12. Chenopodium murale L. (nettle-leaved goosefoot)
Pl. 355 c–e; Map
1532
Plants annual,
without an odor. Stems 10–80 cm long, erect or ascending, few- to much-branched
above the base, glabrous or sparsely white-mealy, green to pale green. Leaves
mostly long-petiolate. Leaf blades 2–5(–8) cm long, mostly 2.0–2.5 times as
long as wide (1–3 cm wide), ovate to ovate-triangular or occasionally rhombic,
bluntly to sharply pointed at the tip, broadly angled, truncate or shallowly
cordate at the base, green, relatively thin and herbaceous in texture, the
margins irregularly several-toothed, the upper surface glabrous or sparsely
white-mealy, the undersurface sparsely to moderately white-mealy. Venation
noticeably branched, with 1 or 3 main veins. Inflorescences axillary and
terminal, consisting of short spikes with small clusters of flowers, these
usually grouped into small to relatively large panicles. Flowers not all
maturing at the same time. Calyx 5-lobed to below the midpoint, extending past
the widest part of the fruit but not reaching the stylar area, leaving much of
the portion of the fruit above the rim exposed at maturity, the lobes 0.5–0.8
mm long, ovate, rounded or bluntly pointed at the tip, keeled (often narrowly
so) dorsally, glabrous or sparsely white-mealy. Stamens 5. Stigmas 2. Fruits
1.1–1.5 mm wide, depressed-ovoid, the seeds positioned horizontally, the wall
thin, membranous, and somewhat translucent, finely wrinkled or roughened at
maturity, but occasionally becoming smooth with age, difficult to separate from
the seed. Seeds black, dull, finely wrinkled or roughened at maturity, sharply
angled along the rim. 2n=18. June–November.
Introduced,
uncommon and sporadic in Missouri (native of Europe, Asia; introduced widely in
the U.S. and Canada). Banks of rivers; also pastures, gardens, railroads, and
open, disturbed areas.