POLYPODIACEAE (FERN FAMILY) 41 



short-stalked, rigid (1-6 dm. long) ; pinnae broadly lanceolate-scythe-shaped, 

 acute, the lowest short-triangular, strongly auricled on the upper side, spinulose- 

 dentate ; sori biseriate, at length subconfluent. (Aspidium Svv.) Rocky (calca- 

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

 westw. and north w. (Eu.) 



* * Fronds bipinnate. 



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

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

 truncate and almost rectangular at base, short-stalked, or the upper confluent, 

 sharply toothed, beset with long and soft as well as chaffy hairs. (Aspidium 

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

 L. Superior. (Eu.) 



14. ASPIDIUM Sw. SHIELD FERN. WOOD FERN 



Fronds tufted, 1-3-pinnate ; veins simple or branched. Sori orbicular, borne 

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

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

 centrally attached. Stipes not articulated at the base. (Name from avirldiov, 

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



a. Veins simple or once forked ; fronds not evergreen ; stipes and slender 



rootstocks nearly naked. 

 Lowest pinnae scarcely smaller than the middle ones. 



Fertile veins once forked 1. A. Thelypteris. 



Fertile veins simple . . . . 2. A. (simulatwm. 



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

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

 green ; stipes and rootstocks scaly b. 



&. Pinnae 40-60, small, 4-8 mm. broad 4. A. fragrant. 



b. Pinnae fewer, 12-90 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 . . 6. A. Filix-mas. 



Basal scales ovate-oblong to deltoid. 



Basal scales firm, shining, dark chestnut-colored . 7. A. Goldianum. 



Basal scales thiu, dull, membranous, light brown. 

 Indusium glandular-puberulent. 

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



in diameter . . . . (9) A. cvixtatwm, var. Clintonianum. 

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

 Indusium glabrous. 



Frond conspicuously narrowed at the base . . 9. A. cristatum. 



Frond scarcely or not at all narrowed at the base. 

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



Lobes spinulose-dentate 10. A. spinulosum. 



C. Fronds trlpinnate or tripinnatifid d. 

 d. Fronds tripinnatifid. 



Basal scales large, lance-oblong, dark brown (10) A. apinulosum, var. dilatatum. 

 Basal scales small, deltoid-ovate, light brown. 



Indusium glandless (10) A. spinulowm. 



Indusium glandular-puberulent . . (10) A. spinulosum, var. intermedium. 

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



1. 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. (Nephrodium 

 Strempel ; Dryopteris Gray.) Marshes; common. Aug. (Cosmop.) Forma 

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

 at the tip. 



2. A. simul&tum Davenp. In habit similar to the preceding; veins simple ; 

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

 Davenp.) Boggy woods, etc., Me. to Vt. and Md. ; reported from Mo. 



3. A. noveboracSnse (L.) Sw. Fronds pinnate, lanceolate in outline, taper- 

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



