Kerner states, however, that later on the flower becomes pendulous and the stigmas are brought into the line of fall of the pollen. While all the flowers are hermaphrodite in the Alps, Hermann MuUer also found some purely female ones in his garden at Lippstadt. Ekstam describes the flowers in Nova Zemlia as dark blue in colour, smelling faintly of honey, and 30-5 mm. in diameter. They are protogynous or protogynous- homogamous, with a large amount of variation in the development of the reproductive organs. Fig. 268. Polemonium caeruUum, L. (alter Herm. MuUer). A. Flower in the first (male) stage. ./I'. Reproductive organs of do. (X 7). A Flower in the second (hermaphrodite) stage. B'. Repro- ductive organs of do. (x 7). 1-5, anthers. Visitors.— Herm. Miiller (H. M.) in Westphalia, and Buddeberg (Budd.) in Nassau, observed the following. — A. Coleoptera. Telephoridae \ i. Dasytes flavipes F., freq. in the flowers (H. M.). B. Hymenoptera. Apidae : all skg. : 2. Apis mellifica L. 5 (H. M.) ; 3. Chelostoma campanularum K. J (Budd.); 4. C. nigricorne Nyl, J (Budd.); 5. Coelioxys sp. J (H. M.) ; 6. Osmia rufa L. %, po-cltg. (Budd.), 27. 6. '73; 7. Megachile sp. $ (H. M.). The following were recorded by the observers, and for the localities stated. — Lindman (Dovrefjeld), a humble-bee. Herm. Miiller (Alps), a beetle, 2 flies, the honey-bee, and 6 humble-bees. Knuth (on garden plants), the honey-bee, freq., skg. and po-cltg., its baskets thickly covered with orange-coloured pollen. It climbs up the style and stamens to the nectar, thus regularly eff"ecting cross-pollination. The same remarks apply to three humble-bees — i. Bombus hortorum Z. }^; 2. B. lapidarius Z. 5; 3. B. terrester Z. ?. Schneider (on garden plants in Arctic iia ANGIOSPERMAE—DICOTYLEDONES Norway), the humble-bees Bombus pratorum Z. 5. and B. terrester L, 5 (Troms0, Mus. Aarsheft., 1894). 1934. P. htimile Willd. (=P. pulchellum Bunge). (Ekstam, 'Blutenbiol. Beob. a. Spitzbergen/ pp. 8-9, Bot. Jahrb., Leipzig, xxii, 1897, p. 185; Andersson and Hesselman, ' Bidrag till Kanned. om Spetsbergens o. Beeren Eil. Karlvaxtflora,' pp. 17-18.) — Ekstam says that in Nova Zemlia this species exhales a strong and extremely unpleasant goat-like odour. The flowers are homogamous, and the nectar secreted in their bases is protected by glandular hairs lining the corolla-tube. The plants observed in Spitzbergen by Andersson and Hesselman, also by Ekstam, bear blue or sometimes white flowers, which either possess a sweet smell suggesting that of Viola lutea, or a disagreeable musky one. At the opening of the corolla-tube there is an orange-yellow nectar-guide with a violet margin. There is a hypogynous annular nectary, the secretion of which is protected by long hairs on the bases of the filaments. The pollen -grains are normally developed, and rupture in a few minutes when placed in distilled water. The pollen is protected against damp partly by the position of the flowers, and partly by the facility with which the thin petals fall together during rain. Ekstam found marked protogyny in some cases, though homogamy is the general rule. The anthers are situated at a slightly higher level than the stigmas, so that autogamy is easily possible. The plant flowers in Spitzbergen from the end of June till the beginning of August, but in spite of this early anthesis fruits do not always ripen. Visitors. — Ekstam observed medium-sized flies in Nova Zemlia, and also a hybrid P. humile Willd. x P. caerulem Z., indicating insect-visits. In this cross 90 % of the pollen-grains were abortive. No visitors were observed in Spitzbergen. 587. Phlox L. Protandrous Lepidopterid flowers. 1935. P. paniculata L. (Sprengel, 'Entd. Geh.,' pp. 105-6; Herm. Muller, * Fertilisation,' p. 407 ; Knuth, ' Bloemenbiol. Bijdragen,' ' Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,' p. 238.) — In this species nectar is secreted at the base of the ovary, and stored in the corolla-tube, which is 18-22 mm. long and 3 mm. broad at its centre. The dehisced anthers are situated in the entrance of the corolla-tube when the flower opens, and the still apposed stigmas about its centre. While the anthers are being robbed of their pollen, the style gradually elongates till it reaches their level, when the stigmas diverge and expose their papillose inner surfaces. Insect visitors will consequently transfer pollen from youngei flowers to the stigmas of older ones. Visitors. — The following were recorded by the observers, and for the localitiei stated. — Knuth (gardens at Nieblum, Fohr, 22. 7. '23), the diurnal hawk-moth visiting numerous flowers in succession; (his own garden at Kiel), the same moth. The form of the corolla-tube corresponds to that of the moth's proboscis, being slightly 1 ii POLEMONIACEAE 113 l)ent. Sprengel, Lepidoptera. MacLeod, the moth Plusia gamma L,, skg. (Bot. Centralbl., Cassel, xxix, 1887). Herm. Muller, 2 Diptera — i. Conops flavipes L., skg. (but scarcely reaching the nectar, its proboscis being only 4-5 mm. long); 2. Eristalis tenax L., po-dvg. Schletterer and von Dalla Torre (Tyrol, two bees — I. Anthidium strigatum Lir. ?; 2. Halictus smeathmanellus K. 5. Loew (Berlin Botanic Garden), the Muscid Echinomyia fera Z,, as an unbidden guest. 1936. P. reptans Michx., and 1937. P. subulata L. — Visitors. — Loew observed the honey-bee in the Berlin Botanic Garden. — 1938. P. setacea L. (=P. subulata L., according to the Index Keivensis). (Francke, Inaug. Dissert., Halle, 1883.) — Francke describes this species as pror tandrous. Self-pollination by the wind or by insects is possible. 588. Cobaea Cav. 1939. C. penduliflora Hook. f. — Visitors. — A. Ernst states that this species is polhnated by hawk-moths (Kosmos, Leipzig, vii, 1880, pp. 44-6). 1940. C. scandens Cav, (W. J. Behrens, Flora, Marburg, New Ser., xxxviii, 1880, pp. 403-10; Knuth, ' Bloemenbiol. Bijdragen ' ; Kerner, 'Nat. Hist. PI.,' Eng. Ed. I, n, pp. 304, 384-5.) — The flowers of this species observed by me in the Botanic Garden of the Kiel Ober-Realschule were greenish-white in colour when they opened, and therefore not very conspicuous. At first the anthers are not ripe nor the stigma mature. The lower corolla-lobes gradually assume a faint purple colour, but the whole flower does not become purple until the anthers dehisce. The breadth of the corolla seems to me much too considerable to make it probable that humble-bees are the pollinators of this plant in its native country, Mexico ; and I think it far more likely that the larger humming-birds are the visitors. Kerner describes the flower mechanism somewhat as follows. — At first the pollen-covered anthers are so disposed in the entrance of the flower that animals trying to secure the concealed nectar must brush against and remove the pollen. At this time the internal papillose surfaces of the three stigmas cannot be touched, for they are closely apposed, and concealed beneath the anthers owing to the shortness of the style. The filaments now elongate, so that the anthers are applied to the lower margin of the entrance of the flower, while the style curves upwards, and the stiginas diverge, taking up the position occupied by the anthers in the first stage of anthesis. Should there be no visits from pollinating animals, autogamy- takes place as a last resort. The so far nodding flowers become pendulous, and the style and stamens curve more strongly, so that anthers and stigmas are brought into direct contact. Visitors, — Vide supra. W. J. Behrens says that humble-bees are the polli- nators. 1941. C. macrostemma Pav. (Herm. Ross, Flora, Marburg, Iviii, 1898, pp. '25-34.)— Hermann Ross states that the flowers of this species open in the evening, and appear to be adapted for pollination by hawk-moths. Should insect-visits fail, 114 ANGIOSPERMAE—DICOTYLEDONES the style describes rotatory movements, bringing the stigmas into contact with the anthers, so that automatic self-pollination necessarily takes place, and this is effective. 589. CoUomia Nutt. 1942. C. grandiflora Dougl. (Ludwig, Bot. Ztg., Leipzig, xxxv, 1877 ; Scharlok, op. cit., xxxvi, 1878.) — Ludwig and Scharlok state that this species is cleistogamous. 1943. C. linearis Nutt. (Comes, ' Ult. oss.') — Comes describes this species as self- fertile. LXX. ORDER HYDROPHYLLACEAE DC. (including HYDROLEACEAE ENDL.) Literature. — A. Peter, * Hydrophyllaceae,' in Engler and Prantl's ' D. nat. Pflanzenfam.,' IV, 3 a, p. 57. 590. Phacelia Juss. 1944. P. tanacetifolia Benth. (Warnstorf, Verb. bot. Ver., Berlin, xxxvii and xxxviii, 1896.) — The flowers of this species are feebly protandrous. The style only bears stigmatic papillae on its extreme tip, and is at first curved inwards. The anthers dehisce a little before it straightens itself. Willis says the flowers are capable of automatic self-pollination (J. Linn. Soc., Bot., London, xxx, 1895). The pollen-grains are of a pale bluish colour, biscuit-shaped, smooth, with several longitudinal streaks: they measure about 16-19 /* i^^ breadth and 37*5 /* in length. Visitors. — Warnstorf observed the honey-bee, and Herm. Milller noticed the following in his garden at Lippstadt (' Weit. Beob.,' Ill, p. 9). — A. Coleoptera. i. Dasytes flavipes F.^ po-dvg. ; 2. Meligethes sp., po-dvg. Staphylinidae : 3. Tachyporus obtusus Z., its mouth-parts busy with the anthers. B. Diptera. Syrphidae : 4, Rhingia rostrata Z., skg. and po-dvg. C. Hymeno- ptera. Aptdae: 5, Apis mellifica Z. 5. in very large numbers, skg.; 6. Bombus hortorum Z. j and 5, freq., skg.; 7. Haliclus sexnotatus K. 5, do.; 8. Osmia rufa Z. 5, do. 1945. P. divaricata A. Gray. — Willis states (op. cit.) that the flowers of this species are capable of automatic self-pollination. 1946. P. campanularia A. Gray ; 1947. P. Whitlavia A. Gray ; and 1948. P. Parryi Torr. — Willis states (op. cit.) that these species bear large brightly coloured flowers, adapted for cross-pollination. 