Hymenophyllum.| FILICES. 929 
with a stout central costa. Sori marginal, terminal or lateral, more 
or less immersed in the frond or quite free, always terminating a 
vein or costa. Indusium cup-shaped, more or less deeply 2-lipped 
or 2-valved, sometimes to the base, of almost the same texture as 
the frond, margins of the lips entire or toothed or fringed. Recep- 
tacle linear or oblong, not exserted beyond the indusium. Sporangia 
sessile or nearly so, depressed, surrounded by a broad complete 
horizontal ring, bursting transversely. 
One of the most beautiful of the genera of ferns, almost wholly confined to 
shaded localities, and remarkable for the filmy texture of the frond, a peculiarity 
which it shares with Trichomanes. Species about 90, widely distributed in 
tropical climates and in the south temperate zone, especially abundant in New 
Zealand, rare in the north temperate zone. Of the 20 species found in New 
Zealand, 7 or perhaps 8 are endemic, the remainder are for the most part widely 
dispersed. 
A. Euhymenophyllum. Margin of the frond entire. 
* Fronds glabrous; or, if hairs are present, they are confined to the stipes, 
rhachis, and coste. 
+ Rhachis winged throughout; wing often decurrent down the stipes, 
sometimes to the base. 
Fronds 1-4in., pendulous, flaccid, 2-pinnatifid. Stipes 
capillary; rhachis often wingless below. Sori large, 
terminal, immersed ; indusium orbicular ae 1. H. rarum. 
Fronds 2-9in., olive-green, 3-pinnatifid, sometimes with 
scattered hairs on the rhachis and stipes. Sori ter- 
minating short lateral Pipi free ; indusium broadly 
ovate .. 2. H. polyanthos. 
Fronds 2- Gin., brownish- -green, 3-4- pinnatifid ; ‘segments 
narrow, crowded. Stipes, rhachis, and coste usually 
villous. Sori numerous, terminal, free; indusium 
broadly ovate as a6 oe .. 3. A. villosum. 
Fronds 3-9 in. , triangular. Rhachis with a broad much- 
crisped wing ‘decurrent almost to the base of the stipes. 
Sori terminal, free ; indusium orbicular be .. 4. A. australe. 
Fronds 2-3in., linear-oblong, dull dark-green. Rhachis 
with a broad flat wing decurrent almost to the base of 
the stipes. Sori terminal, free; indusium ovate, margins 
often jagged 3c SC ao .. 5. H. atrovirens. 
Rhizome short, bristly. Fronds 9-20 in., ovate-lanceolate, 
pale-green. Rhachis with a narrow flat wing de- 
current down the Buide: Sori terminal, free; indusium 
orbicular .. : Se ane ate » GO. H. pulcherri- 
mum. 
Rhizome long, glabrous. Fronds 9-20 in., ovate-lanceolate ; 
segments broad, flat. Rbhachis with a narrow flat wing 
decurrent along the stipes. Sori terminal, immersed ; 
indusium orbicular .. 56 oe 3c .. 7. H. dilatatun. 
tt Rhachis winged only towards the top; lower part and stipes 
naked (often narrowly winged in H. demisswm). 
Fronds 4-12 in., ovate-deltoid, bright-green; stipes and 
rhachis glabrous. Sori terminal, free; indusium ovate 8. H. demisswn. 
30—FI, 
