148 
R. Ruggles Gates. 
very remote indeed. A minute but distinctive difference is in the 
large hairs of the calyx. On the hud-cone they are strongly 
ascending except around the top of the hypanthium where they 
are retrorse or perpendicular. 
The cruciate form from Jaffrey, New Hampshire, is described 
by Bartlett, in the same paper, under the name CE. Robinsonii. 
There is said to be “ enough likeness between CE. venosa and CE. 
Robinsonii , so that a close relationship between them seems not 
unlikely.” The differences from venosa are chiefly in the smaller 
size of Robinsonii , its more sharply dentate leaves, narrower bracts, 
longer more slender buds with dense erect viscid puberulence, and 
shorter calyx tips. The range of variation in bud length overlaps, 
however, and most of the differences are only obvious in the living 
plants. These two forms evidently represent closely allied 
elementary species rather than species in the Linnean sense. 
Both having cruciate flowers, one from New York State, and the 
other from New Hampshire, in the absence of local species of which 
they could be varieties the common character of cruciateness 
probably originated some time ago, and we may suppose that the 
series of small differences which distinguish the two species 
throughout have originated since. 
Contrasted with these forms, in which the cruciate character 
appears to be of relatively ancient origin, is another cruciate species, 
CE. stenopetala Bicknell, described from Nantucket Island in 1914. 
It is closely allied to the broad-petalled species CE. Oakesiana Wats., 
from which it is probably descended. Yet the two have diverged 
in certain respects. In the case of CE. biennis leptomeves , which 
apparently is still appearing as a mutation from biennis in Holland, 
the single difference in the flowers is unaccompanied by any other 
differences. This series is a most instructive one as a basis for 
contrasting the conspicuous unit difference of sudden and repeated 
origin, with the other smaller differences relating to all parts of the 
plant, by which the species have subsequently become differentiated. 
Whether the same type of evolutionary change is represented in 
both cases, is a matter worthy of close and prolonged study. By 
comparison and crossing of these cruciate forms, definite evidence 
might be obtained on this point. In many cases such elementary 
species differ from each other in physiological characters or 
methods of reaction to environment. An intensive study should 
make it possible to determine what relation if any these physiological 
and morphological differences bear to each other. 
