336 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 



Petioles hollow; heads smaller, 2 to 2.7 cm. broad; involucre more or 



less arachnoid A. tomentosum. 



a'. Heads racemose or sub-racemose, rarely long-peduncled; leaf -blades ovate- 

 oblong, usually less obtuse; petioles slightly 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. — {A. minus Man. 

 ed. 7; vid. Rhodora, 12: 47, 1910.) 



Waste ground and roadsides ; common. 



A. NEMOROSUivi Lejeune. — Waste ground, Stockbridge. This 

 species is very variable. 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 w oods 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. 



