TUBER. —TUBERCULE. 121 
obtain nourishment for themselves, and in this manner to form 
independent plants. The Potato (fig. 236), and Jerusalem 
Artichoke (jig. 237), are good illustrations of tubers. A case 
was reported in the Gardener’s Chronicle of a Potato plant in 
which the buds in the axils of the true leaves above ground 
Fig. 286. 
Fig. 236, Tubers of the common Potato (Solanum tuberosum). 
showed a tendency to form tubers (fig. 238), by which their 
analogy to stems was also clearly indicated. The stem-like 
nature of the tuber is likewise corroborated by the common 
experience of gardeners, who, by surrounding the lower part 
Pie. 237. Fig. 238. 
Fig. 237. Tubers of the Jerusalem Artichoke (Helianthus tuberosus),—— 
Fig. 238. A monstrous branch or bud of the common Potato. From the 
Gurdener’s Chronicle. 
of the aerial stems of the Potato with earth, convert the 
buried buds (which under usual circumstances would have pro- 
duced ordinary branches) into tubers, and thus increase their 
number. 
The tubercules of certain terrestrial Orchids and other plants 
