Trianthema sedifolia Visiani (1836a: 203

Clementi, Moreno, D’Antraccoli, Marco & Miola, Antonella, 2019, Nomenclatural and taxonomical notes on some taxa described by Roberto de Visiani from Egypt and Sudan, Phytotaxa 399 (1), pp. 49-64 : 55

Trianthema sedifolia Visiani (1836a: 203 ; also treated in Visiani 1836b: 19; 1836c: 66)

Locus classicus: —“circa Chartum in Sennaar”.

Lectotype (designated here):—Illustration in Visiani 1836a: tab. 3 fig. 1 (see Fig. 4 ).

Additional specimen examined: — EGYPT. s.l., [1824–1826], Brocchi s.n. (PI005425!).

Note:—The only available specimen we examined bears, in the handwriting of Visiani and with his signature, the indication “In Aegypto”, while the locus classicus mentions Khartoum, Nubia. It is possible that in this occasion Visiani used “ Egypt ” as a generic term to refer to the whole area, especially taking into account that Khartoum was indeed an Egyptian city at that time (see introduction). It was also certainly recognised by Visiani himself as pertaining to his T. sedifolia . Nevertheless, according to the identification key available in Hassan et al. (2005), the description in Hartmann et al. (2011), the protologue itself ( Visiani 1836a), and as was confirmed by Aizoaceae expert Sigrid Liede-Schumann (pers. comm.), the said specimen certainly does not belong to T. sedifolia : the most striking inconsistencies being the size and shape of its leaves (2.5–3.0 × 1.5–2.1 mm, vs 5–12 × 0.5–2.0 mm in T. sedifolia ) and the fact that it is completely covered in idioblasts, whereas they are sparse in T. sedifolia , in the sense that this taxon is now accepted by e.g. Hartmann et al. (2011) and other recent authors. We could only tentatively identify PI005425 as pertaining to Sesuvium sesuvioides (Fenzl) Verdcourt (1957) . The only available specimen from the original material is therefore “in serious conflict with the protologue”, so that “an element that is not in conflict with the protologue is to be chosen” (see Art. 9.19, Turland et al. 2018). Given that the treatment in Hartmann et al. (2011) was based on the illustration accompanying Visiani (1836b), we consider it particularly suitable as a lectotype. Due to the challenges presented and the scant material available, any attempt at designating an epitype should be left to the specialists on this group of plants.

Figures

FIGURE 4. Lectotype of Trianthema sedifolia Vis. Reproduced from Visiani (1836a: tab. 3 fig. 1).