486 University of Calif oryiia Publications in Botany [Vol. 5 



type 14. A few of the sessile individuals, instead of exhibiting gradual 

 and uniform narrowing toward the base of the leaf, were constricted 

 to a degree intermediate between aubiculata of type 10 and sessili- 

 FOLiA of type 15. With respect to stenophylla versus sessilifolia 

 the observed segregation was 67 stenophylla : 32 sessilifolia. 



I7F3H2P17P3 was a sowing of seed of I6F2H2P17P3, an F. sessili- 

 folia selection. The leaves throughout had the sessile type of leaf 

 base characteristic of macrophylla, but there were many modifications 

 of it in the population. A rough classification with respect to these 

 modifications of the macrophylla type of leaf base gave the following 

 results : 



On 59 plants, the leaf bases were very nearly the form typical for 



macrophylla. 

 On 22 plants, the leaf bases were gradually attenuated toward the 

 base, resembling lanceolata of type 13 as a mean. This at- 

 tenuated form of the sessile leaf was a very striking feature of 

 this population. 

 On 10 plants, the leaf bases were intermediate in type between 



lanceolata of type 13 and the typical macrophylla form. 

 On 2 plants, the base of the leaf immediately above the point of 

 attachment was noticeably constricted, the leaf base thus formed 

 being intermediate between the macrophylla type and auricu- 

 LATA of type 10. 

 On 2 plants, the leaves were intermediate in constriction of the 

 leaf base between the strict macrophylla type and that of the 

 two plants described immediately above. 

 The classification here given is presented only to show that the 

 sessile type of leaf base characteristic of macrophylla is subject to a 

 number of very definite modifications which probably account for some 

 of the complex types of segregation observed in other populations. 



I7F3H0P17P10 was a sowing from I6F0H0P1-P12, a sessilifolia 

 selection. With respect to leaf base segregation there were two dis- 

 tinct classes, sessilifolia (type 15) and auriculata (type 10). There 

 was here also a marked degree of variation within the classes. Within 

 the sessile class the variation was in amount and kind of narrowing 

 of the leaf blade toward the base. A few plants showed a condition 

 approaching the auriculata type in this respect, whereas others 

 showed a gradual attenuated form of narrowing such as has been 

 noted before in other populations. Within the auriculata class most 

 of the individuals instead of possessing the slight wing and flaring 



