The water-conducting cells are probably tracheids and the architecture of the xylem in general is similar to that of the extant family Trochodendraceae
The families of extratropical origin that spread throughout the temperate and cold temperate zones of the Northern Hemisphere included the Betulaceae, Platanaceae, and Trochodendraceae
Either the abaxial side of the young flower is delayed (in Eupteleaceae, Ranuneulales) or the adaxial side (in Achlys of Berberidaceae, Ranunculales, and in Trochodendron of Trochodendraceae
, Troehodendrales) (see above).
The upper altitudes between 3,281 ft (1,000 m) and 5,577 ft (1,700 m) (a total area of about 30,300 acres [12,250 ha]) are covered with mixed coniferous forests of sugi (Cryptomeria japonica) and Japanese hemlock (Tsuga sieboldii), and broadleaf trees, such as yamaguruna (Trochodendron aralioides), the only member of the family Trochodendraceae
The primary xylem in Winteraceae and Trochodendraceae is evidently vesselless, also (Carlquist, 2009).
Secondary vessellessness has been claimed for Winteraceae and Trochodendraceae (Young, 1981, and subsequent authors), and those two families are limited, as are the monocots just mentioned, to highly mesic localities in which there is little fluctuation in water availability.
New diversity among the Trochodendraceae
from the Early Eocene McAbee and Early/Middle Epocene One Mile Creek floras, Okanogan Highlands of British Columbia, Canada.
Gray Tetracentraceae Tetracentron 10f, 11B TETR Trochodendraceae
alticola to be related to the vesselless families Winteraceae or Trochodendraceae.
Likewise, based on a number of conflicting characters, they found very little support for the notion that the family might be related to Trochodendraceae, Eucryphiaceae, or Medusagyne.
This problem is also present in some more basal eudicots, such as Ranunculales (Endress, 1995), Trochodendraceae
(Endress, 1986), Buxaceae (von Balthazar & Endress, 2002), and Myrothamnaceae (Jager Zurn, 1966).