208 STUDIES IN THE POLLINATION ON INDIAN CROPS 



flowers had opened since 7-15 a.m. of which 31had been sprung. In the two suc- 

 ceeding days, 77 more flowers opened, all of which were sprung. 



Practically no setting takes place under nets but seed is pn duced under 

 these conditions if the flowers are artificially made to explcde. The amount 

 of setting however is less than that obtained in the case of free-flowering plants 

 visited by bees. 



Attempts to cross Java and Sumatrana indigo at Pusa have so far failed. 

 On several occasions, plots of these two crops have been allowed to flower side 

 by side in October and November but no natural crosses have been observed 

 in succeeding generations. 



III. Oil seed crops. 



1. Linseed. 



The mode of pollination of the European cultivated forms of linseed 

 {Linum usitatissimum L.) grown for fibre purposes has been described in 

 detail by Fruwirth^ who found that self-pollination is the rule and that 

 good setting is obtained under bag without loss of vigour. 



For some years, a large collection of pure lines of Indian linseed, obtained 

 from the black soil areas of Peninsular India and also from the plains, have 

 been under investigation at Pusa and observations have been made on the 

 flowers of this crop. Indian linseed is cultivated for the oil in the seeds 

 and is a short, much branched plant with thick stems and numerous capsules 

 very difierent from the types grown for fibre in Europe (Plate IV). 



Flowering. The flowers open in the early morning and as a general rule 

 in all such buds, the folded corolla is visible the evening before. In rare cases, 

 however, a flower opens in which the corolla is not visible the previous evening. 

 As soon as the corolla becomes visible, the filaments are still short and the 

 unburst anthers stand well below the slightly twisted stigmas. The rapid 

 growth of the filaments, however, soon brings the anthers to the same level as 

 the stigmas and this is the position when opening begins. The time of opening 

 of the flowers depends chiefly on the temperature and humidity and to a less 

 extent on the particular type. On warm mornings and when there is little 

 or no dew, opening begins very early, while on cold dewy mornings the process 

 is distinctly delayed. In February 1916, the following observations were 

 made on this point : — 



* Fruwirth. Dte Ziichtung der landw. Kulturpflanzen, Bd. Ill, 1906, s. 45. 



