Rourea martiana Baker, in Martius, Fl. Bras. 14(2): 178. 1871.

Toledo, Cassio A. P., Souza, Vinicius Castro & Lucas, Eve J., 2020, Nomenclatural and taxonomic updates in Rourea subgen. Rourea sect. Multifoliolatae (Connaraceae), PhytoKeys 169, pp. 137-175 : 137

Rourea martiana Baker, in Martius, Fl. Bras. 14(2): 178. 1871. Fig. 1B

Santalodes martianum (Baker) Kuntze, Revis. Gen. Pl. 1: 155. 1891.

Type.

Brazil. Minas Gerais: Tabuleiro ad. fl. S. Francisco, prope Salgado, s. d. (fl.), C. F. P. von Martius 1675 (Lectotype: M, first step designated by Schellenberg 1938; lectotype: M barcode M-0243940!, second step designated here; isolectotype: M!).

Description.

Shrubs or scandent shrubs, (0.8-)1-3 m tall; branchlets sparsely hirsute to hirsute, lenticels abundant, inconspicuous. Leaves 9-13(-15)-foliolate, congested or loosely disposed; petiole 0.8-1.8 cm long, sparsely hirsute, with glandular trichomes; rachis 4-6 cm long, sparsely hirsute, with glandular trichomes; leaflets opposite to subopposite, subsessile; blade of the basal pair of leaflets 0.9-1.8 × 0.6-1.2 cm, orbicular, ovate or narrowly elliptic, others 1.2-3(-4) × 0.7-1.6 cm, oblong, narrowly elliptic or narrowly obovate, chartaceous, slightly discolorous, abaxially hirsute or villous, brownish or greenish, adaxially subglabrous, sparsely hirsute or sparsely villous, dull, base slightly asymmetric or symmetric, cordate, subcordate or rounded, apex rounded, rarely obtuse, margin flat, ciliate; midvein abaxially prominent, adaxially flat, secondary veins ca. 6 pairs, abaxially slightly prominent, adaxially flat, tertiary veins slightly prominent on both surfaces. Inflorescences in axillary or pseudoterminal cymes; bracts ca. 3 mm long; peduncle 0.9-3.8 cm long, hirsute, with glandular trichomes; rachis 0.5-2.2 cm long, hirsute, with glandular trichomes. Flowers congested apically; buds 4 × 2.5-3 mm, elliptic or orbicular; pedicel ca. 2 mm long, with glandular trichomes, 2 bracteoles located up to the lower half, persistent; sepals 5 × 2-2.5 mm, chartaceous, ovate, outer surface hirsute, with glandular trichomes, inner surface glabrous or subglabrous, sparsely sericeous at the apex, margin ciliate, more densely at the apex; petals ca. 7 × 2.5 mm, narrowly obovate, glabrous on both surfaces; stamens connate at base by ca. 1 mm, shorter series ca. 5 mm long, longer series ca. 7 mm long, glabrous; ovary ca. 1 mm long, hirsute, style ca. 2 mm long, hirsute, glabrous only at the apex, stigma peltate, bilobate. Fruits 1-1.2 × 0.4-0.5 cm, orangish or reddish, outer surface subglabrous or sparsely villous, more densely at the apex, inner surface glabrous or subglabrous, apex obtuse, style partially persistent, calyx covering one third of the fruit; seeds ca. 0.8-0.9 × 0.4-0.5 cm, arillode yellowish.

Distribution, habitat and phenology.

This species occurs in central and northeast Minas Gerais and southwest Bahia (Fig. 8 ). Rourea martiana is a shrub, occasionally with climbing branches and grows in the Cerrado or in transitional areas with Caatinga or Atlantic Forest. Specimens have been collected with flowers in April and August and with fruits in October.

Specimens examined.

