Amaranthus scleropoides Uline & W. L. Bray

Raus, Thomas, 2022, Taxonomic, nomenclatural and floristic review of Amaranthaceae of Greece and neighbouring countries, Willdenowia 52 (3), pp. 335-357 : 347

20. Amaranthus scleropoides Uline & W. L. Bray in Bot. Gaz. 19: 316. 1894 ≡ Amaranthus blitoides var. scleropoides (Uline & W. L. Bray) Thell. in Ascherson & Graebner, Syn. Mitteleur. Fl. 5 (1. Abt.): 293. 1914. – Lectotype (designated by Henrickson 1999: 790): North America , U.S.A., Texas, Western Texas to El Paso, 2 Aug 1849, Wright 582 (GH GH00037010 ; isolectotype: US US 00106262).

Remarks — Amaranthus scleropoides is introduced as a casual alien with unknown status along the Black Sea coast of Bulgaria ( Assyov & al. 2012: 66; Iamonico 2015a) and is not known from Greece so far. In its native range (Texas, NW Mexico; Mosyakin & Robertson 2003), it occupies seasonally wet, disturbed habitats. To raise awareness of this possibly spreading xenophyte, the main characters are given here (based on Mosyakin & Robertson 2003: 433; Bayón 2015: 356–357): plant annual, glabrous; stems ascending to prostrate, erect when young, 10–60 cm long; leaves petiolate, elliptic to lanceolate, 1.0–3.0 × 0.3–2.0 cm; inflorescence arranged in axillary clusters from base to apex, with axes thickened and inflated, becoming indurate at maturity (only so in A. scleropoides and A. crassipes ); floral bracts keeled (only so in A. scleropoides and A. crassipes ), ovate-triangular, minute; perianth segments 5, narrowly spathulate, slightly clawed, claw indurate at maturity; fruit orbicular to compressed obovoid, 1.1–1.5 mm long, shorter than perianth, smooth to tuberculate in distal half, transversely dehiscent (circumscissile). Amaranthus crassipes , native to South America and doubtfully reported once from Italy ( Iamonico 2011: 208–209; 2015b: 67), differs in its markedly decumbent growth form and conspicuously tuberculate, indehiscent fruits ( Iamonico 2011: 213; Bayón 2015: 319).