282 ESSENTIALS OF BOTANY 
leaves. In some cases the spore-bearing leaves are ar- 
ranged. in spherical cones (Fig. 218), while in others 
spores are borne by the ordinary leaves scattered along 
the stem. 
~ 361. Occurrence of Ferns.-— Many of our commonest 
ferns are shade-plants, flourishing in moist woods, but 
there are widely distributed species, such as the bracken 
fern (Pteris aquilina), which grow readily in full sunshine. 
A few, such as Notholena, Cryptogramma, Polystichum, 
and Pellea, are decided xerophytes, growing usually on 
nearly bare rocks. Some species are highly local in their 
distribution, occurring only in a few localities, often of 
very. limited area. 
ASPLENIUM, A FERN 
362. Gross Structure. Using fresh or preserved material for the 
underground portion and fresh material or dried and pressed herba- 
rium sheets? for the portion above ground, note: 
(a) The color, size, shape, and appendages of the rootstock. 
(6) The mode of development of the leafy portion .of the plant 
from the rootstock (Fig. 204). 
(c) The mode of origin of the leaves, or fronds, from the root- 
stock and their general form and the amount and manner of division, 
The main axis is called the rhachis, the leaflets pinne, and their sub- 
divisions pinnules. Draw a leaf. 
(d) The sori, or fruit-dots, on the under surface of the leaves.’ 
Draw a group of sori, as seen with the magnifying glass. 
1 This outline applies in detail only to Asplenium filix-famina, a species 
common in moist woods, though with slight modifications it will apply to any. 
Asplenium and, in considerable part, to most genera. 
2 Fronds, or parts of fronds, may also be mounted like passepartout-framed 
pictures, between two sheets of glass, and are very convenient to pass from 
hand to hand, showing both sides of the frond. 
In the bracken fern (Pteris) and the maidenhair fern (Adiantum) the 
spore-cases are borne near the edges of the leaves and covered by the incurved 
edges of the frond. 
