Weissia.-] APLOPERISTOMI. 75 



3. Pt. filiforme ; stems irregularly branched curved, leaves ovate 

 subacuminated concave their margins recurved serrated, nerve 

 single or forked short faint, lid conical. (TAB. XIV.) 



Pterogonium filiforme. Hedw. St. Cr. v. 4. t. 7. Engl. Bot. t. 

 2297. Moug. et Nestl. n. 210. Hook. Fl. Scot. P. II. p."' 129. Am. 

 Disp. Muse. p. 49. Schwaegr. Suppl. v. 1. p. 100. JBrid. Meth. p. 

 126. Punch, Deutschl Moose, t. 13. n. 1. 

 Pt. csespitosum. Engl. Bot. t. 2526. 

 Grimmia filiformis. Mohr. 



Hypnum cylindricum. Dicks. Crypt. Fasc. 2. p. 12. Smith, Fl. 

 Brit. p. 1280. 

 HAB. Mountains in Scotland and Ireland. Ben Lawers, 



common. Arnott and Greville. 



In this and the preceding species the leaves are closely im- 

 bricated and subsecund, but the present plant is the smaller 

 and more slender of the two. The cellules of the leaves are 

 larger than in Pt. gracile, and project on the back and margins, 

 which gives the foliage a papillose appearance as in Hypnum ca- 

 tenulatum, H. proliferum, and a few others. The nerve of the 

 leaf, though sometimes scarcely visible, is at others more evi- 

 dent, single, or forked so as to resemble that of Pt. gracile. 

 We have examined specimens of the Pt. ccespitosum of English 

 Botany, which differ in nothing from Pt. filiforme, but in being 

 somewhat larger, and in having their branches less attenuate. 



XVII. WEISSIA. 



GEN. CHAR. Fruitstalks terminal; Peristome single, of 16 

 entire, equidistant teeth ; Calyptra dimidiate. (TAB. II.) 



We cannot agree with Mohr in uniting this genus with the 

 Grimmice, to which it bears a relation similar to that of Didymo- 

 don with Trichostomum, and of Gymnostomum with Anictangium, 

 genera which are now universally adopted. 



* Capsule with an apophysis. 

 1. W. splacknoides ; leaves Ungulate rounded at the top their 



