250 EFFECTS OF EXPOSING GERM-CELLS TO RAYS OF RADIUM 



strikingly thick and almost brittle. The radium was of 1,500,000 

 activity, and the period of exposure 24 hours. With pollen thus 

 treated the stigma of an unexposed pistil was pollinated, and this 

 plant was from one of the resulting seeds. Below is the taxonomic 

 description. 



Stem 6 dm. tall, with several erect-ascending branches from near the 

 base, nearly as tall as the stem; stem-leaves spreading; blades lanceolate to 

 oblong-lanceolate, acute at the apex, undulate-sinuate; bracts similar to the 

 stem-leaves, but shorter and relatively broader; hypanthium about 35 mm. 

 long; sepals about 15 mm. long, or shorter, fully one half as long as the free 

 portion of the hypanthium, the free tips in the bud stout, about 1.^-2.5 mm. 

 long; petals nearly 15 mm. long, notched at the apex; capsules columnar, 

 more or less tapering at the apex, nearly 20 mm. long, much narrower than 

 the bracts. (See plate 12, figures y"->^.) 



The most interesting and novel result of all was the plant shown 

 in FIGURES 72 and 73, and in plates 13 and 14. The antecedent 

 treatment was an exposure of the ovary for 24 hours to the rays from 

 radium bromide of 10,000 activity, after which the stigma was pollin- 

 ated with unexposed pollen. Among the young seedlings in the 

 seed-pan, I thought I had detected one of the narrow-leaved variety 

 growing close to a more typical plant. But when I started to separate 

 the two plants for re-potting, I found that, instead of two plants, I had 

 onl}' one, this one bearing two rosettes on the same root (figure 72). 

 The anomaly cannot be called a bud-sport, as that term is generally 

 used, unless, keeping in mind that the plumule is a bud, we decide 

 that there was an early bifurcation in the developing embryo, of such 

 a nature that, after the cotyledons were laid down, there was a divi- 

 sion of the growing-point, accompanied by a separating out of antag- 

 onistic characters, and resulting in the formation of two morpho- 

 logically as well as physiologically different shoots. 



The seedling was very carefully freed from soil, and after 

 thorough examination, the above conclusion seemed to be the only 

 one warranted. There was absolutely no evidence that a lateral bud 

 had formed early on the main stem. There were to all appearances 

 two epicotyls, one in the axil of either cotyledon. This plant was 

 carefully protected, and after it was transplanted into the experi- 

 mental garden both rosettes sent up cauline stems, in which the dif- 

 ferences, so marked in the rosettes, were continued (figure 73). 

 One half of the plant, as is clearly shown in the illustration, was a 

 typical O. biennis in every respect. The other and narrower leaved 



