16. HYMENOPHYLLUM. 57 



down, furnished only with a central costa and a few faint irregular free spurious 

 venules, the margin not thickened ; sori solitary, terminal, the cuneate base 

 sunk in the frond, divided about halfway down ; valves rounded, entire. Baker, 

 in Linn. Proceed, inedit. cum icone. 



Hab. Moulmeine, Rev. C. S. Parish. The smallest and simplest species of the genus, 

 rivalling in minuteness Trichomanes Barklianum and Vitiense. 



3. H. corticola, Hk. ; st. 2 to 4 lin. 1. ; fr. 1-1 \ in. 1., 1 lin. br., subcuneate in 

 circumscription, two or three times dichotomously divided ; segm. linear-oblong, 

 emarginate, with only a single central costa in each ; sori solitary, terminal, the 

 cuneate base sunk in the frond, the semi-orbicular lips free. Hk. in Thwaites 

 Enum. PL Ceyl. p. 397. 



Hab. Ceylon, on trees, Gardner, Thwaites. Very like //. marginatum in habit, but 

 thinner in substance, darker in colour, the pagina nearly flat, and the margin not 

 thickened. 



4. H. marginatum, Hk. & Gr. ; st. 2-4 lin. 1. ; fr. linear, once or twice forked, 

 about 1 in. 1., 1 lin. br., furnished with a central costa ; texture firm ; margin 

 bounded by a thickened line, the apex emarginate ; sori terminal, solitary, sub- 

 orbicular, divided down nearly to the base, with convex entire valves. Hk. & Gr. 

 Ic. Fit. t. 34. Hk. Sp. 1. p. 87. Pachyloma, V. D. B. 



Hab. Port Jackson, Australia, rare. Substance of the frond undulated. 



5. H. asplenioides, Sw. ; st. 1-2 in. 1., slender ; fr. 2-4 in. 1., by ^-1 in. br., 

 pendulous, oblong in general outline, pinnatifid to within a short distance of 

 the rachis ; lower lobes rhomboidal-cuneate, cleft on both sides or one only ; 

 upper lobes simple, linear-oblong ; sori 1-4, terminal on the segments of the 

 lobes; invol. orbicular, free, cleft nearly to the base. Hk. Sp. 1. p. 87. Ic. 

 PL t. 957. 



Hab. Tropical America, from Cuba and Mexico southward to Brazil. Easily recog- 

 nizable by its peculiar habit of growth. 



** Fronds glabrous, one to four times pinnatifid. Sp. G-30. 



6. H. abruptum, Hk. ; st. about | in. 1., very slender ; fr. -1 in. 1., -| in. br., 

 oblong, pinnatifid to within a short distance of the main rachis ; pinnce linear, 

 erecto-patent, about in. 1., 1 lin. br., sometimes dichotoinously forked, only a 

 central midrib in each division ; sori 1 or 2 to a frond, terminal on the apex or 

 upper segments ; invol. not divided more than halfway down, the base cuneate, 

 the valves rounded ; recept. occasionally protruded. Hk. Sp. 1. p. 88. t. 31. B. 

 H. brevifrons, Kunze. 



Hab. Jamaica, Cuba, Guatemala, Venezuela, and Brazil. Allied to H. rarum, but 

 the main rachis has a broader wing below, and the pinnae are at most simply forked. 



7. H. mnioides, Baker; st. not more than ^ in. 1., very slender ; fr. 1-2 in. 1., 

 J in. br., linear, once pinnatifid ; rachis winged throughout ; the segm. all 

 quite simple, linear, the lower ones slightly imbricated, erecto-patent, 2 lin. 1., 

 \ lin. br, the upper ones pressed close to the rachis and much imbricated ; sori 

 solitary on three or four of the upper segments, large compared with the size of 

 the plant, divided about halfway down, the base campanulate ; valves more than 

 half a circle, large, membranaceous. 



Hab. New Caledonia, Pic du Mont Mu, Deplanche.A minute moss-like plant, with 

 the habit of Mnium undulatum or serratum, but dark-brown in colour. It is allied to 

 the preceding and the following, but whilst the segments are quite simple, the main 

 rachis is scarcely winged below. 



