2b. var. texanum Pax
A. negundo var. interius (Britton) Sarg.
Twigs densely
short-hairy, not glaucous, green to olive green. Ovaries and fruits glabrous or
short-hairy. April–May.
Scattered in the
western half of the state and disjunctly in Lincoln
County (mostly western and southern U.S.; Canada,
Mexico).
Bottomland forests, banks of streams, mesic upland forests in bottoms of
ravines, and bases of bluffs; also shaded ditches and moist roadsides.
The var. interius
is said to differ from var. texanum in its glabrous or nearly glabrous
(vs. minutely hairy) ovaries and fruits, as well as its hairy (vs. glabrous)
petioles. In Missouri
material, there is no correlation between these characters, and a range of
pubescence densities exists on the petioles. McGregor (1986b) suggested that
individuals from Kansas and Missouri with hairy twigs and glabrous or
nearly glabrous fruits might represent hybrids between var. negundo and
var. texanum, but this requires further study.