Brazil. Bahia: Caetité, 5-8 km S, 21 Oct 1995 (fl.), G. Hatschbach & J. T. Motta 63237 (RB); Riacho de Santana, Estrada para Igaporã, km 89, 13.7487S, 42.7673W, 12 Oct 2007 (fr.), J. Paula-Souza et al. 9376 (CTES, SI, SPF). Minas Gerais: Grão Mogol, Assentamento Americana. 19 Nov 2014 (fr.), A. B. Giroldo & J. B. Pereira 330 (CEN); Divisópolis, próximo da cidade, s. d. (fl.), G. M. Magalhães 15790 (BHCB); Januária, Vale do Peruaçu, Carascal, 26 Oct 1997 (fr.), A. Salino & L. C. N. Neto 3706 (BHCB, MBM, SPF); Comunidade Boa Vista, 02 Nov 2006 (fr.), A. C. Sevilha 4597 (CEN); Juramento, Plantar MG 15, Fazenda Tamanduá, 10 Apr 2005 (fl.). E. Temeirão Neto 4225 (BHCB); E. Temeirão Neto 4273 (BHCB).

Recognition and notes.

Rourea martiana is recognised by possessing glandular trichomes, a relatively long-peduncle (0.9-3.8 cm) and a short pedicel (ca 2 mm long).

Baker (1871) described Rourea martiana based on the collections of Martius 1675 and Warming 1849, without mentioning the type; the former is only deposited in M, while the latter is deposited in C, GH and K. Schellenberg (1938) inadvertently indicated the lectotype of R. martiana (Martius 1675) and described R. cnestidifolia , citing Warming 1849 as paratype. Forero (1976) followed Schellenberg’s position, although he called the specimen Martius 1675 holotype of R. martiana , and selected Warming 1849 from K as lectotype of R. cnestidifolia after the holotype from B (Sellow s. n.) was considered missing. Baker (1871) indeed described R. martiana based on two specimens that should be treated as different taxa, so Schellenberg (1938) was right in selecting a type for R. martiana and describing R. cnestidifolia . The former differs by the middle and apical leaflets up to 4 cm long with usually rounded apex, while in the latter, leaflets are longer than 4 cm with obtuse, acute or narrowly rounded apex.

After fixing the application of R. martiana to Martius 1675, however, both Schellenberg (1938) and Forero (1976, 1983) seem to have confused the identity of the species and grouped specimens morphologically distinct and geographically isolated. The type of R. martiana was collected in Minas Gerais and, although without a precise location, this specimen matches those collected in central and northeast of the state and south-western Bahia, which are characterised by leaves 9-15-foliolate and a short pedicel (ca. 2 mm long). The specimens, here treated under a new species ( R. diamantina ) - but identified as R. martiana by Schellenberg (1938) and Forero (1976, 1983) - are restricted to central Bahia and characterised by leaves 5-9(-13)-foliolate and a longer pedicel (5-13 mm long). Additionally, leaflets in R. martiana become slightly larger towards the apex and are usually oblong or narrowly elliptic with rounded apex (Fig. 1B ), whereas in R. diamantina , they become significantly larger towards the apex and are usually narrowly ovate with obtuse or narrowly-rounded apex (Fig. 7B ). Both species are morphologically similar due to the presence of glandular trichomes, leaves and leaflets relatively small and flowers and fruits with similar characteristics. Geographically, these two species are separated by the Chapada Diamantina (Fig. 8 ), a mountain range located in central Bahia approximately 41,700 km2 long and altitudes up to 2,000 m. They also occur in different environments: R. martiana grows in areas of Cerrado s. s. (occasionally with rocky soils), while R. diamantina grows in seasonal forests on Inselbergs.

The position taken by Schellenberg (1938) and Forero (1976, 1983) may be explained because the specimens from Minas Gerais were not available at the time. Nevertheless, the disjunct distribution and the morphological differences are consistent enough to recognise R. martiana and R. diamantina as distinct species.

The type collection from M is composed of two herbarium sheets mounted separately, but one of them (barcode M-0243940) has an original blue label of Martius, whereas the other (barcode M-0243941) has a different label. According to the Code ( Turland et al. 2018, Art. 8.3, Ex. 10), these should be regarded as duplicates, so a second step lectotypification is here proposed.

Figures

Figure 1. Leaves in Rourea subgen. R. sect. Multifoliolatae: A R. discolor B R. martiana C R. tenuis D R. cnestidifolia.

Figure 7. Rourea diamantina: A flowering branchlet B leaf, abaxial surface C indumentum, leaflet abaxial surface D flower, external view E flower, internal view F stamens G ovary, external view H ovary, internal view and ovules I fruit and seed, external view J seed, external view K sepal indumentum, external view.

Figure 8. Geographic distribution of Rourea diamantina (circles) and R. martiana (triangles).