238 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
COMMELINACEAE. SPIDERWORT FAMILY. 
TRADESCANTIA. Spidehwimit. 
T. viRGiNiANA L. Spiderwort. — One clump in a meadow near 
the Housatonic River, Great Barrington (Walters). 
PONTEDERIACEAE. PICKEREL-WEED FAMILY. 
HETERANTHERA. Mud Plantain. 
H. dubia (Jaeq.) MacM. Mud Plantain. — Shallow ponds and 
sluggish streams; occasional in the valley. Muddy Pond, Washing- 
ton (altitude 1450 feet); Pontoosuc Lake, Pittsfield; outlet of Stock- 
bridge Bowl, Stockbridge; Crane and Cranberry Ponds, West Stock- 
bridge; Lake Buell, Monterey (Walters); lagoons of the Housatonic 
River, Sheffield. 
PONTEDERIA. Pickerel-weed. 
P. cordata L. Pickerel-weed. — Shallow water, margins of 
ponds and slow streams; common. 
var. angustifolia Torr. — Occasional with the type. Great 
Barrington; New Marlboro. 
JUNCACEAE. RUSH FAMILY. 
JUNCUS. Rush. 
Key to Junciis. 
a. Inflorescence appearing lateral; the involucral leaf erect, similar to and 
continuing the naked, or essentially naked scape; rootstock creeping. 
Stamens 3. Rare /• fiUformis. 
Stamens 6. Common but extremely variable, represented in Berkshire Co. 
by four varieties, differing in the. size and arrangement of flowers, and 
the thickness of the culms J. effusus, vid. p. 240. 
o'. Inflorescence terminal. 
6. Leaves never septate, i. e., with no transverse divisions. 
c. Annual with soft base and fibrous roots, stems low and slender; 
flowers remote J- hufonius. 
c'. Perennial, flowers mostly aggregated, leaves flat (in age becoming 
involute). 
d. Base not bulbous. 
e. Auricles at the summit of the sheaths scarious, whitish, conspicu- 
ously extended beyond the point of insertion. 
J. tenuis and varieties. 
