Muscti Exortic:.—AHumnboldtiani. 
DIDYMODON GRACILE. 
Didymodon, caule dense cespitoso elongato, foliis lan- 
ceolato-subulatis, pilo longo colorato terminatis, cap- 
sula erecta cylindracea, operculo subulato, calyptra 
basi ciliata. (Tas. V.) 
Jian. In monte Quindiu, regione temperata, Andes de Cundi- 
namara. Humboldt ef Bonpland. 
Caules 3-4-unciales, rigidi, dense caspitosi, simplices vel divisi, 
apicibus attenuati (f.1). Folia ( f.2) erecto-appressa, stricta, 
vel paulujum curvata, rigida, inferiora nigricantia, superiora 
flavescentia, omnia lanceolato-subulata, acumine longo pili- 
formi colorato, sub lente serrulato (f. 4), terminata, nervo la- 
tissimo percursa. Perichetialia (f. 3) his minora, nervo te- 
nuiore. Seta sesquiuncialis, erecta, parum flexuosa. Cap- 
sula (f.5) cylindracea, erecta, intense fusca. Calyptra (f.6) 
subulata, dimidiata, basi ciliata, ciliis longis. Operculum su- 
bulatum, rectum. Peristomium (f. 7, 8) sedecim-dentatum, 
dentibus longis filiformibus, erectis, pallidis, vix per paria ap- 
proximatis. 
I am aware how liable I am to censure in assigning this plant 
to a genus different from that in which Dicranum flexcuosum 
holds a place; since with that it accords so well in habit, in the 
foliage, and particularly in the fringed base of the calyptra. But 
with the genus Dicranum the more essential character, taken 
from the peristome, is wholly at variance ; and even with Didy- 
modon I cannot satisfy myself that the teeth agree in being placed 
in pairs. The habit however does not materially differ, and the 
teeth resemble in form those of many Didymodontes ; 3; and in 
Didymodon capillaceum and heteromallum it is not easy to oi 
cover the approximation of the teeth in pairs, 
Did. gracile has a striking peculiarity, not only in the long 
and slender, rigid stems, but also in the colour, which belowis a 
deep and shining brown, inclining to black; whilst above it is of 
a pale and bright yellow hue. 
Fig. 1. Tuft nat, size. The rest are more or less magnified, 
