TUBERS—BULBS. 59 
Galanga). When besides a central rootstock a secondary or 
lateral rootstock is present, both of them occur in commerce 
(Zingiber), although rarely as two separate commercial varie- 
ties (Curcuma rotunda and longa, the latter of which forms the 
secondary, the former the primary rootstock). Of Zedoaria 
only the primary rootstock is in use. 
The roots of a rhizome (either alone or connected with the 
latter) form the sarsaparillas of commerce. ’ 
Branched rootstocks (many-headed) are not of rare occur- 
rence, and then possess many buds (Galanga’). 
The rhizomes serve also as receptacles for reserve substances, 
and are nearly always densely filled with reserve nutritive sub- 
stances (starch, etc.). 
Still more pronounced receptacles for reserve materials are: 
The Tubers (7udera).—These are underground portions of 
the stem, or ramifications of the roots of phenogams (Orchis), 
which are so thickened that their diameter approximates their 
development in length or exceeds it. This growth in thickness 
stands in connection with the periodical accumulation of 
constructive materials, especially starch. They present a fleshy 
structure, which after drying is mealy and horn-like, not woody, 
as, ¢. g., Tuber Aconiti, Tuber Jalape and Tuber Salep. 
Tuber Chine deviates from the ordinary type of the tuber by its 
often very considerable length and strongly developed vascular 
bundles. * 
It is, however, not only the stem which participates in the 
formation of underground organs, occasionally it is also leaves 
(under-leaves) which form these to a predominating extent, as, 
for example, in the case of the bulbs. 
Bulbs (Buldi).—These are fleshy, thickened under-leayes or 
parts of leaves, serving for the storage of starch and other sub- 
stances serving as nourishment, which, similarly to buds, are 
severally inwrapped, scale-like, about a very short axis pro- — 
‘Compare A. Meyer, Archiv der Pharm., 218 (1881), 280, with cs 
illustrations, . 
* A. Meyer, loc. cit. 425, with iitiateatiods, ae 
* Compare A. Meyer, Archiv der Pharm., 218 aan ae 
