280 



WEEDS AND USEFUL PLANTS. 



179 



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 Pennsylvaiiian Polygonum (P. Peunsylvanicum.) 180. An enlarged 

 flower, opened. 



