Euphorbia chamaesyce 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 : 12-15

2. Euphorbia chamaesyce Linnaeus, Sp. Pl. 1: 455. 1753.

Type (lectotype, designated by Khan 1964: 150):—[s.l.]. Löfling 373, Herb. Linn. 630.15 ( LINN image!)

≡ Xamesike vulgaris Rafinesque (1838: 115) , nom. illeg.

≡ Chamaesyce vulgaris Prokhanov (1941: 8)

= Euphorbia canescens Linnaeus (1762: 652) . Type: (lectotype, designated by Benedí & Orell 1993: 149):—[s.l.]. Alströmer 146a, Herb. Linn. 630.16 (LINN image!)

≡ Euphorbia chamaesyce var. canescens (L.) Sm. in Sibthorp & Smith (1809: 324)

≡ Chamaesyce canescens (L.) Prokhanov (1933: 19)

= Euphorbia massiliensis DC. in Candolle & Lamarck (1815: 357). Type (lectotype, designated by Benedí & Orell 1993: 149):—Not found, see taxonomic annotations.

≡ Euphorbia reichenbachiana var. massiliensis (DC.) Lojacono (1907: 330)

≡ Euphorbia chamaesyce [Rasse] massiliensis (DC.) Thell. in Graebner (1917: 457)

≡ Euphorbia chamaesyce var. massiliensis (DC.) W.Zimm., Hegi & Beger in Hegi (1924: 145)

≡ Euphorbia chamaesyce subsp. massiliensis (DC.) Chopinet (1950: 138)

≡ Chamaesyce canescens subsp. massiliensis (DC.) Soják (1972: 169)

≡ Chamaesyce massiliensis (DC.) Galushko (1974: 299)

≡ Chamaesyce vulgaris subsp. massiliensis (DC.) Benedí & Orell (1992b: 46)

= Euphorbia chamaesyce var. maculata Parlatore (1869: 448) .

Type (lectotype, here designated):— ITALY. Boboli, 18 September 1860, Parlatore s.n. ( FI 002624!), Fig. 6

= Euphorbia pinnulosa Lojacono (1907: 329) . Type (lectotype, here designated):—[s.l.]. “ Euphorbia pinnulosa Lojac. ” in Lojacono 1907: pl. 3 fig. upper left [icon.], Fig. 7

= Euphorbia libassii Lojacono (1907: 329) . Type:—Not found

≡ Chamaesyce libassii (Lojac.) Giardina & Raimondo in Giardina et al. (2007: 11)

= Euphorbia reichenbachiana Lojacono (1907: 330) , nom. illeg. Type (lectotype, here designated):—[s.l.]. “ maculata L.” in Reichenbach 1843: CXXXI, Fig. 4752 [icon.], Fig. 8

Description:—Herbs, annual, with taproot. Stems prostrate, ramified from the base into maximum 30 cm length branches, glabrous to sparsely pilose. Leaves opposite; stipules usually distinct, laciniate on both node surfaces; petiole 0.5–1.0 mm; blade ovate to obovate, 2–9 × 1.5–8.0 mm, base usually asymmetric, margins entire, crenate or serrate, apex obtuse to retuse, adaxial surface occasionally with reddish blotch, glabrous to sparsely pilose. Cyathia solitary or in small, cymose clusters at distal nodes, with 4–5 uniflorous male cymes. Involucre ovoid, glabrous to sparsely hirsute; glands 4, yellow–orange to chestnut, concave-oblate, 0.12–0.15 × 0.25–0.50 mm; appendages white, 0.1–0.4 × 0.5–0.7 mm, margin truncate, crenate or lobulate. Capsules oval, sulcate, 1.4–1.7 × 1.5–1.8 mm, glabrous, glabrescent or hirsute. Seeds grey to chestnut, ovoid-subtetrahedral, apiculate, 1.0–1.5 × 0.6–0.9 mm, irregularly granulosetransversely rugose.

Iconography:— Mifsud (2018: 157, Fig. 1), Pignatti et al. (2017: 324), Pahlevani & Riina (2011: 306, Fig. 1), Fig. 9.

Chromosome number:—2n = 14 ( Benedì & Orell 1992b); 2n = 18 ( Vignal & Reynaud 1992); n = 9 ( Vignal & Reynaud 1992).

Ecology:—Nitrophyte proper to ruderal communities of trampled biotopes ( Benedì & Orell 1992a). It is reported as species that colonize rocky hillsides, gravel plains, saline and sandy soils, fields, gardens and roadsides ( Pahlevani & Riina 2011).

Chorology:—Native to Old World, from Macaronesia to Central Asia and Pakistan.

Alien status:—Native species to Italy but considered as neophyte naturalized in FVG. The effective area of origin and its subsequent naturalisation are however dubious and require further investigations ( Benedì & Orell 1992a).

