H. M. Leake 221 



(Fig. 1) by the measurement e. It is not proposed to enter into a 

 detailed discussion as to the significance of the constancy of this factor 

 for the various types of Gossypia. It may be noted, however, that its 

 identification was purely empirical and it is not to be taken as an 

 absolute figure for each leaf of a plant ; there is a fair range of fluctua- 

 tion as would be expected in the measurements of any series of 

 multiple organs. In spite of these fluctuations it is a matter of little 

 difficulty to recognise what may be termed a " typical " leaf and there 

 is a very marked agreement between the leaf factor, as determined 

 on such " typical " leaves, of individuals of the same type. 



The degree to which the leaf is incised forms a striking feature of 

 the plant and has been adopted freely as a means of classification. 

 Todaro (16) divides the Indian group (subsectio Indica) of Gossypia into 

 two sections : 



A. Lobi breves, ratione longitudinis latiusculi. 



B. Folia palmato-partita, lobis angustis, oblongis, vel elongato- 

 lanceolatis. 



Gammie (9), though he does not accord this character of the leaf a 

 primary position in his scheme of classification, throughout refers to 

 two gioups with the leaf lobes either broad or narrow. 



Watt (20) uses the leaf character to subdivide the section of 

 " Fuzzy seeded cotton with united bracteoles." He distinguishes three 

 groups : 



Leaves two-thirds palmately (sometimes almost pedately) 3 — 7 lobed. 



Leaves half-cut into 3 — 5 (mostly 3) lobes. 



Leaves less than half-cut into 5 (more rarely 3 or 7) lobes. 



It will be noticed that while these three schemes deal generally 

 with the same character there is some difference in detail in the exact 

 points involved. Watt simply deals with the degree of incision which 



is, perhaps, most closely given by the ratio r • 



Todaro's group B, as fully defined, is distinguished by not only the 

 factor J- but by the breadth of the lobe, thus including the measure- 

 ment e ; while for his group A he makes use of an expression which is, 

 perhaps, the best form of definition that could be found for the author's 



" leaf factor." Gammie refers simply to the ratio , — %-r of the lobe, 



'^ •' breadth 



which is identical with the leaf factor. 



In a preliminary series, among other measurement determinations. 



