7 1 



SYNOPSIS OF THE FAMILIES OF FERNS. 



Subclass I. . Ophioglossales. 



Gen. i. (Fig. 47.) 1. Ophioglossaceae 



Subclass II. Filices Eusporangiatae. 



Gen. 2. 2. Marattiaceae 



Subclass III. Filices Leptosporangiatae. 

 1. Order : Filices. 



A. Sporangia often crowded on special fronds or segments, sessile or 

 with a very short and stout stalk ; no real ring, but at the apex a group of 

 thick-walled cells ; opening by a longitudinal slit. (Plate 8 ; Fig. 48.) 



Gen. 3, 4. 3. Osmundaceae 



B. Sporangia sessile or almost so, solitary. Ring horizontal, near the 

 apex ; slit longitudinal. Fertile fronds or segments much modified. 

 (Figs. 49, 50.) 



Gen. 5 — 8. 4. Schizaeaceae 



C. Fronds dichotomously branched. Sori on the back of the frond 

 without indusium. Sporangia few in a sorus (2 — 8), with a large equatorial 

 ring and opening by a longitudinal slit. (Plate 8 ; Fig. 51.) 



Gen. 9. 5. Gleicheniaceae 



D. Sori with or without indusium, mostly at the back of the frond, 

 formed of numerous, generally stalked sporangia. Ring of sporangium vertical 

 but incomplete, being interrupted near the base and opening at this spot by a 

 horizontal slit. (Plates 9 and 24 ; Figs. 52, 53, 54.) 



Gen. 10 — 34. 6. Polypodiaceae 



E. Trunk arborescent. Ring complete, subvertical ; slit transverse. 

 (Plates 10 and 11 ; Fig. 55.) 



Gen. 25, 36. 7. Cyatheaceae 



F. Delicate pellucid ferns. Sori marginal on an elongated receptacle 

 and surrounded by a cup-shaped or labiate indusium. Sporangium compressed ; 

 ring complete, oblique. (Plates 8 and 24; Fig. 56.) 



Gen. 37, 38. 8. Hymenophyllaceae 



