T Mem TAMEO TTA ESL a RI. ee E ERE T S a A 
COLOR-CHARACTERS 25 
violet or lavender containing blue. Such reddening is occasionally 
strongly marked in A. divaricatus, A. rupicola, A. listriformis, 
A. aucuparius, A. carmesinus, A. Claytoni, and A. Erzensis, and 
probably it is latent and may be elicited in any species of the 
Divaricati or Curvescentes whatever, though I have not yet observed 
it in a wide range of specimens of A. Schrebert, A. curvescens, A, 
Jultanus, A. glomeratus and A. olivaceus, 
Similar tendencies exist in many other ordinarily-white Asters, 
asin A. ericoides and relatives, A. vimineus and relatives, in which 
reddening occurs ; A. dumosus, A. paniculatus, etc., in which either 
reddening or violaceous change occurs, but most frequently the 
latter ; A. sagittifolius, with violaceous tinge, but its subspecies or 
connate species, wrophyllus, with white rays only. 
Among Biotian species, certain ones, as A. ardens, show a 
stronger tendency to develop reddening than others; but no 
specific or varietal distinction seems to be discoverable in the more 
frequent occurrence of this reddening ; as indicated by the follow- 
ing reasons : 
(a) It is frequently found throughout certain heads and not 
others, on the same plant; or even certain rays only, of a head. 
(4) It often characterizes certain plants of a colony and not 
others, though otherwise similar. 
(c) Its occasional increase with the progress of the season sug- 
gests an origin in such a chemical change in the cell-sap as may 
be possible in all though not equally frequent. 
Against the supposition that it is a normal color-change in the 
cell-sap and associated with old age of the individual flower it is 
due to mention the following observations : 
(d) Where the heads are partly reddened and — not, those 
not reddened are often equally old. 
(e) Where the reddening is only partial in a single head, all 
the rays are nevertheless of equal age. 
Against a supposition that it is due to mere inequality of illu- 
mination is the fact that in cases d and e the chance of illumina- 
tion has seemed on inspection to be equal and well-diffused. Yet 
that prolonged sunlight is a necessary factor seems indicated from 
the following fact: (f), no reddening has been seen in the deep- 
woods species or in deep-woods specimens of well-diffused spe- 
