34 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
7. Hemitelia arachnoidea (Underw.) Maxon, sp. nov. PLATE 21, a, b. 
Cnemidaria arachnoidea Underw. MS. 
Caudex not noted; fronds 2 to 3 meters long, spreading; stipes stout, about 85 cm. 
long, brownish green from a light castaneous base, armed with scattered stout conical 
introrse spines 2 to 3 mm. long, eventually tuberculate, and bearing occasional light- 
ish scarious lanceolate scales (these dark-centered at their base), otherwise closely 
covered with a thin subpersistent whitish-arachnoid tomentum; rachis greenish, 
muricate, arachnoid-tomentulose; middle pinnae subopposite, spreading, spaced 
their own width or more (10 to 12 cm. apart at point of insertion), ligulate-lanceolate, 
40 to 50 cm. long, 5 to 6.5 cm, broad, sessile, slightly falcate, at the middle and base 
pinnatifid nearly to the costa, gradually less deeply so below the acuminate crenate- 
serrulate apex; basal pinnz smaller, about 20 cm. long, 3 cm. broad, strongly deflexed; 
segments of middle pinnz about 30 pairs, linear-oblong, 2.5 to 3.5 cm. long, 10 to 12 
mm. broad at the slightly dilatate base, a little narrower toward the rounded apex, 
the basal pair one-half the size of the second (or even vestigial), joined to them by a 
narrow costal wing about 1.5 mm. broad, this gradually broader outward, 4 to 5 mm, 
broad upon each side of the costaat the middle of the pinna; all the segments separated 
by narrow acutish sinuses; margins slightly revolute, subentire or obscurely crenulate; 
cost stout, elevated, stramineous, glabrous above, below minutely whitish arach- 
noid tomentulose and deciduously paleaceous, the scales flaccid, lanceolate to oblong- 
ovate 4 to 7 mm. long, minutely erose, dirty white, dark-centered at the base; costules 
prominent, yellowish and glabrous above, whitish-tomentulose below, the veins 
similar; veins free, oblique, about 14 to 17 pairs to the segment, the lower ones arc- 
uate, these and the middle ones forked at the base, the branches divergent, distant, 
both usually soriferous midway to the margin, or often the anterior branch divari- 
cately forked, with one or both divisions immediately soriferous; sori large, con- 
tiguous, forming a straight or slightly irregular heavy medial line nearly to the apex 
of the segment; indusia ample, 2 or 3 lobed; receptacle cylindric-capitate, squamulose- 
pilose; leaf tissue rigidly herbaceous, lustrous upon both surfaces, dark green above, 
yellowish-green below. 
Type in the U.S. National Herbarium, nos. 575819 and 575820, collected on wet 
slopes in partial shade, vicinity of La Palma, Costa Rica, altitude 1,450 to 1,550 meters, 
May 6 to 8, 1906, by William R. Maxon (no. 453). 
Allied to HH. mutica, from which it differs in dimensions and in the characters 
enumerated in the key. Known only from the type collection. 
EXPLANATION OF PLATE 21.—a, b, Portions of characteristic middle pinne of the type specimen of H. 
arachnoidea; c, fragment from type of H. mutica, furnished by Doctor Christ. All natural size. 
8. Hemitelia mutica Christ, Bull. Soc. Bot. Genéve II. 1: 233. 1909. Phare 21, ce. 
Rhizome ‘“arborescent” but presumably very short; stipe stout, about 45 cm. long, 
yellowish brown, bearing numerous short spines, these dilatate at the base, and a few 
ovate scales up to 4 mm. long, these with shining blackish brown rounded centers 
and delicate whitish fimbriate margins; lamina deltoid-oblong, about 1 meter long 
and 60 cm. broad, very deeply bipinnatifid, the rachis clothed with flaccid grayish 
appressed scales; pinnee spreading, about 15 pairs, the lower ones petiolulate, the 
middle ones sessile, those above broadly adnate and crenately lobed, the uppermost 
decurrent, crenate or subentire; characteristic lower or middle pinne lanceolate-lig- 
ulate from a slightly narrower base, about 30 cm. long, 4.5 to 6 cm. broad, nearly 
straight, close, at the base and middle pinnatifid to within 2 or 3 mm. of the costa, 
beyond this the costal wing gradually broader, about 4 mm. broad on each side below 
the acuminate-caudate serrate apex; coste lightly sulcate and glabrous above, below 
very stout, yellowish brown, sparingly muricate, canaliculate, at the base deciduously 
paleaceous like the rachis, also lightly yellowish araneose-furfuraceous; segments 27 to 
30 pairs, elongate-oblong, mostly falcate, 2 to 3 cm. long, 9 to 11 mm. broad at the 
