3. THYRSOPTERIS. 15 



22. G. (Mevt.) pectinata, Pr. (character given in the section). — G. Rlaucescens, 

 H. D. K. Hk. Sp. \.p. 11. Mertensia Hemianni, Ilk. et Gr. Ic. F. t. 14 {exd. 

 sj/>io}}yms). 



Hab. Tropical S. America, common everywhere. — The only species of this section, and 

 not to be confounded with any other. Glabrous or pubescent beneath, very frequently 

 glaucous. Sori of 8-10 capsules. 

 er 



§ 4. Stipes zigzag, re'peatedly di- or trichotomous , the ultimate branches bearing 

 a pair of forked pinnce : a distinct pair of pinnce also arises from the base of the 

 forked branches {not of the frond). tSegments never decurrent, Sp. 23. 



23. G. (Mart.) dichotoma, Willd. (character given in the section). — Hk. Sp. 1. 

 p. 12. G. Hermanni, Br. {not Hk. & Gr.). Besides the many synonyms given in 

 Sp. Fil. I, c, I may add M. pteridifolia, Pr. Epim. p. 23. t. 14 (a terminal fork 

 only) ; M. rufinervis. Mart. Hk. Sp. I. p. 11. G. Klotzschii, Hk. Sp. I. p. 13. 

 t. 5. B. M. revoluta, Kl. Hb. nostr. {not of H. B. K.). M. crassifolia, Pr. Epim. 

 p. 23. 1. 13. G. ferruginea, Bl. {not Desv.). Hk. Sp. l.p.lO. Mett. in Miq. Ann. 

 Mus. Bot. L.Bat. \.p. 50. M. emarginata, Brack. Fil. U. S. Expl. Exp. p. 297. i. 42. 

 (very ferrugineo-tomentose beneath, and with the segments often emarginate ; 

 as they are in the glabrous var. of G. dichotoma). 



Hab. Tropical and subtropical regions, almost universal, in the New and in the Old 

 Worlds ; Pacific Islands, and as far north as Japan. — As 0. pectinata is a solitary species 

 of its section, so is G. dichotoma of the present one. Besides being most extensively 

 geographically distributed, it is very variable in the size of the pinn^ and in the shape 

 of the segments, and in being more or less glabrous or densely tomentose beneath, green 

 or glaucous, and very variable in the texture of the frond : but the pairs of accessory 

 pinnae at the base of a fork are invariably present. There are also abnormal or 

 aberrant forms. Among them I have specimens with lobes of the pinnte free (pin- 

 nules) and more or less deeply pinuatifid, from Penang and Java. I have others from 

 Java, which Mettenius (Ann. Mus. Bot. L. Bat.) calls var. alternans, in which the 

 primary divisions of the stipes are scarcely dichotomous, but alternate, "frondes 

 inasqualiter dichotomse." — In regard to size, some of the pinnae are 1-14 ft. 1., and some 

 are 6 in. br. Occasionally, the lowest pair of lobes is much elongated, reflected, and 

 pinuatifid. 



Sub-Ord. II. POLYPODIACE^. 



Sori dorsal or marginal, subglobosc, of many capsules, with or without an involucre, 

 usually pedicellate, more or less completely surrounded with a jointed vertical and 

 elastic ring, and bursting transversely {except in Hymenophyllesc). Tribe I.-XIII. 

 Gen. 3-61. Tab. I, f. 3-12, and Tab. I.-VIII. f. 13-Gl, inclusive. 



A. iNvoLucRATiE. Sori furuishcd with an involucre {except in Alsophila). 

 Tribe I.-VIII. Gen. 3-47. 



Tribe I. CvATHE^ffi. 



Sori dorsal, globose, often at or near the forking of a vein. Caps, numerous, often 

 very compact, sessile or stalked, generally on an elevated receptacle, often mixed with 

 hah~s, obovate, usncdly with a broad, vertical, or siihoblique elastic ring. Invol. {loant- 

 ing in Alsophila) inferior, including thesorus, lateral and resembling a scale on the 

 under side of thesorus, or cup-shaped,often,when young, cnvelopingthesorus, eventually 

 opening at the summit, or breaking down, with a more or less regular margin. — Vaud. 

 very generally arborescent. Tropical or subtropical. Gen. 3-8. 



Gen. 3. Thyrsopteris, Kze. 



Sori globose, marginal, collected into a panicle distinct from the sterile pinnge. 

 Caps, sessile, on a globose receptacle. Invol. inferior, cup-shaped, the mouth entire. 

 — Fronds decompound, sterile portions bipinnate, with lanceolate, incised pinnules ; 

 fertile ones ^-pinnate, of which each pinnule becomes a raceme of stalked involucres. 

 Tab. 1. f. 3. 



