POLYPODIACEAE 19 



ones broadly triangular, with a single pair of stalked basal pinnae, these crenately 

 lobed below, the terminal portion of the blade deltoid to ovate, lobed or deeply incised: 

 sori few, in irregular rows: indusia ample, orbicular or nearly so. 



On shaded limestone, in hammocks, southern peninsular Florida. Also in Cuba and the 

 Bahamas. 



4. Tectaria Amesiana A. A. Eaton. Leaves numerous, ascending, fasciculate; 

 petioles 1-3 dm. long, yellowish brown; blades not proliferous, 9-16 cm. long, oblong- 

 ovate; leaflets 1 or 2 pairs, the basal pair distant, stalked, deltoid-ovate, coarsely 

 crenately-lobed, deeply so below; upper half of blade ovate to deltoid-lanceolate, with 

 3 or 4 pairs of oblique obtuse lobes, the apex acuminate, undulate: sori large, apart: 

 indusia reniform, ample, persistent. 



In limestone sinks, hammocks, southern peninsular Florida. 



25. POLYSTICHUM Koth. 



Coarse and usually rigid plants, often with chaffy foliage. Leaves mostly tufted: 

 petioles not jointed to the rootstock; blades 1-4-pinnatifid or pinnate, the sterile and 

 fertile usually similar, with free veins. Sori roundish, usually borne on the backs of 

 the veins. Indusium superior, centrally peltate, orbicular. 



1. Polystichum acrostichoides (Michx.) Schott. Eootstocks stout, densely 

 chaffy. Leaves evergreen, 2.5-8 dm. tall; petioles rusty chaffy; blades lanceolate, 

 1.5-6 dm. long, 1-pinnate; leaflets somewhat leathery, linear-lanceolate, 2.5-7 cm. 

 long, falcate, half -hastate at the base, with appressed bristly teeth; fertile leaves 

 contracted at the apex, the reduced leaflets nearly covered below with large con- 

 tiguous sori in 2-4 rows, confluent with age. 



In woods, Nova Scotia to Wisconsin, Texas and the Gulf States. CHRISTMAS FBEN. 



26. DRYOPTERIS Adans. 



Mainly woodland ferns, commonly of upright habit. Fertile and sterile leaves 

 usually similar, not jointed to the rootstock: blades 1-3-pinnate or dissected; veins 

 free or joined. Sori dorsal, round or rarely elliptical in outline, indusiate or non- 

 indusiate, the indusium (if present) commonly orbicular-reniform, vestigial in many 

 tropical species. Often known as SHIELD-FERNS. 



All veins free. 



Indusia present. (Eudryopteris.) 



Leaf-tissue membranous or delicately herbaceous. 

 Blades conspicuously narrowed downwards. 



Rootstock stout, erect, forming a definite caudex. 1. D. Panamensis. 



Rootstock slender, horizontal, wide-creeping. 2. D. Noveboracensis. 



Blades not conspicuously narrowed downwards. 



Veins f9rked. 3. D. Thelypteris. 



Veins simple. 



Blades 2-pinnatifid. 



Rootstock stout, erect; basal segments of lower leaflets 



greatly enlarged, stipular. 4. D. stipularis. 



Rootstock creeping, smaller; segments uniform. 5. D. patens. 



Blades 3-4-pinnatifid. 



Rootstock erect: veins and veinlets short-setulqse. 6. D. ampla. 



Rootstock creeping or ascending: veins and veinlets 



clothed with long spreading whitish hairs. 7. D. seligera. 



Leaf-tissue very firm or leathery. 



Blades 2-pinnatifid or 2-pinnate; segments not spinulose. 

 Sori medial or nearer the midvein; indusia flat, thin. 



Blades narrow, linear-oblong to lanceolate oroblanceolate; 



sori nearly medial. 



Fertile and sterile leaflets similar, the segments alike. 8. D. cristata. 

 Fertile and sterile leaflets unlike, the former with 



remote narrower segments. 9. D. Floridana. 



Blades broader, oblong to ovate or triangular-ovate; 



sori nearer the midvein. 



Leaflets broadest at the base; sori 3-7 pairs. 10. D. Clintoniana. 



Leaflets broadest above the base: sori 6-10 pair. 11. D. Goldiana. 



Sori near the margin: indusia convex, firm. 12. D. marginalis. 



Blades 2-pinnate to 3-pinnate; segments spinulose or mucronate. 

 Indusia glandular; leaflets usually at right angles, the lowest 



unequally lanceolate to ovate-lanceolate. 13. D. intermedia. 



Indusia glabrous or nearly so: leaflets usually somewhat 

 oblique, the lowest broadly and unequally ovate 

 to triangular. 

 Pinnules flat, decurrent; sori terminal on the veinlets: 



indusium glabrous. 14. D. spinulosa. 



Pinnules concave, some not decurrent; sori mostly sub- 

 terminal; indusium glabrous or with a few glands. 15. D. dilatata. 



