Hamamelis
Sp. Pl. 1: 124. 175.
Gen. Pl. ed. 5, 59. 1754.
Shrubs or small trees, suckering or bearing stolons, not aromatic and resinous; twigs, young leaves, and flower buds stellate-pubescent. Bark gray to gray-brown, smooth or slightly roughened. Dormant buds naked, stellate-pubescent; terminal bud and 1 of each pair of lateral buds stalked, with 2 subtending scales. Leaves short-petiolate. Leaf blade broadly elliptic to obovate, pinnately veined, base oblique, cuneate, margins repand to sinuate, apex rounded to acute or short-acuminate. Inflorescences axillary, (1-)3(-5)-flowered, stalked clusters. Flowers bisexual, appearing before or with leaves; calyx lobes 4, reflexed, adnate to ovary; petals 4, yellow or orange to deep red, liguliform, circinnate in bud, notched or truncate, sometimes pointed; stamens 4, very short within cup; anthers introrse, dehiscing by 2 valves hinged adaxially on connective; staminodes 4, opposite petals, bearing nectar; styles 2, subulate, spreading to recurved. Capsules solitary or 2-3 together, fused with persistent tubular calyx, stylar beaks very short, loculicidally 2-valved, woody, appressed stellate-pubescent, explosively dehiscent. Seeds 2 per capsule, black, glossy, bony, not winged. x = 12.
Distribution
Temperate regions, e North America, e Asia.
Discussion
Species 4 (2 in the flora).
In Hamamelis, the explosively dehiscent capsules may eject the seeds to 10 m. The Japanese species H. japonica Siebold & Zuccarini, with reddish to yellow flowers, suggests an affinity with H. vernalis. Both Asian species, H. japonica and H. mollis Oliver of China, and the hybrid H. ×intermedia Rehder (= H. japonica × H. mollis), with a number of cultivars, are widely cultivated.
Selected References
Lower Taxa
Key
| 1 | Flowers appearing in autumn, faintly fragrant; petals pale to deep yellow, rarely reddish, 10–20 mm; staminodes conspicuously dilated; leaves not persistent in winter, blade broad-elliptic to nearly rounded or obovate, base strongly oblique and rounded, sometimes somewhat cuneate, surfaces abaxially pale green, not glaucous; plants suckering. | Hamamelis virginiana |
| 1 | Flowers appearing in winter, distinctly fragrant; petals reddish or deep red to orange, occasionally yellow, 7–10 mm; staminodes not dilated or slightly so; leaves often persistent in winter, blade mostly obovate, base narrowed to somewhat cuneate, rarely rounded, weakly oblique, surfaces often abaxially glaucous; plants stoloniferous | Hamamelis vernalis |