Chenopodium rubrum L.

5. Chenopodium rubrum L. Figs 2E, 5C-F

Linnaeus, Sp. pi.: 218 (1753).

- Type: Linnaean Herbarium 313.5 (LINN) lectotype, sei. by Uotila, Ann. Bot. Fenn. 30: 190 (1993).

D Rød Gåsefod. F punasavikka. N rødmeide. S rödmål la.

Therophyte (summer-annual). (3-)10-50(-100) cm, glabrous (rarely very slightly farinose when young), often strongly red-tinged. Stem subangular or sometimes angular, yellow (sometimes striped with green), usually hard, erect or sometimes procumbent, branched especially near the base; basal branches subopposite, ascending to procumbent. Leaves pure dark-green or sometimes yellowish, succulent; petiole c. half as long as the blade or sometimes almost as long; blade broadly ovate to broadly rhombic, (0.7-)2-12(-20) cm; margin coarsely serrate or sometimes dentate (first or second tooth from the base lobe-like, more prominent than the others); upper leaves successively smaller, with shorter petiole and narrower, less dentate blade, forming a gradual transition to the small, narrow, usually entire uppermost bracts; in very small plants all leaves narrow, bract-like.

Inflorescences on the main stem and on the larger branches, with bracts almost to the top, sometimes panicle-like but usually composed of short, compact, spike-like, axillary and terminal partial inflorescences; glomerules dense. Flowers dimorphic. Terminal flowers bisexual, with 4-5 tepals and 3-5 stamens. Lateral flowers female or sometimes bisexual, with 3 tepals; stamens, if present, 1-3. Tepals connate halfway or less, not or only weakly keeled, with wide membranous margin and obtuse apex. Stigmas 2(-3), 0.1-0.2 mm. Nut usually falling with the perianth; pericarp not adherent to the seed. Seed vertical in lateral flowers, horizontal in terminal ones, broadly ovate in outline, 0.6-0.8(-l.l) mm; edge rounded; seed-coat reddish brown, glossy, almost smooth to finely reticulate especially in the centre of the faces. - Late summer to autumn.

2n=36 (S Sk). - [2n=36]

Distribution. Nem-BNem[-SBor]. - D indigenous, but mainly occurring as an apophyte; common, especially on the islands, but rare in western Jylland. N probably first with ballast in the 19th century; established in farmland and waste ground in 0/and Ak, elsewhere a rare casual in coastal provinces north to SF Jølster; ST Skaun 1924^-1 (mill), Trondheim 1915 (garden); Tr Tromsø 1980's (town ruderal). S fairly common to fairly rare in farmland areas (archaeophytic) and on seashores (possibly secondarily) north to BhG, Vg, southeastern Vsm and UpU rare further north to southern Vrm, southern Dir and Gst; further north casual, mainly in ports. F an archaeophytic village plant in the southwest, but also brought in with ballast, troops during the war, grain, coal, etc.; in A rare (not known from the archipelago); on the mainland established north to southern St, southern EH and EK, declining in the early 1900's but later on increasing; northwards casual to PK Lieksa, KP Kokkola and Raahe, OP Oulu and Vaala, and PeP Kemi.

Europe, except for the easternmost and northernmost parts, rare in the Mediterranean; from SW Asia to Siberia; North America (only partly native).

Habitat. Sheltered seashores (especially reed swamps and clayey erosion hollows in salt marshes); nitrogenrich places in farmland (especially pools, dung- and chalk-heaps), sugar-beet fields, lawns and ornamental plantations; tips (especially on sewage sludge), ports, building places and railway yards.

Variation. Variable in overall size, leaf size and shape, and in habit of the inflorescence. The variation does not seem to deserve taxonomic recognition, at least not in Norden.

Similar taxa. Small plants of Chenopodium rubrum without fruits are sometimes difficult to distinguish from C. chenopodioides (4).