Amaranthus blitum L.

Hassan, Walaa A., Al-Shaye, Najla A., Alghamdi, Salma, Korany, Shereen M. & Iamonico, Duilio, 2022, Taxonomic revision of the genus Amaranthus (Amaranthaceae) in Saudi Arabia, Phytotaxa 576 (2), pp. 135-157 : 138-139

2. Amaranthus blitum L. , Sp. Pl. 2: 990. 1753

Type (lectotype designated by Filias et al. 1980: 149–150):—EUROPE. Habitat in Europa temparatiore, Herb. Linn. No. 1117.14 (LINN!, image of the lectotype available at http://linnean-online.org/11640/) .

= Amaranthus lividus L. , Sp. Pl. 2: 990. 1753, nom. rejec. (see Filias et al. 1980: 149–150) ≡ Amaranthus lividus proles lividus (Loisel.) Thell. in Asch. & Graebn. Syn. Mitteleur. Fl. [Ascherson & Graebner] 5: 274. 1914.

Type (lectotype designated by Reveal & Jarvis, 2009: 978):—[Icon] “ Blitum pulchrum rectum magnum rubrum ” in Bauhin & Cherler (1651: 966); image of the lectotype available at https://www.biodiversitylibrary.org/item/246944#page/1004/mode/1up.

= Amaranthus ascendens Loisel., Not. Fl. France 141. 1810 ≡ Amaranthus blitum var. ascendens (Loisel.) DC., Cat. Pl. Horti Monsp. 4. 1813 ≡ Amaranthus lividus proles ascendens (Loisel.) Thell. in Asch. & Graebn. Syn. Mitteleur. Fl. [Ascherson & Graebner]. 5(1(5)): 321 (v-322). 1914 ≡ Amaranthus lividus subsp. ascendens (Loisel.) Heukels, Geïllustreerde Schoolflora voor Nederland: 169. 1934.

Type (neotype designated by Iamonico 2016a: 520):—[Icon] “ Blitum majus “ from Dodoens (1616: 617); image of the lectotype available at https://bibdigital.rjb.csic.es/viewer/11145/?offset=#page=633&viewer=picture&o=bookmark&n=0&q=.

Description:— Herbs 1–5 (rarely up to 10) dm tall, monoecious, annual (therophyte). Stems prostrate-ascending, glabrous, pale green to pale brown, branched. Leaves green or green-yellowhish, ovate, rhomboidal to deltoid, some subcircular [1.5–3.5(–7.5) × (0.7–)1.5–2.5(–5.0) cm], sometimes fleshy, with entire or undulate margins, apex acute or rounded, often mucronate, base cuneate, glabrous, with marginal white vein, petioled (petiole 1.0– 5.5 cm long). Synflorescences arranged in axillary glomerules, reddish or green. Floral bracts, green or greenish, ovate to lanceolate (1.3–3.0 × 0.4–0.7 mm), shorter than the longest perianth segments, acute, margin entire, glabrous. Staminate flowers with 3(–4) tepals, ovate to lanceolate; stamens 3. Pistillate flowers with (4–)5 unequal tepals, lanceolate, elliptic [the greater 1.5–2.5(–3.5) × (0.7–)1.0– 1.2 mm], with acute to acuminate, and mucronate apex; stigmas 3. Fruit brown or reddish, ellipsoidal (2.0–2.2 × 1.0– 1.4 mm), as long as or longer than the tepals, usually smooth, dehiscent. Seed lenticular (1.5–1.7 mm in diameter), black.

Taxonomic annotations:— Amaranthus blitum shows a high phenotypic variability (both in vegetative and in generative characters) and several names (at subspecies, variety, and form ranks ) were published in the past, especially in the nineteenth century (see e.g., IPNI 2008). As a consequence, misapplication of names and nomenlcatural disorder exsist. We here recognized two varieties which can be distinguished as follows:

1. Seed with minutely punctiform surface and diameter 1.1–1.2 mm ..................................................................................... var. blitum

- Seed with smooth surface and diameter (1.2–)1.4–1.7(–1.9) mm................................................................................. var. oleraceus