Rhodora 
JOURNAL OF 
THE NEW ENGLAND BOTANICAL CLUB 
Vol. 19. August, 1917. No. 224. 
CONTRIBUTIONS FROM THE GRAY HERBARIUM OF 
HARVARD UNIVERSITY.— NEW SERIES, NO. L. 
M. L. FERNALD. 
I. SOME POLYGONUMS NEW TO NORTH AMERICA. 
POLYGONUM LAXIFLORUM Weihe. In September, 1916, Mr. Bayard 
Long and the writer noticed in a roadside ditch at Bowdoinham, 
Maine, a Polygonum which had much the habit of P. Hydropiper L., 
with which it was growing, but which differed at first glance in its 
much deeper rose-colored or crimson flowers and somewhat broader 
leaves. Specimens were collected and upon study the plant proves 
to be P. laxiflorum Weihe, Flora, ix. 746 (1826), the plant which is 
frequently found in herbaria under the name P. mite Schrank. P. mite, 
however, according to Moss! is synonymous with P. minus Huds. 
So far as the writer can determine by close examination of all the 
material in the Gray Herbarium and the herbarium of the New Eng- 
land Botanical Club, P. laxiflorum has not heretofore been collected 
in America, but its abundance in the ditch at Bowdoinham indicates 
its thorough establishment there and the likelihood that, with atten- 
tion especially directed to the plant, it will soon be found to be some- 
what widely distributed with us. The plant, as above stated, 
resembles P. Hydropiper but has deeper-colored flowers; and it is 
at once separated by the fact that its perianth is strictly glandless and 
its achene smooth and lustrous, the perianth of P. Hydropiper being 
glandular-dotted and the achene punctate and opaque or dull. 
1 Moss, Camb. Brit. Fl. ii. 121 (1914). 
