Taxodium is a genus of one to three species (depending on taxonomic opinion) of extremely flood-tolerant conifers in the cypress family, Cupressaceae. It is one of several genera in the family that are commonly known as "cypresses". Within the family, Taxodium is most closely related to Chinese Swamp Cypress (Glyptostrobus pensilis) and Sugi (Cryptomeria japonica).
Species of Taxodium occur in the southern part of the North American continent and are deciduous in the north and semi-evergreen to evergreen in the south. They are large trees, reaching 30-45 m tall and 2-3 m (exceptionally 11 m) trunk diameter. The needle-like leaves, 0.5-2 cm long, are borne spirally on the shoots, twisted at the base so as to appear in two flat rows on either side of the shoot. The cones are globose, 2-3.5 cm diameter, with 10-25 scales, each scale with 1-2 seeds; they are mature in 7-9 months after pollination, when they disintegrate to release the seeds. The male (pollen) cones are produced in pendulous racemes, and shed their pollen in early spring.
Species
The three
taxa of
Taxodium are treated here as distinct species, though some
botanists treat them in just one or two species, with the others considered as varieties of the first described. The three are distinct in
ecology, growing in different environments, but hybridise where they meet.
The most familiar species in the genus is the Bald Cypress, native to much of the southeastern
United States, from
Delaware to
Texas and inland up the
Mississippi River to southern
Indiana. It occurs mainly along rivers with silt-rich flood deposits.
The Pond Cypress occurs within the range of Bald Cypress, but only on the southeastern coastal plain from
North Carolina to
Louisiana. It occurs in still
blackwater rivers, ponds and swamps without silt-rich flood deposits.
The Montezuma Cypress occurs from the
Rio Grande south to the highlands of southern
Mexico, and differs from the other two species in being substantially evergreen. A specimen at Santa Maria del Tule in
Oaxaca, the
Árbol del Tule, is 43 m tall and has the greatest trunk thickness of any living tree, 11.42 m in diameter. It is a riparian tree, occurring on the banks of streams and rivers, not in swamps like the Bald and Pond cypress.
Uses
The trees are especially prized for their
wood, of which the
heartwood is extremely rot and termite resistant, with the notable exception of the host-specific
Pecky Rot fungus (
Stereum taxodii), which causes some damaged trees to become hollow and thus useless for timber. "A biochemical called cypressene is believed to act as a natural preservative in the heartwood, but it takes many decades to build up in the wood, making lumber cut from old-growth trees much more resistant to decay than lumber from younger trees". - Sternberg, G.,
Native Trees for North American Landscapes pp. 476. Bald Cypress wood was much used in former days in southeastern US for shingles. The shredded
bark of these trees is used as a
mulch, although the current harvest rate for this product is not sustainable and is causing substantial
environmental damage especially in the south where cutting boundaries are not being followed.
External links and references
Cupressaceae
Sumpcypres | Sumpfzypresse | Taxodium | Taxodium | Moerascipres (geslacht)