Euphorbia hyssopifolia Linnaeus, Syst. Nat.

9. Euphorbia hyssopifolia Linnaeus, Syst. Nat. View in CoL , 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 View in CoL (L.) Boiss. in Candolle (1862: 24)

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

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

≡ Chamaesyce hyssopifolia View in CoL (L.) Small (1905: 429)

= Euphorbia brasiliensis Lamarck (1788: 423) View in CoL . Type:— BRASIL. Rio de Janeiro. Tithymalus Caulibus View in CoL 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) View in CoL . Type :— SURINAME. In arenosis ad fl. Marowyne, July 1847, A. Kappler 1820 ( holotype U0238720 image!; isotypes FI011603 image!, FR0031319 image!, S10820 View Materials image!, TUB009118 About TUB 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.