TricotylSj He mi-trie otyls, and Tetracotyls. 365 
ciirialis annuci for 8-86% tricotyls between 1 and 
in Silene inflata for 27-73%, in Clarkia pulchella for 
6-16% and in Helichrysum bracteatum for 3-41% tri- 
cotyls, from 2 to 28%. In the individual 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 Phacelia tanaccti- 
folia, Pa paver Rhocas, Helichrysum bracteatum and 
Mcrcurialis 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 which 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 
