1917] 
GATES—THE GENUS TRILLIUM 87 
In his classical paper! in which he compared the flora of 
eastern North America with that of Japan, pointing out the 
many striking similarities, Asa Gray regards Paris hexa- 
phylla as the Japanese counterpart of Medeola virgimana L. 
MEDEOLA Gronov. = TRILLIUM L. 
Deciduous wool on stem. No wool on stem. 
Leaves in 2 (rarely 3) whorls; Leaves in 1 whorl? of nor- 
lower whorl 4-10 leaves. mally 3 leaves. 
Flowers in a sessile umbel, A single flower, usually dark 
small, greenish yellow. red or white. 
Six perianth segments alike. | Three sepals; 3 petals. 
The differences from Trillium are much greater than in 
the case of Paris. The presence of 2, or sometimes 3, whorls 
of leaves recalls a not infrequent teratological condition in 
Trillium, while the variable number of leaves in the lower 
whorl agrees with the condition in the genus Paris. The 
umbel of flowers is a marked progressive step, while the lack 
of differentiation of calyx and corolla is a primitive or rever- 
sionary condition, again resembling certain teratological 
specimens in Trillium. The fluffy wool on the stems is a posi- 
tive character of whose origin we know nothing, but there is 
no reason to believe that it has any selective value. 
It is scarcely to be supposed that Medeola would cross with 
Trillium, but the attempt would be worth making. 
1Gray, Asa. Diagnostic characters of new species of phanerogamous > 
collected in Japan by Charles n Botanist to the North Pacifie Exploring 
Expedition. ке pergere upon the relations of the Japanese flora to that 
of N ca, and of other parts of the northern temperate zone. Mem 
Acad. II. 6: 371-452. 
2 Teratological specimens occur having 2 or 3 whorls. 
