Part 2, 1913] DICRANACEAE 129 
stem-leaves up to 13 mm. long, often more or less undulate, spreading-flexuous, rarely some- 
what falcate-secund at the apex of the stem, long-lanceolate, acute, sharply serrate on the 
margins one half down; costa just above its broadened base about 75 » wide and one tenth 
the width of the leaf or less, ending just below the apex, with two sharply serrate ribs on the 
back above, in cross-section near the middle showing about 5 guide-cells with stereid-bands 
above and below, the lower band with 2 or 3 larger cells on the dorsal side; alar cells brown, 
extending half way to the costa, the cells above all elongate, with thickened, pitted walls 
extending to the apex, the lower cells about 12% wide and 125 » long or more, the median 
ones 40-50 w long; inner perichaetial leaves with a convolute base up to 9 mm. long, more or 
less costate, abruptly narrowed to a slender point 2-4 mm. long, serrulate at the apex: setae 
aggregate, 1-4, dark-red, up to 6 cm. high: capsule cylindric, 3-5 mm. long, curved, nodding 
or horizontal, scarcely or not furrowed when dry, the exothecal cells with walls uniformly 
thickened, those on the convex side elongate, those on the incurved side and at the mouth of 
the capsule nearly square to hexagonal; annulus wanting; lid conic-rostrate, rather shorter 
than the capsule; peristome-teeth reddish-brown, vertically striate, divided more than one 
half down, the inner plates with prominent articulations 20-25 «4 apart: spores rough, up to 
25 » in diameter. 
TYPE LOCALITY: Venezuela. 
DistTRIBUTION: Mexico and southward into South America. 
28. Dicranum Sumichrasti Duby, Mém. Soc. Genéve 20: 353. 1870. 
Dioicous: male plants 2-3 mm. high, on tomentum of the fertile stems: fertile plants in 
compact, broad, glossy-green mats with tomentose stems up to 6 cm. high: stem-leaves 
falcate-secund, narrowly lanceolate, subtubulose above, sometimes undulate, 7-8 mm. long, 
sharply serrate one third down; costa ending just below the apex, with 2 serrate ribs on the 
back in the upper part, in cross-section near the middle showing about 4 guide-cells with 
stereid-bands above and below, the lower band with some larger cells on the dorsal side; alar 
cells golden-brown, the cells above to the apex of the leaf elongate, those in the lower part of 
the blade 10-12 uw wide and about 100 u« long, gradually shorter upward with slightly thickened, 
pitted walls throughout; inner perichaetial leaves rather longer than the stem-leaves, convolute 
about four fifths up, rather abruptly narrowed to a slender point serrulate at the apex: setae 
aggregate, 2-5, rarely solitary, 2-3 cm. long, mostly yellowish: capsule cylindric, nearly erect, 
slightly curved, 3.5 mm. long, furrowed when dry, not strumose, the exothecal cells elongate 
except near the mouth, with unequally thickened walls and stomata in 2 or 3 rows near the 
base; annulus wanting; lid rostrate, about the length of the capsule; peristome-teeth reddish- 
brown, vertically striate, divided about one half down: spores rough, up to 28 » in diameter. 
TYPE LOCALITY: Mirador, Vera Cruz. 
DIsTRIBUTION: Vera Cruz and Puebla. 
ILLUSTRATION: Mém. Soc. Genéve 20: fl. 3, f. 1. 
29. Dicranum neglectum Juratzka, Laubm. 47. 1882. 
Dicranum algidum Kindb. Rev. Bryol. 23:17. 1896. 
Dioicous: male plants minute, attached to tomentum of the fertile stems: fertile plants 
intermediate in habit between D. scoparium and D. Mihlenbecku; tufts compact, usually 4-5 
cm. high, somewhat glossy, sparingly tomentose: stem-leaves erect-spreading, sometimes 
slightly secund, when dry somewhat curved and laxly appressed, 4.5-6 mm. long, from an 
ovate-lanceolate base gradually narrowed to a tubulose, subulate point either nearly smooth 
or serrulate on the margins and rough on the back about one fourth down the leaf; costa : 
percurrent or shortly excurrent, more or less rough toward the apex, just above its broadened 
base about one ninth the leaf-width, in cross-section in the lower part of the leaf showing about 
6 guide-cells with stereid-bands above and below, the outer cells more or less differentiated; 
leaf-blade smooth on the back, the cells mostly elongate with thickened, more or less pitted 
walls, extending to the apex or sometimes with shorter cells in the upper half of the leaf, more 
or less mingled with longer ones, with walls not pitted; alar cells brown, extending not quite 
to the costa; inner perichaetial leaves convolute, abruptly narrowed to a slender, smoothish 
