Downingia, Clintonia. Campanulaceæ.
Seeds should be sown in mild heat in spring.
Draba, including Petrocallis (Whitlow Grass). Cruciferæ.
The annuals or biennials propagated by seeds sown in spring in the open border. The perennials may be propagated by dividing the crowns.
Dracæna (Dragon-tree). Liliaceæ.
Rarely grown from seed. Layers do not succeed very well. The stems of old plants may be cut up in pieces one or two inches long, and placed at any season in cocoanut fiber or light soil, in the bottom heat of a propagating house. The tops of the plants will also strike as cuttings, and the fleshy base of the stem is sometimes removed and used for propagation. Root-cuttings do well in a moderate heat. (See [Fig. 47].)
Dracocephalum (Dragon’s Head). Labiatæ.
The annuals are grown from seeds, sown in the open in spring. Perennials are increased by dividing the roots, or by cuttings of the young shoots in spring.
Dracontium. See [Amorphophallus].