POLLINATION iii 



Stigma, overhung and wholly hidden from the anther 

 by a projecting beak-like hood of it (stigma) known 

 as ROSTELLUM, on the back of which are the two 

 poUinia. The pollen-masses thus situated have ab- 

 solutely no chance of reaching the stigma without 

 external help. The situation of the anthers, at a lower 

 level than the stigma as in many Cruciferce, or of the 

 stigma remote from the anthers as in some Caryo- 

 phyllacece, or where the dehiscent face of the anthers 

 is extrorse as in Gloriosa superba — these are also 

 adaptations unfavourable to self-pollination. Other 

 similar adaptations for preventing self-pollination will 

 be treated of in another chapter. 



Fourth. Dimorphic flowers are common in Gerani- 

 acece, as Biophytum (lak-chana or ban-narenga, and 

 other plants of this genus); in Linacece, as Ery- 

 throxylon lucidum, E. obtusifolium, Reinwardtia tri- 

 gyna, Hugonia Mystax; in Rubiacece, as Adeno- 

 sacme longifolia, Randia uliginosa, Chasalia curvi- 

 flora, Knoxia corymbosa; in BoraginacecB, as Macro- 

 tomia perennis, M. Benthami; in most plants of the 

 genus Primula; in some ChenopodiacecB, as Beta vul- 

 garis, and in some Oleacece, as mallika, juin, kund, 

 Jasviinum, &c. 



Fifth, cleistogamous flowers. Commelina benghal- 

 ensis, known in Bengali by the name of dholapata 

 or jata - kanshira, bears cleistogamous flowers (fig. 

 103). The herb grows as a small weed in ditches 

 and marshy ground, and flowers in the beginning of 

 spring. It bears handsome small open blue flowers 

 in the axils of the upper leaves, with some fertile and 

 some barren stamens and a 2-3-celled ovary. But 

 the plant also bears small inconspicuous closed flowers 

 under the ground. The seeds of these latter flowers 

 have been found to be highly potent, whereas the 



