Euphorbia peplis 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 : 35

14. Euphorbia peplis Linnaeus, Sp. Pl. 1: 455. 1753.

Type (lectotype here designated):— [s.l.]. “ Peplis ” in Clusius, Rar. Pl. Hist. 6: clxxxvii 1601 [icon.], Fig. 23. Epitype (here designated):—[s.l.]. Herb. Linn. 630.18 ( LINN image!)

≡ Tithymalus peplis (L.) Scopoli (1771: 340)

≡ Anisophyllum peplis (L.) Haworth (1812: 159)

≡ Chamaesyce peplis (L.) Prokhanov (1933: 15)

≡ Chamaesyce maritima Gray (1821: 260) , nom. illeg.

Description:—Herbs, annual, with taproot. Stems procumbent, ramified from the base, frequently into 4–5 branches up to 35 cm long, glabrous and somewhat fleshy. Leaves opposite; stipules deeply laciniate on both node surfaces, 2.2–3.5 × 2.1–3.0 mm, non-ciliate; blade falcate, 7–12 × 3–6 mm, base markedly asymmetrical abaxially prolonged into a conspicuous auricle, margins entire with basal auricles occasionally serrate, apex obtuse, rounded to retuse, surfaces without reddish spot, glabrous. Cyathia solitary at the bifurcation of dichasial branches and grouped together in axillary dichasial clusters on the branches of the last order, multiflorous, with 4–5 cymes of male flowers. Involucre glabrous; glands reddish, oblate-reniform, 0.09–0.10 × 0.4–0.5 mm; appendages white-greyish, 0.07–0.08 × 0.4–0.5 mm, margin entire or irregularly lobed. Capsules oval, deeply sulcate, 3–4 × 4–5 mm, glabrous, with keeled mericarps; hypogynous disc polygonal to triangular, 1–2 mm, with laciniate corners. Seeds pale grey, pyriform, apiculate, not tetrahedral, subcircular in cross section, 3 × 2 mm, smooth.

Iconography:— Pignatti et al. (2017: 323), Hegi (1924: 141, Fig. 1755), Clusius (1601: clxxxvii), Fig. 24.

Chromosome number:—2n = 24 ( Benedì & Orell 1992b); n = 12 ( Hans 1973).

Ecology:—Halophyte proper to subnitrophilous communities of sandy coastal areas ( Benedì & Orell 1992a).

Chorology:—Native to the Mediterranean region, naturalized on the Pacific coast of North America.

Occurrence in Italy:—Present in all Italian region, excluding landlocked ones: VDA, PIE, LOM, TAA and UMB. Recently confirmed for LIG ( Ottonello & Longo 2018).

Taxonomic annotations:—The name Chamaesyce maritima Gray is illegitimate, as already stated by various authors ( Wheeler 1943, Burch 1965, Benedì & Orell 1992 a, Yang et al. 2012), being a superfluous name for E. peplis L. (Art. 52.1 of the ICN), and accordingly is typified automatically by its type (Art. 7.5 of the ICN).

Type designation:—The specimen 630.18 preserved in LINN was treated by some authors (for example Khan 1964, El Hadidi 1973) as the type of E. peplis . However, this specimen was collected by Kähler and reached Linnaeus after the publication of Species Plantarum ( Jarvis, 2007), and it is not original material. For this reason, we designate as lectotype the iconography of Clusius (1601), that Linnaeus himself cited in the protologue, and that represents fairly well the morphology and habitus of the plant. Nevertheless, considering that the iconography does not display all the diagnostic characters (i.e. seed morphology), we here designate the specimen 630.18 preserved in LINN as epitype, in order to provide an exsiccata material with all diagnostic features.