591. Hydrophylliim L. Flowers protandrous; with completely concealed nectar, secreted by the base the ovary, and stored in a cavity of the petals. 1949. H. virginicum L. (Francke, Inaug. Dissert., Halle, 1883; Loew, ' Bliitenbiol. Beitrage,' I, pp. 21-4.) — The flowers of this species are almost exclu- sively allogamous. Loew states that the nectar secreted in the base of the flower I HYDROPHYLLACEAE 115 rises into a series of prismatic tubes, each bounded by a pair of longitudinal folds and the midrib of a petal. Visitors. — Loew (Berlin Botanic Garden) observed the honey-bee and the humble-bee Bombus terrester L. 5, vainly trying to suck. He regards as the true pollinators insects that can probe the flowers without alighting, i.e. Bombyliids or hawk-moths. 592. NemophUa Nutt. 1950. N. maculata Benth. (Willis, J. Linn. Soc, Bot., xxx, 1895.) — The very conspicuous flowers of this species are protandrous. Visitors. — In England, more particularly bees. 593. Hydrolea L. 1951. H. spinosa L. (Willis, op. cit.) — Willis states that the odourless blue flowers of this species are adapted to self-pollination, and that this is effective. 594. Wigandia H. B. et K. 1952. W. caracasana H. B. et K. (Francke, Inaug. Dissert., Halle, 1883.) — Francke states that this species is protogj'nous. LXXI. ORDER BORAGINEAE DESV. Literature. — Herm. Miiller, 'Fertilisation,' pp. 408-23, * Alpenblumen,* pp. 265-7 ; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 107, ' Grundriss d. BlUtenbiol.,' pp. 76-7; Loew, Ber. D. bot. Ges., Berlin, iv, 1886, p. 152; M. GUrke, 'Boragi- naceae/ in Engler and Prantl's *D. nat. Pflanzenfam.,' IV, 3 a, pp. 78-9. A considerable but variable number of flowers are associated in cymes, often of scorpioid character. They may be rotate, tubulo-campanulate, or infundibuliform, and secrete nectar from the receptacle immediately below the ovary. It is stored in the corolla-tube, the throat of which is often provided with scale-like appendages promoting concealment. The native German species consequently belong to flower class C, especially the sub-class H, for the visitors are almost exclusively bees. Crossing by insect-visits is ensured or favoured by dimorphism in Pulmonaria ; by marked protandry in Echium and Borago ; by exsertion of the stigma in Cerinthe, Symphytum, and Anchusa; and in Lithospermum, Echinospermum, Myosotis, and Omphalodes by contraction of the corolla-tube, securing that stigma and anthers shall be touched by opposite sides of the proboscis of an insect visitor. Should insect-visits fail, the facility with which automatic self-pollination may take place in a given species is inversely proportional to the conspicuousness of the flowers and their richness in nectar. Cerinthe, Echium, and Pulmonaria, owing to their great conspicuousness and large amount of nectar, receive such a large number of visits that automatic self-pollination is excluded. On the other hand, according to Hermann Miiller, the small scantily nectar-secreting flowers of Lithospermum arvense Z., Myosotis intermedia Link, M. collina Hojffm., and so forth, are very rarely visited by insects, and almost always pollinate themselves. There are numerous transitions between these two extreme cases. I 2 1 16 ANGIOSFERMAE— DICOTYLEDON ES Many forms limit access to their nectar entirely or almost so to bees, e. g. — Pulmonaria by elongation of the corolla-tube ; Anchusa by closure of the entrance to the flower ; Echium by the form of the corolla ; Borago by torsion of the flowers, and apposition of the anthers into a cone closing their entrance ; Symphytum and Cerinthe by elongation of the corolla-tube in addition to this. The species with shorter corolla-tubes from the genera Myosotis, Omphalodes, Echinospermum, Asperugo, Heliotropium, Lithospermum, and Cynoglossum, are visited by bees, I^epidoptera, and flies, more especially by hover-flies. According to Kuhn (Bot. Ztg., Leipzig, xxv, 1867), species of the genera Amsickia, Eritrichium, Hockinia, and Lithospermum, are dimorphous. Darwin ( ' Different Forms of Flowers '), however, denies that this is the case in the first two of these, there being simply a large amount of variation in the length of the styles and stamens. 595. Heliotropium L, Flowers fragrant, short-tubed, and homogamous ; with very scanty or no secretion of nectar. 1953. H. europaeum L. (Kirchner, ' Beitrage,' pp. 49-50,) — The small insignificant flowers of this species are homogamous, and their odour is compared by Kerner to that of vanilla, by Delpino to that of jessamine. The limb of the corolla is 3-3^ mm. across, its throat is of a yellow colour, and its tube (2 mm. long) is entirely surrounded by the calyx. The yellow anthers are produced into points, and situated in the middle of the corolla-tube. The style projects beyond them, and bifurcates at its end into the pointed stigmas, which mature simultaneously with the anthers. During insect-visits crossing is therefore favoured, but these are infrequent. Kirchner was unable to discover any nectar in flowers from canton Valais. 1954. H. peruvianum L. (Sprengel, ' Entd. Geh.,' p. 87 ; Knuth, ' Bloe- menbiol. Bijdragen,') — The bluish-white homogamous flowers of this species smell like vanilla. Visitors. — The follo^ving were recorded by the observers, and for the localities stated. — Knuth (gardens in Kiel), the honey-bee, freq., inserting its proboscis into the base of the flowers; also the Muscid Calliphora vomitoria Z., skg. Errera and Gevaert, butterflies and the diurnal hawk-moth Macroglossa stellatarum L. 596. Asperugo L. Flowers homogamous ; with concealed nectar, secreted by the receptacl- immediately below the ovary. 1955. A. procumbens L. (Kirchner, 'Beitrage,' p. 50; Knuth, 'Flora v. Helgoland.') — At Zermatt the inconspicuous flowers of this species are borne singly in the leaf-axils, and possess a corolla-tube scarcely 2 mm. long, with a dark-brown corolla limb and a violet ring in the throat. The entrance of the corolla-tube is narrowed by five %vhitish projections, formed by inpushings from the outside. The corolla-limb is generally directed obliquely upwards and is then only 3 mm. in diameter; more rarely it is horizontal, in which case it is 5 mm. across. I BORAGINEAE I17 As the style is only ^mm. long, the stigma is below the simultaneously maturing anthers, which alternate with the projections in the throat of the corolla, and are situated just under them. The anthers dehisce introrsely, so that automatic self- pollination is easily effected by fall of pollen on the stigma. This species is very common on the high land of Helgoland, where fruits are always set, although insect-visits are very few^, so that its self-fertility is beyond question. Visitors. — Despite continuous watching during favourable weather in Helgoland I have only seen (5. 6. '97) the small bee Andrena labialis K. J, skg. 597. Echinospermum Sw. Flowers homogamous ; with concealed nectar, secreted by the fleshy receptacle immediately below the ovary. 1956. E. Lapptila Leh. (=Lappula Myosotis il/i^^/zr^, and Myosotis Lappula L). (Herm. Miiller, ' Weit. Beob.,' Ill, p. 19, ' Alpenblumen,' p. 261; Kirchner, ' Flora V. Stuttgart,' p. 553.) — So long as the corolla is enclosed in the bud it is white in colour, becoming pale-red when it emerges from the calyx, and ultimately sky-blue. Its limb is contracted in a companulate fashion, and five yellowish- white involutions which narrow its throat serve as nectar-giiides. The inner margin of these appears yellow as seen from above, and there are ten radial white streaks. The simultaneously maturing stigmas and anthers are close together, and must be touched by opposite sides of the proboscis of an insect probing for Fig. 269. Echinospermum Lappula, L. (after «u_ „„_*_ _4. .u« 1 ^t.1. c iX. u .. Herm. Miiller). A. Flower, seen directly from above. the nectar at the bottom of the short 5. Do., partly dissected from the side (x 7). ^.anthers; corolla-tube, so that crossing is favoured. '». nectaries. Should insect-visits fail, automatic self- pollination is inevitable, owing to the close proximity of anthers and stigmas. A proboscis of 6-7 mm. long is necessary to get at the nectar. Visitors. — Herm. Miiller observed small hover-flies and 2 Lepidoptera in the Alps, and the following in Thuringia. — A. Diptera. {a) Muscidae: i. Anthomyia sp., skg. {b) Syrphidae: 2. Syritta pipiens Z., skg,, freq. B. Hymenoptera. {a) Apidae : 3. Andrena sp. 5, skg. {d) Sphegidae: 4. Cerceris variabilis -SV^r., freq., persistently skg. 598. Cynoglossum L. Flowers usually homogamous ; with concealed nectar, secreted by the fleshy I receptacle below the ovary, and concealed in the base of the corolla-tube. ' 1957- C. officinale L. (Sprengel, ' Entd. Geh.,' pp. 89-90 ; Herm. Muller, 'Weit.. Beob.,' Ill, p. 19; Kirchner, ' Flora v. Stuttgart,' p. 553; Loew, * Bliitenbiol. Floristik,' p. 39 1 ; Knuth, ' Bloemenbiol. Bijdragen.') — The corolla-tube of the dirty- ii8 ANGIOSPERMAE—DICOTYLEDONES purple flowers of this species is 3 mm. long and about the same breadth, but the access to the nectar is narrowed to i mm. by five pocket-shaped hollow scales in its entrance. The darker colour of these enables them to serve as nectar-guides, and their velvety covering of hairs as nectar-covers. The style projects in the middle of the flower to a height of 2 mm., and the five simultaneously maturing anthers project beyond it. As these dehisce introrsely automatic self-pollination necessarily takes place by the fall of pollen, should insect-visits fail. If the proboscis of an insect is inserted into the nectar-secreting base of the flower it touches pollen and stigma with opposite sides, so that cross-pollination is favoured. Visitors. — Herm. Miiller observed the following in Thuringia. — A. Hymenoptera. Apidae : i. Andrena nigroaenea K. ^, skg., remaining a very long time (over ^ min.) on the flowers ; 2. Apis mellifica L. 5, freq., skg. ; 3. Halictus tetrazonius Klg. % in large numbers, skg. B. Lepidoptera. Rhopalo- cera : 4. Lycaena aegon S. V. J. skg. C. Thysanoptera. 