[Illustration: Fragrant Fern. Aspidium fragrans (Mt. Mansfield. Vt.)]
KEY TO THE WOOD FERNS
ASPIDIUM
Fronds pinnate, the pinnæ pinnatifid;
Blade soft and thin, not evergreen;
Lower pinnæ reduced to mere lobes
New York Fern
Lower pinnæ but slightly reduced;
Veins simple......................Massachusetts Fern
Veins forked..............................Marsh Fern
Blade rather thick (subcoreaceous) mostly evergreen;
Fronds small, narrow, glandular, rock species
Fragrant Fern
Fronds large, two or more feet high;
Lower pinnæ short, broadly triangular
Crested Shield Fern
Lower pinnæ longer;
Sori close to the margin.... Marginal Shield Fern
Sori nearer the midvein;
Frond lanceolate....................Male Fern
Frond ovate..............Goldie's Shield Fern
Fronds twice pinnate with the lower pinnules pinnatifid
Boott's Shield Fern
Fronds nearly thrice pinnate................Spinulose Shield Fern
[Illustration: Marginal Shield Fern. Aspidium marginale]
[THE WOOD FERNS]
The ferns of this group, not counting the small fragrant fern, prefer the woods or at least shady places. Although the genus Polýstichum represents the true shield ferns, the wood ferns are also thus designated, as their indusia have nearly the shape of small, roundish shields. The old generic name for them all was Aspídium (meaning shield), first published in 1800. For a long time its chief rival was Nephròdium (kidney-like), 1803. Many modern botanists have preferred the earlier name Dryópteris (1763), meaning oak fern, alluding, perhaps, to its forest-loving habits. THELÝPTERIS, still earlier (1762), may supersede the others.
[Illustration: Marginal Shield Fern. Aspidium marginale (From Woolson's "Ferns," Doubleday, Page & Co.)]
