( 120) 
somewhat recurved and of a double thickness of cells; peri- 
chaetial leaves not sheathing, similar to those of stem; leaf- 
cells pale, thin, hexagonal, 8 in diameter, to oblong, 12 
long in upper part, becoming rectangular and hyaline at base; 
costa vanishing in apex, 60 wide at base, without stereid 
bands, the cell-walls being uniformly thickened throughout 
leaf in cross-section: seta up to 1 cm. in height; capsule 
oblong, about 1.5 mm. long, with obliquely rostrate lid one 
half to two thirds as long ; exothecal cells thin-walled, mostly 
rectangular and 2-3 times longer than broad; stomata in 
about 2 rows at base of capsule; teeth of peristome slender, 
from a very short basilar membrane, erect or nearly so, papil- 
lose, divided almost to base, or more or less cribrose below 
with segments sometimes united above ; annulus narrow, per- 
sistent ; calyptra cucullate, extending one half down capsule: 
spores smooth, up to 16 y in diameter. 
La Paz, 3600 meters, on wet hillside, August 18, 1901 
(2869); Battallias river, 3900 meters, along ditches, August 
24,1901 (1712). In habit this species is much like D. topha- 
ceus, which agrees in having no stereid bands in costa, but 
differs in its leaf-margin not being thickened. 
Didymodon decolorans (Hampe). 
Barbula decolorans Hampe, Ann. Sci. Nat. V. 3: 348. 
Sorata, 2250 meters, on earth, June 3, 1902 (1789); Peli- 
chuco, 3300 meters, May 3, 1902 (2843). The peristome of 
this species consists of 16 teeth, not quite erect and more or 
less united along the median line. Cross-sections of leaf 
show about 5 guide-cells, 2 rows of thin-walled cells above 
and a well-defined stereid band below, also swollen border of 
a double thickness of cells. 
DipyMODON AMBLysTEGIUS (C. Mill.) Broth. 
Sorata, 2250 meters, on rock, October 3, 1902 (1722). 
These specimens are up to 2.5 cm. high, and the exothecal 
cells are inflated or mammillose, especially on the incurved 
side of capsule. Specimens of Herb. Lindig, no. 2146, 
New Granada, resemble these Bolivian plants in every way. 
Trichostomum campylopyxis C. Miill., from Bolivia, evi- 
dently belongs here, as it is stated to differ chiefly in having 
the exothecal cells mammillose. 