5. Thrips, very common. The following were recorded by the observers, and for the localities stated. — Knuth (Kiel), the honey-bee and the humble-bee Bombus terrester Z., both skg. Loew (North Germany), a bee (Osmia sp.). Gerstacker (Berlin), the bee Osmia adunca Ltr. 1958. C. pictum Ait. — Kerner describes this species as feebly protogynous. 1959. C. Coltimnae Bivona. — Visitors. — Loew observed the honey-bee and the humble-bee Bombus pratorum Z., both skg., in the Berlin Botanic Garden. 599. Omphalodes Toum. As Cynoglossum. i960. O. verna Moench (= Cynoglossum Omphalodes Z.). (Herm. Muller, * Fertilisation,' pp. 416-17.) — The flower mechanism of this species agrees essentially with that of Echinos|)ermum. The tube of the corolla is 3 mm. long, while its liml expands into a blue surface 15-18 mm. in diameter. During insect-visits crossing i^ favoured, but should they fail automatic self-pollination is inevitable. Visitors. — Herm. Muller observed 2 bees — Bombus terrester Z. j, and Osmia nifa Z. J, both skg. 600. Eritrichium Schrad. 1961. E. villosum Bunge — This species bears fragrant flowers. Visitors. — Ekstam observed flies in Nova Zemlia. 1962. E. aretioides A. DC. (= Myosotis aretioides CArfw.).— This specie was discovered by Chamisso in Tschukschenland and Kamchatka. 601. Rindera Pall. 1963. R. tetraspis Pall. — Visitors. — Friese {lesk Becker) observed two po-cltg. bees (Eucera albofasciataj Fn'fse, and E. velutina A for.) at Sarepta. BORAGINEAE 119 602. Caccinia Savi. 1964. C. strigosa Boiss. (Loew, Ber. D. bot. Ges., iv, 1886, pp. 164-6.) — The corolla-tube of this species is 14 mm. long and 2^ mm. broad. The five stamens are of various lengths ; one of them is as long as the widely exserted style, two are about 2 mm. shorter than this, and the remaining two are still shorter. Since the four latter stamens dehisce first, autogamy is excluded to begin with, and crossing by insect-visits favoured. Should these fail, automatic self-pollination can ultimately take place when the long stamen dehisces. ^'isiTORS. — Loew observed the humble-bee Bombus hortorum Z. in the Berlin Botanic Garden, skg., and dusting its under-side with pollen. 603. Arnebia Forsk. 1965. A. echioides A. DC. (=Macrotomia echioides Boiss.). (Loew, op. cit., iv, 1886, pp. 164-6.) — This species is particularly interesting because the dark-violet spots on the corolla serving as nectar-guides gradually disappear after one to three days' anthesis, i. e. the ' nectar signals ' are temporary, and exist only on the younger flowers. As the nectar is very deeply concealed, besides which Loew observed the humble-bee Bombus hortorum L., skg., the flowers may be referred to flower class Hh. Loew describes a long-styled plant from the Berlin Botanic Garden as exhibiting much reduced fertility, but not self-sterile. Visitors. — Vide supra. 604. Trachystemon D. Don. 1966. T. orientale D. Don (=Psilostemon orientale DC). (Loew, op. cit., iv, 1886, pp. 155-7.) — The flowers of this species possibly belong to class L. 605. Borago L. Protandrous bee flowers ; with nectar secreted by the receptacle below the ovary, and concealed in a short tube formed by the roots of the filaments. 1967. B. officinalis L. (Sprengel, 'Entd. Geh.,' pp. 94-8; Herm. Miiller, 'Fertilisation,' pp. 409-11, * Weit. Beob.,' Ill, p. 14 ; Kirchner, ' Flora v. Stuttgart, PP- 554-5; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 275.)— The sky-blue hanging flowers expand so as to present a nearly flat surface, from the centre of which the black cone of anthers projects. The anthers which converge to make up this cone dehisce introrsely from apex to base, and the smooth powdery pollen falls into the end of the cone. This surrounds the style with its stigma, but as the latter is still immature automatic self-pollination is excluded. After nectar-sucking insects have removed the pollen from the cone the style grows out of it, and the stigma matures. Only bees are able to open the flowers. When one of these hangs on from below to a flower in the first stage of anthesis, and probes for nectar, its proboscis must be inserted between two filaments, thus J2Q ANGIOSPERMAE—DICOTYLEDONES causing the displacement of two antheis. The apex of the anther-cone is conse- quently opened, and pollen is sprinkled on the under-side of the visitor. Even repeated visits do not permanently open the cone, for the short filaments are broad, and fleshy inwardly directed pouches of the corolla (which surround the base of the cone) direct the stamens back to their original position. The pollen received by bees from younger flowers is deposited on the stigmas of older ones in the second (female) stage. Should insect-visits fail, automatic self-pollination may take place to a limited extent, for the pollen remaining in the cone can fall upon the stigma, though Darwin says this is an exceptional occurrence. Bees grasp the tooth-like appendages of the filaments with their claws, thus displacing the anthers and causing the pollen to fall. Warnstorf describes the pollen-grains as white in colour, in shape like two apposed hemispheres with a central groove, smooth, up to 43 /a long and 25-8 ft broad. Visitors. — Herm. ^Miiller (H. I\I.) for Westphalia, and Buddeberg (Budd.) give the following list. — A. Hymenoptera. (a) Api- dae: i. Anthidium oblongatmn iJr. J, skg. (Budd.); 2. Apis mellifica L. 5, very numerous, skg. and po-cltg. (H. M.) ; 3. Bombus pra- torum Z. 5 and ^i skg; and po-cltg. (H. M., Budd.); 4. Halictus sex- notatus K. 5, freq., skg. (H. M.) ; 5. H. zonulus Sm. $, skg. (H.M.); 6. Megachile centuncularis Z. J, in large numbers, skg. (H. INI., Budd.) ; 7. M. fasciata Sni. J, do. (Budd.); 8. Osmia fulviventris Pz.t, do. (Budd.); 9. O. rufa Z. 5, skg. (Budd.). {b) Vespidae: 10. Odyne- rus parietum Z. J, skg. (?). B. Le- pidoptera. Noctuidae: 11. Plusia gamma Z., skg., in the evening (H.M.). The following were recorded by the observers, and for the localities stated. — Knuth, 2 bees — Apis mellifica Z. 5, and Bombus terrester Z. i, both skg. Friese (Hungary), 2 bees — Eucera crinipes Sm., and E. nilidiventris Mocs. Fig. iyo. Borago qfficiualis, L. (after Heiin. Muller). (l) Flower, after removal of the stamen, seen directly from below. (2) A stamen in the natural position, seen from the side, a, pouches of the corolla; 6, roots of the stamens; r, ovaries ; rf, fleshy thickened filament ; «, process of do. ; f, opening of anther. 606. Anchusa L. Homogamous bee flowers ; nectar secreted by the four-lobed base of the ovary^ and concealed in the lower part of the corolla-tube. 1968. A. officinalis L. (Sprengel, ' Entd. Geh.,' p. 89; Herm. Muller, 'Fertilisation,' p. 411, *Weit. Beob.,' Ill, pp. 15-16, ' Alpenblumen,' p. 261 ; Loew, 'BlQtenbiol. Floristik,' p. 391; Knuth, 'BlQtenbiol. Beob. a. d. Ins. Riigen' Tullberg, Bot. Not., Lund, 1868, p. 14.) — In this species ithe limb of the corolls BORAGINEAE 121 is at first concave and of a violet colour, but expands later on into a dark- blue, five-lobed star. The corolla-tube is 7 mm. long, and its entrance is blocked up by five closely apposed pocket-shaped hispid involutions, so as to give protection against rain and unbidden guests (flies). These pouches may be seen externally as transverse slits at the bases of the corolla-lobes. They also play the part of nectar-guides. The stigma is situated immediately below them, while the simultaneously maturing anthers are placed about the middle of the corolla-tube, and dehisce introrsely. Visitors (bees or Lepidoptera) must first touch the stigma, pollinating it if they have come from another flower, and then the pollen-covered anthers, thus effecting crossing. Should insect-visits fail, automatic self-pollination lakes place as a last resort, for the corolla drops off and the anthers, to which some pollen still clings, are drawn over the stigma. Gynomonoeciously or gynodioeciously distributed female flowers have been observed, though rarely, in ad- dition to the hermaphrodite ones. Schulz (' Beitrage ') states that ihey occur sporadically in larger numbers, and result from the reduction of stamens in a small- flowered hermaphrodite variety. , According to Schulz the hermaphrodite flowers do not everywhere possess the same mechanism. , They are not only of different sizes, but the relative position of stigma and anthers is variable even in flowers on the same stock. Sometimes the stigma is higher than the anthers (as in the description already given from the accounts of Sprengel and Herm. Muller, and verified by myself in Riigen), sometimes lower, or at the same level. Warming even noticed heterostyly in Denmark, while Schulz remarked it, though not in a pronounced form, in Germany and the Tyrol. Kirchner describes well-marked dimorphism for garden plants, the style of one form being 4^ mm. long, and that of the other 8 mm. Where the stigma is at the same or a lower level than the anthers, automatic self-pollination is more easily possible than in lOng-styled flowers, for it can take place simply by the fall of pollen. (Generally, however, this possibility is not made use of, for insect-visits are extremely numerous. Visitors.— Herm. Muller gives the following list for Westphalia (W.) and Thuringia (T.).— A. Hymenoptera. {a) Apidae: i. Anthophora aestivalis Pz. $, skg. (T.);- 2. A. quadrimaculata Pz. 5 and J, do. (T.) ; 3. Apis mellifica Z. 5, numerous, skg. and po-cltg. (W. and T.) ; 4. Bombus agrorum F. 5, 5 and $, skg. (W. and T.) ; 5. B. lapidarius Z. 5 and 5, do. (W.); 6. B. pratorum L. % $ and J, skg. and po-cltg. (W. and T.) ; 7. B. miiscorum Z". (W.) 5 and 5, skg. (W. and T.); 8. B. sylvarum Z. 9, -kg. and po-cltg. (W.); 9. B. tristis Seidl. 