282 ; BOTANICAL GAZETTE [ OCTOBER 
I to 2™™ long, pale yellowish green at maturity, sometimes of 
two colors, pale on the concave side and brown above, becoming 
a uniform light brown or dark chestnut brown, unsymmetric, 
from slightly inclined to horizontal, strongly incurved, con- 
stricted under the mouth when dry; collum one-fourth to one- 
third the length of the sporangium; cells of exothecium paren- 
- chymatous throughout or more or less prosenchymatous on the 
convex side, cells on the concave side 43 wide by 53.5 long, 
ranging from 21.5 to 60m in width and from 30 to 77» in length, 
those on the convex side 34.5u wide by 82.5 long, ranging in 
width from 21 to 43 and in length from 60 to 120, cells under 
the peristome but slightly different, sometimes one or two rows 
a little smaller and transversely elongated, 17 to 21.5 long by 
17 to 26 wide; cell walls 2to 3u thick ; stomata twenty-five to 
thirty-five to the capsule, scattered, 43" wide by 52m long; 
peristome teeth light brown at base, paler above, hyaline at the 
points, narrowly margined, serrate in the upper third, transversely 
striate on the back in the basal three-fifths, with occasional areas 
near the middle with striz running obliquely or longitudinally, 
papillose above, papilla large; endostome shorter than the 
teeth, hyaline, papillose throughout, membrane one-half to two- 
thirds the length of the segments, the latter carinate, frequently 
not open along the keel except in the upper third, never gaping, 
cilia one to four, slender, nodose or appendiculate, equaling the 
segments; operculum rostellate or apiculate from a depressed 
convex to conic base; annulus broad, of two to three rows of 
cells: spores finely tuberculate, 13 to 21m in diameter: calyptra 
equalling the capsule, split half its length or less. 
Has.: In wet localities, either in stagnant or slow running 
water, or on the ground, logs, boards, etc. 
Type locality England, Thames river. Common and vari- 
able everywhere. 
This species is probably the most variable of all our Amblystegia 
though in general habit it is comparatively constant. It is sometimes con- 
fused with Aypnum (Campylium) polygamum. The latter plant generally 
has a different habit; its stems more or less upright, with leaves equally 
spreading in all directions from near the base. 
