468 POLYPODIACEAE. 



2. Adiantum melanoleucum Willd. Sp. PI. 5: 443. 19JO. 



Rootstock short. Stipes slender, smooth, nearly black, shining, 1-3 dm. 

 long. Blades mostly 2-pinnate. sometimes only once pinnate, 1-4 dm. long, 

 glabrous; pinnules usually many, sessile, obliquely oblong, thin, 8-25 mm. long, 

 irregularly toothed or lacerate on the upper and outer margins, the lower 

 margin entire or nearly so; uppermost segments commonly confluent; sori few, 

 oblong or semilinear. 



In sink-holes, New Providence, Eleuthera : Florida ; Jamaica ; Cuba ; Hispaniola : 

 Porto Rico. DARK MAIDEN -HAIR FERN. 



7. SPHENOMERIS Maxon, Journ. Wash. Acad. Sci. 3: 144. 1913. 



Slender mostly small ferns, with creeping rootstocks covered by hair-like 

 scales, the leaves 3-4-pinnately divided into narrow cuneate segments, the veins 

 free. Sori borne solitary on the terminal margins of the segments, the indu- 

 sium cup-like, attached at the base and sides. [Greek, referring to the wedge- 

 shaped leaf-segments.] A few species of tropical and subtropical regions, the 

 following typical. 



1. Sphenomeris clavata (L.) Maxon, Journ. Wash. Acad. Sci. 3: 144. 1913. 



Adiantum clavatum L. Sp. PL 1096. 1753. 



Davallia clavata J. E. Smith, Mem. Acad. Turin 5: 415. 1790. 



Odontosoria clavata J. Smith, Hist. Fil. 264. 1875. 



Rootstock short, 2-7 cm. long. Leaves often many, glabrous, nearly erect, 

 close together, 1.5-6 dm. long, the smooth straw-colored stipe usually shorter 

 than the much divided blade; leaf -divisions alternate; ultimate-segments 8-15 

 mm. long, 1-2.5 mm. wide at the truncate apex. 



In sink-holes, most abundant in pine-lands, rarely on cliffs, Abaco, Great Bahama, 

 Andros, New Providence, Rose Island, Great Guana Cay, Cat Island, Eleuthera : 

 Florida ; Jamaica ; Cuba. PINE-LAND FERN. 



8. BLECHNUM L. Sp. PL 1077. 1753. 



Terrestrial ferns with stout rootstocks and clustered pinnate leaves, the 

 veinlets of the fertile pinnae joined transversely near the base. Sori linear, 

 contiguous, parallel with the midvein of leaf -segments and close to it, the in- 

 dusium membranous. [Greek, tasteless.] Forty species or more, mostly trop- 

 ical in distribution. Type species: Blechnum orientale L. 



1. Blechnum serrulatum L. C. Rich. Act. Soc. Nat. Paris 1: 114. 1792. 



Leaves erect, tufted, 3-9 dm. high, rather stiff, the plants often forming 

 large colonies. Blades subcoriaceous, oblong-lanceolate, once pinnate, glabrous; 

 petiole stout, shorter than the blade; pinnae numerous, oblong, linear or oblong- 

 lanceolate, sessile, mostly close together, obtuse or acute, 3-8 cm. long, the upper 

 ones fertile, all incised-serrulate ; veins numerous, delicate, free beyond the sori; 

 sori approximate to the strong midvein, conspicuous; fertile segments narrower 

 than the sterile. 



Borders of swamps and lagoons, Andros, New Providence : Florida ; West Indies ; 

 continental tropical America. MARSH FERN. 