5, skg. (T.); 10. Coelioxys conoidea III t>, do. (T.); ri. Melecla luctuosa Scop. $, do. (T.); 12. Osmia caementaria Gersi. $. Fig. 271. Anchtisa officinalis, L. (after Herm. Miiller). (i) Flower seen from above. (2) Do. after removal of hah the calyx and corolla, seen from the side. », nectary. 122 ANGIOSPERMAE—DICOTYLEDONES ] do. (T.); 13. O. emarginata Eep. (=0. mustelina Gersi.) $, do. (T.) ; 14. Psithynis | rupestris F. 5, do. (T.); 15. Saropoda bimaculata Pz. j and $, do. (T.). {b) For- \ ynicidae : 1 6. Undetermined sp., vainly trying to force their way into the flowers (T.). j B. Lepidoptera. Noctuidac. 17. Plusia gamma Z., extremely numerous, skg. (W.). \ Friese records the following bees for Fiume (F.), Mecklenburg (M.), Switzerland \ (S.), the Tyrol (T.), Trieste (Tr.), and Hungary (H.).— | I. Anthidium interruptum F. (H.) ; 2. A. variegatum F. (H.) ; 3. Andrena i nasuta Gir., occasional (M.), freq. (H.); 4. Colletes nasutus Sm., freq. (M.); j 5. Eucera bibalteata Dours, infreq. (IVI.); ^. E. chrysopyga P/r., freq. (H.); ^ 7. E. hungarica Friese t, not infreq. (H.); 8. E. interrupta Baer, not infreq. (H.); | 9. E. longicornis Z., freq. (M.); 10. E, nitidiventris Mocs., freq. (H.); 11. E. para- | i\oy.2i Mocs., infreq. (H.); 12. E. seminuda Bridle t>, one (H.); 13. E. semistrigosa j Dours., freq. (H.); 14. E. tricincta Er. (Tr.); 15. Halictus morbillosus Kriechb., \ very common (H.); 16. H. patellatus Mor. (F., teste Korlevic), not infreq. (H.); j 17. H. xanthopus K. (T., H.); 18. Nomada nobilis Mor.^ not infreq. (F., M.); % 19. N. sexfasciata Pz. (M.) ; 20. Nomia femoralis Pall., occasional (F., H.); J 21. Osmia caerulescens Z., not infreq. (M.); 22. O. notata F., freq. (H.); 23. O. | spinolae Schenck (H.); 24. Podalirius albigenus Lep., not infreq. (T,, S., H.) ; 25. P. crinipes Sm., freq. (H.); 26. P. magnilabris Fedtsch, occasional (F., H.) ; 27. P. pubescens F., freq. (S., T.), not infreq. (H.); 28. P. quadrifasciatus Vill., not infreq. (F., Tr., H.); 29. P. saMae Mor., infreq. (F., H.); 30. P. vulpinus Pz., freq. (M.), not infreq. (F., H.). Loew observed the following in Brandenburg (' Beitrage,' p. 43). — A. Diptera. Bombyliidae: i. Systoechus sulphureus Mikan., skg. B. Hy- menoptera. (a) Apidae: all skg.: 2. Andrena nasuta Gir. 5, po-cltg. ; 3. Bombus cognatus Steph. 5 ; 4. B. distinguendus Mor. 5 ; 5. B. lapidarius Z. 5 ; 6. B. latreillellus K. 5; 7. B. rajellus K. 5; 8. B. sylvarum Z. 5; 9- B. terrester Z. 5; 10. Coelioxys punctata Lep. 5 ; 11. Colletes nasutus Sm. ^ and S, numerous, the 5 po-cltg. ; 1 2. Epeolus variegatus Z., } and S ; 13. Megachile maritima A'. S ; 14. Psithyrus campestris Pz. 5; 15. P. rupestris Pz. 5 ; 16, Tetralonia pollinosa Lep. 5, going steadily from flower to flower. (^) Sphegidae: 17. Bembex rostrata Z. 5 and J, skg. C. Lepido- ptera. Rhopalocera'. i8. Pieris daplidice Z., skg. ; 19. Vanessa cardui Z., do. The following were recorded by the observers, and for the localities stated. — Knuth (Riigen). 5 bees, all skg. — i. Bombus agrorum Z'. 5» 2. B. hortorum Z. 5 and 5 ; 3- B. lapidarius Z. 5 and 5 ; 4. B. rajellus K. '^\ 5. B. sylvarum Z. J^. Schmiedeknecht (Thuringia), 3 bees — i. Andrena nasuta Gir. ; 2. Bombus hypnorum Z. 5 ; 3. B. pratorum Z. $. Gerstacker (Berlin), 2 bees — Osmia adunca Ltr. and O. spinolae Schenck. Hoffer (Steiermark), the humble-bee Bombus hypnorum Z. j. Schulz (Bozen), perforations made by the humble-bee Bombus terrester Z. Schletterer and von Dalla Torre (Tyrol), 6 bees — i. Bombus agrorum F. ; 2. B. sylvarum Z. ; 3. Osmia caerulescens Z. ; 4. O. rufa Z., very common ; 5. Podalirius acer\orum Z. ; 6. P. aestivalis Pz. 5. Friese (Hungary), the bee Eucera curvitarsis Mocs. H. de Vries (Netherlands), the humble-bee Bombus agrorum F. 5 (Ned. Kruidk. Arch., Nijmegen, 2. Sen, 2. Deel, 1875). 1969. A. sempervirens Z. ( = Caryolopha sempervirens Fisch. et Traut.). (Loew, 'Bliitenbiol. Floristik,' p. 280, Ber. D. bot. Ges., iv, 1886, pp. 163-4.) — This species is native to England and South Europe, and Loew examined it in the Berlin Botanic Garden, his account being somewhat as follows. — In the sky-blue flowers there are five hispid hollow valves of white colour in th throat of the corolla, which leave only an opening | mm. wide between them. Th( nectaries are situated at the bottom of the corolla-tube, and are covered by foi I BORAGINEAE 123 short inwardly directed hairy projections, rendering access to the nectar still more difficult. A bee which inserts its proboscis into the entrance of the flower touches the dilated stigma with one side of this organ and the anthers with the other, so that during further visits it can easily effect cross-pollination. {Cf. Lithospermum.) The stigma is in the middle of the anthers, so that automatic self-pollination is inevitable should insect-visits fail. Visitors. — Loew observed the honey-bee, skg., as a particularly frequent visitor in the Berlin Botanic Garden, so that the flowers can undoubtedly be referred to class Hb; the bees Osmia rufa Z,, and Halictus cylindricus F. ^. A butterfly ( Pieris brassicae Z.) was also seen, inserting its proboscis into the bases of the flowers. 1970. A. ochroleuca Bieb. (Loew, Ber. D. bot. Ges., Berlin, iv, 1886, pp. 162-3.) — The flower mechanism of this species agrees essentially with that of A. officinalis. Visitors. — Loew observed the following 7 bees in the Berlin Botanic Garden, partly skg., partly po-cltg. — I. Apis mellifica Z. 5, skg.; 2. Bombus agrorum F. 5^, do. ; 3. B. hortorum Z. 5, do.; 4. B. lapidarius Z. 5, do.; 5. B, pratorum Z. 5, do. ; 6. Osmia rufa Z. S, do. ; 7. Prosopis armillata Nyl. 5, po-dvg. 1971. A. italica Retz. (=A. paniculata Ail.). Visitors. — Schletterer and von Dalla Torre record 4 bees for the Tyrol. — I. Andrena thoracica F. ^', 2. Megachile muraria Z. 5; 3. Osmia rufa Z. 5, very common ; 4. Prosopis bipunctata F. 607. Lycopsis L. As Anchusa, but corolla-tube bent in the middle. 1972. L. arvensis L. ( = Anchusa arvensis Bieb.). (Herm. Miiller, ' Fertilisation,' pp. 411, 'Wait. Beob.,' Ill, p. 16 ; Kirchner, 'Flora v. Stuttgart,' p. 555 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 331 ; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 107, 164.) — The flower mechanism of this species agrees with that of Anchusa officinalis (chief type) as regards — secretion and concealment of nectar; nectar- guides and nectar-covers ; promotion of cross-pollination during insect-visits by projection of the stigma beyond the anthers; and the possibility of automatic seif-pollination towards the end of anthesis by fall of the corolla, causing the anthers to be drawn over the stigma. Visitors. — Heinsius observed the following in Holland. — A, Hymenoptera. Apidae: i. Bombus agrorum F. 5 and $, numerous; 2. B. hortorum Z. 5; 3. B. lapidarius Z. $; 4. B. rajellus K.; 5. B. scrimshiranus K. t> ; 6. Megachile maritima K. J ; 7. Melecta luctuosa Scop. ^ ; 8. Psithyrus ibarbutellus K. t>\ 9. P. campestris Pz. J; 10. P. rupestris F. t>; 11. P. vestalis \Fourcr. J. B. Lepidoptera. Rhopalocera: 12. Hesperia lineola 0.t>; 13- H. ihaumas Hfn. J and $; 14. Pararge megaera Z. $; 15. Pieris brassicae Z. $; 1 6. P. rapae Z. 5; 17. Vanessa urticae Z. (Bot. Jaarb. Dodonaea, Ghent, iv, 1892). Knuth (Rom) only noticed a hover-fly (Helophilus pendulus Z.), skg., and Herm. MuUer (Thuringia) a butterfly (Hesperia thaumas Hfn.), skg. J 24 AMGIOSPERMAE—DICOTYLEDONES 608. Nonnea Moench. 1973. N. puUa DC. ( = N. erecta Bernh., and Lycopsis pulla Z.). — The flowers of this species are of a dark or light purple-brown colour, rarely bright yellow or almost white. Visitors. — Friese observed the following 7 bees in Hungary.— I. Eucera hungarica Friese t>; 2. E. difficilis Perez; 3. E. interrupta Baer\ 4. E. nitidiventris Mocs. J ; 5. E. parvicomis Mocs. : 6. E. clypeaia Er. $ ; 7. E.. chrysopyga Pe'r. J. Schulz noticed perforated flowers here and there at Halle ('Beitrage'). 609. Symphytum Tourn. Homogamous bee flowers ; with nectar secreted by an annular ridge at the base of the ovary, and stored in the base of the corolla. According to Kerner, the peduncle bends down in late anthesis, so that the flower assumes a nodding or pendulous position, and the stigma is brought into the line of fall of the pollen, thus rendering automatic self-pollination inevitable. . M 1974. S. officinale ' Fertilisation,' pp. 408-9, L. (Sprengel, ' Entd. Geh.,' pp. 93-4 ; Herm. Muller, 'Weit. Beob.,' HI, p. 14; Kerner, 'Nat Hist. PL,' Eng. Ed. 1, II, p. 275; Kirchner, 'Flora v. Stuttgart,' p. 556; Knuth, ' Bloemenbiol. IMjdragen ' ; Schulz, ' Beitrage,' II ; Loew, ' BlUtenbiol. Floristik,' pp. 279-80.) — The drooping flowers of this species are white or violet-purple in colour, and their mechanism resembles that of Borago. The bell-shaped corolla is 1 4 mm. long, and it is contracted above for a distance of 8 mm., so that onK long-tongued insects can suck the nectar legitimately. At the junction of the narrow and broader portions of the corolla there are triangular hollow scales, alternating with the filaments and covering the spaces between them. The spiny edges of these appendagt - prevent visitors from probing for nectar between the filaments, and they are obliged to insert their proboscis in such a way that it must get dusted with pollen. The anthers converge to form a hollow cone surrounding the style, and they dehisce introrsely in the bud, some of the pollen falling into the apex of the cone and some remaining clinging to them. When an insect probes for nectar with its proboscis the anthers are displaced and some of the pollen falls out. The projecting stigma is the first part of the flower to be touched by a visitor, after which it is dusted by pollen. The arrangement is favourable to crossing by insect-visits, but should these fail automatic self-pollination apparently takes place. Kerner states that the flower is at first horizontal, but comes to droop in late anthesis owing to a bending Fig. 272. Symphyiunt officinale, L. (from nature). .