H. M. Leake 209 



flowering period commences with the development of the secondary 

 branching, while in the monopodial group this period is delayed until 

 the tertiary branches arise. In India the cultivated monopodial types 

 are in the minority and occupy distinct tracts. Cross-fertilisation be- 

 tween the different types is consequently of rare occurrence, arising 

 under exceptional conditions only, and intermediate types are few. 

 The sympodial types on the other hand are widely cultivated through- 

 out continuous areas and consequently, in the absence of any control 

 over the seed supply, have become inextricably mixed through natural 

 cross-fertilisation. The occurrence of crossing between the monopodial 

 and sympodial types is, as in the case of the monopodial types, suffi- 

 ciently infrequent even where these types are grown in close proximity. 

 The monopodial commence flowering about five months after the sowing 

 period while the sympodial are in full flower in three months and are 

 producing only stray flowers when the monopodial types are in flower. 

 While, therefore, natural crosses are fairly frequently observable among 

 the offspring of monopodial types, such crosses have not occurred within 

 the author's experience among the offspring of s3'mpodial types grown 

 in like proximity. 



The types which have been employed in the experiments detailed 

 below are characterised in the subjoined list. In this list no attempt 

 has been made to arrive at a full and accurate botanical description of 

 each type. The references to the current schemes of classification will 

 sufficiently indicate the broad outlines of the type in question while 

 below are given only such characters as it is desirable to emphasise 

 owing to the position they occupy in the course of the experiments 

 about to be detailed. 



Monopodial types. 



Type 1. Perennial ; secondary branches ascending sharply at an 

 acute angle. Leaf factor' is less than entire 2 ; plant almost glabrous. 

 Bracteoles small, triangular, margin entire or dentate. Corolla yellow. 



This plant is the G. obtusifolium Roxburgh Flora Indica of Gammie 

 (9) and Watt (20). The various forms to which the specific name obtusi- 

 folium has been given at different times have been dealt with by 

 Burkill (21). 



Type 2. Perennial ; with secondary branches spreading. Leaf with 

 a factor less than 2. Stem and leaves densely covered with short hairs. 



1 A detailed account of the leaf factor is given below (p. 221). It is the valae obtained 

 for the ratio a-b:e, vide Fig. 1, p. 220. 



