Euphorbia hyssopifolia Linnaeus, Syst. Nat.

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 : 25

9. Euphorbia hyssopifolia Linnaeus, Syst. Nat. , ed. 10 2: 1048. 1759.

Type (lectotype designated by Fawcett & Rendle 1920: 339):—[s.l]. P. Browne s.n., Herb. Linn. 630.9 ( LINN image!)

≡ Euphorbia brasiliensis var. hyssopifolia (L.) Boiss. in Candolle (1862: 24)

≡ Euphorbia domingensis Spreng. ex Boiss. in Candolle (1862: 24), pro syn.

≡ Anisophyllum hyssopifolium (L.) Haworth (1812: 161)

≡ Chamaesyce hyssopifolia (L.) Small (1905: 429)

= Euphorbia brasiliensis Lamarck (1788: 423) . Type:— BRASIL. Rio de Janeiro. Tithymalus Caulibus erectiusculis foliis oppositis subsessilibus ovatis ovatis ferrulatis. L’ile aux chats dans La Rade de Rio de Janeiro, June-July 1767, Commerson 239 (holotype P00607991 image!, isotype P00607992 image!), https://science.mnhn.fr/institution/mnhn/collection/p/item/p00607991

= Euphorbia klotzschiana Miquel (1851: 95) . Type :— SURINAME. In arenosis ad fl. Marowyne, July 1847, A. Kappler 1820 (holotype U0238720 image!; isotypes FI011603 image!, FR0031319 image!, S10820 image!, TUB009118 image!), https://plants.jstor.org/ stable/viewer/10.5555/al.ap.specimen.u0238720

Description:—Herbs, annual, with taproot. Stems erect to ascending, 80 cm, sparsely to densely pilose proximally, usually glabrous distally. Leaves opposite; stipules connate, irregularly lacerate, 0.5–1.0 mm, glabrous or occasionally with few marginal hairs; petiole 1–2 mm, glabrous; blade lanceolate to oblong-falcate, 8–35 × 7–15 mm, base asymmetric, rounded, margins serrulate, apex broadly acute, abaxial surface glabrous or sparsely pilose, adaxial surface glabrous; palmately veined at base, pinnate distally. Cyathia solitary or in small, cymose clusters occasionally with bractlike leaves at distal nodes or on congested, axillary branches; peduncle 0.5–2.5 mm. Involucre obconic, 0.9–1.1 × 0.7–0.9 mm, glabrous; glands 4–5, yellow-green to maroon, elliptic to circular, 0.1–0.2 × 0.1–0.3 mm; appendages white or reddish, reniform or semilunate, 0.1–0.3 × 0.2–0.6 mm. Staminate flowers 4–15. Pistillate flowers: ovary glabrous; styles 0.5–0.9 mm, 2-fid ½ length. Capsules ovoid, 1.5–1.6 × 1.7–1.8 mm, glabrous; columella 1.5–2.0 mm. Seeds brown to greyish white, ovoid, slightly 4-angled in cross section, 1.0–1.4 × 0.7–1.1 mm, with 2–3 prominent transverse ridges, or inconspicuously reticulate.

Iconography:— Jercinovic (2007: Tab. 12, under the name Chamaesyce hyssopifolia ), Fig. 16.

Chromosome number:—2n = 12, 14 ( Steinmann et al. 2016); n = 6 ( Ward 1983); n = 7 ( Subils 1977).

Ecology:—Accidentally dispersed by humans as contaminant; globally considered as weed of cereals, orchards, plantations and pastures. It typically grows in disturbed areas, ditches and gardens ( Steinmann et al. 2016).

Alien status:—Neophyte native to the New World tropics, recorded in Italy by mistake (see Galasso et al. 2018b). In Europe it was recorded for the first time in Greece ( Vladimirov et al. 2015).

Occurrence in Italy:—Absent. Recorded by mistake in PUG and SIC.

Taxonomic annotations:—It was recorded for the first time, as naturalized, in SIC by Banfi & Galasso (2014) and subsequently, as casual, in PUG ( Buono et al. 2017). However, according to Galasso et al. (2018b) those records corresponded to E. hypericifolia . Euphorbia hyssopifolia can be confused with E. hypericifolia and in some cases with E. nutans (see taxonomic annotations of E. hyssopifolia and E. nutans ).

Type designations:— Lamarck (1788), in the protologue of E. brasiliensis , cited specimens from Commerson’s collection, collected in Brazil (without any further indication of a specific locality), indicating the sentence “ Tithymalus Caulibus erectiusculis foliis oppositis subsessilibus ovatis ovatis ferrulatis”. We found in P two specimens reporting the original Commerson’s label, stating that the specimens were collected in Brazil (Rio de Janeiro) in 1767, and reporting the same sentence cited by Lamarck in the protologue. Accordingly , we can be sure that Lamarck based the description on these specific specimens .

Concerning the name Euphorbia klotzschiana, Miquel (1851) in the portologue cited explicitly specimen n. 1820.