56 NORTH AMERICAN FLORA [VoruME 16 
4. Dicranopteris retroflexa (Bommer) Underw. Bull. Torrey 
Club 34: 260. 1907. 
Gleichenia intermedia flexuosa Baker, Jour. Bot. 25: 24. 1887. 
Gleichenia retrofleza Bommer ; Bommer & Christ, Bull. Soc. Bot. Belg. 351: 175. 1896. — Christ, 
Bull. Herb. Boiss. 11.5: 15. 1905. 
Rhizome short-creeping, freely but intricately branched, slender, 2 mm. or less in 
diameter, brown, bearing a few small caducous thick broadly ovate entire brown scales and 
numerous roots; fronds numerous, 30-65 cm. high, weakly ascending, closely entangled ; 
primary leaf-axis slender, 1-1.5 mm. in diameter, reddish-brown, wholly glabrous (like 
the entire plant), continuous; primary branches 3-5 pairs, 12-15 cm. apart in large fronds 
(much closer in others), spreading, once-pseudodichotomous, the internode 1.5-3.5 cm. 
long, straight, naked, but provided with several relatively large incised foliaceous stipules 
at the base, the pinnae fully pectinate and similarly stipulate; pinnae 7-22 cm. long, 3.5-8 
em. broad, widely divaricate (90-120°), the rachis slender, stramineous to light-castaneous, 
conspicuously, sharply, and regularly flexuose, each angle bearing a strongly retrorse pin- 
nule (at an angle of about45°) ; pinnules bright- or yellowish-green, distant, linear, slightly 
narrowed at the base and sometimes a little surcurrent, 2-5 cm. long, 2-4 mm. broad, obtuse 
or acutish, the margins entire or rarely somewhat undulate or sinuate, often revolute in 
drying, the costule stramineous, elevated; veins 20-35 pairs, elevated, distant, mostly once- 
forked, the branches divergent; sori 3-5-sporangiate, medial or nearly so, seated upon the 
anterior branch, commonly protected by the widely revolute margins. 
TYPE LocaLIty: La Palma, Costa Rica. 
DISTRIBUTION: Rather widely distributed in the interior mountain region of Costa Rica, at 
from 600 to 2000 meters elevation. 
ILLUSTRATIONS: Bull. Herb, Boiss. II. 5: 15. f.; 6: 287. f. 3. 
5. Dicranopteris pteridella (Christ) Underw. Bull. Torrey 
Club 34: 260. 1907. 
Gleichenia pieridelia Christ, Bull. Herb. Boiss. Il. 6: 284. 1906. 
Rhizome undescribed; primary leaf-axis elongate, rigidly ascending, terete, subflexu- 
ous, yellowish or dull greenish-brown, glabrate, 2.5-3.5 mm. in diameter, 50 cm. or more 
long, continuous above, bearing 2 or 3 pairs of spreading primary lateral branches about 
12-16 cm. apart; lower primary branches with a continuous (secondary) slender naked 
axis bearing 2 (or rarely 1) pairs of lateral branches, the first internode 2-3 cm. long, with 
simple stalked pinnae or once-forked branches at the node above, the second internode 
elongate (up to 11 cm. long), with small mostly twice-forked lateral branches at the node 
above, these with mostly short naked internodes and stalked pinnae; tettiary lateral axes 
normally abortive, the buds (as in the minor dichotomies) sharply ovate in outline, the 
scales dark reddish-brown, oblong-ovate, acute, with whitish ciliate margins; upper pri- 
mary branches usually once-pseudodichotomous, the internode 2.5-4 cm. long, naked, the 
pinnae stalked (or very rarely the segments descending to the upper part of the internode), 
15-22 cm. long, 3.5-4.5 cm. broad, lanceolate, acuminate, pectinate, slightly or not nar- 
rowed at the base, the rachis (like the internodes) nearly glabrous or with a few small 
scattered appressed scales like those of the buds; segments rigidly herbaceous, close, 
spreading or slightly decurved, linear from a slightly dilatate base, 1.5-2.4 cm. long, about 
3 mm. broad, acutish, dull yellowish-green, much paler below, the margins entire and 
lightly revolute, the costa prominent below, yellowish, glabrate; veins about 25-32 pairs, 
subimmersed below, slightly elevated and conspicuous above, once-forked near the base; 
sori inframedial, seated upon the anterior branch, 4-6-sporangiate; leaf-tissue whitish- 
granulose below, bearing also minute scattered whitish simple or mostly substellate gland- 
like scales, these sometimes dark-centered. 
TYPE LOCALITY: Costa Rica. . 
DISTRIBUTION : Interior mountain region of Costa Rica, up to 1450 meters elevation. 
ILLUSTRATION : Bull. Herb. Boiss. II. 6: 287. 7. 22, representing a young state in which a con- 
tinuous secondary leaf-axis is not developed. 
