POLYPODIACEAE (FERN FAMILY) 41 



short-stalked, riirid (1-G dm, long) ; pinnae broadly lanceolate-scythe-shaped, 

 acute, the Umest short-triangular, strongly uuricled on tlie upper side, spiuulnse- 

 dentate ; sori biseriate, at length subcoiifluent. {Aspidium S\v.) — iiocky (calca- 

 reous) woods, Gulf of !St. Lawrence ; and from Niagara Falls, Ont., to L. Superior, 

 westw. and northw. (Eu.) 



* * Fronds bipinna^e. 



3. P. Braunii (Spenner) F6e. Fronds ovate- or oblong-lanceolate (4-9 dm. 

 long) tapering to a very short-stiped base ; pinnules ovate or oblong, obtuse, 

 .runcate and almost rectangular at base, short-stalked, or the upper continent, 

 5barply toothed, beset with long and soft as well as chaffy hairs. (Aspidinm 

 aculeatum, var. Doll.) — Rich, mostly upland woods, Nfd. to N. Y., and 

 L. Superior. (Eu.) 



14. ASPIDIUM Sw. Shield Fern. Wood Fern 



Fronds tufted, 1-o-pinnate ; veins simple or branched. Sori orbicular, borne 

 on the back of the scarcely modified fertile frond. Indusium reniform or, ii 

 orbicular, exhibiting a distinct narrow^lepression or sinus at one side, although 

 centrally attached. Stipes not articulated at the base. (Name from da-Tldiov, 

 a small shield, from the shape of the indusium.) Nephrodium Rich. 



a. Veins sinii)le or once forked ; fronds not evergreen ; stipes and slender 

 rootstwcks nearly naked. 

 Lowest pinnae scarcely smaller than the middle ones. 



Fertile veins once forked 1. ^. Thelypteris. 



Fertile veins simple . . 2. A. simulatum. 



Lower pinnae gradually decreasing in size, the lowest very small . 3. A. noveboracenee 

 ft. Veins, at least the lowest, more than once forked ; fronds mostly ever- 

 gi-een ; stipes and rootstocks scaly b. 



h. Piimae 40-60, small, 4-S mm. broad 4 A. fragrans. 



h. Pinnae fewer, 12-1)0 mm. broad c. 



c. Frond bipinnatifid or bipinnate (or sub-tripinnatifid near the base). 



Sori marginal 5. A. marginale. 



Sori not marginal. 

 Basal scales lance-linear, caudate-attenuate . . . . &. A. Fili-v-mas. 

 Basal scales ovate-oblong to deltoid. 

 Basal scales firm, shining, dark chestnut-colored . . 1. A. Goldianum. 



Basal scales thin, dull, membranous, light brown. 

 Indusium glandular-puberulent. 

 Lobes of frond with incurved teeth; sori 1.5-1.8 mm. 



in diameter . . . . {'d) A. ciifitatum, var. Clintoni anuria. 



Lobes with spreading teeth ; sori 1-1.2 mm. in diameter. 8. A. BooUii. 

 Indusium glabrous. 

 Frond conspicuously narrowed at the base . . . Si. A. cristatum. 

 Frond scarcely or not at all narrowed at the base. 



Lobes incurved -serrate. . . .(9) A. cristatum, var. Clintonianum. 



Lobes spinulose-dentate 10. ^. spinulonuin. 



e. Fronds tripinnate or tripinnatifid d. 

 d. Fronds tripinnatifid. 



Ba.sal scales large, lance-oblong, dark brown (10) A. ftpinulosuvi, var. dilaiatum. 



Basal scales small, deltoid-ovate, light bro\vn. 



Indusium glandless (10) A. spmn?oi^um. 



Indusium glandular-puberulent . . (10) A. spimilosum, \av.interinediuni. 

 d. Fronds tripinnate (10) A. spinolusum, var. concordianum. 



L A. Thelypteris (L.) Sw. Fronds pinnate, lanceolate in outline; pinnae 

 horizontal or slightly recurved, linear-lanceolate, deeply pinnatifid ; lobes 

 oblong, entire, obtuse or appearing acute when in fruit from the strongly revo- 

 lute margins; veins forked, bearing the (numerous and soon confluent) fruit 

 dots near their middle ; indusium minute, smooth and naked. (Kephmdiinn 

 Strempel ; Dryopteris Gray.) — Marshes; common, Aug. (Cosmop.) Forn a 

 PiTFrknAE (A. A. Eaton) Robinson is a form with pinnae variously forked 

 at the tip. 



2. A. simulatum Davenp. In habit similar to the preceding; veins simple ; 

 fruit dots few (3-10 on each lobe) ; indusium glandular-ciliolate, (Dryopteris 

 Davenp.) — Bogccy wo >ds, etc.. Me. to Vt. and Md. ; reported from Mo, 



3. A. noveboracense (L.) Sw. Fronds pinnate, lanceolate in outline, ?(7/)fr- 

 ing both ways from the middle ; pinnae lanceolate, the lowest 2 or more pairs 



