352 THE PLANT PHYLA 
Phylum IX. PTERIDOPHYTA. The Ferns 
Chlorophyll-green, small, sexual plants (gametophytes), pro- 
ducing a large-leaved, rooted generation (sporophyte). 
(Here restricted to the ferns alone and 
including about 3,800 sp.) 
Class 20. EUSPORANGIATAE. Old-fashioned Ferns. Spor- 
angia developed from internal cells. 
Order OpHioaLossaLes. Adder-tongues. Gametophyte 
tuberous, subterranean; sporophyte 
with large leaves, some parts sporog- 
enous. 
Family 1. Ophioglossaceae. Including Ophioglos- 
sum, Botrychium, etc. . 
Order Maratriates. Marattias. Gametophyte flat, 
green, superficial; sporophyte with 
large compound leaves; sporangia 
hypophyllous. 
Family 2. Marattiaceae. Large tropical ferns, from 
the Paleozoic to the present.—Angi- 
opteris, Marattia. 
Order Isozrates. Quillworts. Gametophytes dioecious 
rounded; sporophyte with erect, 
crowded, narrow leaves; sporangia 
epiphyllous, basal. 
Family 3. Isoetaceae. Aquatic, rush-like plants.— 
Isoetes. 
Class 21. LEPTOSPORANGIATAE. Modern Ferns. Spor- 
angia developed from superficial cells. 
Order Fiticates. Land Ferns. Spores of one kind; game- 
tophytes foliose, monoecious. 
Family 4. Osmundaceae. Sporangia globose, split- 
ting vertically —Osmunda. 
Family 5. Schizaeaceae; 6, Gleicheniaceae; 7, Maton- 
iaceae; 8, Parkeriaceae. 
Family 9. Cyatheaceae. Tree Ferns. Sporangia 
compressed, splitting transversely.— 
Alsophila, Cyathea, Dicksonia. 
Family 10. Hymenophyllaceae. Filmy Ferns. Spor- 
angia compressed, splitting vertically. 
—Hymenophyllum, Trichomanes. 
