40 HOW PLANTS GROW. 
rests on the soil; as in the Houseleek (Fig. 65), where one plant will soon produce 
a cluster of young plants or offsets all around it. 
103. A Rootstock is any kind of horizontal stem or branch growing under ground. 
Slender rootstocks occur in the subterranean part of the suckers of Roses, of Pepper- 
mint, or of Canada Thistle, and of Quick-Grass or Couch-Grass 
(Fig. 75), which spreads so widely, and becomes so troublesome 
to farmers. They are well distinguished from roots by the 
leaves which they bear at every joint, in the form of scales, and 
by the buds which they produce, one in the axil of each scale. 
These buds, which are very tenacious of life, are what renders 
the plant so exceedingly difficult to destroy. For ploughing and 
hoeing only cut up the rootstock into pieces, each with a tuft of 
roots ready formed and with a bud to each joint, all the more 
ready to grow for the division. So that the attempt to destroy 
Quick-Grass by cut- 
ting it up by the 
roots (as these shoots 
: are called), unless the 
F Hootstoglt of: Quuictt-sranss . pieces are carefully 
taken out of the soil, is apt to produce many active plants in place of one. 
104. Thickened or fleshy rootstocks, such as those of Solomon’s Seal (Fig. 63) 
and Iris (Fig. 64), have already been illustrated (76). 
105. A Tuber is a rootstock thickened at the end, as already explained in the 
Potato and Ground Artichoke (74, 75, Fig. 59, 60). The eyes of a tuber are lively 
buds, well supplied with nourishment for their growth. 
106. A Corm or Solid Bulb, as of Gladiolus and Crocus 
(Fig. 76), is a sort of rounded tuber. If well covered with 
thick scales it would become 3 
107. A Bulb. This is a (mostly subterranean) stem, so 
short as to be only a flat plate, producing roots from its lower 
surface and above covered with thickened scales, — as was 
fully explained in the last section (77). aed 
108. Bulbs are scaly, as in the Lily (Fig. 66), when the Corm.of Crocns, swithibuts. 
scales are narrow ; or coated, as an onion, when the scales enwrap each other, and 
form coats. 
