Trochodendraceae is a family of flowering plants with two living genera found in southeast Asia. The two living species share the feature of secondary xylem without vessels, which is quite rare in angiosperms. As the vessel-free wood suggested primitiveness, these two species have attracted much taxonomic attention.
The current classification of Trochodendraceae is the APG III system published in October 2009. Unlike the APG and APG II systems, this system places the family in the order Trochodendrales and places Tetracentron synonymizing Tetracentraceae fully with Trochodenraceae.
The APG II system, of 2003 retained the classification used in the 1998 APG system recognizing Trochodendraceae as a family. APG and APG II did not place the family in an order, leaving it among the basal lineages of the eudicots. Both APG systems accepts this as a family of two modern species, but it does allow the option of separating out the family Tetracentraceae.
Classification System: APG II Classification System: APG II (down to family level)
Ordo: Unassigned Eudicots
Genera: †Nordenskioldia - Tetracentron - Trochodendron - †Zizyphoides