-/. Flower seen from the side. B. Do., partly dissected. a, anthers, placed within the hollow scales ; .;, stigma. BORAGINEAE 125 of the peduncle, so that the stigma is brought into the line of fall of the pollen, when autogamy results. A proboscis of at least 11 mm. in length is required to reach the nectar by probing between the anthers, but one of 8 mm. would be able to get at it between the filaments. As already explained, however, the latter way is barred by means of hollow scales, the edges of which are beset with minute prickles. Insects with a proboscis less than 1 1 mm. long can therefore only secure the nectar by perforating the corolla. This is done extremely often by three kinds of humble-bee, i.e. Bombus terrester L. 5 (proboscis 7-9 mm.), B. pratorum Z. 5 (prob. 8-9 mm.), and B. lapi- darius L. 5 (prob. 9-10 mm.). The honey-bee also sucks nectar through the holes thus made, but Loew says that but little harm is done to the flowers in this way. Warnstorff describes the pollen-grains as white in colour, ellipsoidal, smooth, on an average 33 fx long and 27 /a broad. Visitors. — Herm. Miiller gives the following list, in which only those insects indicated by an asterisk (*) suck legitimately and effect pollination. — A. Coleoptera. Nitidulidae : r. Meligethes. B. Diptera. Syrphidae: 2. *Rhingia rostrata Z., skg. C. Hymenoptera. Apidae : 3. *Anthophora personata ///., skg. ; 4. *A. pilipes Z'. 5 ; 5. Apis mellifica Z. ^, carefully examining the bases of the flowers, but not perforating them ; only skg. through holes (made by Bombus terrester) already present (Westphalia and Strasburg) ; 6. Bombus agrorum P.^ and 5, very common, skg. legitimately (Westphalia and Strasburg) ; 7. B. lapidarius Z. 5, perforating the narrow part of the corolla-tube from outside ; 8. B. pratorum Z. 5, do. ; 9. *B. rajellus A'. ^ and ^ ; 10. *B. sylvarum Z. 5 and 5 ; n. B. terrester Z. j, as 7 (Westphalia and Strasburg); 12. Eucera longicornis Z. J, creeping right into the flowers ; 1 3. Halictus sexnotatus J^. 5, skg. through holes made by humble-bees ; 14. *Osmia aenea Z. 5, skg. (Strasburg); 15. *Xylocopa violacea Z. 5 and J, skg. (Strasburg). Loew observed the following bees in the Berlin Botanic Garden. — I. Anthidium manicatum Z., using holes made by humble-bees; 2. Andrena nitida Fourcr. 5, po-cltg. ; 3. Anthophora pilipes F. 5, skg. ; 4. Apis mellifica Z. 5, skg. through holes made by humble-bees ; 5. Bombus agrorum F. ^, skg. ; 6. B. hortorum Z. 5, skg. legitimately; 7. B. hypnorum Z. 5, skg.; 8. B. lapidarius Z. 5^, do., and perforating the flowers; 9. B. terrester Z. ^^ perforating the flowers; 10. Halictus sexnotatus K. 5, creeping into the flowers and trying to suck. Also in the var. (occineum Hort. — 11. Bombus pratorum Z. 5, vainly skg. The following were recorded by the observers, and for the localities stated. — Knuth (Kiel), the following 7 bees, skg. legitimately — i. Bombus agrorum F. 5; 2. B. hortorum Z. 5 ; 3- B. lapidarius Z. J ; 4. B. rajellus K. 5, as a nectar-thief; 5. Apis mellifica Z. ^ ; 6. Bombus lapidarius ^ ; 7. B. terrester Z. 5. von Fricken (Westphalia and East Prussia), the Nitidulid beetle Meligethes symphyti Heer. Alfken (Bremen), 5 bees — i. Bombus agrorum F."^; 2, B. arenicola Ths. j; 3. B. cierhamellus A". 5 ; 4. B. lucorum Z. 5 ; 5. B. ruderatus F. 5, skg- Krieger (Leipzig), the bee Eucera longicornis Z. J. MacLeod (Flanders), 8 humble-bees, 2 bees (Eucera sp. ; and Apis, stealing nectar), a hover-fly, and a Lepidopterid (Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 333). H. de Vries (Netherlands), 3 humble- bees — I. Bombus agrorum F. 5; 2. B. hypnorum Z. 5; 3. B. pratorum Z., var. subinterruptus K. 5 (Ned. Kruidk. Arch., Nijmegen, 2. Ser., 2. Deel, 1875). Scott- Elliot (Dumfriesshire), 3 humble-bees ('Flora of Dumfriesshire,' p. 123). I975. S. cordatum Waldst. et Kit. (Loew, ' Bliitenbiol. Floristik,' p. 280.)— This Hungarian species bears yellowish-white flowers, which are shorter than those 126 ANGIOSPERMAE—DICOTYLEDONES of S. oftlcinale, but with longer prickles on the triangular scales, according to a description given by Loew of plants cultivated in the Berlin Botanic Garden. 1976. S. tuberosum L. — Visitors. — The following were recorded by the observers, and for the localities stated. — Ducke (Trieste and Austrian Silesia) and Friese (Fiume and Hungary), as a typical visitor the bee Andrena symphyti Per. 5 skg. and po-cltg., S skg. Loew (Berlin Botanic Garden), 4 bees (Ber. D. boL Ges., Berlin, iv, 1886, p. 160) — i. Anthophora pilipes F., steadily skg.; 2. Apis mellifica Z. 5, po-cltg.; 3. Bombus hortorum L. 5, skg. ; 4. B. lapidarius Z. 5, skg. (.?). 1977. S. grandiflorum DC. — Visitors. — Loew (Berlin Botanic Garden) observed the same 4 bees as for S. tuberosum (loc. cit.). 1978. S. asperrimum Donn. — Visitors. — The following were recorded by the observers, and for the localities stated. — Morawitz (Caucasus), 2 bees — Bombus vorticosus Gerst., and Podalirius parie- tinus F. Loew (Berlin Botanic Garden), the honey-bee, skg. through perforations made by humble-bees, and the humble-bee Bombus terrester Z., vainly (?) skg. 1979. S. caucasicum Bieb. — Visitors. — Loew observed the bee Anthophora pilipes F. 5, skg., in the Berlin Botanic Garden. 1980. S. peregrinum Ledeb. (=S. asperrimum Donn^ according to the /W< Knuensis). — Visitors. — Loew observed 7 bees in the Berlin Botanic Garden. — I. Anthidium manicatum Z. ^, skg. through holes made by humble-bees ; 2. Anthophora pilipes F. $, skg. ; 3. Bombus agrorum F. 5, skg. and po-cltg. ; 4. B. hortorum Z. } and g, skg., and then visiting S. officinale; 5. B. hypnorum Z. 5, skg. legitimately ; 6. B. pratorum Z. §> perforating the flowers ; 7. B. terrester Z. 5, first trying to suck legitimately and then thrusting its proboscis into holes made by humble-bees. 610. Pulmonaria L. Heterostylous-dimorphous, usually homogamous humble-bee flowers ; with nectar secreted by the four-lobed base of the ovary, stored in the lowest part of the corolla, and protected from rain by a ring of hairs in the throat of the corolla. 1981. P. officinalis L. (Sprengel, ' Entd. Geh.,' p. 91 ; Hildebrand, Bot. Ztg., Leipzig, xxiii, 1865, pp. 13-15; Herm. MtiUer, ' FertiHsation,' pp. 412-14, ' Weit. Beob.,' Ill, p. 16; Kirchner, 'Flora v. Stuttgart,' pp. 558-9; Schulz, 'Beitrage'; Loew, ' Blutenbiol. Floristik,' p. 1392; Knuth, ' Bloemenbiol. Bijdragen.') — The flowers of this species are at first of a red colour, but subsequently become blue- violet, while their openings widen a little, enabling insects to insert their heads for a few mm. into the uppermost part of the corolla-tube, so that a proboscis of 8 mm. is long enough to reach the nectar secreted at the base. In short-styled flowers (Sprengel only noticed these) the stamens are situated in the opening of the corolla- tube (10-12 mm. long) and the stigma about its middle. In long-styled flowers the style is 10 mm. in length, so that the stigma is situated in the entrance of the coroU lin„ I BORAGINEAE 127 lube, and the stamens half-way down. The pollen-grains of the short-styled flowers are larger than those of the long-styled ones. Nectar-sucking bees or Lepidoptera touch the anthers or stigma in the entrance of the flower with their heads or the base of their proboscis, while the middle of the latter comes into contact with the reproductive organs placed half-way down the corolla-tube. Legitimate crossing is thus effected. Smaller insects which creep into the flowers bring about either legitimate or illegitimate union. Owing to the large amount of nectar in the flowers, their conspicuousness, and the fact that they flower very early in the year, when there are but few other competing species, insect-visits are very numerous. In correlation with this we find that the flowers are unable to automatically pollinate themselves (though Kerner says that the long-styled form may do so), and illegitimate union is ineff"ective. The experiments on artificial pollination carried out by Hildebrand have demonstrated that when flowers are fertilized by means of their own pollen, or that from others of the same kind, no fruits are set, while legitimate union is followed by about the same amount of fertility as in nature. It has further been shown by the researches of Cobelli (Nuovo Giorn. bot. ital., Firenze, xxv, 1893) ^^^ "o fruits are set when visitors are excluded. In wild plants investigated by Hildebrand the first flowers were often infertile, and this was almost always the case with the terminal one on each branch. He suggests that the first fact can be explained on the assumption that there are no visitors when the plant begins to flower ; while as to the second he suggests that the supply of nutriment passing up the branches is not sufiicient to reach their tips, but is appropriated by the fruits developing below. Schulz observed protandry as well as homogamy. Visitors. — Herm. Muller gives the following list for Westphalia (W.) and Thuringia (T.). — A. Coleoptera. Staphylinidae : i. Omalium florale Payk., freq., creeping about in the flowers (W.), B. Diptera. {a) Bombyliidae : 2. Bombylius discolor Mg., freq., but only during warm sunshine, casually skg. (W.) ; 3. B. major Z., do. (W.). (b) Syrphidae : 4. Rhingia rostrata Z., very common, skg. (W.). C. Hymeno- ptera. Apidae-, 5. Andrena gwynana A'. 