Amaranthus albus 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

1. Amaranthus albus L. , Syst. Nat., ed. 10. 2: 1268. 1759

Type (lectotype designated by Raus 1997: 143):—NORTH AMERICA. Habitat in Philadelphiae maritimis, Herb. Linn. No. 1117.1 (LINN!, image of the lectotype available at http://linnean-online.org/11627/) .

Description:— Herbs 1–85(–120) dm tall, monoecious, annual (therophyte), rarely biennial. Stems usually erect, ± glabrous (sometimes sparsely pubescent in the inflorescence region), white to white-greenish, much branched. Leaves green (usually pale green), ovate, elliptic to spathulate (3.5–6.0 × 1.5–3.0 cm in the main axis, greater than the leaves on the branches), often with undulate margins (sometimes with a white marginal vein), apex obtuse and mucronate, base cuneate, glabrous (rarely pubescent on the veins), petioled (petiole 1.6–3.0 cm long). Synflorescences arranged in axillary glomerules, light green. Floral bracts greenish, ovate-lanceolate [(2.0–)3.0–4.0(–6.0) × 0.3–0.6 mm], 2(–2.5) times longer than the perianth, awned, margin entire, glabrous. Staminate flowers with 3 tepals, lanceolate; stamens 3. Pistillate flowers with 3 tepals, linear to lanceolate [0.9–1.1 × 0.3–0.4(–0.5) mm], with acute apex; stigmas 3. Fruit brownish-black, ellipsoidal [(1.2–)1.4–1.8 × 1.0–1.2(–1.4) mm], as long as or slightly longer than the perianth, rugose when dry, dehiscent. Seed lenticular [(0.8–)0.9–1.1(–1.3) mm in diameter], black to brownish-black.

Iconography:— Chaudhary (1998: 245, Plate. 126a–e), Bayón (2015: 304, Figura 19).

Phenology:— Flowering time April ( Al-Eisawi & Al-Ruzayza 2015).

Habitat and elevation:— Human-made habitat, at about 300 m a.s.l. ( Al-Eisawi & Al-Ruzayza 2015).

Chromosome number:— 2n = 32, 34.

Alien status:— Neophyte species native to North America, it can be considered as invasive in Saudi Arabia (see Aljeddani et al. 2021).

Occurrence in Saudi Arabia ( Fig. 1 ):— Jizan, Qassim ( El-Ghazali & Al-Soqeer 2013), Makkah ( Al-Eisawi & Al-Ruzayza 2015), Tabuk and Taif (Aljieddani et al. 2021). No finding was done during the field surveys. Further researches are necessary to verify the distribution of Amaranthus albus in the country.

Figures

FIGURE 1. Map of Amaranthus albus.