Clethra is one of two genera in the family Clethraceae (the other being Purdiaea). The species may be evergreen or deciduous, and all bear flowers in clusters (inflorescences), which correspond to racemes or panicles. The flowers are quite small, white or pinkish, and each bear 5 free petals, numerous stamens, and a 3-chambered seed capsule. The leaves, simple, ovate, and alternate or opposite, bear characteristic stellate hairs. The seeds are very small and numerous.[7]
Clethra species are native to a variety of habitats, including swamps, woodland, and rocky sites[8] from temperate to tropical climates in eastern and southeastern Asia, Malesia, North and South America, and one species (C. arborea) on the island of Madeira.[2]
The number of species accepted varies between different authorities depending on taxonomic interpretation, but with a recent trend to reduce the number recognised as distinct. The recent Flora of China (series)[10] has cut the number accepted for China from 35 to seven species, and the US Department of Agriculture[11] recognises only two in the United States, synonymisingC. tomentosa with C. alnifolia. The following are accepted by the World Checklist of Selected Plant Families:[2]
Guía de Arboles de Bolivia by Killeen, T.J.; García E., E.; & Beck, S.G. (eds.). Bolivia: Herbario Nacional de Bolivia and Missouri Botanical Garden. 1993. p.214.
Angiosperm Fruits and Seeds from the Middle Miocene of Jutland (Denmark)
by Else Marie Friis, The Royal Danish Academy of Sciences and Letters 24:3, 1985
USDA, NRCS (n.d.). "Clethra". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 11 November 2024.
