Swamp Cypress Family (Taxodiaceae)
Members Of The Taxodiaceae
Athrotaxis comprises three species found only on the islands of Taiwan in east Asia. It is possible that one species is a hybrid between the other two, due to its intermediate characteristics. These are moderately tall, pine-like trees.
Cunninghamia is a tall tree of great commercial importance in its native China and Taiwan. Two, rather similar species are known.
Another genus, with two or three species, is Taiwania, from China, Taiwan, and north Burma. These are felled for their timber, but they are rather scarce in their native habitats, provoking much concern among conservationists.
Cryptomeria is similar to the above groups, but the several species are more-widely spread in their native Japan and China. Due to the fast growing nature and height of this group, they have been widely introduced to other areas where they are important timber producers.
The big-tree or giant redwood (Sequoiadendron giganteum) produces the world's most massive trees, with the tallest measured example being 344.5 ft (105 m) tall with a trunk diameter of 39 ft (12 m). These massive trees are native to California; they will not survive an intense frost and are intolerant of pollution. They are, however, remarkably fire tolerant due to their fibrous bark. In fact, disposal of their seeds is aided by fire, which makes the cones open, and also reduces competition for the new seedlings.
A closely related, and physically slightly taller genus is the coast redwood (Sequoia sempivirens), found naturally from southwest Oregon to California in small numbered groups.
All of the above genera are evergreens, that is, they do not lose all of their leaves in the autumn. The remaining members of the Taxodiaceae are all seasonally deciduous.
Perhaps the most endangered member of the whole group is the dawn redwood (Metasequoia glyptostroboides), which was found for the first time in 1941, in a small valley in Central China. No other wild populations have ever been discovered. The specific name is due to the initial physical similarity to the previous genus. While endangered in the wild, the dawn redwood can be cultivated and is widely grown.
Another endangered species endemic to China is Glyptostrobus pensilis. The swamp or bold cypress (Taxodium distichum) is a moderately hardy tree native to the southeastern United States. This species is not as massive as some of its relatives, but it is more hardy, and is a cultivated species. Two other Taxodium species are known.
Kubitzki, K., K.U. Kramer, P.S. Green, and C.N. Page. "Pteridophytes and Gymnosperms," The Families and Genera of Vascular Plants. vol. 1. Springer, 1990.
Vidakovic, M. Conifers: Morphology and Variation. Groficki Zavod Hrvatske, 1991.
Welch, H. and Haddow, G. The World Checklist of Conifers. Landsmons Bookshop, 1993.