444 FILICES. [Acrostic/ium. 



often miicli longer, and all more or less decurrent on the rhachis. Primary 

 veins pinnate, the secondary reticulate, with free branches in the areoles. Fer- 

 tile fronds like the barren ones, but the segments narrower and smaller. 



Hougkong, Harland; among rocks near the top of Mount Gough, WUford. Also in 

 Formosa. 



3. A. repandum, Blume, Enum. Fl. Jav. 104. Rhizome thick, shortly 

 creeping. Fronds 1 to 1| ft. high, pinnate. Segments of the barren ones 

 11 to 21, lanceolate, more or less sinuate; the terminal one longer, almost 

 pinnatifid, ending in a point, often \dviparous ; lateral ones mostly petiolidate. 

 Primary veins pinnate, sparingly branched, and anastomosing, with here and 

 there a free branch. Fertile fronds distinct, with the pinnae rather smaller. — 

 Heteroneiit'ou proUferum, Fee ; Hook, in Kew Journ. Bot. ix. 359. A. J/dero- 

 6'//i^«y/2, Presl, Eel. Ha^nk. i. 15, t. 2, f. 2. Pwcilopterh heterocUta, Presl; 

 and P. repauda, J. Sm. in Seem. Bot. Her. 426. 



Hongkong, Hance ; Tank Ravine and Water Ravine, UrquJiart, In India, the Archipe- 

 lago, S. China, and Formosa. 



7. DHYMOGLOSSUM, Presl. 



Sori forming two continuous lines between the midrib and tlie margin, at 

 length covering nearly the whole under surface of the narrow fertile fronds. 

 Indusium none. — Ehizome creeping. Fronds small, undivided, the barren 

 ones broader than the fertile. Veins reticulate. 



A small tropical Asiatic genus. 



1. D. camosuxn. Hook. Gen. Fil. t. 78 A, midin Kew Journ. Bot. ix. 358. 

 A small Fern, with slender creeping rhizomes. Barren fronds varying from 

 nearly orbicular, 4 or 5 lines diameter and almost sessile, to ovate or oblong- 

 elliptical, 1|- to 2 in. long, and narrowed into a petiole of 3 to 4 lines, all 

 rather thick and succulent. Fertile fronds linear-oblong, obtuse, petiolate, 

 the lines of fructification when young about midway between the midrib and 

 the margin. 



Hongkong, Wright. In the mouutaius of N. India, in S. China, and Loochoo. 



8. BLECH2^UM, Linn. 



Sori forming two continuous lines parallel to and either close to the micbib 

 or between the midrib and the margin, with a longitudinal indusium distinct 

 from the margin. — Fronds pinnate, rarely simple or bipinnate ; the fertile 

 and barren nearly similar. Veins simple or forked, rarely anastomosing. 



A genus of several species, chiefly tropical or subtropical, common to the New and the 

 Old World, one species extending into N. W. America. 



1. B. orientale, Linn.; Hook. Spec. Fil. iii. 52; Fll.Exot.i. 77. Stem 

 short, thick, erect or ascending. Fronds pinnate, 1 to 3 ft. long, with narrow 

 glossy scales at the base of the stipes. Segments numerous, sessile, linear- 

 lanceolate, entii-e, mostly 6 to 8 in. long, or sometimes near 1 ft. ; the lower 

 pairs suddenly abbreviated or reduced to small scales. Veins closely parallel 

 and usually simple. Sori close to the midrib, almost concealing it when old. 



Abundant in the island. Champion and others. In India, from Ceylon and the Peninsula 

 to the Archipelago, aud in the Pacific islands, extendiug northward to the Himalaya and S. 

 China. 



