280 



WEEDS AND USEFUL PLANTS. 



A. f, 



4. P. Hydropi'per, L. Smooth, very acrid ; leaves lanceolate, pellucid- 

 dotted, wavy margined ; sheaths ciliate with shortish bristles ; racemes 

 filiform, flaccid and nodding ; fascicles few-flowered, rather distant ; calyx 

 glandular-dotted . 



FIG. 179. The Pennsylvania!! Polygonum (P. Pcnnsylvanicum.) 180. An enlarged 

 flower, opened. 



