PLATE 22, 



POVERTY WEED. Iva axillarh, Putsh. 



Other English name : Small-flowered Marsh-elder. 



Native. Perennial. Stems herbaceous, branching, ascending, from 

 tough, woody extensive underground stems or rootstocks, 6 to 12 inches high, 

 very leafy. Whole plant with a rank odour. Leaves thick, obovate to linear- 

 oblong, entire, rough-hairy. The lower ones opposite, the upper alternate. 

 Flower-heads drooping, solitary, on very short pedicels, from the axils of the 

 upper leaves, \ of an inch across, inconspicuous. Seeds (achenes) pear- 

 shaped, slightly flattened, sometimes keeled on the side and a little curved 

 towards the base; colour variable, olive green, yellowish-brown to almost 

 black; surface mealy and dull, | of au inch long. Achenes [Plate 55, fig. 54 

 — natural size and enlarged 4 times] very few, seldom more than one or two 

 in each flower head, and very many heads have none. 



Time of Flowering : June to August; seeds ripe July to September. 



Proi iigatio/i : Mainly by the extensive system of underground stems,, 

 which seud up a great 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. 



Injury : A most persistent perennial, forming large patches. Very ex- 

 haustive of moisture, thus starving crops and rendering the land hard to work. 



Femedy : This has proved a most difficult enemy to dislodge when well 

 established on the rich farms of the West. It requires, as Mr. T. N. Willing 

 says in his Bulletin, "Hints to Grain Growers," Regina, 1905, well directed, 

 persistent effort with sharp implements. The ploughing for summer fallow 

 should be clean and deep, followed by frequent cultivation afterwards with 

 a broad-shared cultivator. The seed of the low growing- Poverty Weed sel- 

 dom occurs in grain or grass seeds in our country, although Prof. Hillman 

 found it in 11 per cent, of samples of alfalfa seed in Nevada. 



The False Ragweed, Iva xanthiifolia, Nutt., a coarse annual with a 

 remarkable superficial resemblance before flowering to the Great Ragweed, is 

 a very common plant by roadsides, along railways and in corrals in Manitoba, 

 where it grows to a height of 6 to 8 feet and produces an enormous quantity 

 of seeds; these seeds [Plate 55, fig. 55 — natural size and enlarged 4 times] are 

 occasionally found among those of grain, grass and alfalfa from the West. 

 They are of the same general shape as those of Poverty Weed, but are only 

 fxi of an inch long, more tapering and less robust, somewhat darker 

 in colour, the surface finely striated lengthwise; when fresh, with a gray 

 mealy covering which partially rubs off and gives them a mottled appearance. 

 The young i)h\iit has the same habit of growth and leaf outline as the Great 

 Ragweed, but can be recognized at once by taking hold of the stem, which 

 in False Ragweed is perfectly smooth, while in the true Ragweed it and the 

 leaves are noticeably rough ; when full grown, the resemblance between the 

 two plants disappears. The False Ragweed bears at the top of the stem a 

 large, loose panicle of dark-coloured flowers, while the Great Ragweed has 

 many of the leaves distinctly three-lobed and the tip of each branch ends 

 with a long rat tail-like spike of male flowers. 



50 



