L 
Rhodora 
JOURNAL OF 
THE NEW ENGLAND BOTANICAL CLUB 
Vol. 15. December, 1913. No. 180. 
ERIGERON PUSILLUS A VALID SPECIES. 
B. L. RoBINSON. 
WnuiLE collecting during the spring of 1912 in the neighborhood of 
Charleston, South Carolina, I found in sandy soil on the Isle of Palms 
a small and rather loosely branched Erigeron, obviously close to E. 
canadensis L., yet with smoother stem and narrower leaves than are 
found in the common and familiar weed of fields and dry open road- 
sides. On returning to the Gray Herbarium a few weeks later I tried 
to separate the coastal plant in question from E. canadensis, but found 
such variety of habit, stature, pubescence, leaf-breadth, etc., among 
the specimens long referred to the species, that no feasible planes of 
cleavage were discovered, and the South Carolina plant was reluc- 
tantly referred to the common species. 
In examining recently some sets of phanerogams collected for the 
Gray Herbarium in the Bermuda Islands by Mr. F. S. Collins, I was 
much interested to find again the smoothish form of Erigeron. This 
led to its more careful examination. Noticing that the involucral 
scales had minute purplish quasi glandular tips, I found at once that 
it was possible to sort very definitely some forty individuals of Ber- 
muda material into two kinds, some having these purple-tipped scales, 
and the others having more attenuate white-tipped scales. Soon 
concomitant differences appeared and it was evident that the form 
with purple-tipped scales was consistently smoother, more slender, 
entire-leaved and tended to have fewer and slightly smaller heads on 
more elongated pedicels together forming a more open inflorescence. 
With these leading characters in mind, the considerable mass of E. 
canadensis in the Gray Herbarium and the herbarium of the New 
