170 IX. ASPLENIUM. 
notched at the apex, two or three of the lowermost 
having a pair of alternate lateral lobes. There is no 
mid-vein ; the veins which arise from the base of the pinnae 
becoming branched, and a branch extending towards 
each of the teeth into which the apex is divided. 
There are thus two to four or more subparallel longi- 
tudinal venules, two or three of which bear a linear- 
elongate sorus along their inner margin. The sori are 
covered by linear membranous indusia, having the free 
margin entire or sinuous " but not jagged ; and they at 
length become confluent, obliterating the indusia. The 
fructification is mature in August. 
One of the rarest of our native ferns, having been dis- 
covered only near Llanrwst in Carnarvon or Denbigh- 
shire, at Borrowdale in Cumberland, near Kelso in Rox- 
burghshire, and at Dunfennline in Fifeshire, and Dunkeld 
in Perthshire. In the herbarium of Mr. S. F. Gray, 
there is a specimen of this fern, labelled as A. septentrio- 
nale from Arthur's Seat. It is found in other European 
countries, but is nowhere a common plant. 
This rare fern is one which does not thrive under culti- 
vation, except with careful management. If potted in 
porous soD, with the crown well elevated, and covered by 
a bell-glass in a shaded frame, or put in a warm close 
house or pit without a bell-glass, it will generally grow 
with vigour ; but the plants are very liable to perish in 
winter. The safeguard is, not to allow water to reach 
their crowns, to keep their roots just moderately moist, 
and not to suffer the bell-glasses employed to protect them 
from the risk of being wetted, to injure them by retain- 
ing a constantly damp atmosphere, which they will do if 
they are kept permanently closed. 
9. Asplenium septentrionale, Hull Forked 
Spleenwort Fronds linear, simple or two- three- cleft, the 
segments alternate elongate; margin of the indusium 
entire. 
