FERN FAMILY 1041 



rolled into closed balls, finally dehiscent; veins free; sporangia dorsal on the 

 simple or forked veinlets. Damp places: Newf. — Fla. — Tex. — ^S.D. (Black Hills) 

 • — -Sask. Plain — Submont. 



2. PTERETIS Raf. Ostrich Fern. 



Plants with coarse dimorphous fronds, growing in crowns from stoloniferous 

 rhizomes. Sterile fronds foliaceous. Fertile fronds contracted, with revohite 

 margins covering the sori. Sori roundish, on elevated cylindrical receptacles 

 partly covered by delicate lacerate fugacious indusia inferiorly attached. [Stru- 

 thiopleris Mett., Matteuccia Todaro.] 



1. P. nodulosa (Michx.) Nieuwland. Scales of base of stipe pale brown to 

 cinnamon-colored, thin, membranous; fronds abruptly acimiinate at apex, gradu- 

 ally reduced towards base; sterile fronds 0.6-3 m. long, broadly oblanceolate or 

 spatulate, with lanceolate or hnear, pinnatifid pinnae 5-18 cm. long; segments 

 oblong, obtuse or acute; fertile fronds shorter, with rigid, upcurved, commonly 

 pinnatifid necklace-shaped pinnae; veins free, pinnate; veinlets simple. Onoclea 

 nodulosa Michx. Related to but distinct from the European P. struthiopteris 

 (L.) Nieuwland [Matteuccia struthiopteris (L.) Todaro.] Wet places: Newf. — 

 Va.— S.D.— B.C. Mont.— Submont. 



3. WOODSIA R. Br. 



Small plants with tufted pinnately compound fronds. Sori round, borne on 

 the veins. Indusia placed under the sporangia, sometimes enclosing it at first, 

 often variously divided. Veins free. 



stipe articulate near the base. 1. W. glabella. 



Stipe not articulate. 



Blades pulverulent, with flattened articulate bairs and stalked glands. 



2. W. scopulina. 

 Blades without articulate hairs, unless at the ends of the indusia or segments, glabrous 



or minutely glandular. 

 Indusia very smaU, divided almost to the center into a few hau--lLk:e filaments. 



3. W. oregana. 

 ■ Indusia large, cleft more or less deeply into several lobes. 



Lobes of the indu-sia divided at least halfway down into slender articulate 



flattened hairs. 4. W. mexicana. 



Lobes of indusia merely jagged, rarely with an occa.sional jointed extension, 



often glandular. 5. W. obtusa. 



1. W. glabella R. Br. Fronds tufted, 2.5-15.5 cm. long; stipes u.sually 

 straw-colored; blades linear or narrowly lanceolate, somewhat narrowed toward 

 base, smooth, pinnate; pinnae deltoid to roundish-ovate, crenately lobed; indusia 

 divided into narrow jointed hair-hke curving divisions. Moist rocks: Alaska — 

 Greenl.— Que.— Alta. ; N.H., N.Y.; "Minn."; Eu. Boreal— Subarctic. 



2. W. scopulina D. C. Eat. Fronds 5.5-35 cm. long; blades lanceolate, 

 pinnate; pinnae mostly oblong-ovate, deeply pinnatifid; segments short, ovate 

 or oblong, crenate-serrulate ; indusia delicate, deeply cleft into laciniae which 

 terminate in short hairs. On rocks: B.C. — Neb. — Ariz.— Calif.; (Gas le Penin- 

 sula) Que. and (Great Craggy Mts.) N.C.; reported from Minn, and nw la. Sub- 

 ?nont. — Mont. 



3. W. oregana D. C. Eat. Fronds 5-26.5 cm. long; blades lanceolate- 

 oblong, pinnate; pinnae triangular-oblong, obtuse or subacute, pinnatifid; seg- 

 ments oblong or ovate, obtuse, toothed or crenate; teeth often reflexed over the 

 sori; sori submarginal. On rocks: B.C. — Calif. — Ariz. — Colo. — (? S.D.) — Sask. 

 — Que. Submont. — Subalp. 



4. W. mexicana Fee. Fronds 5-30 cm. long; blades lanceolate, pinnate, 

 rninutely glandular; pinnae triangular-lanceolate or rarely suboblong, pinnately 

 divided; segments finely toothed, the teeth ending in delicate semitransparent 

 tips which are cihated in yoimg fronds; sori submarginal. (?) W. Cathcartiana 

 B. L. Robins. Rocks: S.D.— Colo. — N.M. — Ariz.; Minn, and Mex. Son.— 

 Mont. 



5. W. obtusa Torr. Fronds 6-62 cm. long; blades broadly lanceolate, 

 slightly reduced at base, pinnate to bipinnate, minutely glandular; pinnae oblong 



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