2. Elaeagnus umbellata Thunb. (autumn olive)
Pl. 374 j, k;
Map 1637
Plants shrubs to
3(–5) m, usually multiple-stemmed, rarely with a few thorns. Bark gray to
reddish brown, the younger branches densely covered with both rusty and silvery
scales. Leaf blades 30–80 mm long, 10–40 mm wide, narrowly elliptic to
elliptic, silvery beneath, green above even when young, the silvery
undersurface with at least a few scattered, rusty scales. Flowers short-stalked
(to 5 mm), 6–8 mm long. Hypanthium (beyond the constricted area above the
ovary) 2 or more times as long as the sepals, silvery with scales on the outer
surface, the sepals cream-colored to yellow on the inner surface. Mature fruits
short-stalked (to 5 mm), 5–8 mm long, circular in outline, more or less
translucent, red, with scattered, rusty scales appearing as tiny dots to the
naked eye. 2n=28. April–June.
Introduced,
scattered, mostly south of the Missouri River, but probably throughout the
state (native of Asia; widely naturalized in the eastern U.S. and adjacent
Canada west to Nebraska and Louisiana). Mesic upland forests, upland prairies,
sand prairies, glades, savannas, and banks of streams; also old fields,
pastures, fencerows, roadsides, and open, disturbed areas. April–June.
Autumn olive is
popular in horticulture as an ornamental shrub. Although its introduction into
North America dates back to the 1830s, beginning in about the 1940s, the
federal Soil Conservation Service (since renamed the Natural Resources
Conservation Service) and various state conservation agencies began promoting
its use as a valuable wildlife food plant and also as a windscreen and for use
in erosion control. However, birds and small mammals have spread its seeds into
various natural habitats, where it can take over the understory, and the
species is now considered an invasive exotic in a number of states. In
Missouri, its introduction is relatively recent; the earliest definitely
determined collections of plants growing outside of cultivation date back to
the 1980s (Yatskievych and Figg, 1989). Smith (1993) indicated that because of
widespread planting, E. umbellata is probably now naturalized in most
Missouri counties.
Steyermark
(1963) tentatively included the superficially similar E. multiflora
Thunb. (cherry silverberry) in his treatment, based on a single historical
collection from St. Louis County. He stated, however, that this vegetative
specimen “cannot be satisfactorily or definitely determined as this species or E.
umbellata.” As no further plants have been discovered to verify the
presence of this species in Missouri, it is here excluded from the flora (the
lone voucher is too incomplete to allow precise determination). Elaeagnus
multiflora, which has escaped from cultivation sporadically in several
eastern states, including Illinois, differs from E. umbellata in its
longer flower and fruit stalks (10–15 mm) and in its shorter hypanthium (about
as long as the sepals).