216 STUDIES IN THE POLLINATION ON INDIAN CROPS 



developing into extra floral nectaries. Sometimes, instead of one flower and 

 two nectaries, three flowers are developed and in these types there is little or no 

 branching. This pair of characters however is not always differentiated as 

 some plants bear two or three flowers in each leaf axil at the tips of the 

 branches only while on the rest of the plant there is only one in each axil. 



6. Divided and entire leaves. As a rule the leaves of this crop are entire 

 except when the vegetative vigour is great as happened in 1909 at Pusa. Most 

 of the plants had divided leaves and very few entire-leaved plants were seen. 

 In the following year, when the plants were sown later and the vegetative 

 vigour was less, entire leaves were common. It would appear likely therefore 

 that the form of the leaf depends on the conditions of growth and in any case 

 further study of this leaf character is required before it can be used for breeding 

 purposes. 



7. Branched and unhranched habit. Those types with one flower in the 

 axil are generally much branched while those with three flowers have few or 

 no branches. 



8. Earliness and lateness. There is a great range as regards this 

 character. Some of the Indian forms are so late that they can hardly be 

 grown at Pusa. 



4. Niger. 



Guizotia ahyssinica Cass, is an important oil seed crop in Centra] and 

 Southern India where it prefers a light sandy soil. 



Pollination and fertilization. Examination of the capitulum shows that 

 this plant falls into the sunflower group of the Composite^ and that the details 

 relating to pollination are no exception to the general rule in this group. There 

 is a marginal ray of 7 to 12 liguiate florets (female) surrounding a disc of 40 to 60 

 tubular hermaphrodite flowers. The flowering period of each capitulum 

 extends from 7 to 8 days. The tubular flowers open in the early morning 

 and liberate their pollen in the tube at the time of opening. The style emerges 

 covered with pollen about noon, the stigmas separating and curling back to 

 the staminal tube the same evening. Earely do the stigmas in bending back 

 touch the pollen on their o^\^l style, a circumstance which perhaps explains the 

 failure of this crop to set seed readily under muslin. The self-fertilized seed 

 formed under bag however germinates and develops normally. From the 

 character of the flowering, cross -fertihzaticn is generally to be expected but 

 some self-fertilization is also likely. 



