3. Atriplex micrantha Ledeb. (two-seeded orach, Russian atriplex)
A.
heterosperma Bunge
Pl. 352 d; Map
1513
Stems 30–150 cm
tall, erect, unbranched or the branches ascending. Leaves mostly alternate,
those toward the stem base often opposite or subopposite, sessile to short- or
less commonly long-petiolate. Leaf blades 1–7 cm long (those of basal leaves
occasionally to 10 cm), 2–4 times as long as wide and mostly widest toward the
base, oblong-ovate to triangular, truncate to angled at the base, rounded to
bluntly or sharply pointed at the tip, often with a pair of short, blunt, spreading
basal lobes, the margins otherwise entire or with few to many irregular teeth,
silvery gray on the undersurface when young, the mealiness usually disappearing
by flowering and the surfaces then uniformly green. Staminate flowers axillary
and terminal, appearing as elongate spikes with clusters of flowers and/or
panicles with short, spicate branches. Pistillate flowers intermingled with the
staminate ones, of 2 kinds on the same plant (best seen at fruiting), differing
in the size of the bracts, all lacking a perianth. Bracts at fruiting fused
only at the very base, in some flowers 1.5–2.5 mm long, in others enlarging to
5–6 mm long, broadly ovate to nearly circular in outline, appearing sessile or
nearly so, the free portions of the margins entire, at maturity becoming more
or less uniformly papery or leathery, the surfaces prominently veined. Fruits
easily separable from the bracts. Seeds of 2 kinds, those of larger-bracted
flowers 2–3 mm long, yellowish brown, dull; those of the smaller-bracted
flowers 1.2–1.5(–2.0) mm long, black, shiny; in both types, the tip of the
radicle (seedling root) positioned below the remaining body of the seed. 2n=36.
July–September.
Introduced,
uncommon, known thus far only from the city of St. Louis (native of Europe,
Asia; introduced widely but sporadically in the western U.S. and Canada).
Railroads.
This species was
first reported for the state by Mühlenbach (1979) under the name A.
heterosperma. That name has been placed in synonymy under A. micrantha
in most of the recent floristic literature on eastern Europe and Asia, as well
as by Kartesz and Meacham (1999), in their checklist of North American vascular
plants.