264 
THE FERNS OF SOUTH AFRICA 
in Pteris. The generic distinction given by the indusium is 
not always evident or easily seen, but the general habit, and 
especially the very long underground rhizomes, help to indicate 
a generic difference. 
150. Pteridium aquilinum (Linn.) Kuhn. 
Plate 134. Frond and rhizome much reduced, b Fertile pinnule, 
nat. size, c Pinnules from young seedling plant, nat. size. 
Rhizome subterranean, stout, creeping, several yards long, 
slightly branched, and with few roots. Frond three-pinnate, 
one to three feet long, one to two feet broad, on a stout, naked 
stipe one foot long. Pinnae in opposite pairs, sessile, all alike 
in shape, tapering from a wide base, the lowest sometimes 
longest, but more frequently rather shorter than the next 
pair. Upper pinnae pinnatifid or simply pinnate, generally 
cut almost to the rachis into close, linear, bluntly pointed 
pinnules, fertile throughout; lower pinnae similar at the point, 
but towards the base having distinct pinnae cut in a similar 
manner, which increase in size downward, and are about equal 
in the upper and lower side of the pinna. Pinnae set nearly 
horizontal, so that each pair overlaps those under. Involucre 
continuous round the entire pinnule, intramarginal, much 
fringed at the edge. Sometimes it has an indusium under 
as well as over the capsules, which is the characteristic of 
the section Paesia of Pteris in which this species has formerly 
been placed. Fronds coriaceous, glabrous above except when 
quite young, but villose below in the S. African form, which 
was separated by Thunberg under the name P. capensis on 
this account. Veins forked, but free. 
The Bracken, as this is called, is the most cosmopolitan, 
and, in many parts of the world, the most common fern; but 
with us, though not uncommon, it is confined to certain 
localities. Engler uses it as the characteristic plant of one 
of his sub-regions in tropical East Africa. It has a very 
long underground rhizome, from which the fronds rise singly 
at considerable distances, and this makes it a difficult fern 
to introduce from the wild state into the rockery. If taken 
when a seedling, however — before the rhizome has begun to 
