SECTION C] STEMS. 43 



they grow ; from their consistiug of a succession of joints ; and from tlie 

 feaves which they bear on eacli node, in the form of small scales, just like 

 the lowest ones on tlie upright stem next the ground. Tlicy also pro- 

 duce buds in the axils of these scales, showing tlie scales to be leaves ; 

 whereas real roots l)car neither leaves nor axillary buds. Placed as 

 they are in the damp and dark soil, such stems natui-ally produce roots, 

 just as the creeping stem does wliere it lies on the surface of the 

 ground. 



105. It is easy to see M'liy plants Avitli these running rootstocks take 

 such rapid and wide possession of the soil, and why tliey are so iiard to 

 get rid of. They are always perennials ; the subterranean shoots live over 

 the first winter, if not longer, aud are provided with vigorous buds at every 

 joint. Some of these buds grow in spring into upright stems, bearing 

 foliage, to elaborate nourishment, and at length produce blossoms for re. 

 production by seed ; while many others, fed by nour- 

 ishment supplied from above, form a new generation 

 of subterranean shoots ; and this is I'cpeated over aud 

 over in the course of the season or in succeeding 

 years. IMeanwhile, as the subterranean shoots in- 

 crease ill number, the older ones, connecting the suc- 

 cessive growths, die off year by year, liberating the 

 already rooted side-branches as so many separate plants ; and so on indefi- 

 nitely. Cutting these running rootstocks into pieces, therefore, by the hoe 

 or the plough, far from destroying the plant, only accelerates the propaga- 

 tion ; it converts one many-branched plant into a great number of separate 

 individuals. Cutting into pieces only multiplies the pest ; for each piece 

 (Fig. 9S) is already a plantlet, with its roots and with a bud in the axil of 

 its scale-like leaf (cither latent or apparent), and with prepared nourishment 

 enough to develop this bud into a leafy stem ; and so a single plant is all the 

 more speedily converted into a multitude. Whereas, when the subterra- 

 nean parts are only roots, cutting away the stem completely destroys 

 the plant, excejit in the rather rare cases where the root freely produces 

 adventitious buds. 



106. Rootstocks are more commonly thickened by the storing up of 

 considerable nourishing matter in their tissue. The common species of 

 Iris (Fig. 164) in the gardens have stout rootstocks, which arc only partly 

 covered by the soil, and Avhich bear foliage-leaves instead of mere scales, 

 closely covering the upper part, while the lower produces roots. As the 

 leaves die, year by year, and decay, a scar left in the form of a ring marks 

 the place where each leaf v/as attached, that is, marks so many nodes, 

 separated by very short internodos. 



107. Some rootstocks are marked with large round scars of a different 



Fio. 98. A piece of tlie running rootstock of the Peppermint, witli its node oi 

 joint, and an axillary bud ready to grow. 



