Tribe II— III. Gen. Ill— VI. 
either at the base or apex and forming a kind of cup whence this 
genus takes its name. A large genus of tree-ferns. 4 Species, 
Gen. III. Alsophila. Sorus on the back of the frond ; re- 
ceptacle prominent ; no involucre ; trunk generally arborescent, 
but in the New Zealand species often absent. 1 Species. 
Gen. IV. Dicksonia, Sorus near the edge of the frond ; 
globose, on an elevated receptacle, involucre two-valved, the “true’' 
ane springing from the point of a vein and often very inconspicuous, 
the “false” one formed of a lobe of the pinnule turned back and 
covering the other. Having generally an arborescent stem. 3 Species. 
Tribe III. — Hymenophylle^e. 
Gen. V. Hymenophyllum. Sorus marginal ; the receptacle 
->n which the capsules are arranged is either immersed in the edge 
)f the frond or protruded beyond it. The cup-shaped or boxlike, 
)ften flattened, involucre is formed of the substance of the frond, 
;he outer edges of the valves do not unite ; the involucre is 
sometimes produced beyond the edge of the frond and stalked, 
rhese ferns are almost always to be found in damp forests 
ind are easily recognized by their delicate, pellucid, bright green 
ronds in which only two genera at all resemble them. 15 Species, 
vhich may be divided into : 
§ A. Fronds quite smooth ; margins toothed like a saw but 
vithout hairs. Species 1 — 5. 
§ B. Fronds smooth or with the costa and rachis only hairy; 
nargins not toothed. Species 6 — 13. 
*a. Fronds pinnatifid, rarely pinnate below; the rachis, and 
;enerally the stipes having a margin of the texture of the frond. 
Species 6 — 10. 
*b- Frond pinnate below, stipes and lower part of rachis 
without the fine margin. Species 11 — 13. 
§ C. . Costa, margins and sometimes the surface of the frond 
lothed with hairs, which, when closely observed, may be seen to 
adiate in little bunches from various points. Species 14, 15. 
Gen. VI. Trichomanes. Sorus marginal ; involucre tubular, 
f the same texture as the frond, narrowed at the base, widening at 
ie apex ; the receptacle often protruding like a hair. This is a 
lore tropical genus than Hymenopyllum from which it may be 
distinguished by the tubular or trumpet-shaped involucre which is 
' ss obviously two-lipped, often quite circular at the mouth, and 
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