FILICES. 117 



brown with a darker centre ; fronds broadly ovate or triangular- 

 ovate, oftenest tripinnate ; pinnules lance-oblong, the lowest 

 often much elongated ; indusia smooth and naked. (A. dila- 

 tatum Swz., A. campylopterum Kunze., Nephrodium dilatatum 

 Desv., Lastrea dilatata J. Sm.) A dwarf form is var. dume- 

 torum. Canada and New England to Oregon. 



23. D. Boottii (Tuck.) Unde. Scales of stipes pale brown; 

 fronds elongate oblong or elongate lanceolate in outline ; pin- 

 nules broadly oblong, very obtuse, the lower pinnatifid, the 

 upper and smaller merely serrate ; indusia minutely glandular. 

 (A. spinulosum, var. Boottii Gray.) New England, New York, 

 and northward. 



24. D. patula (Swz.) Unde. Stipes 8' 12' long, stra- 

 mineous, scaly at base; fronds pale green, i 2 long, 6' 12' 

 broad, ovate-lanceolate ; pinnae lanceolate or the lower sub- 

 deltoid ; rachis and both surfaces naked ; sori in rows midway 

 between edge and midrib; indusium conspicuous, naked. (Ne- 

 phrodium patulum Baker, N. Mexicanum Hook. Distributed 

 by Lemmon as A. Karwinskyanum.) Huachuca Mountains, 

 Arizona (Lemmon). 



XXI. NEPHROLEPIS Schott. 



Sori round, arising from the apex of the upper branch of a 

 vein, usually near the margin. Indusia reniform or roundish. 

 Veins all free, the fronds simply pinnate, the pinnae articulated 

 at the base, and bearing white cretaceous dots on the upper 

 surface. Name from Gr. recppaoS, a kidney, and keitis, a scale. 

 A tropical and sub-tropical genus containing seven species. 



1. N. exaltata (L.) Schott. Stipes 4' 6' long, naked or 

 slightly scaly; fronds i 6 long, 3' 6' broad; pinnae close, 

 lanceolate, the edge entire or slightly crenate, the upper side 

 auricled at the base, the lower rounded ; rachis nearly naked ; 

 sori sub-marginal; indusia firm, distinctly reniform. Florida; 

 frequent in cultivation. 



2. N. acuta (Swz.) Presl. Stipes 4' 8' long, naked or 

 slightly scaly; fronds 2 4 long, 8' 12' broad; pinnae 4' 8' 

 long, ' i' broad, acute, entire or slightly crenate, the upper 

 side auricled, the lower rounded at base; rachis and both sides 

 nearly naked ; sori submarginal ; indusia suborbicular, subpel- 



