19. Observations on Pollination in Alysicarpus. 



By K. Cheriatst Jacob, L.Ag. {Formerly Post-Graduate 



Student, Pusa), Agricultural College, Goimbatore. 



There are more than half a dozen species of Alysicarpus 

 which are verv common throughout the plains of India. 

 According to Hooker 1 "Species of Alysicarpus are weeds 

 everywhere in the tropics of the old world." They form some 

 of the chief constituents of the pastures of Southern India, 

 and in some places whole areas are covered by these plants, 

 and they can be seen cropping out from among the tufts of 

 grasses. In January last during my tours in Godavan I 

 observed that the flowers of Alysicarpus have a strong explo- 

 sive mechanism. This year, at Goimbatore, I extended my 

 observations on this subject, the results of which I propose to 



lay before you in this paper. ., . 



The Indian species of Alysicarpus may be divided into 

 two groups according to their differences in floral structure and 

 modes of pollination. One of these groups is characterised by 

 a large glnmaceous calyx divided to the base, as in A. rugosus 

 A. longifolius, A. bupleurifolius and A. be gaumensis In this 

 group the corolla does not open before the calyx ; the calyx 

 opens out by the flexion of its base possibly due to the , actum 

 of the sun/ and closes again when the sun gets less poaerf nl, 

 and either one or both of the geminate flowers arc .ready for 

 pollination at one time in an inflorescence, so that a angle 

 ■spike may take a, long time-sometimes even three aeeks-tor 

 the complete fcrlilisation of the whole series ff , linvirp01is 



In the other group the calyx is small ««d notjaumaeeo u£ 

 and possesses a distinct calyx tube and slender ^x teeth as 

 exemplified by A. vaginalis, A. momlifer ^ A" h amo^u g Lo 

 this SUson the corolla can open independently of the catf*. 



Vgain a number of flowers, as ^y™}?j53£ of which 

 taneonsh open on any inflorescence, the fertilisation ot 



will be completed in three or four days. 



The structure of the other P^"^ ^hdp 

 less similar in both the groups, and a kno" Jeog e ° ^ 



one in undemanding the flora meehan sm. K rugosns, .y 

 reason of its possessing rather large fl»» »» as Qm 



being a familiar species m the plains, ma> 



tVPe The rose-red corolla has »»^%X^ red 

 yellowish red colour, but the wings are always orig 



1 Hooker's Flora of British India 



