Family 7. LEUCOBRYACEAE 
By Rosert StatHam WILLIAMS 
Dioicous, autoicous, or pseudautoicous. Perennial, cespitose plants of 
medium to large size, usually pale-green to whitish-green or pale-brown in 
color. Stems without a central strand, bearing crowded, sometimes fragile and 
deciduous leaves and radicles mostly at the base of the stems or sometimes at 
the apex of the leaves. Leaves consisting for the greater part of a broad costa 
of three or more layers of two different kinds of cells, the outer large, hyaline 
and porose on the internal walls (leucocysts), enclosing usually a single row of 
small, green, three- or four-sided cells (chlorocysts). Seta solitary and erect. 
Capsule erect and regular or irregular, nodding and strumose; annulus rarely 
present; peristome inserted mostly below the mouth, the teeth 16 or sometimes 
only 8, lanceolate, mostly strongly articulate, either vertically striate or papillose 
to nearly smooth; lid subulately beaked. Calyptra cucullate. 
Costa with a stereid-band. 1. LEUCOPHANES. 
Costa without a stereid-band. 
Capsule regular, erect. 2, OCTOBLEPHARUM. 
Capsule irregular, nodding. 3. Leucosryum. 
1. LEUCOPHANES Brid. Bryol. Univ. 1: 763. 1827. 
Dioicous. Plants of medium size, in mostly pale-yellowish or greenish, compact tufts 
with rather slender stems usually without radicles and with fastigiate branches. Leaves 
mostly crowded, erect-spreading to somewhat squarrose, rather broadly lanceolate to linear- 
lanceolate, sometimes bearing gemmae at the tips, or scattered radicles that produce new plants, 
in cross-section showing mostly a single layer of leucocysts on either side of the nearly median 
layer of four-sided chlorocysts and a costa-like stereid-band extending down the middle of the 
leaf on the under side, also the border of the leaf of a compact stereid-band. Seta terminal or 
lateral, slender, elongate. Capsule oblong or cylindric, erect, thin-walled, mostly somewhat 
irregularly ribbed when dry and empty; peristome-teeth lanceolate, without a median line, 
papillose on both sides, the articulations mostly indistinct; lid with a long, slender beak. 
Calyptra cucullate, extending well down the capsule, the margin entire. 
Type species, Leucophanes octoblepharoides Brid. 
Costa-like median band sharply denticulate on the back, 40-50 wide. pay oe guadalupense. 
Costa-like median band smooth on the back, less than 25y wide. 2. L. Mittenii. 
1. Leucophanes guadalupense Lindb. Oefv Sv. Vet.-Akad. 
Forh. 21: 608. 1865. 
Flowers and fruit unknown. Plants in densely cespitose, somewhat shining, greenish- 
brown cushions; stems short, branching, densely foliate: leaves up to about 4 mm. long, 
greenish from a paler base, erect-flexuous or somewhat spreading-recurved, narrowly lanceolate, 
acute, carinate, the colored border flat and serrulate above, of stereid-cells extending from the 
apex to near the base; costa-like stereid-band shortly excurrent, 40-50 » wide, slightly tapering 
above and sharply denticulate one third down on the back, in cross-section showing 4 or 5 
rather small guide-cells near the upper side of the band; leaf-blade chiefly of a single layer of 
leucocysts on either side of the chlorocysts except in the lower part of the leaf where there are 
Vorume 15, Part 2, 1913] 159 
