A genus of two species, one from southern China, one from eastern North America; hybrids have arisen in cultivation. They are large deciduous trees, glabrous in all parts. Buds alternate, the terminal buds flattened and enclosed by two large smooth scales. The leaves are long-stalked, untoothed and are characteristically emarginate with usually two pairs of lobes, creating a saddle shape; autumn colour is always yellow. The underleaf is glaucous, with a light covering of waxy papillae. Flowers are carried singly at the end of short shoots in late spring; they are erect and tulip-like, but with nine tepals, the outer three reflexed, the inner six incurving. Carpels are densely packed on a spindle-shaped receptacle about as tall as the tepals; the fruit is a brown samara with a long narrow wing and one or two seeds, carried in an erect cone, which breaks up through winter. (Xia, Liu & Nooteboom 2008, Flora of North America).
The leaf shape and brilliant autumn colours make tulip trees endearingly easy to recognise, and the American species is a popular ornamental across the temperate world. The ‘tulip’ flowers are exquisite in detail but are not showy since they are carried high among the expanded foliage and are not produced until the fast-growing tree is in its late teens. Hybrids can flower earlier, and grafted specimens may bloom when quite young. Like magnolias, tulip trees have fleshy, fragile roots, making them tricky to transplant when more than a few years old and militating slightly against their use in public places as tall standards. Again like magnolias, they are long-lived plants relatively free from pests and diseases but are vulnerable even as adults to barking by rabbits (Elwes & Henry 1906–1913). They are best raised from seed, though only a small percentage of these tend to be fertile. The scentless but nectar-rich flowers are typically pollinated by bees but may well have evolved, like Magnolia blooms, to be pollinated by larger beetles (Huang et al. 1999; Moisset 2015). Selections are propagated by grafting, which is best done in March (Bean 1981). The seed can be dried and stored easily for years; it needs about 20 weeks at a temperature below 4°C to stimulate germination (Forest Research 2018).