13. DICKSONIA, § CIBOTIUM. 49 



3-4 in. 1., bipinnate ; jnnnce lanceolate, sessile, the central %-^ in. 1., cut down to 

 the rachis or a narrow wing into blunt oblong crenate lol)es, the lower distant 

 gradually reduced ; racliis stramineous ; texture moderately firm ; liotli sides green, 

 glabrous ; sori sulimarginal ; inv. minute, hidden by the sorus, obscurely ciliated. 

 — Canad. Nat. 18G5, p. 90. 



Hab. Eocky Mountains ; Oregon and Lake Winnipeg.— Close to obtusa, from wliich 

 it dififers by its glabrous surfaces and smaller involucre. 



Gen. 12. Sph^ropteris, Wail. 



Sori globose, on the back of a vein or veinlet, Accept, large. Tnvol. inferior, 

 globose, coriaceous, stipitate, at first enclosing the whole sorus, at length bursting 

 vertically into 2 spreading lobes or lips. Tab. 1. f. 12. 



1. S. barbata. Wall. PL Asiat. Bar. l.t. 18. Hl\ Sp. 1. p. 58. Peranema 

 cyatheoides, D, Don, Prodr. Nep. 12 (oldest name). 



Hab. Nepal, Sikhim, Khasya {Hh. f. and Tlioms.), Western Ghats of Nilghiii, 

 Beddome. — Fr. 2-3 ft. 1., tripinnate. Pinnl. oblong, deeply pinnatifid. 



Gen. 13. DiciisoNiA, L'IKrit, (See p. 460.) 



Sori placed at the apex of a vein, intra-marginal. Invol. inferior, subglobose, 

 coriaceous or membranaceous, cup-shaped and entire, or more or less distinctly 

 2-valved. — About half the species are arborescent, loith large decompound coriaceous 

 fronds ; the others have creeping rhizomes, and, with two exceptions, are at least 

 fully bipinnate. They principally inhabit Tropical America and Polynesia ; hit one 

 species reaches as far north as Canada, and several others are scattered throughout 

 the southern parts of the Temperate Zone. Veins in all free. Tab. II. f. 13. 



§ Cibotium, Kaulf, — Involucre distinctly 2-valved, the outer valve coriaceous, 

 distinct from the substance of the frond. Sp. 1-5. 



1. D. {Cibotium) glauca. Smith ; arborescent ; fr. trpinnate, ovate-lanceolate, 

 12-18 in. 1., 6-9 in. br. ; pinnl. linear-acuminate, cut quite down to the rachis in 

 the lower part ; lobes linear-oblong, subfalcate ; texture subcoriaceous ; surface 

 naked on both sides, glaucous beneath ; veins prominent ; lateral veins of the 

 segments once or twice forked; sori 2 to 12 to a lobe, inner valve oblong, nar- 

 rower than the outer. — Hk. Sp. Fil. 1. p. 82. t. 29. A. 



Hab. Oahu, Sandwich Islands, discovered by Menzies eighty years ago. 



2. D. {Cibotium') Barometz, Link ; arborescent ; fr. trpinnate ; lower pinnce 

 ovate-lanceolate, 1-2 ft. 1., 6-12 in. br. ; pinnl. linear-acuminate, cut down within 

 a short distance of the rachis above, and sometimes quite down to it at the base ; 

 segm. linear-oblong, acute, subfalcate ; texture subcoriaceous ; upper surface 

 naked, shining, lower glaucous, sometimes furfuraceous ; veins prominent ; lateral 

 veins of the segments rarely forked ; sori 2 to 12 to a lobe, the valves nearly equal, 

 transversely oblon?. — C. glaucescens, Hk. Sp. Fil. 1. p. 82. C. Assamicum, 

 Hk. Sp. Fil. 1. p. 83. i. 29. B. C. glaucum, Bedd. Fil. Brit. Lid. t. 83. 



Hab. Assam, S. China, Malayan Peninsula and Islands. 



8. D. {Cibotium) Menziesii, Hook, and Baker; fr. tripinnate; lower pinnce 

 12-18 in. L, 6-9 br. ; pinnl. linear-acuminate, cut down usually not more than 

 half-way to the rachis ; lobes rounded, blunt ; texture subcoriaceous ; surface 



o 



