DICRANACEJJ.] 9 6 [Ditrichum. 



Male infl. gemmiform, axillar ; the bracts ovate, acuminate, nerve 

 obsolete. 

 HAB. Fallow fields and wet heaths. Not uncommon. Fr. 5 6. 



N. Wales (Bowman). Kinnaird (Gardiner 1844) ! ! Welburn (Spruce). Near Shotover 

 (Boswell) \ Hale, Ashley and Helsby (Hunt) ! ! Newtimber and Pylcomb Downs 

 (Davits 1862) ! ! Haversham head, Westmoreland (Barnes 1871) ! Mere, Cheshire 

 (Wilson 1844) ! ! 



Great confusion exists in the early authors between this species and the 

 last, and Archidium alternif. and after the latter is separated, we still find the 

 majority of references to PL subulatum belong to the present plant, due no 

 doubt to the fact that it is by far the commonest species on the continent, 

 while PI. subiilatum is much more frequent with us. Hedwig's beautiful figure 

 well shows the male infl. and the position of this, with the long perich. bracts 

 suddenly dilated at base, enable us readily to indentify PI. alternifolium. 



3. DITRICHUM TIMM. 



(Fl. Megapolit. 216 (1788). ) 



Plants caespitant, dwarf, or tall and slender, living on the ground or 

 on rocks. Leaves lanceolate-subulate, smooth and glossy, the areolation 

 narrowly rectangular above, lax and hexagono-rectangular at base. 

 Calyptra narrow, cucullate. Capsule on a slender straight seta, usually 

 erect, oval or subcylindric, annulate ; peristome erect, of 16 longish 

 teeth cleft to base into two filiform articulate papillose legs, fixed on a 

 short membrane. Spores very small, smooth. Deriv. Sis two, M hair. 



Hampe in Regens. bot. zeit. 1867, p. 181, points out that this genus was 

 founded by Timm on D. pusillum, and must supersede his own Lcptotrichum 

 not only by right of priority, but also because the latter was already in use 

 for a genus of Fungi. About 25 species are known; but L. vaginans of 

 Schimper's Synopsis, 2 ed. 140, and of Sullivant's Exsicc. is only a variety of 

 D. tortile, and differs from L. vaginans Sull. Icones. (see LINDBERG Revis. 

 crit. ic. Fl. Danica, p. 107.) 



CLAVIS TO THE SPECIES. 



Leaves squarrose. Capsule very narrow, cylindraceous. tenuifolium. 



Leaves erecto-patent or secund. Capsule ovate or elliptic. 



Paroicous. Leaves patent, setaceous. subulatum. 



Dioicous. Leaves subsecund or falcate. 



Stems short, straight ; leaves lanceolate-subulate. 



Capsule cylindric, lid shortly rostellate. tortile. 



Capsule elliptic, lid conic, obtuse. homomallum. 



Stems tall, slender, flexuose ; leaves flexuose, falcate. flexicaule. 



Sect. i. TRICHODON (Schimp.). Plants dwarf, slender ; leaves sheath- 

 ing at base, suddenly subulate, flexuoso-squarrose. Capsule narrowly cylin- 

 draceous. 



