Pben Sxettctcee and Sexuaii Deteiopment. 



Probably no class o£ plants are Bueh general favourites as ferns, 

 therefore a few words as to the botanical names of their various parts 

 may be here given. 



The Roots proper of ferns are entirely fibrous, often rigid and 

 wiry; when young, often covered with soft haira. 



The Stem is spoken of under different terms, as rootstocA, 

 rhizome, and caudex, this latter being usually applied to the stem 

 when above ground, whether in the form of a tree-trunk or resembling 

 the stem of a trailer or climber, the term rhizome being applied to 

 the underground stem ; in some of these latter, beneath the crown are 

 formed a number of brittle roots resembling the tubers of a Dahlia. 



The Leaves are termed fronds, and their vernation, with few 

 exceptions (the Adder- tongues and their allies), circinate (coiled). 

 The stalk from the rhizome to the lamina or ramification is called the 

 stipes ; its continuation through the ramification of a compound frond 

 is termed the rhachis ; jpinna and pinnule being used for leaflets as in 

 other plants. 



The Fruetijioation is borne upon the back, edge, or on a separate 

 frond or portion of frond. The clusters of fructification are called 

 sori, and the part to which these are attached the receptacle. The 

 sori is a cluster of sporangia or spore-cases, and may be naked, as in 

 Polypodium, or covered with an indusium, as in Asplenium, and nearly 

 flat, tubular or funnel-shaped, as in Trichomanes. The spore-cases or 

 sporangia in most cases are one-celled, and more or less surrounded 

 with a jointed ring or annulus. These spore-eases are stalked or 

 stalkless (sessile), and the ring is vertical or transverse, according to 

 the tribe or suborder to which the plant belongs. 



Germination. — The spores of some ferns take a longer time than 

 others to germinate after leaving the sporangia. The first stage of 

 their growth is the formation of what is known as the prothallus. 

 This is usually somewhat reniform in shape, and composed of cellular 

 tissue. On the under surface are two sorts of organs analogous to 

 the stamens and pistils of flowering plants ; these are respectively 

 known as antTieridia duxdi archegonia. The position of these organs 

 has been found to vary in different tribes. 



Antlieridia. — These are small masses of tissue developed in the 

 same manner as the root-hairs, consisting of a single layer of cells 

 forming the wall and containing a number of spirally-coiled threads, 

 usually with a number of ciKa on their anterior coils. At maturity 

 the antheridium swells by the absorption of water and finally bursts 

 its wall, discharging these coiled filamrats, which possess the power 

 of locomotion, and for this reason are called antherozoids. These 

 antherozoids often drag with them a little vesicle, which seems to play 

 no part in the process of reproduction. 



Areliegonia.-^Tke archegonium is also a rounded mass of tissue 

 usually less prominent than the antheridia, consisting of an external 

 layer of cells and a large central cell, which soon divides into two. 

 The lower portion, at first the larger, develops into a roundish cell, 

 which is analogous to the ovule of flowering plants, and is called the 

 oospTiere. The upper portion of the central cell develops between 

 those composing the neck of the archegonium into a canal filled with 



