PLATE 13. 



WHITE COCKLE, Lychnis alba. Mill. 



Other English names. Evening Lychnis, White Campion. 



Other Latin names : Lychnis vespertina, Sib. ; L. dioica, L. ; Silene pra- 

 tensis, Gf/dr. and Gren. 



(Noxious: Dom.) 



Sparingly introduced in Ontario. Biennial or short-lived perennial. 

 Rootstock thick, sending up a few short barren shoots and long decumbent 

 branching flowering stems 1 to 2i feet high. Whole plant rather viscid 

 hairy, not so much so as in the Sticky Cockle, which plant it resembles 

 somewhat, but is wider branching, has many stems, the leaves are larger 

 and the flowers, which are much more numerous, are pure white, with a 

 more conspicuous crown of short white scales around the centre; the male 

 and female flowers are on separate plants. Styles 5, not 3 as in Sticky 

 Cockle, and the capsule has 10 teeth at the top instead of 6 as in that 

 species. When mature, the calyx containing the capsule is in the White 

 Cockle much larger and more swollen; the seeds [Plat© 53, fig. 11 — natural 

 size and enlarged 8 times] are paler gray and rather larger than in Bladder 

 Campion and Sticky Cockle. 



Time of Flowering : June ; seeds ripe in July. 



Propagation : By seeds only. 



Occurrence : Grain crops and meadows. The White Cockle is by no 

 means a common woed in Canada, but has been introduced occasionally with 

 crop seeds imported ffom Europe. In the vicinity of Guelph, it is abund- 

 ant and troiiblesome, and it also occurs in a few other places in western 

 Ontario. 



Injury: Crowding crops; seeds an impurity in grass and clover seeds. 

 This is a very persistent weed. Professor Day, of the Guelph Agricul- 

 tural College, states that the roots are fleshy and hard to kill, unless 

 dragged right up to the surface of the soil. If there is a little earth cover- 

 ing any part of them, they will grow and try to produce seed. Wlien 

 spudded below the surface, they will grow again but do not produce seed that 

 season ; persistent spudding is efPective. 



Remedy : A regular short rotation with frequent introduction of hoed 

 crops. In meadows mow often to prevent seed from forming. 



3.5 



