Page:An introduction to physiological and systematical botany (1st edition).djvu/170

 140 to any that may have existed in the parent plants. How propagation by seed is accomplished will be explained in a future chapter, as well as the causes of some varieties produced by that means.

Mr. Knight, in the Philosophical Transactions for 1805, has shown that buds originate from the alburnum, as might indeed be expected. The trunks and branches of trees, and the knobs of genuine tuberous roots, like the potatoe, are studded with them; in which respect, as Professor Willdenow judiciously observes, Principles of Botany, p. 15, such roots essentially differ from bulbous ones, which last are themselves simple buds, and produce their shoots, as well as their offsets, either from the centre or from the base.

The contents of buds are different, even in different species of the same genus, as Willows. The buds of some produce leaves only, others flowers; while in other species the same bud bears both leaves and flowers. Different causes, depending on the soil or situation, seem in one case to generate leaf-buds, in another flower-buds. Thus the Solandra grandiflora, Tr. of Linn. Soc. v. 6.