58 MORPHOLOGY, 
surface of the ground or at a slight depth, and develop hori- 
zontally, often to a considerable length. They possess under- 
leaves, at least in a rudimentary state, often contain chlorophyll, 
and inclose a clearly defined medulla. At some distance from 
the point of origin, the runners are able to develop roots and 
sprigs of foliage; if their connection with the mother plant is 
subsequently severed, they develop new individuals. Radix 
Glycyrrhize and Rad. Saponarie consist to a large extent of 
runners. 
The typical form of stolon is shown very nicely in the so-called — 
Rhizoma Caricis (Carex arenaria Lin.). The sheath-like under- 
leaves here surround the nodes, which are provided with root- 
bundles. Rhizoma Graminis (Triticum repens Lin.) may also be 
classed with the stolons. 
The runners are botanically connected with the creeping or 
repent and decumbent stems. 
Of the underground stem formations which bear under-leaves 
there are furthermore to be mentioned: the Rootstocks or 
Rhizomes (Rhizomata'). These are perennial stems or 
branches of vascular cryptogams and phenogams, growing half 
or entirely under the surface of the ground, which are provided 
with the rudiments of leaves, the remnants of leaf-sheaths or 
leaf-nodes, and send out roots (secondary roots). We also re 
tain the name rhizome for those cases where the roots (secondary 
roots) are collected with it, or even when these preponderate, as 
with Valeriana. Radix Sarsaparille alone forms an exception; 
_ for although its rhizome occurs in part in commerce, it is never- 
theless inadmissible for medicinal use. 
The rhizome is provided at its apex with a bud, and annually 
develops new, ascending, herbaceous stems (leaves). 
The peculiarity of the rootstock and the bulb, so definitely 
characterized by nature in opposition to the root, had already 
been rendered prominent by the Greek naturalist Theophrastos * 
(371 to 286 B.c.), Las 
For the most part the rootstock alone is collected (Jris, 
1“Pil@ua root, stem. eta eg pee 
_ * Compare Jessen, ‘* Botanik der Gegenwart und Vorzeit,” 1864, 26. 
t 
