Many species spread by means of a creeping much-branched rootstock, or as in house-leek, by runners which perish after producing a terminal leaf-rosette.
It has a fleshy rootstock, creeping beneath the surface of the soil and sending up luxuriant tufts of narrow, swordshaped leaves, from 4 to 8 ft.
Sometimes there is attached to the rootstock a portion of stem, which is round and not prickly, differing in these respects from that of Smilax officinalis, which is square and prickly.
In some varieties, as the Guayaquil and Mexican, the whole plant, including the rootstock, is pulled up.
The underground stem or rootstock (rhizome) of perennial grasses is usually well developed, and often forms very FIG.
B, C, D, E, enlarged.) branched rootstock from which spring slender aerial shoots which are green, ribbed, and bear at each node a whorl of leaves reduced to a toothed sheath.
2) (P. vulgare) is widely diffused in the British Isles, where it is found on walls, banks, trees, &c.; the creeping, densely-scaly rootstock bears deeply pinnately cut fronds, the fertile ones bearing on the back.
Palustris, is a perennial plant growing to a height of 6 to 18 in., with rootstock creeping, stem clothed with lax spreading hairs, leaves light green, and somewhat shining, buds pink, becoming blue as they expand, and corolla rotate, broad, with retuse lobes and bright blue with a yellow centre.