DESCRIPTIONS OF SOME COMMON WEEDS 



203 



Common St. John's-wort (Hypericum pcrforatum, L.). 

 A much-branched perennial with numerous sterile 

 shoots at the base ; leaves sessile, oblong or linear, punc- 

 tate with black dots ; flowers borne in cymose clusters, 

 and have five green sepals shorter than the five yellow 

 and black dotted petals ; stamens many, in several clusters. 

 Common in the eastern states, but rarely found west of 

 the Mississippi or in the 

 southern states. It is be- 

 lieved in some localities to 

 be poisonous. 



Violet Family (Violaceae). 

 Usually herbs or rarely 

 shrubs or trees, caulescent 

 or acaulescent; with alter- 

 nate, simple, entire, or lobed 

 leaves with stipules; flowers 

 mostly irregular ; sepals 

 five, corolla of five petals, 

 one of which is spurred, 

 hypogynous ; stamens five, 

 short ; filaments broad and 

 flat, often cohering with 

 each other around the pis- 

 til ; ovary simple, one-celled, 

 with two parietal placentae; 

 fruit a capsule ; seeds anat- 

 ropous. About 300 species 

 of wide distribution. 



Heart 's-ease, or Pansy 

 (Viola tricolor, L.). A leafy-stemmed, smooth annual, 

 branched and ascending; upper leaves oval-lanceolate 

 and crenately toothed, lower broader and often heart- 

 shaped, with large leaflike stipules ; flowers solitary with 

 five spreading petals, variously marked with yellow, 

 purple and white, the lower petal being the largest; 



Fig. 130. St. John's-wort (Hy- 

 pericum perforatum), common in 

 fields of the North. ( Ad a H ay d en . ) 



