34 Maidenhair 



bearing at apex two pinnae and, except in very small leaves, on 

 upper side about two to twelve radiating pinnae interspersed 

 with single pinnules, a single pinnule also borne on rachis below 

 one of basal pinnae : pinnae lanceolate or linear-lanceolate or the 

 smaller oblong or suboval, obtuse, pinnate, the basal six to ten 

 inches long, the outer successively shorter: pinnules numerous, 

 two-fifths of an inch to one inch long, alternate, stalked, oblong or 

 oblong deltoid, the apical cuneate, the lower mostly becoming cu- 

 neate or transversely oblong, attached at acute lower corner, other 

 comers rounded ; entire on sides next footstalk, otherwise dentate 

 and on upper side or both upper and outer sides cut into oblong 

 often oblique lobes; apical pinnules, and outermost basal pinnules 

 of outermost pinnae, sometimes bifid: surfaces glabrous; the 

 upper repelling water, bright green or darker; the lower paler; 

 texture elastic, membranaceous. 



Venation conspicuous, free: principal vein of each pinnule 

 dividing at base of pinnule into two branches: in oblong or 

 deltoid-oblong pinnules, the outer branch forming a unilateral 

 midvein next pinnule's lower margin, bearing branches on upper 

 side; the inner branch appearing as basal primary branch of 

 the outer, little, if any, more complex than primary branch next 

 it: in cuneate or transversely oblong pinnules both branches 

 forming unilateral midveins, one each side of pinnule's footstalk, 

 next pinnule's margin, bearing branches on upper side : primary 

 branches of midvein three to four times forked at midvein's 

 base diminishing to once-forked or simple at midvein's apex, 

 pinnule's lobes each occupied by one. 



Sori borne at apices of veinlets on under side of indusia: 

 indusia consisting of reflexed altered portions, chiefly ends of 

 lobes, of pinnule's upper margin, transversely oblong or linear 



