Oakleaf Goosefoot

Several entities (segregate species, subspecies, varieties, and forms) have been described within the Chenopodium glaucum group. Most of the taxa represent morphological traits of individual or ecological variability and have little or no taxonomic importance. However, several entities are well delimited geographically. The native North American taxon is recognized here as a separate variety.

Chenopodium glaucum is a variable species represented by various forms of little or no taxonomic significance. However, throughout its extremely wide range it is also differentiated into several morphologically intergrading but geographically defined subspecies or microspecies.

Chenopodium amurense Ignatov (Byull. Moskovsk. Obshch. Isp. Prir., Otd. Biol. 91: 111. 1986) was described from the Amur River area of the Russian Far East. This little-known entity clearly belongs to the C. glaucum aggregate (as a species or subspecies), differing from C. glaucum s.str. by having 3-lobed leaves and distinctly spatulate perianth segments. Such plants probably also occur in NE China. It should be noted, however, that 3-lobed leaves are characteristic of the rare hybrid, C. ×schulzeanum Murr (C. glaucum × C. rubrum).

Chenopodium glaucum seems to be fairly uniform in our area: it is an erect plant, the leaves are relatively long, coarsely and fairly acutely dentate, and the inflorescence is predominantly terminal and has a spicate appearance.

Stems erect to prostrate, branched from base, 0.5-2.5(-4) dm, farinose. Leaves nonaromatic; petiole to 1 cm; blade lanceolate to oblong or ovate, 0.5-4 × 0.3-1.5 cm, base cuneate, margins undulate-dentate, teeth obtuse or acute, apex obtuse or acute, densely farinose, glaucous abaxially. Inflorescences glomerules in terminal or lateral spikes, 5-10 cm; glomerules subglobose, 1.8-2.5 mm diam.; bracts leaflike in inflorescence, elliptic, 0.2-1 × 0.1-0.5 cm, or absent at least in terminal ¹/2 of inflorescence. Flowers: perianth segments 3-4; lobes obovate to oblong, 0.5-0.7 × 0.4-0.5 mm, apex obtuse, rounded, not keeled, covering fruit at maturity; stamen 1; stigmas 2. Utricles ovoid; pericarp nonadherent, smooth. Seeds mostly horizontal, some vertical, margins rounded; vertical seeds ovoid to round, 0.6-1.1 mm diam.; horizontal seeds round, 0.6-1.1 mm diam.; seed coat reddish brown, rugose-punctate. 2n = 18.

Herbs annual, 20-40 cm tall. Stem decumbent or diffuse, green or purple-red striate, ribbed. Petiole 5-10 mm; leaf blade oblong-ovate to lanceolate, 2-4 × 0.6-2 cm, fleshy, abaxially gray-white farinose, sometimes slightly reddish purple, adaxially glabrous, base attenuate, margin irregularly erose to dentate (sometimes indistinctly lobed), apex acute or obtuse; midvein prominent, yellow-green. Flowers bisexual and female, usually several per glomerule, arranged on branches in spicate or paniculate inflorescences (and/or in axillary glomerules), these shorter than leaves and interrupted. Perianth segments 3 or 4, light green, narrowly oblong or obovate-lanceolate, less than 1 mm, slightly succulent, usually not farinose, apex usually obtuse. Stamens 1 or 2; filaments not exserted from perianth; anthers globose. Stigmas 2, very short. Utricle protruding from perianth; pericarp yellow-white, membranous. Seed horizontal, oblique, or vertical, dark brown or red-brown, compressed globose, ca. 0.75 mm in diam., pitted, rim margin obtuse. Fl. and fr. May-Oct.

Annual, 5-20(-50) cm, almost glabrous except for the leaves beneath; usually erect to ascending, sometimes procumbent, often much branched especially in basal parts. Leaves somewhat fleshy; blade (0.5-)1-3(-4.5) cm, usually elliptic to ovate, sometimes narrowly elliptic, lanceolate or fairly broadly ovate, mostly coarsely sinuate-serrate to sinuate, sometimes subentire or slightly 3-lobed, usually ± obtuse at apex, variously attenuate at base, green and glabrescent above, glaucous - whitish and densely mealy below except for main veins, sometimes red especially on margins; bracts ± narrowly elliptic, dentate to seldom entire. Inflorescence mostly leafy, axillary and terminal; composed of small, dense glomerules arranged spicately or paniculately. Flowers dimorphic, terminal flowers bisexual, with 3-5 perianth segments and 1-5 stamens; lateral flowers mostly female, with 3 perianth segments and 0 or 1 stamen. Perianth segments free to base, glabrous, obovate, margin broadly membranous, apex ± truncate, back green, swollen in apical part. Stigmas 2, short. Fruits falling with perianth. Pericarp thin, greenish and free or almost so. Seeds vertical in the lateral flowers, horizontal in the terminal ones, reddish to dark brown, 0.9-1.0 mm long, roundish-ovoid, margin rounded; testa sometimes with reticulate striations especially in central parts, minutely pitted.

Distribution: Europe, except for northernmost and westernmost parts; rare in the Mediterranean and Gulf of Persia area; C and E Asia; introduced in N America and Australia; other races and allied species are in western North America, southern Africa, Australia and New Zealand.

Fl. & Fr. Per.: July-August.

Gardens, roadsides, lake shores. 1800-2500 m.

Fields, vegetable gardens, peripheries of villages, slightly saline-alkaline soils. Fujian, Guangdong, Guangxi, Guizhou, Jiangxi, Yunnan [N and S temperate zones].

Blitum glaucum (Linnaeus) W. D. J. Koch.

Annual up to 70 cm, branched from the base, sometimes forming cushion-like habit at high elevations; stem often prostrate to ascending, rarely straight. Leaves up to 6 × 2 cm, petiolate, cuneate at base, oblong or lanceolate, dentate or lobate with 2–5 lobes, rarely entire, green adaxially, grey or whitish below. Inflorescence leafy, loose. Perianth segments 3 to 5, almost free with hyaline margins, keeled along midrib, opened at fruiting stage. Fruit 0.65–0.8 mm in diameter, pericarp smooth, whitish, often ruptured. Seed reddish, without keel; embryo in both vertical and horizontal positions (spatial heterospermy), structural (latent) heterospermy expressed in different thickness of seed-coat testa.

Annual up to 70 cm, basally branched with ascending stems. Leaves triangular, oblong or rhombic-triangular, entire or dentate, sometimes with two marginal lobes; upper leaves lanceolate. Inflorescence leafy in lower part. Female flowers in axillary clusters and intermixed with male flowers forming terminal inflorescences. Bract-like cover enclosing the female flowers sessile or shortly pedunculate (peduncles up to 3.0 mm), ovate, rhombic or triangular, 1.2–5.0(7.0) mm long, sclerified but not or slightly inflated, entire or dentate, usually without outgrowths on the back. Seeds heteromorphic: red seeds convex, 0.7–1.2 mm in diameter, brown seeds 1.2–1.8 mm, flattened.

See Fig. 15.

See Fig. 16.