197 



Fam. 21. NECKERACE/E. 



Primary stems creeping, the secondary erect, horizontal, pendulous- 

 or floating in water, pinnate and bipinnate. Leaves in 8 rows, equal on 

 all sides or complanate and unequal, with a single nerve or two short 

 ones, densely areolate, with rounded cells or sometimes with longer 

 narrow ones. Capsules often immersed in the perichaetium, or exserted 

 on a short seta ; calyptra cucullate or mitriform ; peristorne usually without 

 cilia, sometimes simple or none. 



We can form but a faint conception of this vast family if we only know our 

 native species, for the bulk of them are confined to the Southern Hemisphere, and 

 the whole family includes at least 800 species. The genus Meteorium is almost 

 entirely tropical, and comprises probably TOO species. These mostly hang in long 

 sheets from the branches of trees, and are sometimes rivalled by our Antitrichia 

 curtipendula, which I have gathered in the forest of Fontainebleau quite 2 ft. long. 

 The family is closely allied to the Pterygophyllaceae, both exceedingly well dealt 

 with by Mr. Mitten in his Musci Austro-Americani (Journ. Linn. Soc., vol. xii), 

 whose arrangement I have followed. 



Sect. i. NECKERE^E. Fertile branches pinnate, plumiform, or tree-like 

 and stipitate. Leaves compressed or rarely equal all round, usually unequal 

 and distichous, glossy, rarely obscure ; cells small and dense, smooth. Calyptra. 

 cucullate ; peristorne hypnoid or simple. 



i. POROTRICHUM (Brid) Mitt. 



Bryol. univ. ii, 275 (1827). 



Stem creeping, beset with rhizoids, the secondary erect, stoloniferous 

 at base, free from branches in the lower half, dendroid above, the branches 

 sub-bifarious and pinnate. Lowest leaves appressed, scattered ; upper 

 crowded, ovate or lanceolate ; the cells roundish, the basal similar or 

 elongated. Capsule erect or cernuous, ovate, with a rostrate lid ; peristome 

 as in Hypnum, inner with or without cilia. Der. -TTO/JO? a perforation, 6pi 

 hair, in reference to the foramina in processes of endostome. 



This large genus of 175 species appears to connect the Hypnaceae with 

 Neckeracese, having the peristome of the former, but the habit and areolation of 

 the latter. The newer name Thamnium cannot be maintained ; it only differs 

 from Porotrichum by the cernuous capsule and presence of cilia in the endostome, 

 and besides had already been used for two genera of lichens and one of Ericaceae. 



CLAVIS TO THE SPECIES. 



Leaves ovate ; nerve well defined, round. 



nearly linear ; nerve very broad and flattened. 