Occurrence in Italy:—Present as native in PIE, LOM, VEN, LIG, EMR, central and southern Italy, SAR and SIC; no longer recorded in VDA. It is recorded as alien in TAA (no longer recorded) and FVG (naturalized).

Taxonomic annotations:—Thellung in Graebner (1917) reported infraspecific ranks of E. chamaesyce and indicated the epithet massiliensis at level of “rassen”, as intermediate rank between subspecies and variety (see Art. 4.3 of the ICN). This statement was interpreted for the first time as variety and subspecies rank respectively by Hegi (1924) and Chopinet (1950). While WCSP (2018) and Bartolucci et al. (2018) do not consider infraspecific ranks of E. chamaesyce , many authors ( Radcliffe-Smith & Tutin 1968, Benedì & Orell 1992a, Pignatti et al. 2017) identify the subspecies rank as valid and provide the two taxa E. chamaesyce subsp. chamaesyce and E. chamaesyce subsp. massiliensis . Nevertheless, among the italian specimens, we analysed the characters indicated by Benedì & Orell (1992a) for subspecies rank identification, but they showed a high level of variability, so that we did not identify a clear separation of the two taxa. Hence, we agree with Pahlevani & Riina (2011), that such characters are insufficient to separate the two taxa.

Euphorbia chamaesyce , especially those morphs with widespread hairs, may be confused with E. prostrata : the ornamentation of seeds is sufficient to differentiate the two species, even when distribution pattern of capsule hairs is not clear. Glabrous forms are instead very similar to E. humifusa , but easily differentiable for rugose seeds (see Fig. 3 and Fig. 9).

Type designations:—According to Jarvis (2007), the type material of E. chamaesyce L. indicated by Wheeler (1941) cannot be considered as original material as it is a specimen (i.e. 630.17 LINN image!, collected by Browne in Jamaica) that Linnaeus did not receive until 1758.

Within the protologue of E. libassii, Lojacono Pojero (1907) refers to specimens collected by Todaro in Porto Empedocle in 1880 and preserved in PAL. Nevertheless, after searches in PAL, we could not find any specimen corresponding to these data. We note here that we found a specimen preserved in FI and collected by Todaro in Palermo in 1864 ( FI 057652!), but there is not a clear indication that Lojacono studied this specimen.

Benedí & Orell (1993) designated a lectotype for E. massiliensis basing on the information that de Candolle received the plant from Requien, who collected the specimen in Marseille. Indeed, they indicate that they found in G-DC a single folder from Marseille, and selected as lectotype the lower specimen, but did not provided any further reference allowing to retrieved unambiguously the specimen. We searched it in G-DC, but we could not find it. We found some specimens, from different sheets, that may correspond to original material, but we could not find any clear evidence to unambiguously indicate one of them as type material.

The name E. reichenbachiana should be considered as nom. illeg., considering that Lojacono included in this species also E. massiliensis DC. (as E. reichenbachiana var. massiliensis mihi). Indeed Lojacono should have used this latter name as valid species rank (Art. 52.2 of the ICN), at most, describing his taxa as E. massiliensis var. reichenbachiana . Lojacono (1907) refers to herbarium specimens collected by various Sicilian botanists and presumably preserved in PAL. However, we did not retrieve in PAL or in FI any specimen that may correspond to Lojacono’s indications. Hence, we chose as lectotype the iconography by Reichenbach (1843) that Lojacono himself indicated as corresponding to E. reichenbachiana .

Lojacono (1907) indicates for E. pinnulosa : “ E. perforata Tin. In Herb. Pan (non Guss.) ” as specimens that he referred to for the formalization of E. pinnulosa . We visited PAL in person, searched the PAL virtual herbarium and directly contacted the PAL curator ( G. Domina), but we did not retrieve any herbarium specimen that may correspond to Lojacono’s indications. Hence, we chose as lectotype the iconography that Lojacono proposed within the protologue.

The specimen designated as lectotype of the name Euphorbia chamaesyce var. maculata Parl. reports a label containing the locality of collection (Boboli gardens, Florence), the date of receipt of Parlatore’s collection in FI (1860), and the citation of the protologue. Moreover, on the label the name “ Euphorbia canescens L.” was later overwritten with “ Euphorbia chamaesyce β Parl. Fl. It. ” by Parlatore (both names correspond to his handwriting). Indeed, notwithstanding Parlatore stated in the protologue that the varieties γ and β grow together, the same Author clearly attributed this specimen to β variety, thus to the name Euphorbia chamaesyce var. maculata .

Figures

FIGURE 8. Euphorbia reichenbachiana Lojac. lectotype from iconography by Reichenbach (1843: CXXXI, Fig. 4752, under the name E. maculata).