Rourea diamantina C. Toledo, 2020

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 diamantina C. Toledo sp. nov. Fig. 7

Type.

Brazil. Bahia: Itatim, interior da mata da base do Inselberg, 12°45'12"S, 39°46'59"W, 26 Jan 1997 (fl.), E. Melo et al. 1985 (Holotype: ESA 84255!; isotypes: HUEFS!, UEC!, VIC!).

Diagnosis.

Akin to R. martiana due to the presence of glandular trichomes, relatively small leaves and leaflets and flowers and fruits with similar characteristics, but differs by the leaves 5-9(-13)-foliolate (vs. 9-15-foliolate), leaflet apices narrowly rounded or obtuse (vs. rounded) and pedicels 5-13 mm long (vs. ca. 2 mm long).

Description.

Lianas, shrubs or scandent shrubs, rarely treelets, 3-4 m tall; branchlets subglabrous or sparsely pubescent, lenticels abundant, conspicuous. Leaves 5-9(-13)-foliolate, congested; petiole 1.3-2.2 cm long, sparsely hirsute to glabrescent, eglandular; rachis 3-6(-8.5) cm long, sparsely hirsute to glabrescent, eglandular; leaflets opposite to subopposite, pulvinulus ca. 1 mm long; blade of the basal pair of leaflets 1.4-2 × 0.9-1.4 cm, ovate, others 2-4.5(-5.8) × (0.8-)1.2-1.7(-2.2) cm, narrowly ovate, rarely oblong, chartaceous, occasionally membranaceous, slightly discolorous, abaxially hirsute or villous, brownish or greenish, adaxially subglabrous, dull, base slightly asymmetric, rounded or subcordate, rarely obtuse, apex narrowly rounded or obtuse, margin flat or slightly revolute, ciliate; midvein abaxially prominent, adaxially flat or slightly impressed, secondary veins 5-7 pairs, abaxially slightly prominent, adaxially flat, tertiary veins abaxially slightly prominent, adaxially flat or slightly prominent. Inflorescences in pseudoterminal cymes, rarely ramiflorous; bracts 1.5-2.5 mm long; peduncle 0.8-1.7 cm long, sparsely hirsute, eglandular; rachis 1-2.5 cm long, sparsely hirsute, eglandular. Flowers loosely disposed; buds not seen; pedicel 5-13 mm long, with glandular trichomes, 2 bracteoles located up the lower half, persistent; sepals 4.5-5 × 2-3 mm, chartaceous, ovate, outer surface pubescent, with glandular trichomes, inner surface sericeous, margin ciliate; petals 7-8 × 2.5-3 mm, narrowly obovate, glabrous on both surfaces; stamens connate at base by ca. 1 mm, shorter series 2-3 mm long, longer series 3-4 mm long, glabrous; ovary ca. 1 mm long, densely hirsute, style ca. 4 mm long, sparsely hirsute, stigma peltate, bilobate. Fruits 1.1-1.4 × 0.6-0.7 cm, yellowish or orangish, outer surface subglabrous, sparsely hirsute at the apex, inner surface subglabrous, apex acuminate, style partially persistent, calyx covering one third of the fruit; seeds 0.7-0.9 × 0.4-0.5 cm, arillode colour not seen.

Distribution, habitat and phenology.

Rourea diamantina is only known from the east side of Chapada Diamantina, a mountain range of about 41,700 km2 and approximately 2,000 m altitude, located in the centre of Bahia (Fig. 8 ). Individuals of the new species are mostly shrubs with scandent branches, occurring in seasonal forests of Inselbergs. Specimens have been collected with flowers from September to December and with fruits from November to February and in July.

Paratypes.

Brazil. Bahia: Estrada para o Riacho do Meio, 12°18'18"S, 40°29'11"W, 07 Feb 2005 (fr.), D. Cardoso 242 (CEPEC, HUEFS, NY); Itaberaba, Fazenda Itaberaba, ilhas de vegetação em Inselbergs, 12°30'06"S, 40°05'03"W, 08 Feb 2007 (fr.), J. L. Ferreira et al. 301 (HUEFS); Morro do Agenor, 12°42'S, 39°46'W, 26 Nov 1995 (fl.), F. França et al. 1482 (HUEFS); Morro das Tocas: 12°43'S, 39°42'W, 28 Sep 1996 (fl.), F. França et al. 1844 (ALCB, HUEFS, SPF); 29 Sep 1996 (fl.), F. França et al. 1866 (HUEFS, SPF). Mucugê, Chapada Diamantina, caminho para Marimbus, 14 Dec 2013 (fr.), M. K. Guedes et al. 21064 (ALCB); Chapada Diamantina, Marimbus, 12°76'30"S, 41°30'91"W, 14 Nov 2014 (fr.), M. K. Guedes et al. 23112 (ALCB, MBML); Rodovia BR 116, Feira de Santana, Milagres, 12°43'S, 39°42'W, 24 Nov 2001 (fr.), J. G. Jardim 3973 (CEPEC, HUEFS); Morro do Agenor ou da Madeira, 12°43'S, 39°42'W, 17 Dec 1995 (fl.), E. Melo et al. 1409 (ALCB, HUEFS); Morro da Torre, 12°43'S, 39°42'W, 09 Nov 1996 (fr.), E. Melo et al. 1832 (ESA, HUEFS, RB); Itatim, interior da mata da base do Inselberg, 12°45'12"S, 39°46'59"W. 26 Jan 1997 (fr.), E. Melo et al. 1981 (ESA, HUEFS, UEC); Andarai, Alagados Marimbus, 12°45'55"S, 41°18'52"W, 07 Dec 2012 (fr.), E. Melo et al. 11815 (HUEFS); Rui Barbosa, Serra do Orobó, base da encosta da serra, 12°18'S, 40°29'W, 18 Dec 2004 (fl.), L. P. de Queiroz et al. 9894 (HUEFS); Machado Portello, 23 Jul 1915 (fr.), J. N. Rose & P. G. Russel 19932 (NY, US); Cachoeira, 03 Jan 1977 (fr.), P. de Souza s. n. (ALCB, CEPEC).

Etymology.

The specific epithet " Rourea diamantina " refers to Chapada Diamantina (Bahia, Brazil), where the new species is presumed to be endemic. This epithet is a noun in apposition ( Turland et al. 2018, Art. 23.5).

Recognition and notes.

Rourea diamantina is recognised by the leaves 5-9(-13)-foliolate, leaflets abaxially hirsute or villous, pedicel with glandular trichomes and sepals with indumentum sericeous internally. An interesting characteristic is the leaves whose leaflets become significantly larger towards the apex. The new species is similar to R. martiana , but differs by the reduced number of leaflets (usually 5-9), which are normally narrowly ovate with obtuse or narrowly-rounded apex, and longer pedicel (5-13 mm long) vs. leaves 9-15-foliolate, leaflets normally oblong or narrowly elliptic with rounded apex and a shorter pedicel (ca. 2 mm long). Additionally, both species are geographically isolated by the Chapada Diamantina (Fig. 8 ).

Some specimens, cited here under Rourea diamantina , were previously identified as R. martiana by Schellenberg (1938) and Forero (1976, 1983). After analysing modern collections from Bahia and Minas Gerais, this revision considers that the morphological differences indicated above and their disjunct distribution provide evidence to recognise R. diamantina apart from R. martiana . For a complete discussion on this subject, see "Recognition and notes" section of R. martiana .

Figures

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).