46 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



on most soils, especially those of a light sandy character. Tillage 

 operations, with surface cultivation and thorough hoeing, must be 

 faithfully practised if it is to be suppressed. 



In the seedling stage (fig. 20) it has a pair of very narrow slender 

 linear cotyledons (about ^ in. in length), which are almost characteristic 

 of the mature plant, for though the true leaves are progressively broader 

 than the cotyledons, they are quite small, elongate oval or narrowly- 

 lanceolate, entire, and very shortly stalked, with chaffy silvery stipules 

 at their base. The flowers are minute and variable in colour — white, 

 greenish, pink or crimson — and clustered in the axils of the leaves 

 almost the whole length of the somewhat reddish slender stems. ' 



Black Bindweed (fig. 19) is an annual of the same family but of quite 

 a different type, for it is a twiner, with rather large heart- or arrow- 

 shaped leaves and slender angular stems. It is a most mischievous weed, 



Fig. 18, — Seedlings of Persicaeia or Redshank (Polygonum Persicaria L.). 

 a, showing cotyledons and first leaves ; b, more advanced stage. Natural size. 



r!esembling Field Convolvulus (Convolvulus arvensis) in the damage it { 



does, twining itself round the cultivated crop, dragging it down, and in | 



general choking it. It may be combated by ensuring pure seeds; by 1 



surface cultivation to encourage the seeds to germinate, and by thorough j' 



and frequent hoeing; by a short rotation with increased root or hoed i 



crops; and by harrowing after harvest to encourage seeds to germinate | 



for subsequent destruction of the seedlings. j' 



As in the case of Knotweed the newly-unfolded cotyledons are long | 



and narrow (1 in. long by | in. broad), but larger and broader than in jr 



Knotweed (fig. 21). The stem below the cotyledons is reddish. The t 



first true leaves, though small, are typical of those of the mature plant — f 



heart- or arrow-head shaped. The growing plant soon begins to elongate, ?■ 



and a little later to branch and twine round the nearest plants ! 



which will support it. The leaves are 1-4 inches long and shortly { 



stalked ; the flowers are very small, greenish- white, and in 4-10-flowered : 



