My big RHS book says there are 2,T.distichum and says that T.ascendens is a synonym of distichum var.imbricarium. It doesn't mention what the second species is(1 species and 1 variety of that species) Looking on the Wiki it lists ascendens as a distinct species and also lists mucronatum as the 3rd(second?) species. It also says that this one is the world's stoutest tree at 11.4 m girth! So are there 3 or 2 species,and why doesn't my book list mucronatum at all,given its a big book with over 15,000 plants listed!
GreenLarry the gymnosperm database lists 2 species Taxodium disticum and taxodium mucronatum http://www.biologie.uni-hamburg.de/b-online/earle/cu/tax/index.htm flora of north america list 1 species and 2 varieties http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=132353 I think I'd go with the FNA description it seems to be the most comprehensive and latest treatment
Anything from one to three species. Personally, I reckon 3 species is probably best, as T. distichum and T. ascendens are ecologically separated and distinct.
Interesting and I noticed that the gymnosperm database has a citation for the FNA. It seems mucronatum is a variety of distichum even tho it has a different common name(Montezuma Cypress)
Wiki is written by anyone who wants to, hopefully most of the content is reliable or will become so as the process continues. Meanwhile, reader beware. And plant taxonomy generally consists of interpretation and opinion, same as other science. A concept becomes The Truth when enough recognized experts in the field hold the same opinion. Some topics may go on for a long time without a consensus appearing to develop.
The Missouri Botanical Gardens' TROPICOS lists these: Species and subspecific taxa of Taxodium T. ascendens Brongn., 1833 T. ascendens fo. nutans (Aiton) Rehder, 1926 T. ascendens var. nutans (Aiton) Rehder, 1927 T. distichum (L.) Rich., 1810 T. distichum (L.) Kunth, 1817 T. distichum var. ascendens Carrière ex Mast., 1892 T. distichum fo. confusum E.J. Palmer & Steyerm., 1938 T. distichum var. distichum T. distichum var. fastigiatum Knight ex Carrière, 1855 T. distichum var. imbricatum (Nutt.) Croom, 1837 T. distichum var. mexicanum (Carrière) Gordon, 1858T. distichum var. microphyllum (Brogniart) Carrière, 1855 T. distichum var. mucronatum (Ten.) A. Henry, 1906 T. distichum subsp. nutans A.E. Murray, 1982 T. distichum var. nutans (Aiton) Sweet, 1827 T. distichum var. nutans Carrière, 1867 T. distichum var. patens Sweet, 1827 T. distichum var. pendulum (Forbes) Carrière, 1867 T. giganteum (Lindl.) Kell. & Behr, 1873T. heterophyllum Brongn., 1833 T. imbricatum (Nutt.) R.M. Harper, 1902 T. japonicum (Thunb. ex L. f.) Brongn., 1833T. japonicum var. heterophyllum Brongn., 1833T. juniperoides (L.) Steud., 1840T. lineatum (Poir.) Druce, 1917 T. mexicanum Carrière, 1855T. microphyllum Brogniart, 1833 T. montezumae Decne., 1854 T. mucronatum Ten., 1853 T. nuciferum (L.) Brogniart ex J.O. Voigt, 1845 T. sempervirens D. Don, 1824T. sinense Nois. ex Gordon, 1858 T. sinense J. Forbes, 1839 T. sinense var. pendulum Forbes, 1839 T. washingtonium Winsl., 1854
Go to TROPICOS at: http://mobot.mobot.org/W3T/Search/vast.html Just type in the genus name and you'll see a link for the species list will pop up. Click that and you can search each individual species.
The tropicos list doesn't distinguish what is and isn't currently accepted - there's plenty of names there that are now universally regarded as synonyms. Taxodium sempervirens is of course now Sequoia sempervirens, and T. giganteum is Sequoiadendron giganteum.
On TROPICOS, if you check the species list each name will tell you if it is a snyonym or has synonyms.
The Flora of North America treatment won't be accepted by everyone (there's no official list of plant names equivalent to the American Ornithologists' Union Check-List), but it does give a good idea of distribution and variation.
