252 ELEMENTS OF BOTANY 
327. Fern-Plants (Pteridophytes).— The Pteridophytes 
(literally fern-plants) include in their general category 
not only ferns as commonly recognized, but several other 
small groups which are very interesting on account of 
their diversity. All cryptogams higher than mosses 
belong in this group. In moss-plants the individuals 
growing from spores and bearing antheridia and arche- 
gonia, the gametophytes, are full-grown leafy plants, and 
the spore-bearing plant, or sporophyte, is merely a stalk 
bearing a spore-capsule. In all the fern-plants the reverse 
is true. The individuals growing from spores and _bear- 
ing antheridia and archegonia are of minor vegetative 
development (prothallia), while the spore-bearing plant is 
a leafy plant, even a tree in some ferns. 
The ferns in the strictest sense have sporangia derived 
from the cells of the epidermis, while a few plants closely 
resembling them in general aspect (Botrychiwin, etc.) have 
sporangia formed in the tissue of the leaf. 
The horse-tails have only one kind of spore and are 
peculiar chiefly in their vegetative aspect (Fig. 174), while 
the spore-bearing leaves or sporophylls are arranged in the 
form of a cone, as already shown. 
The club-mosses include some plants which, as their 
name imphes, have a superficial resemblance to a large 
moss, with the addition of a club-shaped stalked fruiting 
spike (Fig. 173). These are the so-called “ ground pines” 
and the running ground * evergreens ” used for Christmas 
festoons in New England. Technically the group is distin- 
guished hy the possession of firm-walled sporangia formed 
singly near the bases of the leaves. 
328. High Organization of Pteridophytes. — The student 
may have noticed that in the scouring-rush studied there 
