116 A COMPENDIUM OF 
TUBERA ET BULBI., TUBERS AND 
BULBS. 
Tubers and bulbs.—The first is a fleshy un- 
derground root, with many branches, bearing 
upon its surface rudimentary stems or leaf 
buds, as the potato, These buds are commonly 
known as eyes. The jalap and aconite are also 
tubers, but are totally unlike the much-esteemed 
potato. The bulbs are another class of roots, 
termed subterranean stems, which are covered 
by segments, scientifically known as leaves, or 
bases of leaves, which are arranged in concen- 
tric layers, as in the onion, and send downward 
into the earth a number of small rootlets. 
These, however, would be inadequate to hold 
erect the plant if not aided by the bulb, which 
is either partly or wholly beneath the earth. 
In the bulbs the leaves are usually broad, and 
the seed has but one cotyledon. The corm differs 
from the tuber and bulb by the absence of all 
leafy structure, asin the colchicum. The char- 
acteristics of the above mentioned will be spoken 
of under their own proper heads. 
