POLYPODIACEAE (FERN FAMILY) 35 



' 2. PHEG6pTERIS (Presl) F^e. Beech Pern 



Fruit dots small, round, naked (no indusium), borne on the back of the veins 

 below the apex. Stipe continuous with the rootstock. — Our species have free 

 veins and bright green membranaceous fronds, decaying in early autumn 

 (Name composed of 0i;76s, an oak or heenh, and Trr^pis, /ern.) 



* Fronds twice pinnatifld ; pinnae all sessile, adnate to the winged rhachis. 



1. P. polypodioides F6e. Fronds triangular, longer than broad (8-26 cm. 

 long), hairy on the veins, especially beneath ; pinnae linear-lanceolate, the 

 lowest pair deflexed and standing forward ; their divisions oblong, obtuse, entire 

 the basal decurrent upon the main rhachis ; fruit dots all near the margin. (P 

 Phegopteris Underw.) —Damp woods, Nfd. to N. Y., " Va.," Wise, la.. Wash., 

 and Alaska. (Eurasia.) 



\y 2. P. hexagon6ptera (Michx.) F6e. Fronds triangular, usually broader than 

 long (14-30 cm. broad), slightly pubescent and often finely glandular beneath: 

 pinnae lanceolate ; upper segments oblong, obtuse, toothed or entire, those of the 

 very large lowest pinnae often elongated and pinnately lobed, basal ones very 

 much decurrent and forming a continuous many-angled wing along the main 

 rhachis ; fruit dots near the margin ; some also between the sinus and the mid- 

 rib. — Rather open woods, centr. Me. to w. Que., w. to Minn., and southw. ; 

 common.— Larger and broader than the last, which it often closely resembles. 

 * * Fronds ternate, the three divisions petioled ; rhachis wingless. 



3. P. Dry6pteris (L.) F^e. (Oak Feen.) Fronds smooth, broadly triangular 

 (1-1.5 dm. wide), the three triangular primary divisions all widely spreading, 

 1-2-pinnate ; segments oblong, obtuse, entire or toothed ; fruit dots near the 

 margin. — Rocky woods ; common northw. (Eurasia.) 



4. P. Robertiina (Hoffm.) A. Br. Fronds minutely glandular and some- 

 what rigid, dull green ; lowest inferior pinnae of the lateral divisions smaller in 

 proportion than in the last species. (P. calcarea F6e.) — Shaded limestone, 

 " Lab." and Antioosti to N. B., la., and Man. ; rare. (Eu.) 



3. NOTHOLAENA R. Br. Cloak Fern 



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

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

 Veins always free. Fronds of small size, l-4^pinnate, the lower surface almost 

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

 yellow powder. (Name from ySBos, spurious, and Xotra, a cloak, the woolly 

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



1. N. dealbata (Pursh) Kunze. Fronds triangular-ovate, 3-8 cm. long, 

 3-4-pinnate ; rhachis and branches straight, black and shining ; ultimate pin- 

 nules ovate-oblong, scarcely 2 mm. long, white and powdery on the lower surface. 

 (iV. nivea, var. Davenp.) — Clefts of dry calcareous rocks. Mo., Kan., and 

 southwestw. July, August. 



4. ADIANTUM [Toum.] L. Maidenhair 



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

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

 reflexed to form an indusium ; the sporangia attached to the approximated tips 

 of the free forking veins. — Main rib (costa) of the pinnules none (in our species) 

 or at the lower margin. Stipes black and polished. (The ancient name, from 

 a- privative and Siaha, meaning unwetted, the foliage repelling rain-drops.) 

 / 1. A. pedMum L. Frond forked at the summit of the upright slender stalk 

 (2-5 dm. 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 vines all proceed, 

 and cleft and fruit-bearing on the other. — Rich moist woods. July. 



