SPERMATOPHYTA— POLYGONACEAE 421 



in fruit; pedicels nodding, shorter than the fruting calyx; valves broadly ovate 

 with a conspicuous ovoid tubercle. 



Distribution. Common throughout the northern part of the Unitec' States. 



Rumex crispus L. Curled Dock 



A smooth perennial from 3-4 feet high ; leaves with strongly wavy and 

 curled margins, lanceolate and acute; in the lower leaves bases are somewhat 

 truncate or inclined to be ear-shaped ; flowers collected in dense whorls, extended 

 or prolonged into racemes, entirely leafless above, but below with small leaves; 

 flower consists of 6 sepals, fruiting pedicels as long as the calyx wings; wings 

 heart-shaped, erose dentate, each showing a tubercle ; achene 3-angled, smooth. 



Poisonous properties. The docks contain rumicin Cj^H^^O^, which is a 

 tasteless, golden-yellow substance, slightly soluble in hot water. It acts as a 

 rubefacient and discutient and is used for diestroying parasites of the skin. 



Rumex has found a place in Pharmacopoea and is also used in medical 

 practise. It causes nausea, watery brown faeces, copious urination, a dry spas- 

 modic cough, and perspiration. The Rumex orbiculatus. Great Water Dock, 

 according to Dr. Johnson, is tonic, astringent, and slightly laxative. 



Medical properties. It is used as a stimulant and diuretic. 



3. Po\ygonu>n L. Smartweed 



Annual or perennial herbs, occasionally woody; stem erect, climbing or 

 floating; leaves alternate, entire, ochreae cylindrical, often fringed; flowers 

 mostly perfect, green white, pink, or purple; calyx 4-5 parted or cleft; strmens 

 5-9, filaments filiform or dilated to the base; style 2 or 3 parted oi cleft; 

 achene lenticular or 3-angIed, rarely 4-angled; endosperm present. Ab'^ut 200 

 species of wide distribution. The P. tinctorium of China furnishes the Chinese 

 indigo. The Saghalen knotweed (P. sachalinense) was widely advertised as 

 a forage plant a few years ago and is used in Japan and Manchuria as we use 

 asparagus. The prince's feather (P. orientale) is cultivated for ornpmental 

 purposes. The tanweed (P. Muhlenbergii) , smartweed (P. Persicaria), knot- 

 grass (P. aviculare) and black bindweed (P. Convolvulus) are troublesome 

 The Pennsylvania persicaria (P. pennsylvanicum) is a valuable honey plant and 

 its seed is a common impurity in clover. 



Polygonum Persicaria h- Lady's Thumb 



A nearly smooth and glabrous annual from 12-18 inches high ; leaves lanceo- 

 late or linear, marked with a lunar blotch near the middle, acuminate ochreae 

 somewhat bristly; ciliate spikes ovoid or oblong, erect; stamens mostly 6; 

 style 2-3 parted; achene lenticular. 



Distribution. Across the continent in moist places; naturalized from Eur- 

 ope. 



Poisonous properties. None of the species is relished by stock; the P. 

 acre and P. Hydropiper are very acrid and produce gastro-enteritis and ery- 

 thema, like that caused by buckwheat. The following species produce simi- 

 lar troubles. 



Polygonum acre H.B.K. Water Smartweed 



A nearly smooth perennial; stems rooting at the decumbent base; leaves 

 linear-lanceolate ; ochreae strigose, fringed with long bristles ; spikes erect, 



