26 VARIATION IN ASTER 
cies; and is confirmed (g) by occasionally finding A. Clayton 
and A. ardens and perhaps other species reddened in the sun on 
surface of rocks while similar plants on the same rocks under 
bushes were not so. 
It may therefore be thought that continued exposure to sun 
may produce more numerous reddened rays toward the end of 
the flowering season. While a great many of the best examples 
of reddening are September collections, there are a few of October 
dates. Those of August, as the reddened 4. Erienszs, fall toward 
the end of the blossoming-period for the respective species. 
On the whole, species of the Divaricati and Curvescentes vary 
greatly in their liability to reddening ; in some species the tend- 
ency is certainly very much more easily excited than in others ; 
it is not called out in deep shade; it is active in sunlight, whether 
the unmixed sun of the open (A. Zvtensis, A. ardens) or the dif- 
fused broken sunlight of thin woods (A. divaricatus, A. listrifor- 
mis); it is more often observed after the height of the flowering 
season, but it also occurs well-developed before the middle of 
August; and I have found it persistent as much as seven years in 
certain individuals of a colony and yet not developed in the other 
offshoots of the same group and in the same conditions. 
Full rose or pink coloration replacing white is much more 
common in Aster than rose-color replacing violet or purple. The 
latter has perhaps its most conspicuous occurrence in A. Novae- 
Angliae roseus ; among others are occasional rose-red sports of A. 
undulatus, A. cordifolius, A. junceus, A. Novi-Belgit. 
Distribution of reddening over the surface of ray is usually 
uniform, at least till toward the base, which is paler and remains for 
some time whitish in many plants, A. dumosus, A. Novi-Belgii and 
some Biotian species. In a very few sporadic Biotian examples 
the red occurs only as a narrow margin around one or both edges 
of the ray ; in a few others it colors the whole ray except the tip. 
Blue in such mixture with red and white as to make violet, 
is common in the rays of A. multiformis and relatives, and with a 
large proportion of white, making lavender rays, it occurs widely 
among these and the other Macrophylli. Nearly pure deep blue, but 
with a little red in it, is common in A. zostemma and A. gremialis. 
Deep violet turning whitish is common in the preceding and in A. 
