1916] Goodspeed-Branclt : Notes on Trillium 7 



logical data. At the suggestion of Professor R. Ruggles Gates we 

 attempted to determine the relative cell size and the relative 

 chromosome number and chromosome size of the eastern and Cali- 

 fornia varieties of T. sessile and to make the same comparative studies 

 in the case of T. grandiffornm and the rather closely allied T. ovatum. 

 This investigation is still in progress, but it appears desirable to 

 mention such results as are at hand. It seems certain that there 

 is no doubling of the chromosome number, as in Oenothera gigas, 

 giant races of Primula sinensis, Spiranthcs cernua, etc., in the 

 California variety of T. sessile, nor is there any distinction in 

 chromosome size or constitution between the eastern and Californian 

 varieties of this species. Similarly we have been unable to note 

 any increase of cell size in the Californian as compared with the 

 eastern T. sessile, though the measurements made are too few to allow 

 of a definite conclusion in this connection. Trillium grandiflorum 

 and T. ovatum are not set apart by conspicuous size differences and 

 in cytological details they correspond rather closely one to the other. 

 The chromosome number in T. sessile var. giganteum was determined 

 by a study of root tips and of the maturation divisions of the micro- 

 spore mother-cells, while the tentative conclusions as to comparative 

 cell size are based upon measurements of cells of the root tip. 



As stated above, the entire investigation in progress dealing with 

 the Californian species of Trillium had its origin in an effort to map 

 the distribution of particular color varieties of T. sessile var. 

 giganteum and to trace their relationships. Our field studies have 

 led us to distinguish three main color types within the Californian 

 form of sessile. First, a white-flowered form which is peculiar to 

 the northern portion of our district and which only in isolated cases 

 occurs elsewhere. So far as color of flower is concerned and also 

 with respect to some other characters, this form corresponds to the 

 species described as Trillium chloropetalum by Howell. We have 

 studied it most thoroughly in Napa Valley, Napa County. In caiions 

 of the hills on the sides of the valley and in the nearby Napa Range 

 at an altitude of 2000 feet this pigmentless form occurs in rather 

 great abundance. The petals are dull white, somewhat greenish at 

 the bases, and the flower parts within are light green throughout 

 with the exception of the anther coats, which are a light yellow. 

 This form has been sent in from Sonoma, Sonoma County, and appar- 

 ently occurs also in Lake County. White-flowered individuals only 

 occur near Dutch Flat, Placer County, and may be characteristic of 



