DIMORPHIC BRANCHES OF THE COTTON PLANT. 25 



amounts to an abnormality, no less than the failure of a character to 

 come into expression. 



These abnormal intermediate forms of branches might also be com- 

 pared to the hermaphrodite individuals that occur occasionally in 

 plants that normally have the stamens and pistils on separate in- 

 dividuals, such as the fig tree, the date palm, and the hop vine. The 

 dioecious habit is a condition of dimorphism inside the species. The 

 abnormalities of the intermediate individuals support the analogy with 

 hybridization. The behavior of hermaphrodite hop plants has been 

 studiexl recently by Dr. W. W. Stockberger." 



These phenomena are of interest from the standpoint of the study 

 of heredity as well as for agricultural purposes, since they show that 

 characters having little or no direct relation to the external conditions 

 may be seriously affected by changes of environment. Xew conditions 

 appear to disturb the functions of heredity, not only to bring about 

 substitution of characters and thus cause diversity between the plants, 

 but they also appear to break down specializations inside the plant, 

 to disarrange the patterns, as it were, of the different kinds of inter- 

 node individuals that form the normal plant. 



This conclusion does not refer alone to the fact that these abnor- 

 malities are very frequent in the newly imported varieties of cot- 

 ton, but is also justified by the fact that different parts of the same 

 field may differ distinctly in these respects, as the result of relatively 

 slight differences of external conditions. Even in hj^brids that are 

 showing Mendelian segregations of parental characters of branching 

 in the second generation, experiments in different places may give 

 very different results. Hybrids between the Kekchi cotton of Guate- 

 mala and the Triumph variety of United States Upland cotton 

 showed, in one place (Del Rio, Tex.), many Triumph-like plants 

 with short basal branches, while at another place (Victoria, Tex.), 



" Stockbergrer, W. W. Some Conditions Influencing the Yield of Hops, Cir- 

 cular 50. Bureau of Plant Industry, IT. S. Dept. of Agriculture, 1910, p. 11. 



" In some sections hop vines are occasionally found which bear both staminate 

 and pistillate flowers. Such plants are known locally as ' bastai'ds,' ' mongrels,' 

 or ' bull-hops.' When they occur they rei»resent a total loss, so far as yield is 

 concerned, since the few hops borne by these vines are inferior and never 

 gathered. On the acre under consideration there were only five of these plants, 

 but they have been observed in much greater px'oportion in other years and 

 in other localities * * *. In 1!)0S a number of cuttings were taken from one 

 of these 'bastard' jtlants and removed to a locality about 40 miles distant. 

 The vines from these cuttings came into flower in 1909 and in every case re- 

 produced the malformation of the original plant from which they were taken. 

 In view of this fact care should bo taken to prevent the use of cuttings from 

 'bastard' plants by promptly digging tluMu otit and destroying the roots as soon 

 as they are observed. In this way their i)erpetuatiou may be prevented and 

 the loss in yield due to their occurrence avoided." 

 198 



