Forsythia ovata Nakai
A deciduous shrub normally not more than 5 ft in height; young shoots glabrous, terete, pale greyish brown, sprinkled with small dark lenticels; pith lamellate. Leaves roundish ovate, with a short slender point and a rounded or slightly heart-shaped base, coarsely toothed to nearly entire, 11⁄2 to 31⁄2 in. long, 11⁄4 to 21⁄2 in. wide, glabrous on both surfaces; stalk 1⁄4 to 1⁄2 in. long. Flowers opening in March, bright yellow, 5⁄8 to 3⁄4 in. wide; calyx-lobes broadly ovate, shorter than or equalling the corolla-tube. The flowers are usually solitary, two at each joint. Fruits 1⁄2 in. long, ovoid, but drawn out to a slender apex before splitting into two parts. Bot. Mag., t. 9437.
Native of Korea; introduced by Wilson in 1918 under his number 10456. It is usually in bloom in early March if the weather is mild, and is quite an attractive shrub, although scarcely equal to the later-flowering kinds in beauty, its flowers being smaller and not making such a display. Its habit is dwarf and compact; an old plant at Kew has made a densely and intricately branched dome 7 ft in diameter and 41⁄2 ft high, with a few shoots rising up to 1 ft above the general top. Some plants distributed in Britain in the 1950s under the name F. ovata bore no resemblance to this species; they were perhaps the same as the “F. ovata robusta” of continental nurseries.
The clone ‘Tetragold’ is a colchicine-induced tetraploid of F. ovata raised in Holland and distributed to the trade in 1963 (Dendroflora, Vol. 1, pp. 35, 38).
F. japonica Mak. – A spreading shrub with glabrous, terete branchlets; pith lamellate. Leaves ovate or broadly ovate, 3 to 43⁄4 in. long, short acuminate at the apex, toothed or more usually entire, glabrous above, downy on the veins beneath; leaf-stalk downy. Flowers bright yellow, solitary, about 1 in. across. Calyx about half as long as corolla-tube. Lobes of corolla narrow-oblong. Native of Japan, rare in the wild and not common in gardens. It is very closely allied to F. ovata, and it is doubtful whether the two are specifically distinct. The chief difference is that in F. japonica the leaves and leaf-stalks are downy beneath, but glabrous in F. ovata (and the corolla-lobes are slightly longer and narrower). It flowers about four weeks later. The following variety of F. japonica is even closer to F. ovata:
var. saxatilis Nakai F. saxatilis (Nakai) Nakai – Described as only 8 in. high in the wild, but reaching about 3 ft in cultivation. It is more likely to be confused with F. ovata than with typical F. japonica. It differs from the former in its smaller leaves, 7⁄8 to 21⁄2 in. long, 7⁄16 to 13⁄16 in. wide with finely and minutely saw-toothed margins and with down in the axils of the veins beneath and on the leaf-stalks. On the plant at Kew, received from the Arnold Arboretum, the leaves are larger than on wild plants (31⁄4 to 4 in. long, 13⁄4 to 2 in. wide) and sparsely downy to almost glabrous on the midrib below. The var. saxatilis is a native of Korea.
If F. japonica and F. ovata were to be united, as they probably should be, the correct name for the species would be F. japonica.
F. ‘Arnold Dwarf’. – A hybrid between some form of F. × intermedia and F. japonica var. saxatilis, raised in the Arnold Arboretum in 1941. It makes a low, self-layering shrub of indefinite width, with ovate, bright green leaves 1 to 2 in. long, strongly toothed. It rarely produces its pale yellow flowers but has some value as ground cover.