HOWAED, HOWARD AND ABDUR RAHMAN 213 



The following year the selfed and crossed seeds in the above experiments 

 were sown side by side. Only two of the selfed seeds germinated and the 

 plants so produced were shorter and less vigorous than those raised from the 

 crossed seeds. These results show that self-fertilization is exceedingly rare 

 in this crop and that practically all setting is a result of cross-fertilization. 

 The crop is, in consequence, a mass of freely crossing heterozygotes. It is 

 possible that the self -sterility met with is a consequence of the existence of 

 heterostyly. The self-sterility observed may turn out to be the consequence 

 of illegitimate pollination. This was confirmed by the results of some pre- 

 liminary experiments carried out at Quetta in 1919. When long and short 

 styled plants were crossed, the flowers set seed freely. 



3. Til.i 



Til {Sesamicm indicum L.) is the source of most of the sweet oil used in 

 India where it is grown as a summer crop in the colder regions and as an 

 autumn or winter crop in the warmer tracts. Til prefers a light soil and is 

 usually grown as a mixed crop. 



Flowering. As the various forms of cultivated til vary very greatly in 

 habit, time of flowering and in growth period, it is only possible to give a general 

 idea of the conditions under which flowering takes place. The flowers are 

 borne in racemes, either singly or in twos and threes in the axils of the upper 

 leaves and possess very short pedicels (Fig. 3.) 



Both the main stem and the side branches, which in some types are 

 very numerous, bear flowers in acropetal succession. In the case of some 

 early t\^es observed at Pusa in 1911, the seeds were sown on May 5th and 

 the first flowers appeared on June 16th when the plants were eighteen inches 

 high. By the time flowering was completed, the total height of the plants 

 was 3| feet. Usually two flowers are open at the same time on any one 

 inflorescence and in much -branched plants more than 20 flowers may be open 

 at the same time. The plants are harvested before they are ripe to prevent 

 the loss of seed by the splitting of the capsules. 



Pollination and fertilization. The flowers open between 3-15 and 4 a.m. 

 and fade soon after midday, the corolla being shed without closing between 3 

 and 4 in the afternoon. They thus remain open not more than 12 hours. 

 In the bud before the flower opens, the four unripe anthers are below the stigma 



^ Die Zijjchiung der landw. KuUurpflamen, Bd. V , 1912, s. 182. 



