Chenopodium glaucum L.

Jonsell, B., Karlsson, 2005, Chenopodiaceae - Fumariaceae (Chenopodium), Flora Nordica 2, pp. 4-31 : 12-14

6. Chenopodium glaucum L. Figs 2F, 6A

Linnaeus, Sp. pi.: 220 (1753).

- Type: Linnaean Herbarium 313.17 (LINN) lectotype, sei. by Uotila, Ann. Bot. Fenn. 30: 190 (1993).

D Blågrøn Gåsefod. F sinisavikka. N blåmelde. S blåmålla.

Therophyte (summer-annual). 5^10(-100) cm, glabrous or almost so except for the leaves beneath. Stem yellowish, green-striped or sometimes reddish, erect to procumbent, often richly branched, especially basally. Leaves with petiole usually less than 1/3 as long as the blade (in the lowermost leaves rarely as long as the blade); blade green and glabrous above, glaucous and densely farinose below (except for veins), elliptic-ovate to lanceolate (sometimes broadly ovate and slightly 3-lobed), rarely narrower, 1-5(-6.5) x 0.4-2.5 (-3) cm; base cuneate to truncate; margin usually coarsely sinuate-serrate to sinuate, rarely subentire or entire.

Inflorescences usually leafy almost to the top, composed of short, spike- or panicle-like partial inflorescences (terminal part of inflorescence sometimes spikelike, ebracteate); glomerules small, dense. Flowers dimorphic, Terminal flowers bisexual, with 3-4(-5) tepals and 1(-5) stamens. Lateral flowers female or sometimes bisexual, with 3 tepals and 1 or no stamen. Tepals connate at base, weakly keeled near the apex, with membranous margin; apex obtuse to erose. Stigmas 2 or 3, 0.1-0.2 mm. Nut falling with the perianth; pericarp not or only slightly adherent to the seed. Seed horizontal, oblique or vertical in lateral flowers, horizontal in terminal ones, broadly ovate to orbicular in outline, 0.6-0.8(-l. 1) mm; edge rounded; seed-coat reddish brown to black, glossy, almost smooth to finely reticulate especially in the centre of the faces. - Mid-summer to autumn.

2n=18 (F V, {/, S Sk 2). - [2n=18]

Distribution. Nem-BNem(-SBor)[-MBor]. - Probably indigenous on seashores in D and southwestern S; much more widespread as an apophyte. - D common on the islands and in parts of 0Jy and NJy; rare in areas with nutrient-poor soils in Jylland. N southeastern lowland areas, possibly declining; casual in northern He Os, Te Porsgrunn, AA Arendal, VA Kristiansand and Mandal, and ST Skaun and Trondheim; not on seashores. S fairly common in most areas north to middle BhG, southeastern Vrm, southeastern Vsm and central Upl, but rare in part of the southern uplands; further north rare and declining to southeastern Dir and Gst and in Mpd; casual in Hrj Lillhärdal 1918, and along the coast from �ng to Nb (mainly old records from ballast). F formerly a permanent weed (archaeophytic or at least a relatively old alien) north to southern St and the old inland towns of EH Hämeenlinna and ES Savonlinna; declining as an archaeophyte, most recent records from tips and wasteland and clearly of recent origin; more or less casual north to OP Oulu and PeP Simo and Kemi, brought in during wartime and with ballast, coal, sugar beet and grain.

Europe, except for the northernmost parts, rare in the Mediterranean; C and E Asia; in E North America, South America and Australia probably anthropochorous.

Chenopodium rubrum

Chenopodium glaucum

Habitat. Seashores (pools and bare dried-up soil in littoral meadows, banks of seaweed); more frequent on nitrogen-rich ground in farmland (ponds, damp places in yards, dung-, coal- and chalk-heaps), sugar-beet fields, ornamental plantations; also (mainly casual) tips, ports, railway yards and sugar- and grain mills.

Variation. C. glaucum belongs to a variable species aggregate in need of revision. It is treated here in a strict sense, excluding, e.g., the North American C. salinum (rare casual).

In Nordic material of C. glaucum three morphological groups, partly with different origin and habitats, can be distinguished, although they are not well-defined.

(1) Seashore plants, usually low; stem greenish, procumbent, richly branched basally; leaves small, blade fairly narrow, teeth numerous, small, obtuse; inflorescences ± leafy. Frequently observed in seashores and other saline habitats in Europe (also on ballast in the north).

Chenopodium urbicum

Chenopodium polyspermum

(2) Village and town weeds, of medium size; stem greenish, erect, more branched in the upper parts; leaves larger, blade ovate, teeth few, obtuse; inflorescences ± leafy. Common in Europe, including Norden.

(3) Casuals brought in during later years, often tall (up to 1 m); stem yellowish to reddish, erect, branches basal, ± ascending; petioles fairly short; leaf-blades long and relatively narrow, often reddish, teeth numerous, acute (blade sometimes conspicuously large, undulate, with coarse teeth); inflorescences spike-like, partly terminal and bracteate only in the basal part. Frequent especially in SE Europe and adjacent Asia; in some cases immigration to Norden from the east is evident.

Similar taxa. Chenopodium glaucum is similar to C. salinum (rare casual).