Family 6. DICRANACEAE 
By Ropert STaTHaM WILLIAMS 
Dioicous, autoicous or pseudautoicous; male plants sometimes minute, the 
male flowers mostly budlike, rarely discoid, with filiform paraphyses. Plants 
large to very small, with dichotomously branching stems growing in compact 
hemispheric cushions or broad mats, or rarely gregarious; stems usually with 
a central strand, mostly densely leafy and radiculose to tomentose. Leaves 
from straight and erect to curved and secund or sometimes crispate, smooth or 
often mamillose or papillose on one or both sides; costa of heterogeneous cells 
(except in Dicranum § Arctoa), usually stout and percurrent or nearly so, some- 
times strongly ribbed on the back ; lower cells of the leaf-blade mostly pale and 
rectangular, the upper ones shorter, sometimes round, the cell-walls often 
thickened, pitted, and sinuous, the alar group from unchanged to greatly dif- 
ferentiated. Setaelongate, erect or curved. Capsule from irregular and curved 
to symmetric and erect, sometimes furrowed or strumose, usually with superficial 
stomata in the short neck; peristome single, rarely lacking, of 16 teeth from a 
low basal membrane, mostly divided more than one half down into two lanceo- 
late or sometimes filiform forks, the outer face usually vertically striate below, 
more or less papillose above, the inner face with mostly prominent cross-walls ; 
lid convex* or conic, mostly beaked. Calyptra cucullate, never plicate nor 
hairy, sometimes ciliate at the base, the apex often rough. 
Alar cells not differentiated. 
Cells of the leaf-blade smooth; leaves not crispate when dry. I. DIcRANELLEAE. 
Cells of the leaf-blade more or less mamillose on both sides; leaves 
crispate when dry. JIT. RHABDOWEISIEAE. 
Alar cells mostly strongly differentiated (exceptions occur in the entire 
genus Symblepharis and in certain species of Dicranoweisia and Onco- 
phorus). II. DicrRaNnEak. 
I. DicRANELLEAE 
Seta erect or irregularly flexuous and weak. 
Stem-leaves erect-appressed, with or without a more or less spreading 
bristle-like point; stems erect, filiform, often much elongate; male 
flowers conspicuous, more or less discoid. 1. ANGSTROEMIA. 
Stem-leaves spreading from the base, or with clasping base and lance- 
olate spreading point; male flowers budlike and usually inconspicuous. 2. DICRANELLA. 
Seta stout, regularly and strongly curved, more or less sigmoid when moist. 3. CamMpyLOPODIUM. 
II. DicRaNEAE 
Stems, with few branches, weak and flexuous, more or less pendent, up to 
30 cm. or more long. 9, DICRANOLOMA, 
Stems erect or ascending, much shorter. ; 
Capsule with stomata; seta erect; costa usually narrow and semi-terete. 
Auttoicous. 
Peristome-teeth not vertically striate on the outer face. 4. DICRANOWEISIA. 
Peristome-teeth vertically striate on the outer face. 
Costa of homogeneous cells. 11. Dicranum. 
Costa of heterogeneous cells. 
Leaves with recurved and thickened borders, or capsule 
curved and strumose. 
Leaves with flat borders and capsule symmetric. 
Dioicous or psetidautoicous; costa of heterogeneous cells. 
VoLuME 15, Part 2, 1913] 77 
. ONCOPHORUS. 
. SYMBLEPHARIS. 
an 