5, po-cltg. (T.); 6. Anthophora pilipes F. $ and 5, numerous, skg. and po-cltg. (W., T.) ; 7. Bombus agrorum F. 5, freq., skg. (W.); 8. B. hortorum Z. $, very common (W.); 9. B. lapidarius Z. 5, skg. (W.) ; 10. B. pratorum Z. 5, skg. (W., T.); 11. B. rajellus K. 5, skg. (W., T.) ; 12. B. muscorum F. 5, skg. (W.); 13. B. sylvarum Z. $, freq., skg. (W., T.); 14. B. ter- rester Z. 5, skg. (W., T.); 15. Halictus cylindricus F. 5, po-cltg. (W.); 16. Osmia fusca Chr., 5 and S, freq., skg. and po-cltg. (W.) ; 17. O. pilicornis Sm. J and $, skg. and po-cltg. (W.) ; 18. O. rufa Z. t, skg. (W.). D. Lepidoptera. Rhopalocera \ 19. Rhodocera rhamni Z., freq., skg. (W.). The following were recorded by the observers, and for the localities stated. — Knuth, 5 bees, all skg. legitimately — i. Apis meUifica Z. 5 (2.5. '96, very numerous); 2. Anthophora pilipes Z'. 5 and $(25. 4. '95); 3. Bombus agrorum Z". ? (28. 4. '96); 4. B. hortorum Z. 5 (25. 4. '95); 5. B. lapidarius Z. ? (28. 4. '96). Bail (West Prussia), the butterfly Anthocharis cardamines Z. (Bot. Centralb., Cassel, ix, 1882). Loew (Brandenberg), 3 bees (' Beitrage,' p. 46) — i. Anthophora pilipes F. %, skg.; 2. Bombus agrorum F. 5, do. ; 3. B. lapidarius Z. 5, do., one 5 visited 100 flowers in about 4 minutes ; (Berlin Botanic Garden), the bee Andrena nitida Fourcr. 5, po-cltg. and, on a variety, 3 bees — i. Bombus agrorum F. 5; 2. B. hortorum Z. 128 A NGIOSPERMAE—DICOTYLEDONES 5, skg., and then visiting P. anguslifolia ; 3. Osmia rufa L. 5, skg. Alfken (Bremen ;. 4 bees — I. Bombus agiorum /^. $ ; 2. B. pratorum L. 9 ; 3. Osmia rufa Z. 5 and $ ; 4. Podalirius acervorum L. 5 and S; Schmiedeknecht (Thuringia), 2 bees — Bombus hortorum Z. 5, and B. pratorum Z. 5. Friese (Innsbruck), the bee Osmia uncinata Gersl., occasional. Hoffer (Steiermark), the humble-bee Bombus agrorum F. 5. Schulz noticed flowers perforated by Bombus terrester Z. Hermann Miiller (Kosmos, Stuttgart, xii, 1883, pp. 214 et seq.) noticed that the bee Anthophora pilipes F. ^ visited almost exclusively flowers either in the red stage or those just beginning to turn blue. Only a single individual went first to the blue flowers. In the same locality the bee Osmia rufa Z. and two humble-bees (Bombus hypnorum Z., and B. hortorum Z.) were also observed, visiting the blue flowers as well as the red, perhaps because during their brief stay they had not acquired the necessary experience. Miiller considers that the blue flowers serve a double purpose ; increasing the conspicuousness of the inflorescence, and also indicating to the more intelligent pollinators the flowers to which their visits should be limited to secure the best results for themselves and the plant. 1982. P. angustifolia L. ( = P. azurea ^^jj.). (Hildebrand, 'D. Geschlechts- Vert. b. d. Pfl.,' p. 37 ; Herm. Miiller, ' Alpenblumen,' pp. 263-4 ; MacLeod, ' Pyre- FlG. 273. Puliii07iaria ati£rtisti/olia, L.[a.hf-r\\e:rm.M\:\\\t^r). /I. Long-styled flower (x i.M. R. Do., partly dissected from the sied. C. Ovary and nectary of the same ( X 4i). D. Short-styled flower (X i4). .£. Do., partlydissected from the side. /^ Ovary and nectary of the same (X 4I). d? Corolla- limb of the same, cut through just above the stamens, and seen from above to show the nectar-cover ( x 4I). n, anthers; co, corolla; ^r, style; n, nectary; oj', ovary; s, sepals; sd, nectar-cover; s7, stigma. neenbl.,' p. 310; Schulz, 'Beitrage,' II, pp. 113-15.) — The plants of this specie! examined by Hermann Miiller in the canton GraubUnden were homogamous and markedly heterostylous-dimorphous, the two forms exhibiting strong secondarj differences besides those relating to the reproductive organs. The former wer found by Schulz to be less clearly pronounced in the Tyrol, and were in some case altogether absent. In that district, for example, the relative sizes of the different parts of the flowers were fairly constant, and the two forms usually agreed as to thi nectaries and ovaries. Schulz found the styles of short-styled flowers to be 4-4^ mml long, and those of long-styled ones 8-9 mm. The stigmatic papillae of the fonne ap^)eared to be larger than those of the latter. The flowers present the same coloui change as in P. officinalis, but the blue is darker and more intense. Visitors. — Loew saw the following in the Berlin Botanic Garden. — A. Diptera. Syrphidae : i. Cheilosia pulchripes Lw., settled on corolla ; Syrphus corollae F., do. B. Hymenoptera. Apidat : 3. Apis mellifica Z. 5, vainM BORAGINEAE 129 skg. ; 4. Bombus hortorum L. 5, skg. ; 5. Halictus nitidiusculus K. 5, creeping into the flowers ; 6. Osmia rufa L. j and $, skg. Also on the hybrid P. angustifolia x P. officinalis, 3 bees — i. Apis mellifica L. 5, vainly skg. ; 2. Bombus terrester L. j, skg. ; 3. Osmia rufa Z. J, do. The following were recorded by the observers, and for the localities stated. — Herm. Muller (Alps), 6 humble-bees, a Bombylius, a Rhingia, and a Vanessa. Schulz, humble-bees and Lepidoptera, also flowers perforated by the former. Mac- Leod (Pyrenees), a humble-bee. 1983. P. tuberosa Schrank (= P. angustifolia L., according to the Index Kewensts). — Haussknecht observed two forms of flower in this species at Kreuznach, i. e. gynodynamous with long calyx, and androdynamous with short calyx. 1984. P. mollis Wolff". (=P- montana Z^'.). (Kirchner, 'Flora v. Stuttgart,' p. 560; Loew, 'Bliitenbiol. Floristik,' p. 281.) — The flowers of this species agree with those of P. officinalis as regards colour change and mechanism, but are in all respects considerably larger. The calyx-tube is 11-14 mm. long, and its lobes 3-4 mm. While the corolla is in the red stage its lobes are erect and its diameter only 7-10 mm. By the time it has turned violet the lobes have spread out, increasing the diameter to 15 mm. The length of the corolla-tube up to its throat is 1 1-17 mm., the lower 8-9 mm. being uniformly cylindrical and 1-2-2^ mm. wide, and the upper part gradually widened into a funnel. In short-styled flowers the anthers and stigmas are respectively 9-13 mm. and 5-8 mm. above the receptacle, while in the long- styled ones they are 5-7 mm. and 11-13 ™"^- Loew adds that the hollow scales not mentioned in descriptions of Pulmonaria in systematic works, are here clearly recognizable as very low, small, hairy, bilobed projections within the corolla-tube. Visitors. — Loew observed the honey-bee, vainly skg., in the Berlin Botanic Garden. 1985. P. saccharata Mill. — Visitors. — Loew saw 2 bees, skg., in the Berlin Botanic Garden — Melecta armata Pz. 5, and Osmia rufa Z. $. 6n. Onosma L. Homogamous or feebly protandrous Lepidopterid flowers ; with nectar secreted by a disk under the ovary, and stored in the base of the tubular corolla. 1986. O. stellnlatum Waldst. et Kit. (Schulz, 'Beitrage,' II, p. 112.) — In this species the corolla-tube is bright yellowish-white above, passing into a darker shade below, 20-6 mm. in length and 6-8 mm. broad at its widest part. The short bifid tips of the anthers are at about the same level as the limb of the corolla, and their bases are laterally fused together for a short distance. As a rule the anthers dehisce introrsely immediately after the flower opens. They surround the style (20-7 mm. long), which at first does not project beyond them or scarcely so, but subsequently elongates so as to do so for 1-3 mm. The stigma matures at the same time as the anthers, or shortly afterwards. Only hawk-moths can suck the nectar legitimately, and Schulz actually saw some of the larger species visiting the flowers in the evening at Bozen, but owing to the unfavourable nature of the ground was unable to capture them. An insect DAVIS, lit V 130 ANGIOSPERMAE—DICOTYLEDONES of the kind when it approaches a flower first touches the stigma and then separates the united anthers, thus usually effecting crossing. Should insect-visits fail, automatic self-pollination is now and then possible, owing to the close proximity of the anthers and stigma just after the flowers open. Towards the end of anthesis, but not earlier as a rule, the corolla falls off" and the stigma is drawn between the anthers so as to effect autogamy. Visitors. — Vide supra. Ducke and Graeffe observed the very long-tongued bee Osmia macroglossa Gerst., as a frequent and exclusive visitor at Bozen. Schulz saw a number of flowers perforated at the base by the humble-bee Bombus terrester L. 1987. O. echioides L. (= O. Vaudense Gremit). (Briquet, '£tudes de biol. flor. dans les Alpes Occident.') — The flowers of this species are sulphur-yellow in colour, smell like honey, and secrete abundant nectar from five little scales at the base of the corolla. Briquet says they are visited by humble-bees, bees, and butter- flies, which regularly effect cross-pollination. The horizontal corolla is 20-3 mm. in diameter, and its entrance 5 mm. The long thin style projects 5 mm. from the flower, and is surrounded by the anthers, which are laterally fused at their bases. Kirchner states that, should insect-visits fail, automatic self-pollination can only be brought about by fall of the corolla. Visitors. — Vide supra. 612. Cerinthe L. Homogamous bee and humble-bee flowers ; with nectar secreted by the swolk fleshy base of the ovary, and sheltered in the uppermost part of the penduloi bell-shaped corolla. Kerner states that the peduncle bends down in late anthesis, causing the flowe to assume a nodding or pendulous position, and bringing the stigma into the line fall of the pollen, so that autogamy is inevitable. 1988. C. alpina Kit. (=C. glabra Mill.). (Herm. Mtiller, ' AlpenblumenJ pp. 264-6.) The pendulous flowers of this species are pollinated by humble- with a proboscis at least 9 mm. long. These visitors cling to the corolla froi below, and insert their proboscis into its narrow opening. They first touch widely exserted siigma, and their proboscis then strikes against the anthers, bl which they are dusted with pollen. Visitors. — Herm. Mttller observed the humble-bee Bombus alticola Krchb. the canton Graubtlnden. 1989. C. minor L. (Herm. Mttller, 'Weit. Beob.,' HI, pp. 9-14.)