Euphorbia maculata Linnaeus, Sp. Pl.

Mugnai, Michele, Lazzaro, Lorenzo, Nuzzo, Luca Di, Foggi, Bruno, Viciani, Daniele & Ferretti, Giulio, 2021, Synopsis of Euphorbia section Anisophyllum (Euphorbiaceae) in Italy, with an insight on variation of distribution over time in Tuscany, Phytotaxa 485 (1), pp. 1-65 : 29-30

11. Euphorbia maculata Linnaeus, Sp. Pl. 1: 455. 1753.

Type (lectotype, designated by Croizat 1962: 191):— [ INDIA]. Herb. Linn. 630.11 ( LINN image!)

≡ Anisophyllum maculatum (L.) Haworth (1812: 162)

≡ Tithymalus maculatus (L.) Moench (1794: 666)

≡ Xamesike maculata (L.) Rafinesque (1840: 97)

≡ Chamaesyce maculata (L.) Small (1903: 713)

Description:—Herbs, annual, with taproot. Stems usually prostrate, occasionally ascending, often mat-forming, 5–45 cm, sericeous or villous. Leaves opposite; stipules distinct, linear-subulate, sometimes irregularly 2–3-lobed, 1.0– 1.3 mm, sparsely short-sericeous to sericeous or villous; petiole 0.5–1.5 mm, sericeous to villous; blade oblongovate to elliptic, 4–18 × 2.5–8.0 mm, base strongly asymmetric, margins serrulate or subentire, apex rounded or broadly acute, abaxial surface pale greyish green, villous, adaxial surface usually with reddish spot, glabrate or with sparse hairs; palmately veined at base, pinnate distally. Cyathia solitary or in small, cymose clusters at distal nodes or on congested, axillary branches; peduncle 0.1–0.6 mm. Involucre obconic, 0.8–1 × 0.6–0.8 mm, sparsely strigose to sericeous; glands 4, green to yellow-green or pinkish, narrowly oblong, 0.1–0.2 × 0.2–0.5 mm; appendages white to reddish, lunate to oblong, 0.1–0.3 × 0.2–1.5 mm, margin crenulate. Staminate flowers 2–5. Pistillate flowers: ovary sericeous; styles 0.3–0.4 mm, 2-fid at apex. Capsules ovoid, well exserted from involucre at maturity, 1.3–1.5 × 1.2– 1.4 mm, moderately and evenly sericeous; columella 1.0– 1.2 mm. Seeds white to light brown, oblong-ovoid, sharply angular in cross section, 1.0–1.2 × 0.6–0.9 mm, with 3–4 low, transverse ridges that cross angles.

Iconography:— Pignatti et al. (2017: 324), Pahlevani & Riina (2011: 312, Fig. 5 ), Jercinovic (2007: Tab. 14, under the name Chamaesyce maculata ), Benedì (1997: Fig. 69, under the name Chamaesyce maculata ), Hegi (1924: 146, Fig. 1757), Fig. 19.

Chromosome number:—2n = 28 ( Steinmann et al. 2016); 2n = 12, 40 ( Chung et al. 2003); 2n = 42 ( Benedì & Orell 1992a); n = 7 ( Ward 1983); n = 12, 28 ( Subils 1977).

Ecology:—Accidentally dispersed by humans, other animals and vehicles as contaminant; globally considered as weed of cereals, cotton, orchards, plantations, vegetables and pastures as well as of human settlements. This species is a common weed of disturbed areas, botanical gardens, sidewalk cracks, railroads and roadsides ( Steinmann et al. 2016).

Alien status:—Neophyte native to North and central America, it can be considered invasive in Italy. E. maculata is a globally widespread species naturalized in most of European countries. In Europe, first records are for France at the end of XVIII century, probably introduced from Africa as seed contaminant ( Thellung 1907). First Italian records are from LOM and TOS in 1876 ( Thellung 1907).

Occurrence in Italy:—All Italian regions: invasive in PIE, LOM, VEN, TOS, MAR, LAZ, ABR, MOL, CAM, PUG; naturalized in other regions ( Galasso et al. 2018a).

Taxonomic annotations:— Euphorbia maculata is often confused with E. humistrata and E. thymifolia (see taxonomic annotations of E. humistrata and E. thymifolia ), and in the past it was in some cases a misapplied name (for example to E. nutans ; see Steinmann et al. 2016). It is noteworthy that many Italian authors (see Galasso et al. 2018b) misapplied the name E. thymifolia referring to E. maculata (see Galasso et al. 2018b).

Type designation:—At first Wheeler (1939, 1941, 1960) designated as type material for E. maculata L. the specimen 630.4 ( LINN), but several authors subsequently contributed to an intense debate leading to the subsequent designation by Croizat (1962) of 630.11 ( LINN) (see Jarvis 2007). Indeed, as indicated above, specimen 630.4 ( LINN) has been shown to be the type of E. hypericifolia L.

Figures

FIGURE 5. Euphorbia berteroana:A) exsiccatum from Guadaloupe preserved at TO, B) detail of terminal glomerule with short peduncle (scale = 0.5 mm).