Part 2, 1913] DICRANACEAE 91 
wide; leaf-cells rectangular, the median ones 6-8 » wide and up to 40 p long, with scarcely 
thickened walls; perichaetial leaves longer, up to 4 mm., with ovate, somewhat clasping base, 
rather gradually narrowed to a limb up to twice as long, with an entire or slightly denticulate, 
acute apex: seta yellowish, slender, mostly erect, 5 mm. long: capsule oblong, symmetric, 
smooth or somewhat furrowed when dry, with elongate, irregular, thick, not sinuous-walled 
cells about 20 » wide and 30-50 yw long; lid with a long obliquely rostrate beak; annulus large; 
peristome-teeth red, vertically striate below, pale, papillose above, about 60-1204 high by 
35 » wide at the base, irregularly divided scarcely one half down into unequal forks: spores 
coarsely papillose, up to 22 w in diameter or more. 
TYPE LocaLity: Near Jalapa, Vera Cruz. 
DISTRIBUTION: Mexico and Guatemala. 
: _A single plant from the type collection of Microdus ovatus has been received from the Museum 
d'Histoire Naturelle, Paris; it has the stems 5 mm. high, the pedicel brown, 4 mm. high, the capsule 
erect, oblong, with peristome wanting; the capsule contained spores very rough and up to 25y in 
diameter, this being rather larger than the average for M. Liebmanni, not smaller, as given by 
Bescherelle. 
21. Dicranella Dussii R. S. Williams, sp. nov. 
Platts in loose, brownish-green tufts; stems mostly branching, about 1 cm. high, with 
erect-spreading, flexuous leaves: lower stem-leaves small, lanceolate. gradually larger upward, 
from a short ovate-lanceolate base gradually narrowed to a mostly somewhat curved, grooved 
limb four or five times as long, with the blade distinct almost or quite to the denticulate apex; 
costa about 80 » wide at the base, one fourth the width of the leaf-base, scarcely percurrent; lower 
leaf-cells rectangular, the upper ones shorter, about 6-7 » wide and 10-20 » long, rather thin- 
walled and distinct throughout; perichaetial leaves up to 3.5 mm. long with the base scarcely clasp- 
ing or larger than in the stem-leaves but with a longer, flexuous limb often 6-7 times the broader 
part in length, with a narrow but distinct, more or less recurved blade extending to the denticu- 
late apex and irregularly serrulate some distance down: seta erect, 10-15 mm. long: capsule 
oblong, symmetric, erect, a little more than 1 mm. long, with large annulus and long-rostrate 
lid; peristome-teeth scarcely 200 » high, about 30 « wide at the base, vertically striate below, 
papillose above, divided two thirds down into unequal forks: spores minutely roughened, up 
to 16 » in diameter. 
Type collected on rocks near La Soufriére, Guadeloupe, 1898, Duss 833, in part (herb. N. Y. Bot. 
Gard.). ‘ 
DistRIBUTION: Known only from the type locality. , © 
This species has leaves somewhat like D. angustifolia Mitt., but in the Guadeloupe plant they. 
are distinctly serrulate above and the capsule is longer and erect. From D. brachyblepharis it is 
distinguished by the relatively much smaller basal part of the leaf and the smaller, smoother spores. 
22. Dicranella longirostris (Schwaegr.) Mitt. Jour. Linn. 
Soc. 12: 30. 1869. 
Trematodon longirostris Schwaegr. Suppl. 12: 343. 1816. 
Coscinodon longirostris. Brid. Musc. Recent. Suppl. 4: 51. 1819. 
Weisia longirostris Schwaegr. Suppl. 2!: 54. 1823. 
Seligeria longivostris C. Mill. Syn. 1: 421. 1848. ae 
‘Microdus longirostris Schimp.; Besch. Mém. Soc. Sci. Nat. Cherbourg 16: 162. 1872. 
*Microdus crispulus Besch. Ann. Sci. Nat. VI. 3:179. 1876. 
Dicranella pseudolongirostris Card. Rev. Bryol. 36: 68. 1909. 
Plants in low, rather compact, brownish-green mats; stems mostly simple and less than 
1 em. high, with leaves more or less erect and appressed or somewhat curved: stem-leaves short- 
lanceolate, mostly a little more than 1 mm. long, with stout nearly percurrent costa about 70 uw 
wide below, and leaf-blade three or four cells wide on either side of the costa to the entire, narrowly 
obtuse apex; leaf-cells rectangular with walls somewhat thickened throughout, the basal ones 
narrow, about 84 wide and 50 long, the upper one and a half times to twice.as long as wide; peri- 
chaetial leaves erect, scarcely clasping, up to 2.5 mm. long, from an ovate base gradually 
narrowed to a rather broad, grooved limb not much longer than the basal part, with recurved 
margins and an entire or scarcely crenate apex: seta erect, yellowish, 7 mm. long: capsule oval, 
symmetric, erect, 1.25 mm. long, when dry and empty dark and somewhat ribbed, the exothecal 
cells, with thickened walls, up to 50 » long and 8-10 wide; annulus large; lid obliquely long- 
rostrate; peristome-teeth mostly less than 120 » high, papillose, not striate, irregularly divided 
