BUCKAVHEAT FAMILY. 



281 



Water-pepper Polygonum. Water-pepper. Smart-weed. 



Annual. Stem 1-2 feet high, more or less branched, sometimes decumbent, often pur- 

 plish. Leaves 2-4 inches long, acute at each end, subsessile ; sheaths tubular, somewhat 

 inflated, hairy, fringed with bristles, the length of the tube. Racemes 2-4 inches 



long, slender and interrupted, at first nodding, finally erect; fascicles 2-4-flowered; 

 flowers greenish with white edges ; pedicels proceeding from bristly-ciliate sheathing brocfs. 

 Styles 2-3. Achenium flatfish or obtusely triangular. 



Moist waste grounds : introduced from Europe. Aug. -Sept. 



Obs. A worthless weed, as most 

 of the species are ; and it is, more- 

 over, a highly acrid plant, some- 

 times cansing obstinate ulcerative 

 inflammation when incautiously ap- 

 plied to the skin. The medical 

 men of the Middle Ages highly 

 extolled it for its remedial quali- 

 ties, but it is not used at present. 



^ * Flowers axillary, 2-3 together. 



5. P. avicula're, L. Stems pro- 

 cumbent or spreading ; leaves ses- 

 'sile, lanceolate or oblong ; sheaths 

 lacerate ; stamens 5 - 8 ; akeues 

 triquetrous. 



Bird Polygonum. Knot-grass. 

 Goose-grass. Door-weed. 



Annual, ^fem 6-12 inches long, much 

 branched and spreading, smooth. Leaves 

 % an inch to an inch long. Stipules white. 

 Flowers green, edged with white, and often 

 tinged with purple, small, subsessile. Fruit 

 enclosed in the calyx, dull, minutely wrin- 

 kled or granular under a lens. 



Yards and foot-paths. June-Au^. 



Obs. This humble weed is thor- 

 oughly naturalized, and is one of 

 the commonest everywhere about 

 dwellings. There are several vari- 

 eties, one of which, var. erectum, 

 is quite common in rich shadv 

 places ; its stems are nearly erect, 1 

 1-2 inches in length. 



2 or 3 feet high, with oral leaves 



Fig. 181. A branch of the Halberd-leaved Tear-thumb (Polygonum arifolium.) 



