36 
PRINCIPIA 
perpetuated by their bulbs or ground buds, as well as by seeds; 
they are therefore improperly called roots, being only the hy- 
bernacle of the future shoot. Bulbs are of the following sorts: 
1st. A scaly bulb, (bulbus squamosus) consisting of scales 
laid over each other like tiles, as in the lily . 
2d. A solid bulb, (solidus) consisting of a solid substance, 
as in tulips. 
3d. A coated bulb , (tunicatus) consisting of many coats 
infolding each other, as in onions. 
4th. A stern bulb,* (caulinus) which is produced not only 
from the sides of the principal bulb, called a sucker, or offset; 
but from other parts of the stem; as in crow, or wild garlic , 
and in some species of onion and lily (hence called bulbife- 
rous),; in the onion they are produced at the origin of the 
umbel of flowers, instead of seeds. 
II. A Bud (gemma) is the embryo of the plant seated upon 
the stem and branches, covered with scales; and if a leaf bud, 
it consists of radicles which descend along the bark into the 
earth; and is also furnished with umbilical vessels, which are in¬ 
serted into the alburnum, and form a part of it, and descending 
into the earth, supply it with its first nutrition. (Phytologia). < 
In general there are three sorts of buds :—1st. that containing 
the flower only, as in poplar, ash, &c. where the leaf-buds and 
flower-buds are distinct:—2d. that containing the leaves only, 
as in birch, hazel , &c.:—and 3d. that containing both flower 
and leaves, as in the generality of plants ; and these last some¬ 
times contain leaves and male flowers, sometimes leaves and 
female flowers, sometimes leaves and monoclinian flowers. 
Every flower-bud dies when it hath perfected its seed like an 
annual plant; and it is said to be the same with respect to 
flowering bulbs, they also die after having flowered a few times 
and perfected their seed, and produced other smaller bulbs to 
perpetuate their progeny. 
* Other bulbs, besides those here mentioned, were formerly enumerated, (viz.) 
the jointed bulb, as in moschatel ; and the double bulb, as in orchis . 
