46 Charles E. Bcsscy 



dies, increasing in diameter by a cambial zone. Leaves mostly 

 narrow, distinct. Sporophylls in cones, each sporophyll with one 

 or more heterosporous sporangia. 



Order Calamariales. With the characters of the class. 



Family 3. Protocalamariaceae. Leaves large, forked. Aster- 

 ocalamitcs. (Pf. 1, 4, 588.) 



Family 4. Calamariaceae. Leaves narrow, entire. Calaiiw- 

 dcndron, Eiicalainifcs, Calaiiiosfachys, Huttonia. (Pf. I, 4, 551.) 



Phylum XL LEPIDOPHYTA. The Lycopods. 



Chlorophyll-green, terrestrial plants, exhibiting two genera- 

 tions in each life cycle, viz., (i) the gametophyte, which is small 

 and short-lived, and (2) the sporophyte, which is large, with 

 roots, stems, and leaves, and long-lived. Stems of the sporophyte 

 solid, not jointed, erect or creepmg ; leaves relatively small, scat- 

 tered or crowded upon the stem. 



Class 25. ELIGL^LATAF. Leaves w^ithout ligules ; spores uni- 

 form (isosporous). 



Order Lycopodiales. Gametophyte mucli larger than the 

 spore; sporophyte with a central fibrovascular bundle. 



Family i. Lycopodiaceae. Sporophylls undivi,ded ; sporangia 

 single; leafy, branching evergreen plants. Lycopodiinn, Phyll- 

 oglossinii. (Pf. I, 4, 563.) 



Family 2. Psilotaceae. Sporophylls bifid ; sporangia 2 or 3 ; 

 pale saprophytes or parasites with leafy, or almost leafless stems. 

 Tmcsipteris, Psilotuin. ( Pf . I, 4, 606.) 



Class 26. LIGULATAE. Leaves with ligules; spores of two 

 kinds ( heterosporous ) . 



Order Selaginellales. Sporophyte stem with a central fibro- 

 vascular bundle, incapable of thickening. 



Family 3. Selaginellaceae, Moss-like plants with slender 

 dichotomously branched stems, and the sporophylls in more or 

 less well-defined terminal cones. Sclaginclla. (Pf. I, 4, 621.) 



Order LEriDOPHYTALES. Sporophyte stem v/ith a central fibro- 

 vascular bundle, and thickening by a cortical meristem. Palae- 

 ozoic and Mesozoic trees, long since extinct. 



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