252 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 11 



Leafy stems small, slender, brown, radially symmetric, more or less julaceous, 

 ascending to erect from a branched rhizome, and forming cushions or mats, often 

 with other bryophytes; stems 1-3 cm long, with leaves, to 0.5 mm broad, 

 occasionally branched, the branches lateral and ventral, leafy; rhizome brown, 

 with three rows of scale-leaves, the branches rhizome-like, flagelliform, or 

 erect-leafy. Rhizoids abundant on the scale-leaves of rhizomes and flagelliform 

 branches. Leaves and underleaves quite similar, erect-imbricate, concave, the 

 base of four very large cells, similar to the four cortical cells of the stem to which 

 they are attached. Leaves broadly orbicular-ovate, to 0.3 mm long, 0.45 mm 

 broad, the very short tip blunt, the margins entire, a few-celled ventral wing 

 sometimes present near the apex, a ridge-keel not developed; cells 9-12 p. across, 

 the walls thickened, trigones small, the cuticle faintly verruculose. Underleaves 

 similar, orbicular, concave, a wing never developed, cells as in the leaves. Male 

 and female inflorescences and sporophyte not seen. PI. 56. Fig. 1, a-c. 



Habitat: In mats on moist substrate. 



GUIANA: without locality, Quelch (type G-10917). 



2. Micropterygium duidae Reimers, Hedwigia 73: 147. /. 2. 1933. 



Leafy stems small, slender, dull greenish to yellow-brown, appearing to be 

 more or less radial, ascending to erect from a branched rhizome system, in 

 dense cushions, often with other bryophytes; stems to 2 cm or more long, with 

 leaves to 0.4 to 0.8 mm broad, lateral and ventral branches occasional, the 

 ventral branches leafy or flagelliform. Rhizoids frequent on the bases of 

 underleaves, the scale-leaves of the flagelliform branches, and the rhizome. 

 Leaves ascendent, broadly ovate, deeply concave, 0.24-0.3 mm long, the apex 

 acute, entire or bifid by a pair of cells, a ventral wing one or two cells wide often 

 developed down the middle of the upper third or half, the margins usually entire, 

 a row of four or eight large cells across the base; cells quadrate in outline, 15-20 p, 

 the walls uniformly thickened, the trigones inconspicuous, the cuticle weakly to 

 coarsely papillose with numerous wart-like thickenings per cell. Underleaves 

 similar to the leaves, a little smaller, orbicular, the apex broader, entire or 

 undulate. Plants dioicous, the male and female inflorescences on short ventral 

 sexual branches near the base of the stem. Male inflorescence inconspicuous, 

 short, pale, catkin-like, the bracts in three to five pairs, concave, the bracteoles 

 small, plane, ovate to shortly bifid. Female inflorescence conspicuous, the bracts 

 and bracteoles in three series, ovate, the innermost bracts the largest, to 1.5 mm 

 long, the upper margin long-ciliate. Perianth to 4 mm long, 3-angled, the mouth 

 ciliate, the cells 0.2 mm long. PI. 56. Fig. 2, a-c. 



Habitat: In cushions or mats at the bases of moist sandstone escarpments, 

 and on wet rocks, usually with Aneura. 



VENEZUELA: Estado Bolivar: Chimanta Massif: sw edge of Apacara-tepui, 1800- 

 2000 m, Steyermark 74981 p.p. (NY); summit of Torono-tepui, 2165-2180 m, Steyermark & 

 Wurdack 695 p.p., 704 (NY) ; island in Rio Tirica. about Middle Falls. 1925 m, Steyermark & 

 Wurdack 465 ? (lectotype NY), 466 (NY). [Mt. Duida, 2130 m, Tate 492 (the type, NY & B), 

 cited by Reimers, 1933, but apparently lost.]; Roraima, Vie 629 as M. heterostipa (G). 



3. Micropterygium tatei Reimers, Hedwigia 73: 150. /. 3. 1933. 



Leafy stems, small, slender, greenish to yellow-brown, ascendent to erect 

 from a branched rhizome system, appearing more or less radial, in cushions, often 

 with other bryophytes; stems 1-2 cm long, with leaves to 0.3-0.5 mm broad, 



