About Ulmus davidiana Planch.
Ulmus davidiana Planch. is a tree species that strongly resembles the American elm (Ulmus americana), differing only in its smaller mature size. It reaches a maximum height of 15 m (50 ft), with a relatively slender trunk that measures less than 0.3 m (1 ft) in diameter at breast height. This trunk supports a dense canopy that casts heavy shade. Its bark stays smooth for a comparatively long period of time, before developing longitudinal fissures as it ages. The leaves are obovate to obovate-elliptic, and measure less than 10 cm (4 in) long by less than 5 cm (2 in) wide. According to the original protologue description, the leaf petiole is about 10 mm long; the Flora of China gives a petiole length range of 5-10 mm, with an extreme maximum of 17 mm, while Rehder only described the petiole as 'short'. The upper surface of the leaf is rough. The species produces perfect, wind-pollinated, apetalous flowers on second-year shoots in March. These flowers are followed by obovate samarae that measure less than 19 mm (3/4 in) long by less than 14 mm (1/2 in) wide. In cultivation, Hillier & Sons nursery of Winchester, Hampshire briefly propagated and marketed the tree from 1971 to 1977, and only four trees were sold during this period. No cultivars of this taxon are known to exist, and the tree is not known to be in commercial trade outside of the United States.
