ATHYBIUM FILIX FCEMINA. 73 
masses, becoming, finally, nearly routd, but never 
running together; cover, or indusium, white, at first 
oblong with a broad base, afterwards kidney-shaped, 
but not swollen ; it opens towards the mid-rib, the edge 
of its opening side being finely jagged. The seeds (sori) 
are numerous and brown. 
No Fern native of the British Isles is so variable in 
its forms as this, and Mr. Charles Johnson justly 
remarks: 
" Such differences have afforded a wide scope for specula- 
tive botanists to indulge their fancies in the multiplication of 
species and varieties, and were the wishes and advice of all 
my kind correspondents to be attended to in regard to the 
latter, I might exhaust the Greek alphabet from alpha to 
omega in prefixes. The claim advanced on behalf of a few 
of the varieties to rank as species, should be very cautiously 
examined before its admission; those who recommend or 
incline to their adoption would do well to bear in mind the 
plasticity of vegetable nature, and the very uncertain tenure 
of specific distinction in the aggregate, not in this class only, 
bat in groups far higher in grade, and in which features of 
more determinate character can be arraigned in evidence of 
supposed dissimilarity. The three principal forms, includ- 
ing the normal one, that are considered best entitled to the 
rank in question, are thus characterized : 
" 1. incisum. Fronds more or less drooping, broadly lan- 
ceolate : pinna (leaflets) distant: pinnules (leafits) lan- 
ceolate, distinct, flat, pinnatifid with toothed lobes. Sori 
distinct. A. Filix-fcemina, Roth. 
" 2. molle. Fronds nearly erect, lax, lanceolate : pinnae ap- 
proximate : pinnules oblong, connected by the wing of the 
midrib, flat, toothed. Sori distinct. A. molle, Roth. 
" 3. convexum. Fronds nearly erect, rigid, narrow-Ian ceo- 
