CHARACTERS OF HINDI HYBRIDS. 27 



of the cliaractoi-s of individual plants. Crossing between hybrid 

 j)lants and Egyptian must produce many very dilute hybrids with 

 little or no expression of the Hindi characters. Indeed, it may well 

 be doubted whether any of the Egyptian stock would be found to be 

 entirely free from the Hindi contamination if all of the ancestry 

 could be traced. As yet we have no knowledge of the effects of slight 

 dilutions of the Hindi blo(^d upon the expression of characters, but 

 experiments are being made to obtain information on this point. 



Two principal elements might be recognized in the study of the 

 diversity that exists in the Egyptian fields. One element might be 

 ascribed to the ])revalence of the Hindi cott(m, the other to variation 

 inside the Egyptian type. But in the present state of our knowledge 

 it is often quite impossible to determine at once Avhether a variant 

 l)lant is a dilute Hindi hybrid or an unusual example of the Egj'ptian 

 stock. Evidence on this question can be secured by planting the 

 seed to see whether the progeny " come true " to the characters of 

 the parent, as in a mutation, or show more pronounced reversions 

 to the Hindi type. But many mutative variations are also to be 

 considered as reversions. The practical fact is that the Hindi con- 

 tamination is responsible for a large amount of diversity outside of 

 the obvious hybrid forms that resemble first-generation crosses. 



Among the plants enumerated as Egj^ptian are many that are 

 apiDreciabl}' different from the Eg}'ptian type, even in the early part 

 of the season. Without departing seriously from the Egyptian form 

 and habits of growth, some of the plants have broader or narrower 

 leaves, lighter or darker than their neighbors. Though the form of 

 the leaves may be that of the Egyptian cotton, the bases of the veins 

 may Iw reddened as in the Hindi. Or plants with Egyptian foliage 

 may have unusual habits of growth, the more frequent tendency 

 being toward taller stalks and more strictly upright branches. 



The large cordate bracts that characterize the most obvious Hindi 

 hybrids are not entirely confined to that class of plants, but may be 

 found on other large plants with foliage of Egyptian shape and 

 color. The pulvinus ma}^ have the Hindi size, shape, and color, 

 though concealed by more abundant hairs. In addition to the large 

 circular, or very deeply cordate bracts, with the teeth running well 

 down, such plants often have the calyx distinctly toothed, though 

 the teeth do not have the long slender points that occur so frequently 

 in the Hindi cotton. (See Pis. Ill and IV.) 



As the season advances such differences become more apparent. 

 "Wlien flowering and fruiting begin the hybrid nature of many indi- 

 viduals becomes unmistakable, even in plants that might not have 

 been suspected of hybridity from the vegetative characters alone. 

 Rogiiing must not be limited to the time of thinning in the early 



210 



