Euphorbia ophthalmica Persoon, Syn. 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 : 33-34

13. Euphorbia ophthalmica Persoon, Syn. Pl. 2: 13. 1806.

Type (lectotype, designated by Wheeler 1941: 172):— BRAZIL. Rio de Janeiro, s.d., Commerson 238 ( P00678898 image!, isolectotype P00716314 image!)

≡ Chamaesyce ophthalmica (Pers.) D.G. Burch (1966: 98)

≡ Euphorbia hirta var. ophthalmica (Pers.) Allem & Irgang (1975: 63)

= Euphorbia procumbens Candolle (1813: 111) , nom. illeg., non Miller (1768: EUPHORBIA n° 12). Type (lectotype, here designated):— FRANCE. h. m., 29 August 1812, s.c. s.n. (G00310068 image! individual upper left), https://www.ville-ge.ch/musinfo/bd/cjb/chg/ adetail.php?id=220188&lang=en

≡ Euphorbia pilulifera var. procumbens Boiss. in Candolle (1862: 21)

≡ Chamaesyce pilulifera var. procumbens (Boiss.) Small (1903: 714)

≡ Euphorbia hirta var. procumbens (Boiss.) N.E.Br. in Thiselton-Dyer (1911: 497)

≡ Chamaesyce hirta var. procumbens (Boiss.) Moldenke (1940: 178)

≡ Chamaesyce hirta subsp. procumbens (Boiss.) Croizat (1941: 299)

Description:—Herbs, usually annual, rarely short-lived perennial, with slightly thickened taproot. Stems usually prostrate, rarely ascending, 6–22 cm, usually strigillose. Leaves opposite; stipules distinct, subulate-filiform, undivided or divided into 2–4 segments, with circular glands at base, 0.9–1.5 mm, pilose or strigillose; petiole 0.3–1.2 mm, glabrescent or sericeous; blade usually ovate or oblong, rarely subrhombic, 4–13 × 3–7 mm, base asymmetric, margins serrulate, apex acute, surfaces often with reddish spot, strigillose or sericeous, or adaxial surface glabrescent; 3-veined from base. Cyathia in dense, terminal, capitate glomerules, with reduced, bractlike leaves subtending cyathia; peduncles 0–0.8 mm. Involucre obconic, 0.5–0.7 × 0.4–0.6 mm, strigillose; glands 4, yellow green to pink, circular to oblong, 0.1–0.2 × 0.1–0.2 mm; appendages absent or white to pink, oblong or forming rim around gland, 0.1–0.2 × 0.1–0.3 mm, margin entire or shallowly lobed. Staminate flowers 2–8. Pistillate flowers: ovary strigillose or canescent; styles 0.1–0.3 mm, 2-fid ½ to nearly entire length. Capsules ovoid, 1.0–1.2 × 1.0– 1.3 mm, strigillose; columella 0.7–1.1 mm. Seeds orange-brown to pinkish, narrowly ovoid, 4-angled in cross section, 0.7–0.9(–1.1) × 0.5 mm, usually rugulose, with 3–6 faint, low, transverse ridges, rarely smooth.

Iconography:—Fig. 22.

Chromosome number:—n = 8 ( Subils 1977).

Ecology:—Accidentally dispersed by humans as contaminant. The species occurs in disturbed areas, roadsides, nurseries and potted plants ( Steinmann et al. 2016, Taylor 2016).

Alien status:—Neophyte native to the New World, it can be considered as casual in Italy.

Occurrence in Italy:—Casual in SIC ( Galasso et al. 2018b).

Taxonomic annotations:— E. ophthalmica and E. hirta are very similar and they can be primarily distinguished through leaves morphology (more rhombic in E. hirta ) and position of glomerules of cyathia (strictly terminal in E. ophthalmica ; see also Hassemer et al. 2017).

Type designation:— Candolle (1813) described E. procumbens in the “Catalogus plantarum Horti Botanici Monspeliensis ”. In G-DC we found one sheet including a specimen (the upper-left one) labelled as E. procumbens . According to an analysis using Burdet (1979), we concluded that the label corresponds to Candolle handwriting (in particular see numbers 1812, 9, and letters p, b, r, E). Moreover, the specimen was collected in 1812 in the botanical garden of Montpellier (indicated as “h[ortus]. m[onspeliensis].” in the label), thus prior to Candolle’s protologue. Accordingly, we designated the specimen as lectotype of the name E. procumbens Candolle. We note here that this specimen is also indicated as “ lectotype of E. procumbens ” in a label by Rogers McVaugh dated 1993, but after an extensive search we could not retrieve any typification in the literature. Wheeler (1941) indicated that the type should be “probably a plant from the garden at Montpellier, France, (Geneva?, not seen)”, but did not indicate any specimen.