ROBINSON: PTERIDOPHYTA OF THE HAWAUAN IsLANDs 195 
ILLustRATION: Hook. & Arn. Bot. Beech. pl. 21. f.a. 1832. 
SPECIMENS EXAMINED: Hawaii, Mann & Brigham 482 N; 
Robinson 201 V; Maui, Robinson 336 V; 338 V;352 V; Oahu, Heller 
2245 C, N; Lichtenthaler N; Hawaiian Islands, Baldwin 8r C, N; 
Baldwin B; Hillebrand B; ex Herb. Underwood C; Hillebrand N. 
This is closely allied to P. setosum (Blume) Presl, according to 
Copeland, Polypodiaceae of the Philippine Islands, Bur. Gov. 
Lab. Publ. 21: 119. 1905. 
PoLypopium KnupsEnm Hieron. Hedwigia 44?: 79. 1905 
Polypodium samoense var. glabra Hilleb. Fl. Haw. Is. 554. 1888. 
Not P. glabrum Roxb. 
Polypodium samoense Christ in Engler, Bot. Jahrb. 23: 358. 1896, 
in part. Not Baker. 
TYPE LOcALITY: Kauai, Hawaiian Islands. 
DISTRIBUTION: On trees, Kauai, Hawaiian Islands. 
SPECIMENS EXAMINED: Kauai, Baldwin 17 B; Heller 2708 B; 
C, K, N; Knudsen 7 B; Robinson 405 V; 440 V; 453 V; 826 V; 836 
V 
Hieronymus (Hedwigia 442: 79. 1905) distinguishes P. Knud- 
sentt from P. samoense by the broader, yellow rather than fer- 
ruginous, scales of the rhizome; the fewer, smaller hairs upon the 
leafstalk; the thicker texture and more pointed apex of the leaf; 
the less evident veins; the larger size of the sori and their greater 
proximity to the margin of the leaf. 
Polypodium pumilum sp. nov. 
Rootstock short, erect, less than I mm. in diameter, covered 
with dark brown, linear-lanceolate scales 1-2 mm. long and 0.3-0.5 
mm. broad at the base, with 6-10 rows of cells in the broadest part; 
roots numerous; leaves 3-5, simple, nearly sessile, cespitose, 
linear-oblanceolate, obtuse or bluntly acute at apex, narrowed 
gradually at the base, 4-7 cm. long, 3-5 mm. wide, the margin 
subentire, the midrib green, prominent; veins forked once about 
2 mm. from the midrib; sori oblong, 1.5-2 mm. long by I-I.5 mm. 
broad; sporangia flattened laterally, the annulus of 10-12 cells; 
spores yellow, tetrahedral, 0.040 mm. in diameter, very minutely 
tuberculate. [Fic. 1.] ) 
Type collected on Oahu, 1000 m. elevation, 1890, by D. D. 
Baldwin, distributed by D. C. Eaton as P. sessilifolium (herb. N. Y. 
Bot. Gard.). : 
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