Musci Exortici.—Humboldtiani. 
ORTHOTRICHUM APICULATUM. 
Orthotrichum caule repente ramoso, ramis erectis, foliis 
oblongis apiculatis medio canaliculatis siccitate tortis, 
seta longa, capsula ovato-cylindracea, calyptra glabra 
multifida. (Tas. XLV.) 
Has. Prope Xalapam in regno Mexicano, regione temperata. 
Humboldt et Bonpland. 
Caules repentes, nudiusculi, rigidi, ramosi, ramis erectis subfas- 
ciculatim divisi. Folia numerosa, fuscescentia, superiora pal- . 
lidiora flavo-viridia nitoris expertia, horizontaliter patentia, 
oblonga, margine subundulata, nervo ultra apicem in apiculum 
producto percursa. Perichetialia minora late ovata, subacu- 
minata. Sefa demum lateralis longiuscula. Capsula ovato- 
cylindracea, senectute sublanceolata, Operculum subulatum. 
Calyptra badia, striata, mitriformis, glabra, a basi usque ad 
medium in lacinias angustas fissa, laciniis apice bifidis. Pe- 
ristomium ? 
piodememate rn anne 
So closely does this moss border upon the Sclotheimia squar- 
vosa of Schwaegrichen, that I can hardly point out any essentially 
distinguishing character between them except in the calyptra, 
which is by no means alike in the two plants. I have therefore 
greatly to regret that in all the specimens I possess of O. apicu- 
latum the capsules are either not sufficiently, or else too much, 
advanced to exhibit a peristome.. Those in the latter state are 
quite destitute of teeth ; and as to those upon which the oper- 
culum still remains, I can, on removing this part under the mi- 
croscope, discover nothing but a pulpy mass filling the hollow of 
the lid, the external substance of which, when the capsule is 
arrived at maturity, probably forms the peristome. 
Until T can satisfy myself as to the real structure of the teeth, 
I shall place this species among the Orthotricha, where it will 
rank naturally enough with O. longipes, O. gracile, O. longi- 
rostre and longifolium,—differing however from all in the form 
of the leaves, 
Fig. 1, plant nat. size. Fig. 2, leaves. Fig. 3, perichatial 
jeaf. Fig. 4, capsule with the operculum. Fig. 5, old capsule. 
Fig. 6, calyptra. 
