198 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
marginale, var. elegans J. Robinson, Ferns of Essex County, Mass., 
151, 1875.) 
Rich woods; frequent. 
T. noveboracensis (L.) Nieuwl. New York Shield Fern. — 
Moist well-drained woods; common. 
T. palustris Scliott. Marsh Fern. — (J). Thelypteris 111. Fl. ed. 
2; A. Thelypteris Man. ed. 7.) 
Wet meadows, swampy thickets and moist woodland; common. 
On the summit of Greylock, 3500 feet. 
T. Phegopteris (L.) Slosson. Beech Fern. — Cool woods, espe- 
cially on moist banks; frequent in the valley, common on the plateau. 
T. simulata (Davenp.) Nieuwl. — Swampy woods, in small col- 
onies; occasional. Washington (C. S. Lewis); Ward Pond, Becket; 
Shaw Pond, Otis; Big Pond, Otis; Sandisfield (Walters). 
T. spinulosa (O. F. Miiller) Nieuwl. Spinulose Shield Fern. — 
Swampy woods ; frequent. 
var. americana (Fisch.) Weatherby. — (var. dilatatum, f. anaden- 
ium Man. ed. 7; D. dilatata III Fl. ed. 2.) 
Common in rocky woods on the upper slopes of Greylock, and prob- 
ably occasional on the plateau, as a specimen collected by C. S. Lewis 
from a shady swamp in Washington (altitude 1700 feet) has been 
identified by C. A. W^eatherby as this variety. 
var. intermedia (Muhl.) Nieuwl. — (Z). intermedia 111. Fl. ed. 2.) 
Rocky or swampy woods; common. Broad forms approaching 
var. americana occur in cool woods and swamps, as at Ice Glen, 
Stockbridge; Ice Gorge, Great Barrington; The Dome, Mt. Washing- 
ton. A form with very narrow pinnules, approaching var. concor- 
diana occurs on Fern Cliff, Lee. 
Hybrid forms of Thelypteris. 
T. cristata X marginalis. — Lenox; Washington (C. S. Lewis). 
T. cristata X spinulosa. — Lenox; Washington (C. S. Lewis). 
T. cristata, var. Clintoniana X spinulosa, var. intermedia. — 
Cheshire (Winslow); Washington (C. S. Lewis). 
T. cristata, var. Clintoniana X Goldiana. — North Adams 
(Churchill). 
T. Goldiana X marginalis. — Cheshire (Winslow). 
T. marginalis X spinulosa, var. intermedia. — Washington 
(C. S. Lewis). 
