POLLINATION 113 



bisexual flowers are occasionally met with among 

 both male and female aerial spikes. In Malacca- 

 jhangi {Aldrovanda vesiculosa), lakchana {Biophytuvi 

 sensitwum, a common roadside herb), alak-lata 

 (Cuscutd), and fasminum, cleistogamy has been 

 observed from time to time. Pseudo-cleistogamy 

 has been observed in amrul {Oxalis corniculata), 

 barha-nunia-shag {Portulaca oleraced), and Drosera 

 Burmanni. 



Sixth. Among open homogamous flowers {Clias- 

 mogamy) autogamy has been observed in Portulaca 

 oleracea and Mirabilis Jalapa (krishna-kali), in which 

 latter flower the filaments and the style roll together 

 spirally, and thereby get so entangled that the pollen 

 and the stigma come into contact. In Malacca-jhangi 

 {Aldrovanda vesiculosa) the anthers get bound to the 

 stigma by pollen-tubes. In gandha-raj the stigma 

 rises to the mouth of the corolla-tube and is closely 

 embraced by the mature anthers, which on dehiscence 

 dust the receptive surface of the stigma with pollen- 

 grains. In many Cruciferce during flowering the 

 filaments elongate, so that the anthers, which to 

 begin with are at a lower level, finally reach the 

 level of the stigma and pollinate it. In Grewia 

 asiatica (phalsa) (see fig. 169) and some Malvacece 

 the stigmas, which are at a higher level, either con- 

 tract or bend so as to reach the level of the anthers 

 and get pollinated. In Opuntia (nag-phani) and 

 many CompositcB the filaments are from, the first in- 

 wardly curved; later on, they curve still farther in- 

 wards, until the anthers come in contact with the 

 stigma, or are perpendicularly above the stigma and 

 able to shed the pollen upon it. The effect of auto- 

 gamy is very varied. For instance, in some it is 

 absolutely sterile, in some it is equally potent with 



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