12 STUDIES IN INDIAN TOBACCOS. 



over the work. As only few of the plants, however, were allowed 

 to flower in both years, these opportunities were not numerous. 

 Cross-fertilization, although previously possible in the various 

 tracts of India from which the seed was collected, is not likely to 

 be of frequent occurrence on account of the fact that but few 

 plants are allowed to run to seed by the ryots and that the fields of 

 N. rustica are very scattered. In 1908, it was found that out of 

 45 rows of N. rustica, each grown from the seed of one plant, 

 9 were not uniform but contained plants diff'ering from the rest. 

 In 1908, a large number of these aberrant plants were bagged 

 as well as the parent seed plants selected from the uniform rows. 

 The seeds of these plants were again sown separately the same 

 year. In every case the aberrant plants proved to be crosses 

 and gave rise to the most diverse forms (Plate III). In one case 

 infertile plants, with peculiar foliage which may possibly be 

 hybrids between N. rustica or N. tahacum, were observed (Plate 

 IV). The selected plants from the uniform rows, however, bred 

 true. Natural crossing is therefore frequent in many types of 

 this species, and it will always be necessary in experimental work 

 to obtain seed under bag. No diminution in vigour in the self- 

 fertilized seed obtained under bag has been noticed by us during 

 the past two years. The uniformity of the rows obtained from 

 bao"ged seed is remarkable. Fruwirth,' who grew this species for 

 three years in Germany from selfed seed, did not observe any 

 lack of vigour in the offspring compared with that from free 

 flowerino' plants. He states : — " Ein Zurlickstehen der Pflanzen 

 aus derart gewonnenen Samen gegeniiber solchen, welche aus 

 Samen frei abgebllihter Pflanzen erwachsen waren, konnte ich 

 nicht feststellen. Auch die dritte Generation bei standigem 

 Einschluss war nicht merkbar geschwacht." 



The production of self-pollinated seed. 



The production of selfed seed under bag in this species offers 

 no particular difliculty. Large waterproof bags are desirable, 



^ Fruwirth 1. c. 



