438 lycopodiaceje. [Fsilotum. 



ltliizomc short, thick, and intricately branched. Stems erect (or pendulous 

 when the plant is epiphytal), from 3 or 4 in. to a ft. high, repeatedly dichoto- 

 mous, the fertile branches 3 -angled, the barren ones flattened. Leaves few, 

 distant, very minute, scale-like, subulate, and entire, those which subtend the 

 fruits also small and distant, but forked, bearing each at the base of their 

 fork a single globular capsule of about 1 line diameter. 



Hongkong, Dill; on a rock in a ravine of Mount Gough, Wilford. In most tropical or 

 subtropical moist regions, both in the New and the Old World, although apparently rare in 

 Africa. 



Order CXXV. FILICES. 



No true leaves, but the fruiting branches expanded into leaf-like frc 

 Spores enclosed in minute capsules or spore-cases, sessile or pedicellate, and 

 collected together in clusters or patches called sori, on the under surface or 

 on the margin of fronds, which are either similar to the barren ones or more 

 contracted, sometimes resembling simple or branched spikes ; the sori either 

 naked or accompanied by an involucre or indusium, either cup-shaped or 

 covering the sorus when young, and opening on the side or at the top, or in 

 2 valves. — Main stem usually perennial, either erect and woody, or more fre- 

 quently reduced to a short stock, or to a creeping rhizome, very rarely annual. 

 Fronds radical or alternate, simple or variously lobed or compound ; the stalk, 

 called a stipes, and the rhachis frequently bearing narrow brown glossy scales, 

 always more numerous at the base of the stipes and on the rhizome. In the 

 majority of genera, including all those found in Hongkong, the frond is 

 when young rolled inwards at the top. 



A very large Order, abundantly diffused over the whole surface of the globe, especially in 

 moist climates ; more rare, but seldom eutirely absent, in the driest countries. The genera 

 have of late years been multiplied to an extraordinary degree, founded chiefly upon charac- 

 ters derived from the venation, which however useful, in Ferns as in Phanerogams, for the 

 distribution of species into sectional groups, and however constant they may prove occa- 

 sionally in both classes in large genera or groups of genera, are often far too vague and un- 

 certain to be relied on implicitly for the formation even of purely artificial genera. To me 

 it appears that by maintaining the large genera Acrostichum, Adiantum, Pleris, Asphnimn, 

 Aspidium, Polypodium, etc., nearly as proposed by Swartz and his immediate followers, they 

 are at once better defined, more easily understood by the general botanist, and therefore 

 more practically useful, and not more artificial than the innumerable small genera upon 

 which modern Pteridologists have expended so much ingenuity. And in these views I be- 

 lieve I am doing no more than following tbe example of Sir W. J. Hooker, than whom no one 

 has had more experience nor more ample materials to work upon in this beautiful Order, 

 nor shown more ability and tact in the use he has made of them. 

 Spore-cases globular or ovoid, opening by a longitudinal slit or in 

 2 valves (as readily seen with an ordinary lens). 

 Spore-cases (not numerous), arranged in 2 rows in oblong or shortly 

 linear sori. 

 Sori without indusia, raised and placed side by side in a conti- 

 nuous row on the under surface of the frond-segments. Large 



erect Ferns 1. Angiopteris. 



Sori, with scale-like indusia projecting from the margin of the 



segments. Climbing Ferns .3. Lygodium. 



Spore-cases numerous, covering the contracted fertile segments of 

 the frond.. 



