Amaranthus crassipes Schltdl. subsp. warnockii (I.M. Johnst.) N.Bayón in Ann. Missouri Bot. Gard. 101: 319 (2015). Type: México, Coahuila, W. Coahuila, 1 mi. [1.6 km] SE of Ocampo, silty plain near mogote, 8 Sept. 1941, Johnston 8886 (GH-00037034, holo.!). Image of the holotype at https://plants. jstor.org/stable/viewer/10.5555/al.ap.specimen. gh00037034?loggedin=true.

Diagnostic features

Subsp. warnockii differs from subsp. crassipes by the leaves, which are obovate to oblanceolate, 6–10 mm wide (vs 10–15 mm), and green-glaucous on the abaxial surface (vs green, never glaucous) (Figure 1).

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Vernacular name

Warnock’s amaranth.

Phenology in Tunisia

Flowering time October–November; fruiting time November–December.

Distribution

U.S.A. (SE Texas) and Mexico (E Chihuahua, E Coahulia). Not recorded outside of the Americas up to the present paper (see e.g., Bojian et al. 2003; Mosyakin & Robertson 2003; Palmer 2009; POWO 2022 and literature therein; African Plant Database version 3.4.0).

Habitat and distribution in Tunisia

Human-made habitat on clayey and sandy substrates within ruderal vegetation (almost similar to native habitat and vegetation, which consists of open areas and matorral, see Bayón 2015: 319). Amaranthus crassipes subsp. warnockii is restricted in Tunisia to one locality of Monastir city at alt. 8 m (Figure 2). The population found covers an area of about 100 m 2. The taxon is an alien for Tunisia and Africa and can be considered as casual.

Representative specimens examined

MÉXICO. Coahuila: W. Coahuila, 1 mi. [1.6 km] SE of Ocampo, silty plain near mogote, 8 Sept. 1941, Johnston 8886 (GH00037034) . TUNISIA. Monastir: Monastir city, 35°45’39”N, 10°49’52”E, on clayey and sandy substrates in ruderal vegetation, alt. about 8 m, 8 Oct. 2019, El Mokni s.n. (HFLA!, Herb. R. El Mokni) . U.S.A. Texas: Hudspeth Co. Gypsum Flat: 10 Oct. 1944, Waterfall 5842 (NY3363738); near Rio Grande, common and abundant, low places, 8 Aug. 1919, Hanson 822 (US 03540282).