336 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Petioles hollow; heads smaller, 2 to 2.7 cm. broad; involucre more or 
less arachnoid A. tomerdosum. 
a'. Heads racemose or sub-racemose, rarely lonf^-pcduncled ; leaf-blades ovate- 
ol)lons, usually less obtuse; petioles slight ly angular. 
Heads medium, 2.5 to 3.5 cm. broad; the middle and inner bracts of 
the involucre equalling or exceeding the corollas; achenes dark brown. 
A. nemorosum. 
Heads small, 1.5 to 2.5 cm. broad; the middle and inner bracts of the 
involucre conspicuously shorter than the corollas; achenes gray or 
ashy-brown A. minus. 
A. Lappa L. Great Burdock. — Roadsides and waste places; rare. 
Williamstown; Sheffield (Walters). 
A. MINUS (Hill) Bernh. Common Burdock. — (^4. minus iSIan. 
ed. 7; vid. Rhodora, 12: 47, 1910.) 
Waste ground and roadsides ; common. 
A. NEMOROSUM Lejeune. — Waste ground, Stockbridge. This 
species is very varial)le. The specimen from Stockbridge is treated 
as form c by Fernald & Wiegand (Rhodora, 12: 45, 1910). 
A. TOMENTOSUM Mill. — Frequent in waste ground, Lee. {Vid. 
Rhodora, 12:45, 1910.) 
ARTEMISIA. Wormwood. 
A. Absinthium L. Wormwood. — Roadside near Greenwater 
Pond, Lee; waste ground, Sheffield. 
A. BIENNIS Willd. — Waste ground, Pittsfield ; Lee. 
A. LUDOViciANA Nutt. — Railroad track, Lee. 
A. VULGARIS L. Common Mugwort. — Roadsides and waste 
ground; occasional. Cheshire; West Stockbridge; Great Barring- 
ton; Lanesboro (Walters); Lenox. 
ASTER. Aster. 
A. acuminatus Michx. — Cool rich woods; common. Summit of 
Greylock. The monstrous form with chaffy paleae instead of flowers 
has been found at Otis and Sandisfield (Walters). 
A. cordifolius L. — Borders of woods and thickets, roadsides and 
shaded yards ; common, especially in the valley. A form from Egre- 
mont with flowers almost pure white when fresh, drying bluish-white. 
Many specimens which have been referred to this species have the 
•upper surface of the leaves smooth, almost greasy to the touch. 
