HOFFMANN: FLORA OF BERKSHIRE COUNTY. 197 
Alluvial soil along rivers and brooks to an altitude of 1500 ft.; 
common. 
PTERIDITJM. Brake; Bracken. 
{Pteris Man. ed. 7; ml. Rhodora, 21: 176, 1919.) 
P. latiusculum (Desv.) Maxon. Common Brake. — (Pteris 
aquilina Man. ed. 7; Pteridium aquilinum 111. Fl. ed. 2.) 
Borders of woods, open woodland, rocky upland pastures and 
clearings; common. 
THELYPTERIS. Shield Fern. 
{Aspidium Man. ed. 7; Phegopteris Man. ed. 7; Dryopteris 111. Fl. ed. 2; nd. 
Rhodora, 21: 174, 176, 1919.) 
T. Boottii (Tuckerman) Nieuwl. Boott's Shield Fern. — 
Swampy woods; frequent. Perhaps a hybrid between Thely pteris 
cristata and T. spinulosa, var. intermedia. Specimens collected in 
Washington by C. S. Lewis have the later fronds with laciniate seg- 
ments, apparently due to the presence of a borer in the rootstock. 
T. cristata (L.) Nieuwl. Crested Shield Fern. — Borders of 
swampy woods and low meadows; frequent. 
var. Clintoniana (D. C. Eaton) Weatherby. Clinton's Shield 
Fern.— {D. Clintoniana 111. Fl. ed. 2.) 
Swampy woods; frequent in the valley, occasional on the plateau. 
T. Dryopteris (L.). Slosson. Oak Fern. — Cool woods, often 
under conifers; freciuent. 
T. Goldiana (Hook.) Nieuwl. Goldie's Shield Fern. — Rich 
woods, generally in alluvial pockets spread by brooks at the l)ases of 
slopes of rich soil, often in company with Athyrium a ngusti folium; 
occasional in the valley. Florida (Ilunnewell) ; ^Yilliamstown 
(Churchill); Cheshire (Winslow); Lanesboro (Churchill); Pittsfield; 
Washin<j;t()n (('. S. Lewis); Lenox; Stockbridge; Sh(>fKold (Walters). 
T. hexagonoptera (Michx.) Weatherby. Broad Bkkcm I'krn. — 
Rich moist soil in rather open woodland; occasional in the \ailey. 
Williamstown (Churcliill); Hancock (Churchill); Lenox; Stockbridge; 
Great Barrington; Sheflield. 
T. marginalis (L.) Nieuwl. Mau(;i.\al Smikld Fkux. — Rocky or 
swampy woods, often on rocks; common. 
forma elegans (Robinson) Weatherby, comb. nt)v. — {Anjiidiuin 
