MAXON—STUDIES OF TROPICAL AMERICAN FERNS. 547 
4, Polypodium nutatum Jenman, Journ. Bot. Brit. & For. 24: 272. 1886. 
Type LOCALITY: Jamaica. 
DIstRIBUTION: Mountains of Jamaica and St. Vincent, ascending to 1,800 
meters. 
This species, the type specimens of which are presumably at Kew, is repre- 
sented in the Jenman herbarium at New York by several specimens from St. 
Vincent (where, according to a note in Jenman’s hand, it is “common above 
2,000 ft. altitude”) and a frond from Jamaica. These agree perfectly among 
themselves and with the description, the largest specimen being twice the 
height of P. hartii or P. limula. From these P. nutatum is readily distinguished 
by the key characters. 
5, Polypodium cookii Underw. & Maxor, Contr. U. 8. Nat. Herb. 17: 408. 1913. 
Type LOCALITY: Near the Finca Sepacuité, Alta Verapaz, Guatemala (Cook € 
Griggs 80). 
DISTRIBUTION : Known only from the original specimens. 
A distinct and singular species, to be compared only with the next. 
6. Polypodium williamsii Maxon, sp. nov. PLATE 34. 
Plants small and slender, subfasciculate, erect. Rhizome minute, 2 to 3 mm, 
long, 1 mm. or less in diameter, oblique, freely radicose, conspicuously paleaceous 
at the apex; scales numerous, tufted, spreading, yellowish brown in mass, 
oblong to ovate-oblong, 1 to 1.5 mm. long, 0.35 to 0.66 mm. broad, gland-tipped 
at the acutish or abruptly short-acuminate apex, entire, pale yellowish by trans- 
mitted light, the cells mostly oblong to quadrate, with thin walls; fronds 8 to 8, 
ascending, fasciculate, 2.5 to 5 cm. long; stipe 3 to 6 mm. long, 0.1 mm. in 
diameter, pale brown, bearing numerous short, deciduous, 8 or 4-celled 
branched glandular hairs; lamina linear, 2 to 45 cm. long, 8 to 6 mm. broad, 
scarcely narrowed at the base, slightly so at the apex, subpinnate throughout, 
both surfaces scantily long-setose, the hairs stiff, reddish brown, 1 to 1.6 mm. 
long; segments monosorous, 8 to 20 pairs, alternate (with a similar or slightly 
smaller terminal segment), oblique, subdistant, mostly inequilateral, broadly 
elliptical to rounded-obovate, entire (or, if shallowly notched above, often nar- 
rowly rhombic-ovate), usually narrower at the base, adnate, slightly decurrent, 
all faintly joined, the slender rachis greenish above, brownish and elevated be- 
neath, distinctly flexuous throughout; veins of both the sterile and fertile seg- 
ments simple, nearly straight, extending half or two-thirds the distance to the 
apex, ending in an elliptical hydathode; sori small, round, inframedial upon the 
segment, medial upon the vein, the receptacle minute, punctiform; sporangia 
glabrous, the annulus 15-celled. Leaf tissue delicately herbaceous, translucent, 
sparingly glandular beneath like the stipe. 
Type in the U. S. National Herbarium, no. 700801, collected near Apolo, 
Bolivia, altitude about 1,500 meters, on rocks, July 7, 1902, by R. S. Williams 
(no. 1167). 
Distributed as Polypodium nanum Fée, which it resembles in general appear- 
ance, but from which it departs widely in its entire rhizome scales and simple 
veins. The only American species of the trichomanoides group agreeing with 
P. williamsii in having entire rhizome scales, a long-setose lamina, and simple 
veins is the foregoing P. cookii, recently described from Guatemala ; but 
that is a much coarser plant, with stipe 0.5 mm. in diameter, lamina merely 
pinnatifid, segments close and rather broadly joined, and sori larger, nearly 
basal, and confluent at maturity, the resemblance to P. williamsit being very 
remote. 
EXPLANATION OF PLATE 34.—The type specimens. Natural size. 
