Tricot y!s, Hcini-tricotyls, and Tefracotyls. 365 



ciirialis annua for 8-86% tricotyls between 1 and 16% ; 

 in Silcne inflata for 27-73%, in Clarkia pulchclla for 

 6-16% and in HclicJirysiun bracteatuni for 3-41% tri- 

 cotyls, from 2 to 28%. In the individnal records this 

 ratio is obviously subject to considerable fluctuation on 

 account of the small number of tetracotyls in the indi- 

 vidual crops, and for a proper estimation of this ratio 

 cultures on a much larger scale and especially designed 

 for this end would be necessary. Here I shall content 

 myself with giving an experimental series obtained with 

 Clarkia pulchclla, which shows roughly how the ratio 

 of tetracotyls to tricotyls increases with the number of 

 the latter. 



Percentage ratio of tricotyls 6 7 14 16 27 55 62 63 

 Number of tetracotyls per 



every 100 tricotyls ... 15 5 26 5 10 18 22 20 



Similar figures were obtained with Phacclia fanaccti- 

 folia, Papavcr Rhocas, HclicJirysiun bracteatuni and 

 Mercnrialis annua. 



§ 3. THE INFLUENCE OF TRICOTYLY ON THE ARRANGE- 

 MENT OF LEAVES. 



Elementary characters are not as a rule betrayed by 

 a single external characteristic, but by several. In most 

 cases one of these can easily be recognized as the primary 

 one, and the rest are then termed secondary. In other 

 cases a doubt may arise as to which should be regarded 

 as primary and wdiich as secondary. White-flowered 

 varieties of red or blue species often exhibit the absence 

 of color in the fruits as well as in the leaves or the stem. 

 Moreover they can frequently be recognized as early as 

 in the seedling stage by their pure green color. My new 



