244 RoBINSON: PTERIDOPHYTA OF THE HAWAIIAN ISLANDS 
C1BoTIUM GLAUCUM (J. E. Smith) Hook. & Arn. Bot. Beech. 108. 
1841 
Dicksonia glauca J. E. Smith, in Rees, Cyc. 11. 1819. 
TYPE LOCALITY: Hawaiian Islands. 
DISTRIBUTION: Somewhat rare, on moist, wooded mountain 
slopes and wet flats, at 300-900 m. elevation. 
ILLustTRATIONS: Hook. Sp. Fil. 1: pl. 29A. 1841; Bed. Ferns 
Brit. Ind. pl. 83. 1865. 
SPECIMENS EXAMINED: Hawaii, Beratz B; Lydgate B; Robin- 
son 201 V; 207 V; Maui, Bailey C; Molokai, Hillebrand B; 
C; Oahu, Beechey C, K; Diell C, K; Baldwin N; Kauai, Forbes 
34 BM; 356 BM; Heller 2818; Knudsen B; Lydgate B; Mann 
& Brigham 543 N; Hawaiian Islands, Baldwin ga B; 4 Ci & 
Herb. Mt. Holyoke College C; ex Herb. John Donnell Smith N; 
Wilkes Expedition 1 C. 
4. HYMENOPHYLLACEAE 
Delicate ferns, the leaf blades seldom more than one layer of 
cells in thickness except at the veins; found in very moist locali- 
ties, usually above 500 m. in elevation in the tropics. Rootstock 
slender, creeping or suberect; leaf blades much divided; sporangia 
sessile upon a filiform, usually elongated receptacle within an urn- 
shaped, tubular, or two-lipped marginal indusium, or protruding 
beyond it; annulus complete, transverse, opening vertically. 
Receptacle filiform, projecting beyond the indusium. 1. Trichomanes. 
Receptacle shorter than the indusium, or barely protruding. 2. Hymenophyllum 
1. TRICHOMANES L. Sp. Pl. 1097. 1753 
Rootstock slender, creeping, or suberect; leaves pinnatifid to 
tripinnate; veins free; sori terminal upon the veins; indusium 
tubular or urn-shaped, occasionally 2-lipped; sporangia sessile 
arranged spirally upon the receptacle, which usually projects 
from the margin of the leaf like a trichome. 
Type species: Trichomanes crispum L. 
* m. 
Stem erect; leafstalk and midrib fibrillose; plants mostly terrestrial. T. Bauerian 
: Stem creeping; plants mostly epiphytic, smooth « or nearly so. a. 
Leaf palmate or orbicular, less than 2 cm T.? arvult 
Leaf not palmate nor orbicular, more than 2 cm. high. 
