KEY TO TH# GENERA, 
A. Sporangia dorsal or marginal, surrounded by an elastic ring, 
reticulated and pellucid, opening transversely and irregularly. 
POLYPODIACE. 
* Sort without an indusium and not covered with the ee margin of the 
JAD G scald Oa sve Sa hs Sd Ed cor Gs PO oO : . . POLYPODIE#. 
Polypodium. Sori donnaish, in one or more rows on cock side of the midrib; 
stipes articulated with the root-stock. (Page 33, Plate III.) 
*% Sori marginal or intermarginal, with an sata or covered by the reflex 
margin of the frond,.... . 2 6 6 is ) EET ERIDE AS: 
Adiantum. Sori oblong or roundish, abel aapes black and polished. 
(Page 39, Plate VI.) 
Pteris. Sori continuous at the margin, connecting the tips of the free veins; 
indusium formed by the reflexed margin; stipes light colored. (Page 41, 
Plate VII.) 
Cheilanthes. Sori minute at the ends of the veins; indusium continuous 
or interrupted, formed by the reflexed margin; stipes near the base brown 
or black, shining. (Page 45, Plate IX.) 
Pellzea. Sori on the upper part of the veins; indusium membranaceous, con- 
oo rarely wanting; stipes generally dark colored. (Page 51, Plate 
) 
Allosorus. Sori roundish or elongated, extending far down the free veins, 
covered at first with the reflexed margin; stipes light colored. 
* Sort oblong or linear, the industum attached aby one side to the lateral veins, 
opening at the other, Soy Sgr .. . . ASPLENIEA. 
Woodwardia. Sori forming a cam dike. row on reach side of the midrib; 
veins reticulated. 
Asplenium. Sori elongated, arising from lateral veins, opening toward the 
midrib; veins free. (Page 53, Plate XIII.) 
Scolopendrium. Sori linear, confluent in pairs; indusium double, the two 
portions opening toward each other; veins free. 
Camptosorus. Sori irregularly Santteneat partly on veins parallel and partly 
on veins oblique to the midrib, outer often in pairs; veins reticulated. 
(Page 75, Plate XXIV.) 
“a Sort round or roundish, placed on the back of the lateral veins, rarely 
at the apex; mostly provided with an indusium. . . . . . ASPIDIEA. 
Phegopteris. Sori round, rather small, with an obsolete or no indusium; 
stipes not articulated with the root- -stock ; veins free. (Page 79, Plate 
AVI; 
Aspidium. Sori roundish; indusium attached above the sori, orbicular or 
reniform; veins free. (Page 85, Plate X XIX.) 
Cystopteris. Sori roundish; indusium attached below and partly under the 
sori, convex, acuminate; veins free. (Page 1oz, Plate XX XVII.) 
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