Fam. 7. DICRANACE^. 



Plants varying in size from minute to very tall, innovating dicho- 

 tomously. Leaves broadly lanceolate to subulate, often sheathing at 

 base, nerved, smooth or rarely papillose; areolation quadrate or 

 oblong and chlorophyllose above, elongated rectangular and pellucid at 

 base, with or without larger inflated or coloured basal angular cells. 

 Calyptra large, cucullate or irregular. Capsule erect or cernuous, in a 

 few low forms cleistocarpous ; lid large, usually restate ; peristome of 

 16 teeth, confluent at base, cleft half way or sometimes to base into two 

 lanceolate or subulate legs, trabeculate, minutely striate on outer 

 surface, very rarely entire, very rarely wanting. — Inhabiting the ground, 

 rocks or rarely trunks of trees. 



This immense family embracing probably 600 species is distributed 

 throughout the world, and at all altitudes. Of the six subfamiHes under 

 which the European species are arranged, one — Trematodonteae — is not found 

 with us, though represented on the continent by three species of Trematodon, 

 and three of the cleistocarpous genus Bmchia, one of which B. (Spofledera) 

 palustris may possibly occur here. The larger species of Dicranum have great 

 uniformity in habit and foliation, and require careful examination to determine 

 correctly ; many of them are beautiful mosses with tall stems and glossy 

 lanceolate, often falcato-secund leaves, and our D. Bonjeani and majus, the 

 Scandinavian D. elatum and southern D. Blumei, setosum and Billardieri, are 

 among the noblest of the genus. 



The presence of larger pellucid or coloured cells at the basal angles of the 

 leaf is an important character in separating Dicranum from Dicranella, and 

 the term hasal angular cells is used in preference to alav cells, employed by 

 C. Mueller, as being more definite and correct, for all the cells composing the 

 wing of the leaf are alar cells. The other European genera not represented 

 in Britain, are Atractylocafpus Mitt. (Merceya Scrimv.) — Aongstwemia Br. Sch. 

 — Trematodon Michx. — BrucUa Nestler. — Byyoxiphium Mitt. — Cheilothela 

 LiNDB. — Onoweissia Schimp. 



Suhf. I. DITRICHE^. Plants very small or tall, slender; leaves 

 lanceolate-subulate, without enlarged basal angular cells. Peristome of i5 

 subulate teeth, with a median line, or cleft into 32 cilia, approximate in pairs ; 

 a few species cleistocarpous. 



I. ARCHIDIUM Bridel. 



(Bryol. univ. i, 747 (1826). ) 



Plants very small, slender, branched, innovating below the apex. 

 Leaves ovato-lanceolate, nerved, with lax hexagono-rhomboid areola- 

 tion. Capsule sessile in an imperfect vaginula, cleistocarpous, globose, 

 leptodermous, formed of a single stratum of cells, without a spore-sac 



