XEW VARIETIES OF BRITISH MOSSES 2G7 



my attention to two varieties of P. cdopecurum, which have abeady 

 been described. One, mentioned by Eoth as var. cavernarum, was 

 gathered by Schhephacke in the Hartz Mountains and described by 

 him as a weaker form from calcareous rocks with narrower and 

 generally more pointed leaves. The Harlech plant grows on dry 

 Cambrian rocks, which contain no lime, and the leaves do not answer 

 to that description. The other was described by Schiffner from a 

 specimen gathered in Persia and named var. corticolum. This variety 

 resembles my osur aides Schp. in size and habit : it is not glossy, but in 

 structure is like the type form. My new variety has not the corti- 

 colous habit and further differs from the type in the branching and 

 stem leaves. Thamnium mediterranean resembles the new variety in 

 size, but has very complanate leaves : — 



Porotrichiim alopecuriim Mitt. var. aridulum mihi. 



Plantula forma typica multo brevior Eurhyncliio myosuroidi 

 assimilis tum habitu tum colore. Csespites moUes, prostrati, sat 

 extensi, Isete luteo-virescentes, subnitidi ; caules secundarii sub- 

 dendroidales, nonnunquam flagelliformes, ramis nee curvatis nee 

 complanatis ; folia caulina admodum parva, acuminata, costa breviori 

 interdum fere obsoleta ; folia ramealia typicis multo minora, siccitate 

 crispata, typicis forma consimilia ; cellulis usque ad basim magis 

 uniforme rotundatis aut subquadratis, costa validissima raro furcata. 



Hab. — Ad saxa silicea arida prope Harlech, in comitatu Merioneth, 

 April 1913. 



Pterogonium gracile Swartz var. harlecexse mihi. 



The genus Pterogonium is represented in the British Isles by one 

 species only, viz. P. gracile (P. ornifJiopodioides (Huds.) Lindb.). 

 This is a very distinct moss, with sub-dendroid stems and crowded 

 branches curved to one side, and occurs in about 62 vice-comital 

 areas. In Merioneth it is frequent in woods and is found both on 

 trees and rocks. It fruits not infrequently with us, the rupestral 

 plant being rather more fertile than the arboreal one. A yqyy marked 

 form growing with the type occurs on trees in Llechwedd Woods, 

 Harlech, which has been recognized for some time by British 

 br^^ologists as distinct, though it has never been formally described, 

 and I think deserves varietal rank. It is extremely slender with long, 

 julaceous and flagelliform branches. The leaves are much smaller, 

 more acuminate, the margins scarcely less serrate, and the areolation 

 laxer. Mr. Dixon refers in the Handbook to British 3Iosses to a 

 var. caver narum of this species, described by Pfeffer, the leaves of 

 which have fewer serrations than the type. The Merionethshire 

 form is fairly constant and is distributed along the western border of 

 the county in several localities. Mr. Meldrum has also found the 

 same variety in Perthshire : — 



Pteroyoninm gracile Swartz var. liartecense mihi. 



Caulibus admodum gracilibus ; ramis longis, julaceis, flagelli- 

 formibus ; foliis valde parvis, angustioribus, magis acuminatis. vix 

 minus serratis ; cellulis laxioribus aliquanto majoribus. 



Ilab. — Ad arbores, in silva montana, Llechwedd nuncupata, prope 



