1920] Fernald,—Scirpus acutus 25 
water and with the tubers exposed. "Two weeks later (September 
5) the plants were as fresh as ever, but the tubers had shrunk and 
shriveled to a fraction of their original size. 
The blossoms, which last for three or four days, if not fertilized, 
open only in clear weather. On cloudy days and to a certain extent 
at night the flowers close. So far as I know, this is the only one of 
our native orchids to have this trait. The whole plant, except when 
it first appears in the bud and the capsule, is erect, and it little merits 
its common name of Nodding Pogonia. 
PROVIDENCE, RHODE ISLAND. 
Scirpus AcUTUS Muhl.—In 1904, Mrs. Chase! differentiated in 
our flora four species which had been passing under the aggregate 
name Scirpus lacustris L., at the same time showing that the Old 
World plant is unknown from North America. The four species 
recognized by Mrs. Chase are S. validus Vahl., S. occidentalis (Wats.) 
Chase, S. heterochaetus Chase and S. californicus (C. A. Meyer) 
Britton. It would seem, however, that in proposing S. occidentalis 
as a new species she overlooked, as her followers have done, the clear 
description given in Bigelow's Florula Bostoniensis of S. acutus, 
a new species ascribed by Bigelow to Muhlenberg. Bigelow’s descrip- 
tion was based on the plant of Fresh Pond, Cambridge, which was 
distinguished from S. validus (the S. lacustris of American authors 
of his time) by “Spikes . . . oblong and closely imbricate 
In deep water at Fresh Pond and elsewhere." 
Somewhat later, Muhlenberg himself published S. acutus, splen- 
didly contrasting it with his S. lacustris (S. validus of Mrs. Chase's 
treatment): S. lacustris culmo . . . supra attenuato, S. acutus 
culmo . . . supra aequali nec attenuato, pleno maculato, macu- 
lis fuscis oblongis; S. lacustris spicis . . . ovatis, S. acutus 
spicis . . . oblongis; S. lacustris cal. gluma . . . obtusa 
fusca, S. acuta cal. gluma fusca carinata mucronata pubens; 
! Chase, Ruopora, vi, 65-71, tt. 52, 53 (1904). 
? Muhl. ex Bigelow, Fl. Bost. 15 (1814). 
3 Muhl. Descr. Gram. 33 (1817). 
