Euphorbia nudiflora Jacquin (1791:180)

Steinmann, Victor W., 2023, Typification of Mexican Euphorbia (Euphorbiaceae), Phytotaxa 630 (1), pp. 61-68 : 64

Euphorbia nudiflora Jacquin (1791:180) , nom. illeg. (non E. nudiflora Lamarck 1788: 426 ).

≡ Euphorbia cymosa Poiret (1812: 611) . ≡ Aklema nudiflora (Jacq.) Rafinesque (1836 [1838]: 114).

Neotype (designated here):— AUSTRIA. s.l., s.d., Anonymus s.n. ( W (ex herb. Portenschlag) no. 0051347 photo!).

Euphorbia nudiflora was proposed based on plants obtained from England and cultivated in Austria. These were possibly brought to the elder Nicolas Joseph Jacquin by his son, Joseph Franz Jacquin, who according to Thiselton-Dyer (1891) traveled to England in 1788. The native source of these plants was unknown to him [“sine indicata patria”]. No specimens were cited in the protologue, but two years later an illustration was published in Icones Plantarum Rariorum ( Jacquin 1793: tab. 479).

Jacquin’s name is an illegitimate homonym of E. nudiflora Lam. , published just three years earlier for a different taxon ( Lamarck 1788). Poiret (1812) recognized this problem and conceived the replacement name E. cymosa Poir. However , Poiret’s name was either overlooked or ignored, and for nearly two centuries Euphorbia nudiflora continued to be used (e.g., Grisebach 1859, Klotzsch 1860, Boissier 1862, Adams 1972). Although its native range was initially unknown, Grisebach (1859) reported it as occurring in Jamaica, St. Vincent, and Mexico; Klotzsch & Garcke (1860) listed its distribution as Jamaica and St. Vincent; and Boissier (1862) reported it from Jamaica, St. Vincent, and Santa Martha [ Colombia]. Since then, the range of this drought deciduous shrub has generally been accepted to be the Lesser Antilles and adjacent northern South America ( Govaerts et al. 2000, Acevedo-Rodríguez & Strong 2012), in addition to Mexico (Villaseñor 2016).

Despite not citing specimens in his descriptions of new species, Jacquin material can often be linked to his names ( D’Arcy 1970). In the case of Euphorbia cymosa , original material has not been found in the herbaria of the British Museum (BM) or the J.E. Smith herbarium within the Linnean Herbarium (LINN), two of the institutions most likely to house his collections. At the Naturhistorisches Museum Wien (W), there is a specimen annotated by J. Walter in 2014 as probable type material (W barcode W0051347 photo!). It bears the name Euphorbia nudiflora but does not provide a collector or date of collection. The only information is “hb. Portenschlag,” thus indicating that it was from the herbarium of the Austrian botanist Franz von Portenschlag-Ledermayer (1772–1822). Although this specimen may be from the same cultivated plants that were available to Jacquin, there is no indication of him actually studying it, and the specimen was probably collected after his 1791 publication. With regard to the illustration in Icones Plantarum Rariorum, this too was published after the original description, and it is uncertain if it was available at the time of Euphorbia nudiflora ’s publication. In the absence of proof of the existence of original material, the collection listed above from the Portenschlag Herbarium is hereby designated as neotype. It agrees with the description provided in the protologue and allows a more precise morphological interpretation than the illustration in Icones Plantarum Rariorum, which lacks some details.