POLYPODIUM. 
II 
Tribe V.—ASPLENIEAE. — ii. Asplenium. 
4— 4— Fruit-dots round or nearly so, on the backs or occasionally on the 
tips of the veinlets. 
Tribe VL— ASPIDIEAE. 
12. Plieg'Opteris. — Indusium none, or very minute; fruit-dots very small, borne 
on the backs of the veinlets. 
13. Aspidillin. — Fruit-dots on the back or tip of the veinlets, round or kidney- 
shaped, opening all around the edge or nearly so. 
14. Cystopteris. — Indusium fixed across the back of the veinlets, splitting away 
at the other side and usually turned back like a hood at maturity. Small and very 
delicate ferns. 
15. Woodsia. Indusium fixed beneath the fruit-dot, splitting into several lobes or 
a delicate fringe, borne on the back of the veinlets. Small plants. 
SUB-ORDER II, SCHIZ^ACE^. 
Spore-cases ovate, opening lengthwise, in two rows. 
16. Aneilllia. — Fronds fertile below, sterile above; sterile part long stalked, 
twice-pinnate, divisions very narrow. Very peculiar plants, not at all like Sub-order I. 
TRIBE I.-POLYPODIE^. 
I.* POLYPODIUM, Linnaeus. Polypody, 
Stalk jointed to the chaffy, usually creeping and elongated rootstock. 
Fronds smooth, and pinnate only in our plants. (The name following 
Polypodium and all the other genera and species denotes the person who 
described them.) 
Named from the Greek, meaning many feet, in reference to the branching rootstock. 
A genus of about 350 species, chiefly tropical, 8 in the United States. Several of our 
species appear to run together. 
* Fronds not divided to or near the 77 iidrib ; veinlets free. 
1. P. vulgare, L. (The common P.) 
Fruit-dots rather large, midway between the midrid and margin of the 
divisions; frond almost leathery (thinner in the var.), oblong in outline, 
tapering to a point at the top; divisions obtuse or only acute, linear- 
oblong, scalloped, toothed, or almost entire. Plant i to 12 or more 
inches high. 
In canyons in a few places in Colorado; Cottonwood Canyon, Utah; Oregon and 
eastward; Europe. Rare in our region. 
2. Variety OCcMentale, Hooker. (The western var.) 
Divisions long-pointed and toothed toward the tip. Much larger 
and thinner than the typical form. Hardly deserves the rank of a variety. 
Pacific Coast, San Francisco and northward. 
3. P. falcatlim, Kellogg. hooked V.')^ 
Fruit-dots nearer the midrib than the margin ; divisions tapering 
from a broad base to a slender point, more or less curved and toothed. 
* The numbers of the genera in the Key are repre^nted here by Roman numerals to avoid confusing 
the genera and species. 
