201 
on the margins with somewhat ascending hairs, 7—9-nerved, the 
mid-nerve prominent ; panicle broadly ovate, 3 cm. long or less, 
its branches spreading or ascending, their ultimate divisions several 
times longer than the spikelets, the main axis and usually the 
lower branches sparingly pilose; spikelets about 1.5 mm. long, 
divergent from the branches of the panicle, obovate, obtuse, the 
first scale about one-half as long as the spikelet, thin membra- 
nous, orbicular-ovate, obtuse, I—nerved, the second and third scales 
equal in length, membranous, broadly oval, 7-nerved, the latter 
enclosing a hyaline palet about one-half its length, the fourth 
scale chartaceous, oval, white, enclosing a palet of equal length 
and similar texture. 
Type specimen collected by the writer on Aug. 20, 1895, in 
the “flatwoods” at Tampa, Florida, no. 2420a. A specimen in 
the Columbia University herbarium collected by Chapman be- 
longs here; no. 3875 of Wright’s Cuban Collection of 1865, dis- 
tributed as P. dichotomum L., is also to be referred to this species. 
The narrower leaves, more slender culms, and smaller and 
glabrous. spikelets well distinguish this from P. ciatum EIl., to 
which it is most nearly allied. 
Gyrothyra, a new Genus of Hepaticae. 
By MARSHALL A, Howe. 
(PLATES 302, 303.) 
GYROTHYRA. 
_ Stem creeping, foliose, subsimple or somewhat sparingly branch- 
ing, radiculose. Leaves succubous, entire, alternate ; underleaves 
Present, free, bifid, segments narrowly lanceolate or subulate; — 
walls of the leaf-cells with triangular thickenings at the angles. 
Antheridia short-stalked, in the axils of smaller saccate leaves, form- 
ing short median or, at first, terminal spikes. Involucral leaves 
2-4 pairs (commonly 3 pairs). Perianth terminal, confluent for 
half its length or more with the bases of the involucral leaves, the 
greater part of the calyptra, and the tissues of the stem, to form a 
thick-walled tube(perigynium), with a small bulbous orsaccate base; 
perigynium erect or ascending, making, at maturity, nearly a right 
angle with the stem. Capsule cylindrical, long-exserted, dehiscing 
Spirally by four very long and slender valves ; capsule-valves 
of two layers of cells, whose walls are wholly destitute of spiral, ne 
Semiannular, or other local thickenings. laters free, bispiral, 
