PTERID0PE7TA. 219 



leafy-stemmed, long-lived plant is produced directly. This 

 is the asexual plant, or sporophore, and upon it the spores 

 are produced from which new individuals of the first gen- 

 eration may be developed. 



404. The sexual plant (the " pro thallium ") is composed 

 throughout of a few layers of soft tissue (parenchyma) 

 richly supplied with chlorophyll. From its under surface 

 root-hairs grow out into the soil. The sexual organs re- 

 semble those of the liverworts, and are antherids (produc- 

 ing antherozoids) and archegones. They generally develop 

 upon the under side of the plant, and project slightly from 

 the surface. 



405. The fern worts are divisible into three classes, viz. : 



Stems solid ; leaves mostly broad Class 11, Filicin^ 



Stems hollow, jointed ; leaves small Class 12, Eqtjisbtin^ 



Stems solid ; leaves small or narrow Class 13, Ltcopodin^ 



Class 11. FiLiciNai. The Fekns. 



406. Here the plant-body of the sporophore consists of 

 a solid stem, bearing roots and broadly expanded leaves, 

 the latter usually long-stalked. The stems are mostly 

 horizontal and underground, but in some cases they rise 

 in the air vertically to a considerable height. 



407. The leaves are in nearly all cases supplied with 

 fibro-vascular bundles, which run as veins through the soft 

 tissue ; there is usually a prominent midrib, upon each side 

 of which are small veins, which are/ree (i.e., running more 

 or less parallel from the midrib to the margin) or reticu- 

 lated. Some or all of the leaves at maturity bear spore- 

 cases containing spores. 



408. The ferns are all richly supplied with chlorophyll, 

 and none are in any degree parasitic. Nearly all the species 



