* 
THE ROOT. 37 
economy of Poa bulbosa is curious in this respect.—* This 
grass is peculiarly fitted to inhabit dry sandy ground. The 
bulbs grow in clusters, resembling little onions, and during 
most part of summer remain inactive, blown about at ran- 
dom. With the autumnal rains they vegetate, fix them- 
selves by long downy radicles, then produce thick tufts of 
leaves (a grateful spring food for cattle); and in April or 
. May they flower, having in thé meanwhile formed young 
_ bulbs, which, as soon as the herbage withers, are dispersed 
like their predecessors.” _—English Botany. 
107. The bulb is sometimes simple, consisting of one bud, 
asin the Tulip or in the Squill; in other cases several small 
bulbs are united together, as in Garlic (Allium sativum). 
108. The bulb is found chiefly in monocotyledonous 
plants. 
109. The tuber with eyes (buds) and bulb with the inte- 
rior bud, must not be confounded with the tubercles found — 
_mere reservoirs of nourishment. Some plants, which in or- 
_dinary situations, have no bulb or tuber, acquire one, as a 
storehouse, when they are in a dry situation, or one where 
their supplies of moisture are scanty and irregular ; as Alo- 
pecurus geniculatus, the roots of which become bulbous, and 
_Phleum pratense, in which the roots become swelled, and 
very succulent: the plant is then termed Phleum nodosum. 
110. GranuLatep Root. This root has numerous 
small tubercles capable of reproducing the plant, but con- 
taining little nutritious matter: White Saxifrage (Sazifraga — 
granulata). ae 
term is applied with more propriety to those having a sex 
ed appearance, but without tubers. 
“in the roots of some plants, as the Dropwort, which are — ee 
111. This is sometimes called an articulated root, but this | 
112. Fibrous and fusiform poold siviceniealin sale ne ee i 
some tap-roots are ——— as thie Carrot ; and a bow eee 
