256 ANGIOSPERMAEDICOTYLEDONES 



flowers they are more feebly developed, but nectar is secreted to the same extent as 

 in the large flowers. Insect-visits are equally numerous in the various types. 

 Warnstorf describes the pollen-grains as yellow in colour, smooth, almost globular 

 when examined in water, up to 56 /x in diameter. 



There is a curious and abnormal form of the variety apeiala, which Wetterhahn 

 discovered and first described. This has been thoroughly examined by F. Pax from 

 plants cultivated for years in the Berlin Botanic Garden. The description ' variety 

 apetala' does not correspond to actual facts, for both perianth whorls are present. 

 The calyx forms a bell-shaped tube, the corolla is green and consists of four small 

 lancet-shaped or ovate petals. Stamens are absent ; a number of style-like threads 

 project from the corolla. There is, of course, no seed -formation ; reproduction can 

 only be effected vegetatively. 



Geisenheyner (D. bot. Monatsschr., Arnstadt, xv, 1897) also observed at 

 Kreuznach a reduction of the stamens in this species. The turnpike mechanism was 

 absent, and therefore also the hinge-joint at the apex of the filament. The latter 

 bore a connective, evidently formed by two united threads, facing only towards the 

 side of the upper lip, and cleft at the tip into two somewhat unequal parts, each 

 bearing a free anther-lobe. That attached to the longer part had already dehisced, 

 and almost entirely shed its pollen ; the other had not yet done so, and was still 

 closely packed with pollen. 



Visitors. The pollinators are exclusively long-tongued bees. Other insects 

 are unbidden guests. Herm. Miiller (H. M.) and Buddeberg (Budd.) observed the 

 following in Central and South Germany. 



A. Diptera. {a) Bombyliidae : i. Bombylius canescens Mik., skg. (H. M., 

 Thuringia). (3) Conopidae: 2. Dalmannia punctata F., in the flowers (Budd.). 

 B. Hymenoptera. Apidae: 3. Andrena sp., S, skg. (H. M., Strasburg); 4. Anthi- 

 dium manicatum L. 5 and 5, repeatedly skg. (H. M.) ; 5. Anthophora personata 

 ///. 5 and J, skg. (H. M., Strasburg); 6. Bombus agrorum F. 5, do. (H. M., 

 Strasburg); 7. B. pratorum Z. 5, do. (H. M., Thuringia) ; 8. B. sylvarum L. 9 and 5, 

 do. (H. M.) ; 9. Chelostoma nigricorne Nyl. 5, do. (H. M., Strasburg ; Budd.) ; 

 10. Eucera longicornis L. $, do. (Budd.); 11. Halictus villosulus K. 5, creeping into 

 the flowers (Budd.); 12. Megachile centuncularis Z. J, skg. (H. M., Strasburg); 

 13. M. fasciata Sm. $, do. (H. M.) ; 14. M. sp. S, do. (H. M., Strasburg) ; 15. Osmia 

 adunca, Ltr. S, do. (H. M., Strasburg; Budd.); 16. O. aenea Z. $, do. (H. M., 

 Strasburg); 17. O. rufa Z. 5, do. (H. M.); 18. Xylocopa violacea Z., do. (H. M., 

 Strasburg). Unbidden guests were also noticed butterflies (Pieris sp., also recorded 

 by Sprengel), and the moth Plusia gamma Z. Herm. Miiller further records 5 small 

 bees (i. Halictus morio F. ^, 2. H. nitidiusculus K. ^\ 3. H. nitidus Schenck 5; 



4. H. sextrigatus Schenck 5 ; 5. Prosopis communis Nyl. S and j) obtaining nectar 

 by operating the lever mechanism, but not sufficiently to be of use. 



The following were recorded by the observers, and for the localities stated. 



Sprengel, Hildebrand, and Schulz, humble-bees. Knuth (Kiel Botanic Garden), 

 2 long-tongued bees Bombus agrorum F. 5, skg., and Eucera longicornis Z. j and 5, 

 do. Herm. Miiller (Alps), 5 humble-bees, a beetle, and lo Lepidoptera. Loew 

 (Brandenburg) ('Beitrage,' p. 45). A. Hymenoptera. Apidae: i. Anthophora 

 aestivalis Pz. J, skg. ; 2. A. pilipes F. 5, skg. and po-cltg. ; 3. Bombus hortorum Z. 

 % do.; 4. Halictus xanthopus K. 5, po-cltg. B. Lepidoptera. Sphingidae: 



5. Macroglossa bombyliformis O., skg. : (Tyrol), the mason-bee Chalicodoma 

 muraria Retz. j, skg. and po-cltg. (op. cit., p. 62) : (Berlin Botanic Garden), the bee 



