Bok PRINCIPLES OF BOTANY, ETC. 
send out roots and leaves, and form an entirely new 
plant of the same species. Such plants are called, 
viviparous plants, (vegetabilia vivipara). Several spe- 
cies of garlic, (allium); the Lihum bulbiferum; Poa 
bulbosa and other plants, shew this phenomenon spon- 
taneously. The garden tulip, (Tulipa gesneriana), 
exhibits this curious phenomenon by means of a 
simple manoeuvre of art, if the flower is cut off, 
before impregnation has taken place, and the stem 
with the leaves be allowed to remain, provided it be 
ina shaded spot. Several succulent plants, for in- 
stance, Eucomis punctata, do it when treated in the 
above manner. ‘hus gardeners produce a greater 
number of young plants, by grafting and moculating 
with cions, and by other similar processes. The 
bud of a tree or shrub, when grafted into another 
stock, will there be unfolded, and must indeed be 
regarded as a different plant altogether. It is not 
changed. in its nature, but grows as if placed in the 
earth; the stem only serves to convey the imbibed 
sap to it, which it must digest itself. 
Agricola and Barnes, it appears, were more suc- 
cessful in these operations, for they placed buds di- 
rectly in earth, and produced perfect young plants. 
S297. 
The stem of ligneous plants, we were informed, 
(§ 260), annually adds a new ring of vessels. ‘The 
first and oldest of these circles begin to become lig- 
neous on their sides. The wood has in general, 
when young, a yellowish white colour, which, ac- 
cording to the species of the plants, assumes a darker 
3 hue 
