The plants generally have a rhizome bearing radical leaves, as in asphodel, rarely a stem with a tuft of leaves as in Aloe, very rarely a tuber (Eriospermum) or bulb (Bowiea).
Introduced by Raleigh in 1610, the cultivation of this important tuber developed with extraordinary Depend- rapidity.
A second edition of the Herbal was published in 1636 by Thomas Johnson, with a different illustration from that given in the first edition, and one which in some respects, as in showing the true nature of the tuber, is superior to the first.
489), has reviewed the tuber-bearing species of Solanum from a systematic point of view as well as from that of geographical distribution.
The germinating spores are not only able to pierce the leaves and stems of the potato plant, and so gain an entry to its interior through the epidermis, but they are also able to pierce the skin of the tuber, especially in young examples.