1920] BabcocJc-Collins : Crepis capillans X C. tcctorum 195 



Z 10 Fi (p2 Pg^ X e4 Po) tectorum X capillaris 



This represents the reciprocal of the above mentioned crosses in 

 which capillaris was used as the female parent. All tectorum flowers 

 used in hybridization work were emasculated in the bud stage. 



Six Fi seedlings were secured, all exhibiting tectorum cotyledons 

 on an enlarged scale. All died at the end of the cotyledon stage, some 

 having started to produce plumule leaves which resulted only in 

 rudimentary and abnormally shaped structures too small to be 

 described in detail. Ether treatment of two slowly dying seedlings 

 failed to stimulate them to renewed growth. These plants remained 

 alive in the cotyledon stage thirty days. 



Z 12 Fi (18.42 Pj X p2 P51) capillaris X tectorum 



In this culture capillaris flowers were emasculated in the bud stage 

 before the stigma was receptive. Three heads produced four achenes, 

 only one of which sprouted. It produced a small plant with under- 

 sized distorted cotyledons and no plumule. This weak seedling died 

 in the cotyledon stage. 



Z 13 Fi (el4 P, X 212 P,J capillaris X tectorum (Kew) 



One washed head produced eight achenes. Three sprouted, and the 

 plants had enlarged cotyledons which persisted for some time. One 

 seedling produced several abortive plumule leaves but they all stopped 

 growing when about 4 or 5 mm. long. It appeared unable to produce 

 typical plumule leaves. Those formed were tiny threadlike structures 

 and not at all like plumule leaves of normal seedlings. The diameter 

 of this plant at sixty day.s was three fourths of an inch. (Some of the 

 normal tectorum plants produce seed in ninety days.) Another seedling 

 went through essentially the same process and died when four months 

 old. The third plant had twisted, deformed cotyledons, and each 

 appeared to have a separate root. They were separated, each cotyledon 

 placed in a pot of soil, where one died after four days, the other con- 

 tinuing the struggle for thirty-six days before it too perished. 



It will be noted that cultures Z 10 and Z 12 are reciprocal crosses 

 in which each female parent was emasculated, thus insuring hybridity, 

 and that the behavior of the resulting seedlings was similar. The 

 plants of both cultures failed to develop past the stage in which the 



