PBOPAGATIOK BY EOOT-CUTTIifGS. 185 



doubt all may be propagated by root-cuttings by varying 

 the treatment — some requiring more time and a higher 

 temperature than others in order to secure the production 

 of buds. I now refer to the true roots, not to what are 

 called subterranean stems and branches, which are quite 

 distinct productions from roots, as the former are similar 

 in structure to the aerial stems and branches of the plants 

 that produce them, having joints or nodes at which there 

 is either a single bud or a concentration of a number of 

 buds, as may be seen in such genera of plants as the 

 Calycanthus, Neviusia, and such species as Eamanas Eose 

 (Rosa rugosa), the Smooth Sumach {Rhus glabra), and 

 various kinds of herbaceous plants, like the Canada 

 Thistle, Toad-flax, some of the species of Phlox, Spircea, 

 Fachysandra, and others, all of which produce subter- 

 ranean branches, in addition to their true roots. Fur- 

 thermore, true roots always originate in the form of 

 minute, tapering rootlets, enlarging with age, while the 

 subterranean branch starts from a bud on the main stem, 

 with nearly, or quite, as great a diameter as it will ever 

 acquire, with a tip not pointed, but rather blunt, and 

 often thicker than the part behind, and if it meets no 

 obstacle in its lateral growth, the end will either come to 

 the surface and produce an upright stem, and separate 

 plant, as usually found about old clumps of the plants 

 named, or they terminate in a tuber, as seen in the com- 

 mon Potato, Jerusalem Artichoke, Tuberous-rooted Scir- 

 pus (Chufa), etc. If the terminal bud on these subter- 

 ranean branches is destroyed, the next below will pro- 

 duce a shoot, and this may be repeated until the entire 

 number are forced into growth, as is well known to every 

 farmer who has ever tried to kill out Canada Thistles. 



The roots of the Easpberry and Blackberry, although 

 often referred to as subterranean stems or branches, have 

 really nothing in common with these productions, as they 

 do not show any such system of nodes and intemodes. 



