Taxodiaceae

The Taxodiaceae were at one time regarded as a distinct plant family comprising the following ten genera of coniferous trees:

• Athrotaxis
• Cryptomeria
• Cunninghamia
• †Cunninghamites
• Glyptostrobus
• Metasequoia
• Sciadopitys
• Sequoia
• Sequoiadendron
• Taiwania
• Taxodium

However, recent research has shown that the Taxodiaceae, with the single exception of Sciadopitys, should be merged into the family Cupressaceae. There are no consistent characters by which they can be separated, and genetic evidence demonstrates close relationships; this merging is now becoming widely accepted.

The one exception, the genus Sciadopitys, is genetically very distinct from all other conifers, and now treated in a family of its own, Sciadopityaceae.

As proposed, genera of the former Taxodiaceae are grouped in the following subfamilies within the larger Cupressaceae:

• Athrotaxidoideae Quinn (Athrotaxis)
• Cunninghamioideae (Sieb. & Zucc.) Quinn (Cunninghamia)
• Sequoioideae (Luerss.) Quinn (Sequoia, Sequoiadendron, and Metasequoia)
• Taiwanioideae (Hayata) Quinn (Taiwania)
• Taxodioideae Endl. ex K. Koch (Taxodium, Glyptostrobus, and Cryptomeria)[1]

Evolution

Fossil leave of Taxodium dubium, 8 Mio. years old, Hambach lignite open cast mine, Germany

In earth's history Taxodiaceae were widespread. They are known since the Jurassic and can be found as fossil e.g. in layers from Tertiary times.

External links

• Gymnosperm Database - Cupressaceae
• Gymnosperm Database - Sciadopityaceae