72 



24. ORTHOTRICHUM. 



GEN. CHAR. Frultstalks terminal ; Peristome double ; 

 the exterior of 1 6 teeth approaching in pairs ; the 

 inner of as many ciliary processes lying horizon- 

 tally; Calyptra mitriform, sulcate, more or less 

 hairy. (TAB. II.) 



Two of this genus, viz. 0. dcc'fpiens and 0. a?2omalum, have, 

 no ciliary processes. O. stria turn has them of a peculiar shape 

 and beaded appearance, arising completely within the range of 

 the teeth : but we believe in all the remaining species the ciliary 

 processes arise from the same membrane, and exactly from the 

 sides of the teeth, as we have represented at fig. 2 of the figure 

 of the peristome in TAB. II. Notwithstanding these anomalies 

 of the peristome, no genus of mosses is more natural in habit ; 

 and we cannot accord with Mohr, that the difference of the split- 

 ting of the base of the calyptra, in one instance in the furrow, 

 in another in the elevation or keel, is by any means of sufficient 

 importance to detach O. crispum from the rest of the species. 



f Perislome without ciliary processes. 



0. Qnomalum ; leaves lanceolate, erecto-patent; frtiitstalks 

 exserted 5 peristome of eight double teeth; calyptra slightly 

 pilose. (TAM. XXI.) 



O. anomalum. Hedw. St. Or. v. 2. t. 37- (magnified peristome in- 

 correct, for which see Hedw. Fund. v. 2. t. "]./. 35.) Dicks. Turn. 

 Muse. Hlb.p. 94. Bryum striatum . Linn. Dill. Musc.t. 55. f. <J. 



HAB. On rocks and walls. 



The stems are scarcely an inch in height, and the fruit- 

 stalks are always longer than the leaves ; by which qrcum- 

 stance, as well as by the different configuration of the teeth, 

 it differs from O. cup?tlatum. With this even Hedwig ap- 

 pears to have confounded it, having given the magnified 

 figure of the peristome of it m his plate of the present spe- 

 cies. In our plant the peristome is arched when moist, and 

 the teeth are inclined or erect (never recurved) when dry. 



0. cupulatum ; leaves lanceolate, erecto-patent ; capsule 

 nearly sessile; peristome of 16 double teeth; calyptra 

 slightly pilose. (TAB. XXI.) 



