PLANT FAMILIES: POLYG OA'IFLORsE. 



267 



FOLYGONIFLOR/€. 



516. Buckwheat family (polygonacese). — Besides the common buckwheat, 

 from which this 

 family get* i t s 

 name, the knot- 

 weeds are good 

 representatives. 

 Fig. 348 is of the 

 a now -leaved knot- 

 weed, or arrow- 

 leaved tear-thumb, 

 so called because 

 of the arrow-shaped 

 leaves and from the 

 prominent recurved 

 prickles on the four- 

 angled stem. The 

 plant occurs in low 

 grounds often i n 

 large clumps, and 

 the slender branch- 

 ed stem is support- 

 ed to some extent by 

 neighboring plants. 

 The flowers are in 



Fig. 348- 

 Polygonum sagittatum, portion 

 of plant. 



Fig- 349- 

 Spring beauty (Claytonia virginiana). 



