PLATE 37. 

 FIELD BINDWEED, Convolvulus arvensis, L. 



Other English names : Bindweed, Small Bindweed, European Bind- 

 weed, Small-flowered Morning-glory. 



(Noxious : Dom., N. W.) 



Introduced. Perennial, deep-rooting, with extensive creeping cord-lika 

 fleshy rootstocks; these throw up numerous slender branching and twining 

 smooth stems, which form thick mats on the surface of the land, and twist 

 around any plants growing within reach, using them as supports and chok- 

 ing them out. Leaves about 1 to 1J inches long on slender stalks, ovate or 

 heart-shaped, arrow-shaped at base. Flower-stalks slender, 1 to 2-flowered, 

 about the same length as the leaves, bracted at some distance below the 

 large open funnel-shaped pink flowers, which are over an inch across. Seeds 

 [Plate 56, fig. 72 natural size and enlarged 4 times] rather large, | 

 of an inch, dark brown, pear-shaped ; outer face convex, inner bluntly angled 

 with flat sides. Surface roughened with small tubercles ; basal scar, two 

 smooth pale areas in a depression at the lower end of the inner face. Cap- 

 sules globose, cartilaginous, 2-celled, containing 3 to 4 seeds. Embryo much 

 folded and crumpled in the seed. 



Time of Flowering : From June throughout the summer ; seeds ripe in 

 August. 



Propagation : By seeds and by running rootstocks, every portio'n of 

 which will produce new plants if broken up by the plough. It is notice- 

 able that in many localities, as at Ottawa, this plant produces few seeds. It 

 has, however, everywhere a most persistent habit of growth and deserves 

 perhaps more than any other agricultural pest the appellation of "the worst 

 weed in Canada." 



Occurrence : Although very widespread throughout the Dominion and 

 in restricted localities very troublesome, the Field Bindweed, fortunately, 

 cannot as yet be called a common weed of Canada. 



Injury : Exceedingly hard to eradicate, from its almost incredible per- 

 sistence, owing to the vitality in the fleshy rootstocks. 



Remedy : A short rotation including late sown roots or other, hoed crops, 

 rape being very useful for this purpose. Frequent use of a broad-shared 

 cultivator will destroy new growths and exhaust the vitality of the plants. 

 Great care should always be taken to sow no crop seeds containing those of 

 the Field Bindweed. Applications of salt, lime, or straw, sometimes recom- 

 mended to kill this weed are useless when used in practical quantities. 



72 



