280 
Choice Ferns for Amateurs. 
OL,KASDRAr-continued. 
though somewhat leathery texture; they are 6in. to 12in. 
long, IJin. to 2^in. broad, slightly wiavy, and pointed at 
their summit. The stalks, 2in. to 6in. long land often 
blackish, are jointed not far from the base. The abundant 
and eonspicuous sori are scattered, but placed nearly all in 
the inner half of the frond. 
OLFERSIA. See Acrostichum. 
ONOCLEA. 
Onoclea and Struthiopteris (Sensitive and 
Ostrich-feather Ferns) have been united by Met- 
tenius, the plants, of a hardy nature, being natives 
of North America, Sikkim, Japan, and Eastern 
Europe. These plants require an abundance of 
water at the roots all the year round, and are best 
adapted for planting out in the hardy rockery or 
Fernery, as pots scarcely afford them sufficient 
accommodation for the full development of their 
rhizomes or stolons, which, in some instances, extend 
a very long distance. There are two very widely 
distinct sorts of fronds — the barren ones, which are 
numerous and produced early in the spring, and the 
fertile ones, which are few in number and produced 
late in the summer. The fertile fronds are con- 
tracted, much shorter than the others, and very 
rigid. The soil which Onocleas prefer is a compost 
of three parts of good strong loam and one of leaf- 
mould. Great care should be taken that at all times 
of the year their roots should be kept in a damp 
state. Onocleas may be increased by means of spores, 
but their propagation is effected usually by division 
of their underground rhizomes, or of their stolons, 
an operation which, as the plants are of a deciduous 
nature, is best performed from October to March. 
O. gfermanica. 
This beautiful species (usually found in gardens under 
the name of Struthiopteris g ermanica) , and known as the 
Ostrich Fern, has broadly-spear-shaped fronds that seldom 
exceed 4ft. in length under culture. In North America, 
again, its barren fronds attain 10ft. in length; but under 
cultivation these are much shorter, narrowed from the middle 
to the base, and abruptly terminate in a point at their 
summit; they are furnished with numerous stalkless leaflets, 
