202 
acute or bluntly pointed ; spores minutely papillate. “ Involucel- 
lum” of the sporogonium foot well developed. (Name from 
yopos, twisted, and @0a, door.) 
GYROTHYRA UNDERWOODIANA. 
Dioicous. Plants rather large, 1-2 cm. long, 2-4 mm. wide, 
mostly in compact light green tufts; stems creeping, thick, often 
slightly flattened dorso-ventrally, .5-.65 mm. in diameter, about 
15 cells wide in cross section, very densely radiculose, slightly 
ascending at apex, subsimple or with a few irregularly disposed 
lateral branches, in female plant innovating from near base of 
perigynium ; root-hairs long, nearly colorless or of a dilute yel- 
lowish-brown hue, sometimes tinged proximally with purple, 
springing in older parts of the stem from oblong or linear dark- 
purple callosities, made up of the closely coherent root-hair bases 
and of other ventrally elongated cells; leaves obliquely inserted, 
lingulate or oval, succubous, rather close, translucent, alternate, 
scarcely decurrent dorsally, often crowded and suberect at stem 
apex, marginate, commonly concave below, apex decurved, 
1.4-2 mm. X 1.7-4 mm.; cells of the margin quadrate or ob- 
long, equalling in size the adjacent or twice as large; other leaf- 
cells mostly quite regularly pentagonal or hexagonal, 25—70 p» in 
diameter, oblong and larger towards the base ; all with conspicu- 
ous trigones ; under-leaves free, often wine-colored, .6—1 mm. long, 
bifid %4-% the length into narrowly lanceolate or subulate seg- 
ments, usually running out into a single series of cells at apex, 
concealed by the dense mat of root-hairs, except in the younger 
portions of the stem; perigynium tubular, 1-1%4 mm. in diameter, 
and, with the free portion of the perianth, 3-4 mm. long, erect or 
ascending, nearly at right angles with the stem, tinged with pur- 
ple ventrally, bulbous or saccate at base; wall of perigynium- 
tube 5-20 cells in thickness; involucral leaves 2-4 pairs (com- 
monly 3 pairs), entire or repand, similar in form to the cauline, 
margins approximate at base dorsally, distant ventrally ; upper- 
most pair inserted at about middle of perianth-tube or, more 
rarely, at two-thirds its height, erect, apex and dorsal margins nar- 
rowly reflexed and exposing the perianth, or closely appressed and 
wholly concealing it; next lower pair usually inserted at about 
one-third height of perianth-tube, more broadly reflexed ; the one 
or two basal pairs but slightly attached to perigynium ; involucral 
underleaves inconspicuous, sometimes subentire and slightly ad- 
herent to base of involucral leaves; bulbus of perigynium with- 
out radicles, but a dense tuft of root-hairs springs from the stem 
just back of the bulbus and long root-hairs come from the cells 
_of the involucral leaves near their bases; perianth free for 4-% 
its length, free portion nearly echlorophyllose, subtubular, some- 
