6 
FERNS OF THE WEST. 
etc., branch in various ways ; sometimes the stalk divides at the top into 
two or more rachises, as in the maiden-hair ; at other times there is a 
main rachis with alternate (where the branches come out on opposite 
sides, but one higher up than the other) or opposite branches. Usually 
the veinlets run side by side to the margin, but sometimes branches go 
across from one to the other forming a network. 
There are various outgrowths from the surfaces of ferns ; some 
of them are of the utmost importance. Occasionally fronds bear little 
bulbs at the tip, or rarely along the surface ; almost all have chalfy scales 
on the rootstock, stalk and rarely on the frond itself : many are covered 
with powder, hair or wool : but the most important outgrowths are the 
spore-cases {spora?igid). These are by nature transformed hairs, as the 
flowers of higher plants are transformed leaves and stems. They spring 
from the epidermis (skin of the frond), usually that of the under side of 
the frond. They are flat (except in Aneimia) and coiled into a ring 
which, at maturity, splits cross-wise and releases the minute spores. The 
spore-cases usually are clustered, forming little spots or lines which are 
called fruit dots fori). These are often covered by a scaly or papery 
substance called the indusiu7n ; often they are collected along the margin 
of the frond, which is rolled in so as to cover them, forming a false 
indusium called the involucre. Upon the presence or absence of the 
indusium and involucre and the arrangement of the fruit-dots, depends 
the whole classification of our ferns. It is therefore of the first import- 
ance that we know just what the indusium, involucre and fruit-dots are, 
and where they are. 
Some fronds of all kinds of ferns do not bear, but there are a few 
ferns which have two kinds of fronds — those which always bear, and 
those which never bear ; the former are called fertile fronds, and the 
latter sterile fronds. These two kinds usually differ much in appearance, 
but they always spring from the same root. In the polypodys the fruit- 
dots are situated at the ends ; in others, at the forks; and in others along 
the back of the veinlets or veins (as in the shield and bladder-ferns and 
the Woodsias) : in a few they are along the sides of the veins (as in 
spleenworts and chain- ferns). They also occur either in clusters or lines 
on the ends of the veinlets at the margin of the frond (as in Notholoena., 
the brake, etc). 
§ 6. How TO Analyze. — Having provided ourselves with a pocket 
microscope (the folding brass “linen provers ” are the best, and cost 
only half a dollar; — the writer is not the agent for them, however !) and 
having gathered a ripe fern, with the root and sterile fronds, if there 
are any, we proceed to learn its name. 
Since we know that the fruit is a brown powder, we should search 
out the places from which it comes. If, after blowing off the loose 
grains, we see that it comes from certain round or roundish spots, which 
have no covering (indusium), are not on the very margin of the frond, 
but are on the ends of little veinlets in the frond, it is a polypody. If 
the fruit-dot is round and covered by an indusium (young fruit-dots 
should be examined for the indusium, for the riper ones often obscure it 
by the abundance of powder which they discharge) it belongs to the 
