680 FILICES. (FERNS.) 



1. POLYPODIUM, L. POLYPODY. (PI. 16.) 



Fruit-dots round, naked, arranged on the back of the frond in one or more 

 rows each side of the midrib or central vein, or irregularly scattered, each borne 

 in our species on the end of a free veinlet. Rootstocks creeping, branched, 

 often covered with chaffy scales, bearing scattered roundish knobs, to which 

 the stipes are attached by a distinct articulation. (Name from iro\vs, many, 

 and irovs,foot, alluding to the branching rootstock.) 



1. P. VUlgare, L. (PI. 16, fig. 1-3.) Fronds evergreen, oblong, smooth 

 both sides, 4-10' high, simple and deeply pinnatifid; the divisions linear-ob- 

 long, obtuse or somewhat acute, remotely and obscurely toothed ; veins once 

 or twice forked ; fruit-dots large, midway between the midrib and the margin. 

 Rocks ; common. July. (Eu.) 



2. P. incanum, Swartz. Fronds evergreen and coriaceous, oblong, 

 2 6' high, grayish and very scurfy underneath with peltate scales, simply pin- 

 natifid ; the divisions oblong-linear, obtuse ; fruit-dots rather small, near the 

 margin ; veins forking, free in the N. American plant ! Rocks and trunks 

 of trees, Va. and Ohio to 111., and southward. Aug. 



2. NOTHOLJENA, R. Brown. CLOAK-FERN. 



Fruit-dots roundish or oblong, placed near the ends of the veins, soon more 

 or less confluent into an irregular marginal baud, with no proper involucre. 

 Veins always free. Fronds of small size, 1 - 4-pinuate, the lower surface almost 

 always either hairy, tomentose, chaffy, or covered with a fine waxy white or 

 yellow powder. (Name from voQos, spurious, and \aiva, a. cloak, the woolly 

 coating of the original species forming a spurious covering to the sporangia.) 



1. N. dealbata, Kunze. Fronds triangular-ovate, 1 -3' long, 3-4-pin- 

 nate ; rhachis and branches straight, black and shining ; ultimate pinnules 

 scarcely a line long, white and powdery on the lower surface. Clefts of cal- 

 careous rocks, Mo., Kan., and southwestward. July -Aug. 



3. ADIANTUM, L. MAIDENHAIR. (PI. 17.) 



Fruit-dots marginal, short, borne on the under side of a transversely oblong, 

 crescent-shaped or roundish, more or less altered margin or summit of a lobe 

 or tooth of the frond reflexed to form an iudusium ; the sporangia attached to 

 the approximated tips of the free forking veins. Main rib (costa) of the pin- 

 nules none (in our species), or at the lower margin. Stipes black and polished. 

 (The ancient name, from a- privative and SjaiVco, meaning unwetted, the smooth 

 foliage repelling rain-drops.) 



1. A. pedatum, L. (PI. 17, fig. 1-3.) Frond forked at the summit of 

 the upright slender stalk (9-15' high), the recurved branches bearing on one 

 side several slender spreading pinnate divisions ; pinnules numerous, short- 

 stalked and obliquely triangular-oblong, entire on the lower margin, from 

 which the veins all proceed, and cleft and fruit-bearing on the other. Rich, 

 moist woods. July. A delicate and most graceful Fern. 



2. A. Capillus-Veneris, L. Fronds with a continuous main rhachis, 

 ovate-lanceolate, 9-18' long, often pendent, 2 -3-pinnate at the base, the upper 

 third or half simply pinnate; pinnules wedge-obovate or rhomboid, 6- 12" 

 long, deeply and irregularly incised; veinlets flabellately forking from the 



