Taxodium Rich. (1810), in the Cupressaceae (formerly separated in Taxodiaceae), is a genus of 1 species, T. distichum (L.) Rich., the bald or swamp cypress, from southeastern North America, Mexico, and Guatemala. The 3 varieties have been considered distinct species. Description Trees to 50m, usually rather tall and narrow. Leaves are linear, around 1cm long, alternate, on deciduous branchlets, turning pinkish-brown, then reddish brown before falling. Male flowers are yellowish-green, elongated, in long tassels produced near the tops of the trees. Pollination is by wind. The cones are 1.5–4cm across, almost round, of few scales, each with 2 ovules. Seeds have unequal wings. Key Recognition Features The soft, pale green leaves show this to be deciduous; the alternate leaves and buds in the axils of the branchlets distinguish it from the superficially similar Metasequoia. Evolution and Relationships An ancient genus that has survived in the warmer parts of North America, but not in Asia. Ecology and Geography In swamps, by rivers and lakes from Delaware southwards to Florida and Texas; var. distichum is the most common; var. imbricatum (Nutt.) Croom is found only from the coast of North Carolina to Florida; var. mexicanum (Carr.) Gord., syn. T. mucronatum Ten., extends from central Mexico to Guatemala and possibly southern Texas. Taxodium ascendens and T. nutans are synonyms of var. imbricatum. Comment The roots often produce “knees”, woody protuberances that stand up to 1m above soil level. These help them “breathe”, and are especially common in wet areas; they are a feature of the Florida Everglades. Once established, this is a very hardy tree, both healthy and long-lived, surviving well in areas as different as southwest England and the Mediterranean. The famous tree in Santa Maria del Tule, near Oaxaca in Mexico, has the largest girth of any known tree, measured at 35.8m in 1982; the first mention of it was published in Seville in 1590, and even then it was said to have been much reduced in size by a lightning strike. Photographs:
Taxodium disticum 'Nutans', Autumn colour. Taxodium distichum, detail |
