INDUCTION, DEVELOPMENT, AND HERITABILITY OF FASCIATIONS. 5 



There were also in the field three or four examples of the type in which 

 the alteration of form dated from the rosette stagx:. These individuals 

 were always stalwart plants and produced high, strong" stems, of which the 

 main axis was fasciated from the base. 



In the O. cntfiata the fasciations were remarkably well formed. Some 

 of them dated in their development from the rosette period, though usually 

 the branches did not beg'in to flatten until 20 em. above the base. Many 

 of them suddenly flattened from the time of the appearance on the stem of 

 a hard protuberance, which was usually cylindrical in shape and sometimes 

 2.5 cm. in length, but often reduced to a small lump on the stem (plate in, 

 fig's. 1, 3, 4, 5). Ordinarily the stem fasciated from the point where the 

 protuberance appeared and one or several of the forks were fasciated. If 

 there were no forks the whole stem at once banded. There were also ring' - 

 fasciations, and the three forms appeared on the same plant. 



The description of a typical individual is as follows: 



C. (i. -. The plant developed from a rosette which had been kept in a cold-frame 

 from the previous fall (1904), and most of the branches showed by the early disarrange- 

 ment of the phyllotaxy and by the shape of the stem that the fasciation had started 

 during the rosette period. There were in all 10 branches, of which t was normal: 2 at 

 theendof the second summer were small fasciated rosettes; 7 were repeatedly bifurcated, 

 3 of them eventually into 9 forks. Of these, 3 showed protuberances at the point of 

 the first bifurcation. One stem had a heavy callus at its base, covering an old injury. 

 In these 1905 plants there were no rings, bat they appeared in 1906 on stock from the 1905 

 seed. The largest fasciation on the above plant measured 4.8 cm. by 4 mm. There was 

 frequently a constriction or channel in the stem below, such as appears in the plant in 

 plate II, tig. i, but not such as to be histologically akin to the grooves in the wild O. 

 biennis. 



In the cruciate forms of 1905, on one plant 15 out of 16 branches were 

 fasciated; on another, 10 out of 11. For the microscopic study of this 

 material there were to be examined simple flat fasciations, ring'-faseiations, 

 groove-fasciations, and the fasciations associated with the protuberances. 



In normal structure stems of OnagTace;e are much alike, and it is unnec- 

 essary to call attention to small differences. They possess a continuous 

 bundle-ring', which is bicollateral in character. The medullary phloem is 

 arranged in groups just within and following' the line of the xylem. The 

 outer phloem is in very small and inconspicuous groups amid a quantity of 

 parenchyma cells. There is a stereome ring, and peripheral to this chloren- 

 chyma several rows of collenchyma and the epidermis. The medullary 

 rays are but 1 cell in width. The pith consists of larg'e parenchyma cells, 

 and there are many bundles of raphidcs of calcium oxalate there and in 

 the cortex. 



There is a kind of latex system which consists of parenchyma cells 

 which contain a brown secretion, most dense near the phloem, but con- 

 spicuous in pith, cortex, and epidermis. Sections stained in Delafield's 

 haematoxylin resulted in a bright purple in the cells about to crystallize, 

 in brown or a greenish shade in the latex cells, and in a reddish purple 



