128 FERNS. 
too far, to continue these expositions on this occasion; but what 
is said may initiate the young observer to an investigation of any 
grasses close at hand ; from this he is sure to derive soon much 
pleasure and useful recreation, the interest of which can easily 
be sustained by reference to any descriptive work on Graminee, 
as a large repetition of general forms of this class of plants is 
noticable in every part of the inhabitable earth. 
To give a first insight into the structure of grasses by. an 
illustrative delineation now a figure of Ehrharta stipoides, one of 
our most universally diffused and ever-flowering grasses is pre- 
sented. The genus was dedicated by the Swedish traveller 
Thunberg to the Swiss naturalist Ehrhart, a disciple of Linné 
and scientific writer on grasses. 
XXII.—FERNS 
AND ALLIED PLANTS. 
To commence, a definition of Filices (real Ferns) is given. 
Foliage forming fronds, rarely leaf-like, usually bearing fruit- 
masses (sori) on the underpage or margin. Staminal and pistillar 
organs (antheridia and archegonia) only developed on the under- 
side of a minute scale (prothallus) formed at first germination, 
unaidedly not visible. Individual fruits (sporangia) very minute, 
one-celled, mostly tender-membranous, with numerous spores 
(exembryonate seeds) of extreme minuteness.—Fronds usually 
coiled before development. 
SUBORDER 1.—POLYPODIACEZ. 
Fruitmasses dorsal or marginal, very rarely terminal. Spore- 
cases usually stalked, incompletely encircled by a jointed longi- 
tudinal elastic ring ; dehiscence (manner of bursting) transversal. 
