Propagation.—Tulips are usually increased by offsets, which most varieties produce in fairly large numbers. These are taken off and sown in drills, like seed. They are usually strong enough to flower the third year from this sowing. Some varieties produce offsets sparingly and must be increased by seed—a slow and uncertain method. New varieties are raised from seed. (The colour variation in the flowers of seedlings is discussed above.) Seeds are sown in boxes or cold frames, in light sandy soil, and the young plants are allowed to remain undisturbed until the second year. They are then lifted and treated like offsets, being sown thinly in beds out of doors. They usually flower in about the seventh year. The soil in which tulips are propagated should be sandy, free working and thoroughly drained. A warm shel tered position is a necessity.
Cultivation.—Planting is best effected during September, October and early November. It is usual thoroughly to dig and manure the ground in preparation. Holes 6 to 8 in. apart and 5 in.
deep are then made with a dibbler. Sometimes a little loose earth or sand is put in to the depth of about 1 in., and the bulbs laid singly thereon, the holes being closed by the dibbler and the whole raked over. Valuable varieties are planted at about the same depth, with a trowel, a little sand being placed around them. The early flowering varieties should be potted as early in Sep tember as practicable, later batches for succession being potted during October. Pots 5 and 6 in. in diameter are the most con venient for the early-flowering kinds, but seven-inch pots give the better results for the "Darwin" section of the May-flowering kinds which are now used for gentle forcing. Five or six bulbs are put in each pot and the tops should be covered with half an inch of soil and half an inch left for water. The soil should be a light and fairly rich compost, comprising about 2 parts loam, part decayed manure or horse droppings that have been thoroughly sweetened, i part leaf mould and half a part of sand. Pot firmly, and plunge the pots in several inches of ashes out of doors, to protect the bulbs from frost. As soon as growth commences at the top and a fair amount of roots are formed they may be intro duced into gentle heat, in batches according to the need and amount of stock available. For market a slightly different method is adopted. The bulbs are placed in long shallow boxes, plunged in soil or ashes in semi-darkness, and are afterwards transferred to benches in the forcing houses where they flower. Bulbs which
have been forced are of no further value for that particular purpose. If planted in borders and shrubberies, however, they will continue to bear fairly good blossoms in the open air for several seasons.
Varieties.—Early Single (or Double) Flowering Kinds are the most useful for bedding and pot culture.
Late Single Flowering Kinds.—These are all tall-growing hardy kinds suitable for growing in herbaceous borders where they can be left undisturbed; or for producing massed colour effects in flower beds. They include (a) "Cottage" or May-flowering tulips, so named because they were discovered in the gardens of old cot tages, mansions, abbeys and monasteries, throughout England, Scotland, Ireland, Belgium and France; (b) "Darwin" tulips which are a distinct race, having a wide range of large self coloured flowers, but no yellows.
Parrot Tulips.—This late flowering group is supposed to be de rived from the curious green and yellow striped T. viridiflora. The flowers are mostly heavy and drooping, petals brightly coloured, the edges being curiously notched and wavy.
(Liriodendron Tulipifera), a North American forest tree closely allied to the magnolia (q.v.), called also yel low poplar and whitewood, native from Rhode Island and Ver mont west to Michigan and south to Florida and Louisiana. It is one of the handsomest trees of eastern North America, with a straight trunk sometimes 190 ft. high and to ft. in diameter, deeply furrowed bark, and large smooth leaves, truncate or broadly notched at the apex and two- to four-lobed at the base. The conspicuous tulip-like flowers, about 2 in. deep, yellowish green on the outside and orange-coloured within, are followed by a dry cone-shaped fruit, from which at maturity the numerous seeds hang suspended on short slender stalks. From Virginia to the lower Ohio valley and southward, where the tulip-tree attains its maximum size and abundance, it is a valuable timber tree, furnish ing the light, fine-grained lumber known as yellow poplar, white wood or tulipwood. In 1925 the total cut of yellow poplar lumber in the United States amounted to 375,662,000 bd.ft., valued at the mill at $16,318,857. The largest and oldest tulip-tree in the eastern States is at Annapolis, Md.
The tulip-tree is widely planted for ornament, and, with pro tection when young, thrives in England, sometimes attaining a height of 8o ft.