16. HYMENOPHYLLUM. 59 



Hab. West Indian Islands and Venezuela. Both this and H. myriocarpwm are some- 

 times slightly crisped. 



13. H. reniforme, Hk. ; st. very slender, naked, 2-3 in. 1. \fr. 3-6 in. 1., 1 in. or 

 less br., flaccid, pendent, linear-oblong, fully bipinnate ; main rack-is wingless- 

 throughout ; pinna? usually under 1 in. 1., divided quite down to the rachis ; 

 pinnl. simple or forked, or slightly pinnatifid ; the ultimate segm. very narrowly 

 linear ; sori 2-6 to a pinna, at least twice as broad as the lobes ; invol. divided 

 down nearly to the base ; valves rounded and denticulate. Hk. Sp. 1. p. 1 10. 

 t. 38. C. 



Hab. Andes of Ecuador and Peru. Allied to H. axillare and crispum in habit, but 

 readily distinguishable by its truly bipinnate frond and very narrow segments. The 

 specific name applies here to the shape of the involucre, not, as in Trichomanes, to that 

 of the frond. 



14. H. crispum, H. B. K. ; st. very slender, 1-2 in. 1., wingless ; jr. 3-6 in. 1., 

 1 in. or less br., flaccid, pendent, linear-oblong, tripannatifid ; main rachis only 

 slightly or hardly at all winged above ; pinnae 1 in. 1. or less, rhomboidal-oblong, 

 beautifully and delicately undulato-crisped throughout, divided down nearly to 

 the costa'into pinnl., which are again pinnatifid ; sori numerous, very small, 

 placed at the apex of the segments ; invol. rather wider than the lobes, rounded, 

 crisped at the edge. Hk. Sp. \.p. 106. H. amoenum, Sturm. 



Hab. Tropical America, from Mexico and Cuba southward to Peru and Brazil. 

 Closely allied to H. axillare in habit, but distinguished by its crisped fronds. 



15. H. undulatum, Swartz ; st. 1-2 in. 1., very slender ; fr. 3-6 in. 1., scarcely 

 more than 1 in. br., flaccid, pendent, ovate or linear-oblong, tripinnatifid ; main 

 rachis winged ; pinnae undulato-crisped, oblong-rhomboidal, divided down to a 

 narrow central portion ; pinnl. crowded, the lower ones a little pinnatifid ; sori 

 2-6 to a pinna ; invol. divided down nearly to the base ; valves rounded, slightly 

 crisped towards the margin, but not denticulate. Hk. Sp. 1. p. 105. Ic. PI. 964. 



Hab. Mexico, Jamaica, Peru. Both this species and H. crispum have the segments 

 so much crisped that they bear the appearance of being toothed like a Leptocionium. 

 This and the three preceding resemble one another in their small tender narrow flaccid 

 fronds. 



16. H. myriocarpum, Hk. ; st. 2-3 in. 1., erect, slightly winged above ; jr. 3-12 

 in. 1., 2-3 in. br., flaccid, pendent, ovate-lanceolate, tripinnatifid ; rachis furnished 

 with a narrow wing throughout ; lower pinnae 1-3 in. 1., lanceolate-rhomboidal, 

 divided down nearly to the rachis on both sides into several pinnl., which are 

 again pinnatifid with numerous membranous linear segments, not more than 

 1 lin. 1. ; sori very numerous, terminal and lateral on the segments on both sides ; 

 invol. divided down to the base ; valves ovate or rounded, entire or sinuated at 

 the apex. Hk.' Sp. I. p. 106. t. 57. D. 



Hab. Mexico, southward to the Andes of Peru. Closely allied to H. axillare, but 

 rather stronger in habit, and the fronds broader below. Connects the four preceding 

 species with H. polyanthos. 



17. H. microsorum, V. D. B. ; st. 1-2 in. 1., slender, naked ; fr. 2-3 in. 1., about 

 1 in. br., flaccid, oblong-lanceolate, tripinnatifid ; main rachis naked, furnished 

 with a narrow wing nearly or quite to the base ; lower pinnce oblong-rhomboidal, 

 about 1 in. 1., erecto-patent, divided down to a narrowly- winged rachis into 

 several pinnl., the lower of which are obversely triangular in shape and flabel- 

 lately cut ; sori 2-12, terminal on the segments of both sides of the upper pinnae, 

 very small ; invol. divided more than halfway down ; the valves rounded, 

 entire. 



