Spiræa venusta (Ulmaria rubra var. venusta).—Height, 4 feet; second week of July; flowers, small, bright pink, borne profusely in large panicles. †
Statice latifolia.—Height, 1-1/2 feet; first week of July; flowers, small, blue, borne very profusely in loose panicles. Very effective in the border.
Thalictrum aquilegifolium.—Height, 4 to 5 feet; fourth week of June; flowers, small, white to purplish, very numerous and borne in large panicles.
Trollius Europæs.—Height, 1-1/2 to 2 feet; fourth week of May; flowers, large, bright yellow, continuing a long time.
(See the particular culture of the different kinds in Chapter VIII; and instructions for forcing on *p. 345.)
It is customary to write of bulbs and tubers together, because the tops and flowers of all the bulbous and tuberous plants spring from large reservoirs of stored food, giving rise to similar methods of culture and of storage.
Structurally, the bulb is very different from the tuber, however. A bulb is practically a large dormant bud, the scales representing the leaves, and the embryo stem lying in the center. Bulbs are condensed plants in storage. The tuber, on the other hand, is a solid body, with buds arising from it. Some tubers represent thickened stems, as the Irish potato, and some thickened roots, as probably the sweet-potato, and some both stem and root, as the turnip, parsnip, and beet. Some tubers are very bulb-like in appearance, as the corms of crocus and gladiolus.
Using the word “bulb” in the gardener’s sense to include all these plants as a cultural group, we may throw them into two classes: the hardy kinds, to be planted in fall; and the tender kinds, to be planted in spring.