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. 



Rutnex 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 C 14 H 10 O 4 , which is a 

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

 rubefacient and discutient and is used for destroying 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. Polygonum L. Smartweed 



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



| floating; leaves alternate, entire, ochreae cylindrical, often fringed; nYwers 



I mostly perfect, green white, pink, or purple ; calyx 4-5 parted or cleft ; st"*nens 



, 5-9, filaments filiform or dilated to the base; style 2 or 3 parted 01 cleft; 



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



j 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 ornamental 



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 L. 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; 

 1 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, 



