19 o8] SH UL L—MENDEUA N INHERl TA NCE 1 09 



During the summer of 1905 experiments were also begun for the 

 purpose of testing the relationship between the Russian sunflower 

 and the wild Helianthtis annuiis of the prairie region. Seed of the 

 latter had been received from Nebraska through the kindness of Dr." 

 C. E. Bessey. Several points of contrast were noted between the 

 plants produced from this seed and the Russian sunflower, the most 

 noteworthy being with regard to branching habit and the color of the 

 disk; The lower branches of the wQd sunflower, when given space 

 for full individual expression as they are in my cultures, diverge- 

 almost horizontally, having on this account a slightly wider spread 

 than branches arising at higher points on the stem. At the time the 

 first head is ready to spread its rays, the whole plant has a nearly 

 conical form. The development of the primar}- head checks the 

 growth of the main stem, and some of the upper branches then usually 

 elongate so as to overtop the central axis, thus giving the mature 

 plant a more columnar form. My branched type of the Russian 

 sunflower has aU the branches strongly ascending, the lower being 

 enough longer than the upper to reach ^almost the same level, thus 

 giving the mature plant a cor}'mbose or broadly obconical form. ^ 



I have not yet reached a conclusion in regard to the hereditar}' 

 behavior of these two types of branching, as it is not easy to find 

 decisive criteria for the exact classification of the two forms and their 

 combinations. It has been apparent, howe\^r, in my cultures that 

 there is a combination of both types of branching in many if not aU 

 of the first-generation hybrids, and at least some segregation in the 

 next generation. The indefiniteness of the character wiU probably 



ma 



ma 

 sim 



AU of the western Helianfhus annuus that I have thus far observed 

 have a deep purple disk, the color being found in the tips of die 

 paleae, which are of a deep, metaffic purple ; the margin of the coroHa 

 which is brownish purple ; and the st}'le and stigmas, which are midish 

 purple. In aU my Russian sunflower, the tips of the paleae are 



^ellowish green, the coroUa is a clear iti 

 .nd stigmas usually have the same coloi 

 mall proportion the stigmas are n^rgined 



