246 



REPORT ON THE 



vertically for some little distance without branching, and then giving off short 

 nearly horizontal branches with few root-hairs (except in P. Auricula in which, 

 in some cases at least, the roots are covered with a velvety coat of hairs. Such 

 roots are not surface-feeders, but are capable of penetrating to a considerable 

 depth in search of food, while their succulent habit and reserve store of water 

 obviate the necessity for that dense network of fibrous roots that other species 

 present. Primula rosea (tig. 17, p. 244), P. Kaufmanniana, P. involucrata, 

 and Cortusa Matthioli, afford instances of this densely matted and com- 

 paratively superficial root development. They have few if any large root or 

 conduit fibres ; but, on the contrary, an intricate mass of fine fibrous roots, 

 penetrating in every direction, and availing themselves, as it were, of every 

 scrap of soil within reach. Surely we have here an indication of the necessity 

 in cultivation of supplying these plants with ample depth and breadth of 

 light, rich, moist, not to say wet soil. The utility of a mulch in hot 

 dry weather is also indicated as a means of preventing the drying up of the 

 surface roots. 



In some of the Androsaces we find provision for keeping the roots moist 

 and free from the risk of drought. In seedling plants of A. elongata, for 

 instance, the caulicle is very long and the slender radicle descends vertically 

 for a long distance without branching, and then gives off near its tip a leash 

 of muoh branched fine filaments (fig. 13, p. 242). 



In Soldanella we have a tuft of rather thiok fibres, which descend vertically 

 into the soil, and are unbranched till near the points, where they give off 

 numerous relatively short horizontal fibres. 



STORAGE AND REST. 



In perennials we have specially to consider the arrangements for storage 

 of food in convenient places for use when required, and the modifications of 

 structure associated with the periodic alternations of active growth and relative 

 rest. Of a Primrose, whether "by a river's brim," or elsewhere, whether a 

 yellow Primrose or one of other hue, it may be said that at one season its 

 constant care is to increase its store, while at another its aim is to make all 

 snug for winter. Of course the Primrose is not peculiar in these matters, but 

 we may perchance profit somewhat if we make use of it as an illustration of 

 general application. 



THE ROOTSTOCK. 



The body which emits roots on the one side or beneath and throws up 

 leaves and flowers on the other is the <£ rhizome," or rootstock. It is usually 

 subterranean, and so gets called a root, but inasmuch as it produces leaves, 

 buds, and offsets, and has the internal structure of a stem, botanists will not 

 admit its claim to be considered a root, for a root, under ordinary circum- 

 stances (exceptis prceter •missis), does none of these things. It is a development 

 of the plumule or of the caulicle, or of both together. Usually it is more or 

 less horizontal in its direction, as in the Primrose, in other cases it is vertical, 

 as in the Auricula, where it thrusts itself above ground, and gives off buds or 

 offsets in such a way that no one can mistake it for a root. Horizontal or 

 erect, it throws down feeding-roots into the soil, and these roots are usually 

 fleshy, serving, indeed, not only as feeders, but as storeplaces as well, thus 

 sharing the office of the stock itself. At the free end of the stock is a bud, or 



