DESCRIPTIONS OF SOME COMMON WEEDS 2O$ 



v,anescent or smooth leafy perennial with linear or linear- 

 oblong leaves, entire or denticulate; flowers in loose 

 spikes, rose-colored; fruit roundish or four-sided below. 

 Common in western Minnesota, Iowa and westward. 



Evening Primrose (Oenothcra biennis, L.). A stout, 

 erect annual or biennial, more or less pubescent and 

 hairy; leaves lanceolate to oblong, acute or acuminate, 

 denticulate, the upper sessile, the lower petioled ; calyx 

 tube prolonged beyond the ovary ; the lobes 

 reflexed; petals four, yellow, valves con- 

 taining many small seeds. An immensely 

 variable species. From the Atlantic to the 

 Great Basin of Utah. Often a very 

 troublesome weed. 



Carrot Family (Umbelliferae). Herbs 

 with compound or sometimes simple 

 leaves; petioles often dilated at the base, 

 rarely with stipules; flowers numerous, 

 small in compound or simple umbels or heads, 

 frequently polygamous ; calyx tube adnate 

 to the ovary, limb obsolete or five-toothed ; 

 petals five, inserted on the margin of the 

 calyx; stamens five, inserted on the disk; 

 pistils with two styles ; fruit dry, composed 

 of two carpels, generally spreading from 

 each other at maturity. Fig. 131. 



Poison Hemlock (Conium maculatum, Evening prim- 

 L.). An erect, branching, smooth herb, 

 with spotted stem and pinnately decom- 

 pound leaves ; flowers small, white, in compound umbels ; 

 calyx teeth obsolete, petals white; fruit smooth, ovate, 

 flattened, with prominent, wavy ribs; oil tubes absent. 

 In waste places, Canada to Indiana, California and Mex- 

 ico ; native to Europe. Poisonous. 



Cowbane (Cicuta maculata, L.). A smooth marsh 

 perennial, two to five feet tall, with pinnately compound 