— In thi^ species the nectar is less deeply hidden than in C. alpina, so that bees wit a proboscis not less than 6 mm. long can reach the secreting base of the flowei In doing this they hold on to the corolla-lobes with their first and second of legs, further supporting themselves by placing the hind ones on the same neighbouring flowers, or on the bracts. The anthers are borne on short filaments, and their tips are closely applied to the style, while their margins in contact. The base of each anther-lobe is produced into a filiform appenda^ which interlocks with the corresponding appendage of the adjacent lobe of BORAGINEAE 131 neighbouring anther. The anthers thus collectively make up a pyramid closed all round, with its apex directed downwards, and its axis formed by the style. It becomes filled with the white powdery pollen when this is dehisced. As the corolla-lobes converge, an insect visitor (bee) inserts its proboscis into one of the clefts between them, causing two stamens to become to some extent separated. The anther pyramid is thus opened, and some of the dry powdery pollen falls upon the under-side of the bee's head. As the stigma projects from the flower it is first touched by the bee or humble-bee paying the visit, and pollen brought from other flowers will be transferred to it. Crossing by insect-visits is thus ensured, and the form of the inflorescence favours the transfer of pollen from one stock or at any rate one branch to another. As anthesis progresses an inflorescence continues to A. Fig. 374. 0>'/«M« a///«a, A'»y. (after Herm. Mailer). A. Flower soon after opening. B. Do., partly dissected from the side. C. Do., more strongly magnified. D. Completely expanded flower. (^, B, D X 4; C X 7.) a, a', a", regions of anthers ; co, corolla ; Jt, filament ; ^r, style ; », nectary ; ov, ovary; *, sepal ; st, stigma. elongate, and that part of it bearing fertilized flowers is directed obliquely upwards, while the part bearing unvisited flowers and buds is curved down and rolled inwards. It follows that old flowers in which the corolla is about to fall are feither directed obliquely upwards to a slight extent or are placed horizontally, while younger ones are directed obliquely or vertically downwards. The buds are on the rolled-up part of the inflorescence. Humble-bees only cling to flowers facing obliquely or directly downwards, the former being pulled into a vertical position by their weight. The honey-bee only visits flowers directed vertically downwards. All visitors therefore hang on to the bell-shaped corolla from below, and after a visit have to take wing in order to reach another blossom. Their flight is always to another branch or another stock ; at least Hermann MuUer never saw two flowers on the same inflorescence visited in succession. K 2 132 ANGIOSPERMAE—DICOTYLEDONES Visitors. — The following were recorded by the observers, and for the localities stated. — Herm. Miiller (his garden at Lippstadt), the honey-bee and two humble-bees (Bombus agrorum F. ^, and B. terrester Z. 5), skg. actively and persistently. Loew (Berlin Botanic Garden), 4 bees, all skg. and po-cltg. — i. Apis mellifica Z. g; 2. Bombus agrorum F. ^-y 3. B. lapidarius Z. 5; 4- Osmia rufa Z. 5- Schulz observed flowers perforated by humble-bees. iggo. C. major L. (Knuth, ' Bltitenbiol. a. d. Ins. Capri'; Herm. Miiller erroneously describes C. alpina under this name in his *Alpenblumen,') — This species bears homogamous humble-bee flowers. Visitors. — I observed (April, 1892) 2 long-tongued bees (Anthophora pilipes/'., and A. femorata Oliv.) in the crater of the Solfatara. Morawitz noticed the bee Osmia cerinthidis Mor. 1991. C. aspera Roth. (Comes, * Ult. stud.') — Comes describes this species as self-fertile. 613. Echium Tourn. Mostly protandrous bee-flowers ; with nectar secreted by the fleshy base of the ovary, and concealed in the contracted lower part of the funnel-shaped corolla-tube. \ Sometimes gynodioecious, more rarely gynomonoecious. 1992. E. vulgare L. (Sprengel, *Entd. Geh.,' pp. 99-101; Herm. MallerJ 'Fertilisation,' pp. 418-21, ' Alpenblumen,' p. 262, *Weit. Beob.,' Ill, p. 14; Schulz, 'Beitrage,' I; Kirchner, 'Flora v. Stuttgart,' pp. 557-8; Jordan, Ber. D.j bot. Ges., Berlin, x, 1892, pp. 583-6; Knuth, 'Gnmdriss d. BlQtenbiol.,' pp. 77-8[ ' Bloemenbiol. Bijdragen'; Loew, ' Blutenbiol. Floristik,' pp. 391, 399.) — The largel blue flowers of this species make the plant extremely conspicuous from a distance, sol that it is visited by a very large number of insects, especially bees, hover-flies,! butterflies, and moths. In spite of their great difference in size all these visitors] are adapted to eff^ect crossing, whether they probe for nectar or come for the poUen. In the protandrous flowers the narrowest part of the corolla surrounds the nectar^] and is directed obliquely upwards, its bend corresponding with that of a bee'sj proboscis. The broadened bases of the five filaments are fused with its basal] portion for a distance of 4 mm. At the place where they become free the corolla- tube rapidly widens, so that even the largest humble-bees can conveniently insert] their head and a part of their thorax into the flower, while the smaller ones can] creep completely into it. The filaments run horizontally together from the place] where they become free, and the four lowest ones project 7 mm. beyond the lowei margin of the entrance to the flower, forming convenient alighting-rods for humble-1 bees. Where the uppermost stamen, on the other hand, becomes free, it at once] bends down, dividing the access to the nectar-secreting base of the flower into right and left portions, and then runs horizontally to the opening of the flower with the otht filaments. The free ends of all the stamens are turned slightly upwards, while the anthers dehisce immediately the flower opens, and their pollen-covered surfaces fac in the same direction. It follows that no bee can settle on the flower without getting its under-side dusted with pollen, for the larger humble-bees support their thorax and smaller ones their abdomen on the long stamens, while the ventral surface of a BORAGINEAE 133 smaller bee at least comes into contact with the anther of the short stamen situated in the entrance of the flower. The style runs between the stamens, and its end divides into two short stigmatic branches. When the flower opens it is so short as scarcely to reach the entrance, and is quite straight with its branches closely apposed. In the course of anthesis it elongates till it projects ro mm. beyond the entrance of the flower, and bends slightly upwards, while its branches diverge. At this stage the style projects further and is bent more strongly upwards than any other part of the alighting platform, so that neither large nor small insects can settle without bringing their ventral surface into contact with one of the stigmatic branches. The cross- pollination brought about in this way is ensured by the projection of the stigma, even if at the time when it matures some pollen remains clinging to the anthers. Jordan points out that it is sometimes effected by insects as they settle, and sometimes as they withdraw and fly away. Schulz observed homogamy in rare cases. Hermaphrodite flowers are not the only kind found in this species, for stocks very infrequently occur which bear female ones. In these the corolla is much smaller and the style shorter, while the stamens are short and only produce abortive pollen-grains. Between herma- phrodite and female flowers there are also transitional stages, in which one, two, or three stamens are fully developed and the remainder re- duced. Schulz states that female stocks are very widely distributed, and sometimes as many as three- quarters of the plants in a particular locality are of this kind. He even found places here and there, e.g. at CoUeda, where nothing but female stocks were to be seen. The size of the female flowers varies con- siderably, the corolla being 11-14 mm. long in the larger ones, and only 7-9 mm. in the small ones. Schulz often found the female stocks to be remarkably vigorous. He explains the development of female flowers as due to the excessive strain on the supply of food resulting from the production of infioreficences with a very large number of flowers. Visitors. — Herm. Miiller (H. M.) for Westphalia and Thuringia (T.) and Buddeberg (Budd.) for Nassau give the following list. — A. Coleoptera. Oedemeridae : i. Oedemera virescens L., searching for nectar (H. M.). B. Diptera. (a) Conopidae : 2. Physocephala rufipes F., skg. (H. M.) ; 3. P. vittata F., do. (H. M.) ; 4. Sicus ferrugineus Z., do. (Budd.). {b) Syrphidae : 5. Helophilus trivittatus F., po-dvg. (H. M.) ; 6. Melanostoma ambigua Fall, do. (H. M.) ; 7. Microdon devius Z., do. (Budd.) ; 8. Rhingia rostrata Z., skg. (H. M.) ; 9. Syrphus arcuatus Fall,, po-dvg. (H. M.) ; 10. S. pyrastri Z., do. (H. M.). C. Hymenoptera. (a) Aptdae: 11. Andrena albicrus K. J, skg. (H. M.); 12. A, Fig. 275. Echium vtdgare^ L. (after Herm. Miiller). (i) An older flower, seen from the side (its actual position is horizontal). (2) Basal transverse section of a flower, d/, corolla; gy style ; A, nectar-passages ; k^ sepals ; «, stigma ; st, stamens. 