J. SMITH ON THE GENERA OF FERNS. 47 



four small species, having a rigid habit, and thickly covered 

 with clavate pellucid glands ; and bearing a solitary terminal 

 sorus on each lacinia — but similar glands and solitary sori are 

 common to other species of Polypodium vi^ith large decompound 

 flaccid fronds. 



• Ctenopteris. Blame. J. Sm. 



Fronds linear, entire, sinuose or pinnatifid, pinnate or 

 bipinnatifid. Sori terminal, rarely subterminal. 



Examp. 1. P. obliquatum. Blume. 2. P. celebicum. Blume, 

 3. P. contiguum. J. Sin. (Davallia. Stu.) 4. P. trichomanoides* 

 Sw. 5. P. pendulum. Sw. 6, P. papillosum. Blume. 7. P. 

 vulgare. L. P. taraariscinum. Kmdf. — Illust. Hook, et Grev. 

 Ic. Fil t. 105, 108, 141, 174, 223. 



** Phegopteris. Presl. J. Sm. 



Fronds usually large, varying from pinnate to decompound. 

 Sori lateral or nearly terminal, sporangia sometimes echinate. 

 Examp. B. P. Phegopteris. Linn. 9. P. Dryopteris, Lin7i, 

 10. P. effusura. Srv. 11. P. divergens. Jacq. 12. P. rugulosum. 

 ia^».— Illust. Schk. Crypt, t. 20. 20 b. Hook, et Grev. Ic. Fil. 

 f. 66, 210. Hook. Gen. Fil. «. 69. b. 



5. Struthiopteris* Willd. 



Fertile fronds contracted, their margins revolute, conniving, 

 forming a universal indusium. Veins pinnate, free. Sporangia 

 lateral, base of the pedicels concrete, forming an elevated, 

 thickened receptacle. Sori round, confluent. — Rhizoma cas^ 

 pitose, — Fronds 2 to 3 feet high^ bipinnatijid, the fertile pinnm 

 linear, revolute, moniliform, each lacinice producing five sori- 

 ferous veins, the margin becoming replicate, and lacerated, 

 and tken totally occupied hy the confluent sori. 



Species 1. S.gerraanica. Willd. 2. S. Pennsylvanica. Wilkh 

 —Illust. Schl\ Crypt, t. 105. HooTc. gen. fil. t. 69. A. 



Obs. The form and position of the sori of this genus does 

 not differ from some species oi Polypodium.hui the whole habit 

 indicates its beins; distinct. 



