66 NORTH AMERICAN FLORA [VoLuME 16 
with a central costule bearing several pairs of simple to pinnately branched free veins. 
Sori dorsal, apart from the margin; indusium either (1) cyathiform, not wholly enclosing 
the sporangia, persistent, with even margins, or (2) globose, at first wholly enclosing the 
sporangia, bursting irregularly at maturity, the divisions persistent to evanescent, often 
only the basal portion subpersistent as a disk-like scale; receptacles of various form. 
Type species, Polypodium arboreum LL. 
Indusia cyathiform, often deeply so, never wholly enclosing the sporangia, persistent, the margins 
entire. ; 
Lamina bipinnate. 
Caudex procumbent, 10-40 cm. long. 
Fronds nearly or quite exstipitate; segments mostly adnate, cori- 
aceous. 
Fronds long-stipitate ; segments short-stalked, chartaceous, 
Caudex erect, 2-12 meters high. 
pea slender, 2.5-3.5 cm. in diameter; lamina long-attenuate 
elow. 
a ee acne 8-20 cm. in diameter ; lamina more abruptly reduced 
elow. 
Primary rachis pubescent or hirsute; segments close, adnate ; 
costae pilose below. 
Primary rachis furfuraceous ; segments (pinnules) mostly auric- 
ulate; costae both paleaceous and pilose. 
Lamina tripinnatifid or tripinnate. 
Indusia shallow, more or less saucer-like at maturity. 
Lamina tripinnatifid; pinnules 3 cm. or less long; veins 3-6 pairs, 
sori 1 or 2 to the segment. 
Lamina tripinnate ; pinnules8-18 cm. long; veins 10-15 pairs to the 
Ne 
. C. Nockit. 
. C. Brooksii, 
. C. minor. 
. C. pubescens. 
. C. balanocarpa. 
. C. jamatcensis. 
segment, sori very numerous. 7. C. arborea, 
Indusia deeply cyathiform. 
Lamina irregularly tripinnatifid ; pinnae linear to linear-lanceolate, 
7-8 cm. broad. 8. C. concinna. 
Lamina regularly and deeply tripinnatifid or tripinnate; pinnae 
lanceolate to oblong or deltoid-lanceolate, 13-24 cm. broad. 
Indusia covered with long light-colored simple hairs. 
Indusia glabrous without. 
Segments deeply crenate-serrate to inciso-pinnatifid. , 
Pinnules 16-20 pairs, the larger ones deltoid-oblong and 
up to 4cm. broad, the basal segments inciso-pinnatifid ; 
. C. portoricensis. 
sori large, distant. 10. C. crassa, 
Pinnules 25-35 pairs, lanceolate-oblong, up to 2 cm. broad ; 
margins crenate-setrate ; sori smaller, approximate. 11. C. elegans. 
Segments entire to crenulate or crenulate-serrate. 
ee rachises conspicuously fibrillose-paleaceous 
elow. 
Secondary rachises not fibrillose-paleaceous below or ob- 
scurely so. 
Leaf-tissue rigidly herbaceous; segments crenulate- 
serrulate, at least toward the apex; scales of the 
costules few, flattened, lacerate. 
Leaf-tissue extremely coriaceous; segments entire to 
faintly crenulate ; scales of the costules numerous, 
mostly bullate, apiculate or with dark spinous 
processes. 
Costae densely brownish-strigose above ; segments 
9-10 mm. long, narrowly oblong, falcate ; indusium 
glabrous. 5 
Costae glabrous above; segments 7-9 mm. long, sub- 
falcate, closer; mouth of the indusium delicately 
whitish-araneose-ciliate at maturity. 
Indusia globose, at first wholly enclosing the sporangia, rupturing at ma- 
turity, the divisions persistent, subpersistent or fugacious. 
Segments mostly sessile or nearly so; tertiary rachises (costae) sinuate- 
alate. ; 
Tamina deeply quadripinnatifid, 7. e., the segments cut nearly to the 
costules. 
Lamina tripinnate, the segments not pinnatifid. 
Segments lightly to deeply crenate-serrate, the larger ones subau- 
riculate distally ; veins pinnately branched. 
Segments narrower, deeply crenate-dentate, mostly semihastulate 
by the prolongation of the distal basal lobe; veins mostly once- 
forked. 
Segments mostly adnate, the costae not sinuate-alate. 
Pinnules (or at least the lower ones) manifestly petiolate (these 4 
10 mm.). 
Pinnules Laseotate to linear-lanceolate, the costae deciduously pal- 
eaceous below. 
12. 
14. 
C. Tussactt. 
. C. cubensis. 
C. nigrescens. 
15. C. araneosa. 
16. C. Werckleana. 
17. C. hemiotis. 
18 
19 
. C. hastulata, 
. C. Tuerckheimit. 
