Stillingia pietatis McVaugh (1995: 210)

Mariaathiê-Souza, Sarah, Melo, André Laurênio De, Silva, Marcos José Da & Sales, Margareth Ferreira De, 2016, New synonyms and typifications of Stillingia (Euphorbiaceae), Phytotaxa 266 (3), pp. 183-194 : 186

3. Stillingia acutifolia (Benth.) Hemsley (1883: 135) .— Sapium acutifolium Bentham (1842: 90) .— Gymnostillingia acutifolia (Bentham) Müller Argoviensis (1863: 89) . Type:— GUATEMALA. Sololá: Hacienda de Argueta, 1841, C. T. Hartweg 614 (holotype K 000600955! [photo in MO!], isotypes BM 000947498!, F 869692!, G 00386189!, G-DC 00319723!, K!, LD 1213035!, NY!, P 04864830!).

Stillingia pietatis McVaugh (1995: 210) , syn. nov. Type:— MEXICO. Michoacán: Mpio. Yurécuaro or La Piedad, near summit of Cerro Grande de Cujuarato, SW of La Piedad, 30 August 1994, S. Zamudio, R. González & E. Pérez 9352 (holotype IEB, isotypes MICH 1000017A!, MICH 1000017B!, NY 00023309!, TEX 00000538! XAL!).

Sapium acutifolium was described by Bentham (1842) based on the single collection Hartweg 614 ( Fig. 1 ). Müller Argoviensis (1863) transferred the species to the new genus Gymnostillingia Müller Argoviensis (1863: 89) , probably due to lack of acropetiolar glands and occurrence of staminate cymules with only one flower. Subsequently, Hemsley (1883) proposed the new combination Stillingia acutifolia .

McVaugh (1995) later described Stillingia pietatis based on Zamudio et al. 9352 ( Fig. 2 ), characterizing it, among other characters, by having “... cymulis ♂ unifloris, foliis late ovatis valde acuminatis... ”, characters also found in S. acutifolia .

A comparative analysis of types and specimens of Stillingia acutifolia and S. pietatis showed that both names refer to the same taxonomic entity. The collections share herbaceous and fistulous branches, serrulate and eglandular leaves with acuminate apex, fimbriate stipules with long projections similar to a tuft, achlamydeous pistillate flowers, staminate cymules with only one flower, sessile disciform to ellipsoid glands in the floral bracts, floral bracts with caudate apex, and ecarunculate (rarely carunculate) seeds with a blackish line on the ventral side. Stillingia acutifolia is the oldest epithet and has priority over S. pietatis (ICN Art. 11.4).

Rogers (1951) recorded the occurrence of Stillingia acutifolia in Chiapas, Mexico, and in several departments of Guatemala, while McVaugh (1995) mentioned that S. pietatis was restricted to a volcanic region of Michoacán, also in Mexico. With the inclusion of S. pietatis in the circumscription of S. acutifolia the geographic distribution of the species was broadened and also registered in the state of Guerrero, in Mexico. Therefore, S. acutifolia is herein designated a least concern (LC) species according to the IUCN red list because it is widespread and abundant ( IUCN 2014).

Figures

FIGURE 1. Holotype of Sapium acutifolium Bentham, C.T. Hartweg 614 (K 000600955).

FIGURE 2. Isotype of Stillingia pietatis McVaugh, S. Zamudio, R. González & E. Pérez 9352 (NY 00023309).