148 FARM WEEDS OF CANADA 



TRIBE HELIANTHEAE 

 POVERTY WEED (Iva axillaris Pursh.) 



M 



Other English name: Small-flowered Marsh-elder. 



Native. Perennial. Whole plant with a rank odour. 

 Stems herbaceous, branching, nearly erect, from tough, woody, 

 extensive rootstocks, 6 to 12 inches high, very leafy. Leaves 

 thick, obovate to linear-oblong, without teeth or divisions, 

 rough-hairy; the lower ones opposite, the upper alternate. 

 Flower heads drooping, solitary, on short footstalks, from the 

 axils of the upper leaves, 1/6 of an inch across, inconspicuous. 



The seed (Plate 75, fig. 77) is 1/8 of an inch long; colour 

 variable, olive-green, yellowish-brown to almost black; surface 

 mealy and dull; pear-shaped, slightly flattened t sometimes 

 keeled on the side and a little curved toward the base. There 

 are seldom more than one or two seeds in each flower head, 

 and many heads have none. 



Time of flowering: June to August; seeds ripe July to 

 September. 



Propagation : Mainly by the extensive, underground stems, 

 which send up many flowering, leafy shoots. 



Occurrence: In grain fields and pastures from Manitoba 

 to the interior of British Columbia, thriving in all soils but 

 occurring generally on land where there is some alkali. The seed 

 of Poverty Weed seldom occurs in grain or grass seeds. 



Injury: A persistent perennial, forming large patches. 

 Exhaustive of moisture, thus starving crops and rendering the 

 land hard to work. 



Remedy: This is a difficult enemy to dislodge when well 

 established on the rich soils of the West. It requires well directed, 

 persistent effort, with sharp implements. Plowing for summer- 

 fallow should be clean and deep, followed by frequent cultivation 

 with a broad-shared cultivator. 



