144 maxon: new genus of davallioid ferns 



taxononiic history of Odontosoria in its broad sense and a revi- 

 sion of the American species now properly to be referred to that 

 genus. 



The group of species of upright or ascending habit and deter- 

 minate growth; of which the Odontosoria clavata of authors is a 

 familiar example, has no vahd name. It may be characterized 

 briefly as follows: 



Sphenomeris Maxon, gen. nov. 



Mainly tropical ferns, with slender creeping hairy rhizomes. Fronds 

 subfasciculate, erect or ascending, of small or medium size; stipes not 

 jointed to the rhizome; lamina 3 or 4 times obliquely pinnate or pinnati- 

 fid, the divisions alternate, the ultimate segments strongly cuneate; 

 veins free. Sori terminal at or near the truncate apex of the segments, 

 single or 2 to 4 joined; indusia similar in texture to the opposed leaf- 

 margin, flattish, pocket-like, attached at the base and sides, single at 

 the clavate apices of the veins or, if joined, borne upon a translucent 

 receptacle connecting these. 



The type species and apparently the sole American representa- 

 tive of this genus is: 



Sphenomeris clavata (L.) Maxon 



Adiantu?n clavatum L. Sp. PI. 1096. 1753. 



Davallia clavata J. E. Smith, Mem, Acad. Turin 5: 415. 1793. 



Stenoloma clavatum Fee, Gen. Fil. 330. 1852. 



Lindsay a clavata Mett. Ann. Sci. Nat. IV, 15: 64. 1861. 



Schizoloma clavatum Kuhn, Chaetop. 346. 1882. 



A large series of specimens of S. clavata is at hand from south- 

 ern peninsular Florida, the Bahamas, Cuba, Porto Rico and 

 Jamaica. 



Two common Old World species may also be mentioned: 

 Sphenomeris retusa {Davallia retusa Cav.) and Sphenomeris 

 chinensis {Adiantum chinense L.), both agreeing closely with 

 S. clavata in habit. 



