196 University of California Publications in Agricultural Sciences [Vol. 2 



young seedling is nourished from the food material stored in the seed. 

 Apparently in the combination of capillans and tectorxuti the <jerminal 

 elements are incapable of interacting in such a way as to cause the 

 seedling to develop normally (pi. 36, fig. 3). 



In a number of eases (not listed) where the capillaris female parent 

 was wa.shed and pollinated with tectorum pollen, a number of achenes 

 were secured which germinated well, producing seedlings which 

 appeared and behaved in every way like typical capillaris plants. 

 These did not stop growth at the end of the cotyledon stage but con- 

 tinued normal development. They were maternal in all respects. Thus 

 we get two kinds of results when depollination by water is substi- 

 tuted for emasculation, and tectorum pollen applied: (1) plants which 

 show the tectorum type of cotyledon on an enlarged scale, and which 

 die at the end of the cotyledon stage of development ; (2) plants which 

 show maternal inheritance and are able to develop past the cotyledon 

 stage, the limit of development in class one. Class two occurs only 

 when capillaris is the female parent and the water method of depollina- 

 tion is used. Of eleven crosses where the female was depollinated by 

 means of the water jet, six produced F^ seedlings having tectorum 

 cotyledons on an enlarged scale, and all six failed to develop beyond 

 the cotyledon stage ; five produced F^ seedlings typically capillaris 

 which developed normally into capillaris plants. 



From the evidence furnished by the equivalent results of reciprocal 

 crosses when the female plant was emasculated (Z 10 and Z 12), we are 

 led to conclude that seedlings of the second class described above, 

 exhibiting maternal inheritance, were the result of self-fertilization 

 of the capillaris plant, which may have occurred before washing or 

 because of incomplete removal of the pollen by the water method, and 

 that those of the first class, showing dominance of tectorum in Fj and 

 the failure to continue development, were true hybrids. As a check 

 a number of heads were depollinated with water and bagged without 

 pollination. In one case selfed seeds were produced in a bag covering 

 heads so treated. This indicates that the method is responsible for 

 the appearance of tlie capillaris plants where crossing was attempted. 

 In no case were achenes produced on heads which had Ix'cn emasculated 

 and bagged without pollination as checks. 



The above conclusions were confirmed by cytological examination. 

 Cells from the mature plants (Z 9 P^) were found to contain six 

 chromosomes, the typical number for capillaris. Cells of the root tips 

 from young seedlings of the hybrid class (Z 5) were found to contain 



