Tradescantia schwirkowskiana

Hassemer, Gustavo, Funez, Luís A. & Ferreira, João Paulo R., 2017, Tradescantia serrana (Commelinaceae), a new species from southern Brazil, and notes on T. schwirkowskiana and T. umbraculifera, Phytotaxa 312 (2), pp. 213-227 : 223

Tradescantia schwirkowskiana , taxonomic notes and range extension

Pellegrini et al. (2017: 4) proposed the synonymisation of T. schwirkowskiana with T. crassula . These authors support their decision by saying that …“the specimens cited by Funez et al. (2016) as representing T. schwirkowskiana , fit perfectly the circumscription adopted by us for T. crassula , showing variation only in the degree of branching of the stems, color of the leaf-blades, and degree of impression of the secondary veins”. Towards this end Pellegrini et al. (2017) also proposed an erroneous “correction” to the lectotypification and epitypification of T. crassula done by Funez et al. (2016) (see Hassemer et al. 2017). We disagree with the synonymisation proposed by Pellegrini et al. (2017), on the grounds that important morphological differences that separate these two species were not considered ( Table 3). Furthermore, these states do not represent intermediates or gradation of variation within a species. We highlight that T. schwirkowskiana (see Figs. 1–3 in Funez et al. 2016) has densely branched stems, not fleshy, with a line of trichomes opposite to the insertion of the leaf blade, whereas T. crassula (see Figs. 5–6 in Funez et al. 2016, and Fig. 1 in Pellegrini et al. 2017) has fleshy stems, not branching often, completely glabrous (Funez et al. 2016). Importantly, based on an extensive revision of herbarium specimens indicated below we could observe that the line of trichomes on the stems is a very useful taxonomic character within species in sect. Austrotradescantia. This character is very stable within the species, and it occurs in other species such as T. tenella . Overall, Pellegrini et al. (2017) failed to mention several characters that were given in Funez et al. (2016: 64–68) by which these two species differ. For instance, Funez et al. 2016 noted that “ T. schwirkowskiana has internodes with a line of multicellular trichomes opposite to leaf insertion, vs. glabrous stems in T. crassula ; furthermore, T. schwirkowskiana has membranaceous leaf blades, flat, elliptic to broadly elliptic, with conspicuous midvein and secondary veins on both faces vs. coriaceous to succulent, slightly revolute, elliptic to lanceolate blades, with secondary veins inconspicuous on both sides in T. crassula . The width of the valves of the capsule may also be used to distinguish T. schwirkowskiana , whose fruits have each valve 2 mm wide, while in T. crassula each valve is 3–4 mm wide”.

Until now T. schwirkowskiana was only known from the type locality, in São Bento do Sul, northern Santa Catarina (Funez et al. 2016). During the study of herbarium specimens we came across samples of this species collected in Paraná state, and in southern Santa Catarina (Urubici), which represent an extension of its current distribution range ( Fig. 4 ). Although T. schwirkowskiana still has a rather narrow distribution, discovery of these gatherings allows the reassessment of its conservation status and supports its change to a non-threatened category; i.e., Near Threatened (NT).

Material examined: — BRAZIL. PARANÁ: Piraquara: Fazenda Exp. de Agronomia , 13 October 1969, N. Imaguire 1258 (MBM-170010) ; Fazenda Exp. de Agronomia , 13 November 1973, N. Imaguire 3399 (MBM-170009) ; Quatro Barras: Morro Anhangava , 25 September 1998, A. Dunaiski Jr. & W. Amaral 761 (MBM-384235) ; São José dos Pinhais: Aeroporto Afonso Pena , 26 November 2009, R. Ristow et al. 231 (MBM-357787) ; São Mateus do Sul: Faz. do Durgo , 19 September 1986, W. S. Souza et al. 334 (MBM-120703) ; Tunas do Paraná: Parque Estadual de Campinhos , floresta ombrófila mista, 25°02’ S, 49°05’ W, 900 m, 21 October 2008, G. Weiss 86 (MBM-373234) ; SANTA CATARINA: São Bento do Sul: Serra Alta, ponte do Rio Banhados , 31 December 2013, P. Schwirkowski 197 (paratype FURB-46950; isoparatype MBM-392009) ; borda da ferrovia às margens do Rio Banhados , 16 November 2015, L. A. Funez & P. Schwirkowski 5037 (holotype FURB-50791; isotypes C, HURB) ; Urubici: Morro da Cruz , 9 November 2001, G. G. Hatschbach et al. 72486 (MBM-271372) .

Figures

FIGURE 1. Holotype of Tradescantia serrana (G. Hassemer & L.A. Funez 888, FURB).

FIGURE 2. Tradescantia serrana. A. Overview of upper part of a branch. B. Detail of stem and leaf sheaths.C. Detail of inflorescence. D. Detail of trichomes on pedicel. E. Detail of a trichome on pedicel. F. Detail of anthers. From G. Hassemer & L.A. Funez 888; illustrations by Lucas Cardoso Marinho.

FIGURE 3. Tradescantia serrana. A. Inflorescence. B. Detail of leaf sheath. C. Leaf, abaxial face. D. Leaf, adaxial face. E. Overview of specimens.

FIGURE 4. Distribution of Tradescantia schwirkowskiana (blue dot: previously known distribution; green dots: new records) and T. serrana (orange star).

FIGURE 5. Habitat of Tradescantia schwirkowskiana and T. serrana: edges and clearings of Araucaria forest.

FIGURE 6. Tradescantia chrysophylla. A. Inflorescence.B. Detail of leaf sheath.C. Leaf, adaxial face.D. Leaf, abaxial face.E. Overview of specimen.