664 GENERA OF FERNS. 
few of the sori, situated near the principal rachis of the pin- 
nules, and is evidently an accidental appearance, and may be 
accounted for, according to the law that determines mon- 
strosities or organs with double parts, and in the present 
case may be as follows. The apparent, or evident position of 
the sori of Cyathea, is axillary ; that is, seated on the axis or 
forking of the veins; but on a careful examination I have 
found that such is not always the case, the sori being often 
seen situated a little beyond the axis, on the exterior branch, 
which, from analogy, may be considered as the normal 
position ; in such instances only one simple receptacle is 
produced in the usual way, and to account for the two 
receptacles in one cup, it is simply to assume that both the 
venules have a normal tendency (as in other cases) to pro- 
duce each a receptacle, which by their contiguity or con- 
fluence in the axis of division of the vein, form but one 
series, the two receptacles occasionally remaining distinct, or 
becoming so by desiccation. Such being my view, I do not 
hesitate in rejecting the character of Disphenia as untenable. 
122. ALSOPHILA, R. Br., J. Km., Presl. 
(Hemitelie sp. R. Br. Hemitelia Presl. Chnoophora 
Kaulf. Blume.) 
Veins costeform, pinnate; venules forked or simple, direct 
free: sori axillary, or medial; indusium lateral, interior, 
semicalyciform or sometimes very small, or absent, or triche- 
form.  Receptacle convex or columnar.  Sporangia usually 
compact. 
Fronds large, decompound ; ultimate pinnules pinnatifid, 
lacinie entire or serrate; stipes and rachis often aculeate, 
midrib of the lacinie often lepiferous ; sori usually becoming 
confluent. 
Obs. The species of this and the former genus Cyathea, 
constitute a very natural group of Tree-Ferns, not to be 
recognised as distinct genera by any peculiarity of habit, and 
the following observations will show that, in some instances, 
