t t ELEUTHEROPHYLLE^. 



Leaves in several rows, inserted horizontally, free from adnate 

 stipules. 



Fain. 6. LEUCOBRYACE^. 



Mosses of a pale glaucous green colour, white and brittle when dry, 

 growing in dense spongy tufts. Leaves in many rows, lanceolate, con- 

 cave, composed almost entirely of the dilated nerve, which consists of 

 several layers of empty parenchymatous cells, with their internal walls 

 perforated by foramina, and a central series of 3-4-angled, chlorophyl- 

 lose duct-like cells. Capsule oblong, cernuous or erect ; peristome 

 resembling that of Dicranum, of 16 or 8 teeth. — Inhabiting the ground 

 or rotten wood. 



The very striking plants referred to this family are almost entirely tropical, 

 and are remarkable for their pale colour, and the composite structure of their 

 leaves, compared by some authors to that of Sphagnum, to which however 

 they are not allied. The family was established by Hampe, and named 

 Leucophanese, but was altered by C. Mueller to Leucobryacese to accord 

 with the principal genus, and comprises about 65 species, nearly half belong- 

 ing to Leucobryum, the other genera being Leucophanes, Schistomiirium and Odo- 

 hlephantm. Our British species is the sole representative in Europe, and in 

 the other three quarters of the globe seems to be replaced by the equally 

 common Octoblepharum alhidum. Lindberg reunites the family to Dicranacese, 

 as he finds that the leaves of D. albicans and longifolhtm in section, quite 

 resemble in structure those of Leticobryum. The leaves have generally been 

 described as nerveless, but it is more correct to regard them as consisting 

 almost entirely of nerve, for careful observation will show that near the base, 

 there is at the edges a very narrow but distinct lamina of only a single 

 stratum of narrow elongated cells. On the terminal leaves of the stem of 

 female Leucobryum glaucwm, it is common to find a minute tuft of radicular 

 tomentum developing a cluster of young plants, which falling to the ground 

 grow to a new colony, and thus compensate for the rarity of the fruit. Mr. 

 Barnes tells me that it is difficult to keep the lids on the capsules, as the 

 moss continues its growth even in the press, and to prevent this he 

 recommends those who are fortunate enough to find it in fruit, to dip it into 

 boiling water before pressing. 



LEUCOBRYUM Hampe. 



(Regensb. Bot. Zeit. 1837, Ii 282.) 



Densely csespitose mosses of a whitish or glaucous colour, with 

 dichotomous and fastigiate ramification. Calyptra dimidiate, cucullate. 

 Capsule pachydermous, unequal, often strumose, plicate when dry. 