134 ANGIOSPERMAE—DICOTYLEDONES fulvicrus K. J, do. (H. M.); 13. A. hattorfiana F. S, do. (H. M., T.) ; 14. A. labialis K. J, do. (H. M.) ; 15. Anthidium manicatum L. t, do. (Budd.) ; 16. A. oblongatum Llr. 5, do. (Budd.) ; 17. Anthophora furcata Pz. $ and J, skg. and po-cltg. (H. M., T.) ; 18. A. quadrimaculata F. 5 and $, freq., do. (H. M., T.); 19. Apis mellifica Z. 5. exceedingly freq., skg. (H. M.) ; 20. Bombus agrorum F. $ and 5. skg. (H. M.) ; 21. B. hortorum L. $, 5 and J, do. (H. M.); 22. B. hypnorum L. 5, do. (H. M.); 23. B. lapidarius L. $, 5 and J, do. (H. M.); 24. B. pratorum Z. 5, do. (H. M.); 25. B. rajellus K. ^, do. (H. M.) ; 26. B. sylvarum Z. 5 and 5> skg. and po-cltg. (H. M.); 27. B. terrester Z. 5 and J, skg. (H. M.); 28. Ceratina albilabris F. 5, do. (Budd.) ; 29. C. cyanea K. ?, do. (H. M.) ; 30. Chelostoma nigricorne Nyl., J and $, do. (H. M.); 31. Coelioxys conoidea Klg. 5, do. (H. M.); 32. C. quadridentata Z. 5 and S, freq., do. (H. M.); 33. C. simplex Nyl. 5, do. (H. M.) ; 34. C. umbrina Svi. 2, do. (H. M.) ; 35. Diphysis serratulae Pz. 5 and J, very common, skg. and po-cltg. (H. M.); 36. Eucera longicomis Z. S, skg. (H. M.); 37. Halictus albipes F. t>, do. (H. M.), ? po-dvg. (Budd.); 38. H. cylindricus F. $ and S, skg. (H. M.); 39. H. nitidiusculus K. 5, po-cltg, (H. M.) ; 40. H. nitidus Schenck 5, skg. (H. M.) ; 41. H. sexnotatus K. ?, do. (H. M.); 42. H. smeathmanellus K. 5, do. (H. M., T.) ; 43. Megachile circumcincta K. $, do., skg. and po-cltg. (H. M.); 44. M. willughbiella K. J, skg. (H. M.); 45. Melecta luctuosa Scop. ?, do. (H. M., T.); 46. Nomada sexfasciata Pz. 5, do. (H. M.) ; 47. Osmia adunca Lir. 5, very common, skg. and po-cltg. (H. M., Budd.) ; 48. O. aenea Z. 5 and $, skg, and po-cltg. (H. M.) ; 49. O. caementaria Gersi. j, do. (H. M., Budd.), building its cells in hollows in stones, and feeding its young entirely on Echium nectar and pollen ; 50. O. fusca Christ. ?, skg. and po-cltg. (H. M.); 51. O. leucomelaena K. 2, po-cltg. (H. M.) 52. O. rufa Z. $, skg. (H. M., Budd.); 53. Prosopis hyalinata Sm. ?, do. (H. M.) 54. Psithyrus barbutellus K. 5, do. (H. M.); 55. P. campestris Pz. j and $, do (H. M.); 56. P. rupestris F. j, do. (H. M.); 57. P. vestalis Fourcr. %, do. (H. M.) 58. Saropoda bimaculata Pz. 5 and i, very common, skg. (H. M.) ; 59. Stelis breviuscula Nyl. J, skg. (H. M.) ; 60. S. phaeoptera K. %, do. (H. M.). (<5) Chry- sididae: 61. Cleptes semiauratus Z., skg. (H. M.). (f) Sphegidae: 62. Ammophila sabulosa L. 5, skg. (H. M.) ; 63. Crabwro patellatus v. d. L. 5 and $, skg. (H. M.) ; 64. Psammophila affinis K. 2, do. (H. M.). {d) Vespidae : 65. Odynerus parietum Z. J, skg. (H. M.). D. Lepidoptera. All skg. (a) Noduidae : 66. Plusia gamma Z., freq. (H. M., Budd.). {b) Rhopalocera : 67. Colias hyale Z. (H. M., T.) ; 68. Epinephele janira Z. (H. M.); 69. Hesperia comma Z. (H. M.); 70. H. sylvanus Fsp. (H. M.) ; 7i.LycaenaeuphemusZ^<5. (Budd.); 72. L.sp. (H.M.); 73. MelitaeacinxiaZ. (H.M.); 74. Pieris brassicae Z. (H. M.); 75. P. rapae Z. (H. M., T.); 76. Vanessa urticae Z. (Budd.). (f) Sphingidae : 77. Macroglossa stellatarum Z. (H. M., Budd.) ; 78. Zygaena lonicerae Esp. (H. INI., T.). Miiller adds the following note to his Hst ('Fertilisation,' pp. 420-1). — ' A review of this long list of insects, many of which frequent the flowers of Echium in great numbers, shows that the great majority come seeking honey, and only use the stamens as a landing-place. The females of bees with abdominal collecting-brushes, without any special effort, sweep up pollen with their abdominal brushes, filling them after a few visits. The flower is thus so convenient for them that several of these bees {Osmia adunca and 0. caementaria) resort to it exclusively, both for their own food and for that of their larvae. Syrphidae also make frequent use of the pollen, while bees with tibial or femoral collecting-baskets seldom gather it, and all other insects come solely for the sake of the honey.' Loevv observed the following. — I. In Mecklenburg (M.) and Brandenburg (B.) ('Beitrage,' p. 43). — A. Diptera. Tabanidae: i. Tabanus rusticus Z. $, skg, (B.). B. Hymeno- ptera. Apidae ; 2. Anthophora nidulans F. j (B.) ; 3. A. quadrimaculata /'. 5 (M.) ; BORAGINEAE 135 4. Bombus distinguendus Mor. 5 and J, skg. (M.) ; 5. B. sylvarum L. 5, do. (M.) 6. Coelioxys tricuspidata Forst. j, do. (M.) ; 7. Heriades nigricornis Nyl. j, do. (M.) 8. Megachile argentata F. 5 and J, do. (M.) ; 9. M. centuncularis L. $, do. (M.) 10. M. maritima K. $, do. (M.) ; 11. Osmia adunca Ltr. 5, po-cltg. (M.); 12. O aurulenta Pz. 5, do. (M.) ; 13. O. caementaria Gerst. S, skg, (M.); 14. O. solskyi Mor. 5, po-cltg. (M.); 15. O. bicornis Z. 5, skg. (B.) ; 16. Prosopis confusa Nyl. p, do. (M.). II. In Silesia (op. cit., p. 27). — A. Diptera. [a) Bombyliidae: i. Bombylius minor Z,, skg. {V) Syrphidae 2. Syrphus seleniticus i?^. B. Hymenoptera. {a) Apidac. 3. Apis mellifica Z. 5, skg. ; 4. Bombus cognatus Steph. 5, po-cltg. ; 5. B. confusus Schenck 5, do. ; 6. B rajellus K. 5, do. ; 7. B. sylvarum Z. 5, skg. ; 8. Coelioxys octodentata Lep. J, do. 9. C. punctata Lep. 5, do.; 10. Colletes nasutus Sm. 5 and J skg., 5 also po-cltg. 11. Megachile maritima K. 5, skg.; 12. Osmia adunca Ltr. 5 and J do., 5 do. 13. O. tridentata Duf. S( Perr. 5 (?), skg.; 14. Psithyrus rupestris F. 5, do. 15. Saropoda rotundata Pz. S, do. {b) Sphegidae: 16. Bembex rostrata Z. 5 and S skg.; 17. Cerceris arenaria Z. C. Lepidoptera. All skg. {a) Hc^peridae 18. Hesperia comma Z. {Jb) Noctutdae-. 19. Plusia festucaeZ. ; 20. P. gamma Z. (f) Rhopalocera: 21. Aporia crataegi Z. ; 22. Vanessa urticae Z. III. In Switzerland (op, cit.), p. 61. — Two humble-bees (Bombus sylvarum Z. 5, skg. ? and B. variabilis Schenck, var. tristis Seidl. J, do.) and the hawk-moth Zygaena pilosellae Esp. The following were recorded by the observers, and for the localities stated. — Knuth (Schleswig-Holstein), 5 bees (i. Apis mellifica Z. 5^ ; 2. Bombus agrorum F. ^; 3. B. lapidarius Z. 5 and 5 ; 4. B. hortorum Z. 5, 5 and 5 ; 6- B. rajellus K. j), a hover-fly (Rhingia rostrata Z.), and 2 Lepidoptera (Pieris napi Z., and Plusia gamma Z.) : all skg. Wiistnei (Alsen), the bee Halictus quadristrigatus Lir. Herm. Miiller (Alps), 1 7 bees and 5 Lepidoptera. von Fricken (Westphalia and East Prussia), the Nitidulid beetle Meligethes tristis Strm. Gerstacker (Berlin), 3 bees — i. Coelioxys quadridentata Z. ; 2. Osmia adunca Ltr. ; 3. O. spinolae Schenck. Alfken (Bremen), 6 bees — i. Coelioxys rufescens Lep. 5 and J, skg. ; 2. Eriades nigricornis Nyl. 5 and $ ; 3. Halictus morio Z". j ; 4. Osmia rufa Z. 5 ; 5. 0. adunca Ltr. 5 and J ; 6. Podalirius bimaculatus Pz. 5. Schmiedeknecht (Thuringia), 2 bees — Osmia adunca Ltr., and 0. spinolae Schenck ( = O. caementaria Gerst.). Schenck (Nassau), 5 bees — 1. Ceratina cucurbilina Rossi; 2. C. cyanea K.', 3. Osmia adunca Ltr.; 4. O. spinolae Schenck ; 5. Podalirius bimaculatus Pz. Friese, for Hungary (H.), Baden (B.), Bozen (Bz.), Innsbruck (I.), Mecklenburg (M.), and Switzerland (S.), 14 bees — I. Biastes brevicornis Pz. 5, not infreq. (Bz., Siders, FL); 2. Crocisa major Mor., one (H.); 3. C. ramosa, Lep. (Bz., H.) ; 4. C. truncata Per. a $ (H.); 5. Eucera tricincta Er. (M.) {teste Konow) ; 6. E. dalmatica Lep. (H.) ; 7. Osmia adunca Ltr., freq. (B., M., H.) ; 8. O. claviventris 2'hs. (M., Thuringia) ; 9. O. insularis Schmiedekn. (Mallorca); 10. O. lepelletieri Pe'r., freq. (I., S.); 11. O. spinolae Schenck 5 (B.) and 6 (M.); 12. Podalirius crassipes Lep. a S (S.); 13. P. quadrifasciatus Vill., not infrequent (Thuringia, H.) ; 14. P. vulpinus Pz. not infreq. (B.), freq. (M.V Frey-Gessner (Switzerlana), 2 bees — Osmia rufa Z., and O. dalmatica Mor. $ and 6. Morawitz (Caucasus), 5 bees — i. Bombus haematurus Krchb. ; 2. Eucera similis Lep. \ 3. E. spectabilis Mor. ; 4. Podalirius raddei Mor. ; 5. P. tarsatus Spin. Smith (England), 3 bees — Ceratina cyanea K., and Megachile argentata F, von Dalla Torre (Upper Austria), 3 humble-bees — i. Bombus arenicola Thorns.; 2. B. hortorum Z. ; 3. B. senilis F. (=B. variabilis Schmiedekn.) : (Tyrol), 2 bees (Andrena thoracica F. 5, and Nomada lateralis Pz. 5) and 2 humble-bees (Bombus ruderatus F., and B. sylvarum Z. 5 and 5, extremely freq.). Schletterer, for Tyrol and Pola (P.), 136 ANGIOSPERMAE—DICOTYLEDONES 9 bees — I. Andrena thoracica F.; 2. Bombus agrorum F.; 3. B, pomorum Z. ; 4. B. ruderatus F. ; 5. B. sylvarum L. ; 6. B. terrester L. (P.) ; 7. Ceratina cucurbi- tina Rossi (P.) ; 8. Megachile lefeburei Lep. (P.) ; 9. Nomada xanthosticta ^. Kohl (Tyrol), the fossorial wasp Crabro peltarius Schreh. 5 and i. Ducke (Trieste), 3 bees — I. Osmia adunca Ltr. Q and S, freq. ; 2. O. notata F. 5, freq. ; 3. O. spinolae Schenck 2 and S, rare. Heifer (Steiermark), the bee Rhophites quinquespinosus Spin. Dours (Paris), the bee Anthophora femorata Ltr. ( = Podalirius femoratus Oliv\ freq. Heinsius (Holland), 4 humble-bees, skg. (i. Bombus agrorum F. S and 5; 2. B. terrester Z. S ; 3. Psithyrus vestalis Fourcr. ; 4. P. campestris Pz. 2 S), a short- tongued bee (Halictus sexcinctus F. $, skg.), 2 hover-flies (Rhingia campestris .^. i, skg., and Melanostoma hyalinata F. i, po-dvg.), and 2 butterflies, skg. (Rhodocera rhamni Z. 5> and Pieris rapae Z. $ (Bot. Jaarb. Dodonaea, Ghent, iv, 1892, pp. 108-9). H. de Vries (Netherlands), 5 bees — i. Bombus agrorum Z'. 5; 2. B. elegans Seidl. 4; 3. B. terrester Z. S ; 4. Psithyrus campestris Pz. J ; 5. P. vestalis Fourcr. J (Ned. Kruidk. Arch., Nijmegen, 2. Ser., 2. Deel, 1875). MacLeod (Flanders), 4 humble-bees, the honey-bee, a short-tongued bee, a hover-fly, and a moth (Plusia sp.) (Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 334-5): (Pyrenees), on the vax. pyrenaica, numerous long-tongued and some short-tongued bees, also some Lepidoptera, Bombyliids, and hover-flies (op. cit., iii, 189 1, p. 310). 1993. E. rosiilatum Lange. (Loew,Ber.D.bot.Ges.,Berlin,iv, 1886, pp. 153-5.) — The flower mechanism of this species is similar to that of E. vulgare, but the corolla is shaped more like a handbell, while its greater length and the presence of various constrictions render the nectar more inaccessible, so that an insect requires a proboscis 9-10 mm. long in order to reach it. Visitors. — Loew observed the following in the Berlin Botanic Garden. — Two humble-bees (Bombus agrorum F., and B. hortorum Z.) skg. legitimately, and one (B. terrester Z.) perforating the flowers and stealing nectar. Also 2 po-dvg. hover-flies — Pipiza chalybeata Mg., and Syritta pipiens Z. 1994. £. italicum L. (=E. altissimum /