| Taxodium | |
|---|---|
 | |
| Bald cypress forest in a centralMississippi lake | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Cupressaceae |
| Subfamily: | Taxodioideae |
| Genus: | Taxodium Rich. |
| Type species | |
| Taxodium distichum (L.)Rich. | |
| Species | |
| Synonyms | |
| |
Taxodium/tækˈsoʊdiəm/[1] is agenus of one to threespecies (depending ontaxonomic opinion) of extremelyflood-tolerantconifers in the cypress family,Cupressaceae. The name is derived from theLatin wordtaxus, meaning "yew", and theGreek wordεἶδος (eidos), meaning "similar to."[2] Within the family,Taxodium is most closely related toChinese swamp cypress (Glyptostrobus pensilis) andsugi (Cryptomeria japonica).
Species ofTaxodium occur in the southern part of theNorth American continent and aredeciduous in the north and semi-evergreen toevergreen in the south. They are largetrees, reaching 100–150 ft (30–46 m) tall and 6.5–10 ft (2–3 m) (exceptionally 36 ft or 11 m) trunk diameter. The needle-likeleaves, 0.2–0.8 in (0.5–2 cm) long, are borne spirally on theshoots, twisted at the base so as to appear in two flat rows on either side of the shoot. Thecones are globose, 0.8–1.4 in (2–3.5 cm) diameter, with 10–25 scales, each scale with one or twoseeds; they are mature in 7–9 months afterpollination, when they disintegrate to release the seeds. The male (pollen) cones are produced in pendulousracemes, and shed their pollen in early spring.Taxodium species growcypress knees, when growing in or beside water. The function of these knees is currently a subject of ongoing research.
The three extanttaxa ofTaxodium are treated here as distinct species, though somebotanists treat them in just one or two species, with the others considered as varieties of the first described. The three are distinct inecology, growing in different environments, buthybridise where they meet.
| Image | Name | Common name | Distribution |
|---|---|---|---|
 | Taxodium ascendensBrongn. | pond cypress | Occurs within the range of bald cypress, but only on the southeastern coastal plain fromNorth Carolina toLouisiana. It occurs in stillblackwater rivers, ponds and swamps withoutsilt-rich flood deposits. |
.png) | Taxodium distichum(L.)Rich. | bald cypress | Native to much of thesoutheasternUnited States, fromDelaware toTexas, especiallyLouisiana and inland up theMississippi River to southernIndiana. It occurs mainly along rivers with silt-rich flood deposits. |
 | Taxodium mucronatumTen. | Montezuma cypress, ahuehuete, sabino | Occurs from the LowerRio Grande Valley south to the highlands ofGuatemala, and differs from the other two species in being substantially evergreen. A specimen inSanta María del Tule, Oaxaca, theÁrbol del Tule, is 43 m (141 ft) tall and has the greatest trunk thickness of all trees, 11.42 m (37.5 ft) in diameter. It is ariparian tree, occurring on the banks of streams and rivers, not in swamps like the bald and pond cypresses. |
The trees are especially prized for theirwood, of which theheartwood is extremelyrot- andtermite-resistant. The heartwood contains asesquiterpene called cypressene,[4] which acts as a naturalpreservative. It takes decades for cypressene to accumulate in the wood, so lumber taken fromold-growth trees is more rot resistant than that from second-growth trees.[5] However, age also increases susceptibility to Pecky Rot fungus (Stereumtaxodii), which attacks the heartwood and causes some damaged trees to become hollow and thus useless for timber. Bald Cypress wood was much used in former days in the southeastern United States forroof shingles.[6] The shreddedbark of these trees is used as amulch.
In earth's historyTaxodium was much more widespread in the Northern Hemisphere than today.[7] The oldest fossils were found inLate Cretaceous deposits from North America. The trees persisted in Europe until around 2.5 million years ago, during thePliocene.[8]
{{cite journal}}:Cite journal requires|journal= (help)
Authority control databases: National |
|---|