262 PROPAGATION OF RUMEX ACETOSELLA L. 



This development may be going on through a great part of the 



year 







flowers have done their respective work of fertilising and seed- 

 bearing. A plant now in ripe fruit, in the month of July, has the 

 tips of its rhizome-branches showing fresh vigour, swelling slightly 

 towards their acute greenish-white point, and leaving behind them, as 

 they advance, a part clothed with fresh root-hairs. This new rhizome 

 is very attenuate at first, scarcely thicker than a stout cotton thread; 

 it is strong enough, however, to support a weight of 2 oz. or 3 oz., 

 and in the lapse of time becomes tough and wiry, and is to a certain 

 extent elastic. It increases, too, in thickness, like a tree-root, 

 which it much resembles after a year or two, and may sometimes 

 reach a diameter of J in. 



Now for the reproductiveness of the plant. From the horizontal 

 rhizome numerous subsimple root-fibres descend, and from any of 

 these nodes a sobole or underground shoot may start, which at 

 once curves upwards, and on reaching the surface forms a fresh 

 plant, which in its second year can throw up a flowering branch. 

 These soboles are white, fleshy and brittle, and often thicker than 

 the rhizome from which they spring ; they become pink as they 

 approach the surface, and develop a small rosette of leaves the first 

 year. They are not produced usually with any regularity, but are 



un 



l£ in. of rhizome. Since any fragment of the rhizome may produce 



one or more fresh plants, and since several usually radiate in 



different directions from each centre and branch more or less freely, 



a single plant may become in the course of a year the parent of a 



very numerous family ; and in poor, sandy soil, in which, because 



of its poverty, there is not much competition, a perfect network of 



tough rhizomes is found to occupy the surface of the ground where 

 it is growing. 



The character on which I have been dwelling is not a common 

 one in the British Flora, at least to this extent. Rumex Acetoselta 

 spreads horizontally, and, when found ascending perpendicularly, 

 it is due to a piece having been buried accidentally, or dug in for 

 the purpose of destroying it; a depth of 2 ft. is supposed, perhaps 

 rightly, to be fatal to it. In these points it differs from Convolvulus 

 arventis, which naturally comes up in a sinuous way, from a con- 

 siderable depth, perpendicularly; its rootstock- branches scarcely 

 spreading at all. Cirsium arvense is a better parallel, its rootstock 

 advancing in horizontal sinuosities; but this does not branch 

 freely, and its powers of reproduction are quite limited in com- 

 parison. Of other rhizomatous plants, some of the Mentha, Carices 

 and Qrammm may be compared, and Hydrocotyle vulgaris; but 

 I doubt if any British plant can be found to rival the Rumex 



n rhizomatous propagation, unless perhaps Carex armaria is an 

 nstance. 



