Rourea tenuis G. Schellenb., in Engler, Pflanzenreich IV. 127(Heft 103): 199. 1938.

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 tenuis G. Schellenb., in Engler, Pflanzenreich IV. 127(Heft 103): 199. 1938. Figs 1C , 12 ; illustration: Forero et al. (1984

Rourea carvalhoi Forero, Carbonó & L. A. Vidal, Revista Brasil. Bot. 7(1): 72. 1984. Type. Brazil. Bahia: Km. 6 da rod. Teixeira de Freitas a Alcobaça, 9 Oct 1971 (fr.), T. S. Santos 2094 (Holotype: CEPEC 7633!; isotypes: COL!, NY!).

Type.

Brazil. Vittoria, s. d. (fr.), F. Sellow s. n. (Holotype: B†). Brazil. S. d. (fl.), J. Pohl s. n. (Neotype: BR barcode BR 000000697468!, selected by Forero 1976).

Description.

Lianas or scandent shrubs, (0.5-)1-3 m tall; branchlets sparsely hirsute to glabrescent, lenticels absent or sparse, inconspicuous. Leaves 5-7-foliolate, loosely disposed or congested; petiole 2.7-7 cm long, sparsely hirsute, with glandular trichomes; rachis 2.6-6.5 cm long, sparsely hirsute, with glandular trichomes; leaflets opposite to subopposite, pulvinulus 1-2 mm long; blade of the basal pair of leaflets 2.3-5.7(-7.7) × 1.4-2.5(-4) cm, elliptic or ovate, others 3.5-8.4(-13) × 2.1-3(-6.7) cm, elliptic or ovate, rarely oblong, chartaceous, slightly discolorous, abaxially sparsely hirsute, more densely on the veins, brownish or greenish, adaxially sparsely hirsute on the veins, dull, base slightly asymmetric, symmetric in the apical leaflet, rounded, obtuse or subcordate, occasionally acute in the apical leaflet, apex obtuse or narrowly rounded, occasionally short-acuminate, margin flat to revolute, ciliate; midvein abaxially prominent, adaxially flat or slightly impressed, secondary veins 5-7 pairs, abaxially slightly prominent, adaxially flat, tertiary veins flat on both surfaces. Inflorescences in axillary or pseudoterminal determinate thyrses, rarely panicles; bracts ca. 2 mm long; peduncle 1.9-6.4 cm long, hirsute, with glandular trichomes; rachis (0.7-)2-5.8(-7.7) cm long, hirsute, with glandular trichomes; lateral branches 0.5-3 cm long, hirsute, with glandular trichomes. Flowers loosely disposed or congested apically; buds 2.5-4 × 1.5-2 mm, orbicular or elliptic; pedicel 5-10 mm long, with glandular trichomes, 2 bracteoles located up the lower third, persistent or deciduous; sepals 4-5 × 1-2 mm, chartaceous, ovate, outer surface sparsely hirsute, with glandular trichomes, inner surface glabrous, margin ciliate, more densely at the apex; petals 5-7 × 1.5-2 mm, oblong or narrowly oblong, glabrous or subglabrous on both surfaces; stamens connate at base by ca. 0.8 mm, shorter series 3-3.5 mm long, longer series ca. 5 mm long, glabrous; ovary ca. 1 mm long, densely hirsute, style ca. 1.5 mm long, sparsely villous, subglabrous at the apex, stigma peltate, trilobate to pentalobate. Fruits 1.3-1.5 × 0.6-0.8 cm, reddish or orangish, outer surface sparsely hirsute, more densely at the apex, inner surface glabrous, apex acuminate, style partially persistent, calyx covering one third of the fruit; seeds 1.2-1.3 × 0.5-0.7 cm, arillode colour not seen.

Distribution, habitat and phenology.

Rourea tenuis occurs in Bahia and Espírito Santo, with limits ranging from the municipalities of Itanhém (North) to Linhares (South) (Fig. 11 ). This species is lianescent and grows in ombrophilous or “Tabuleiro” forests. Specimens have been collected with flowers from April to June and from October to November and with fruits from August to October and in March.

Specimens examined.

Brazil. Bahia: Porto Seguro, Parque Nacional de Monte Pascoal, área limite entre o PARNA e a Reserva Indígena Barra Velha, da tribo Pataxó, 13 Apr 1998 (fl.), A. M. Amorim et al. 2530 (CEPEC, NY); Itamarajú, Estrada a Piraji, km 4, 17°15'S, 39°20'W, 1 Jun 1983 (fl.), R. Callejas et al. 1612 (NY); Itamarajú, 2 km de estrada a Piraji, km 4, 5 Apr 1971 (fl.), T. S. dos Santos 1558 (NY!); Itanhém, Fazenda Pedra Grande, 16.2 km west of Itanhém on road to Batinga, then 0.6 km north to Fazenda (owner Otevaldo Resende da Silva), 17°07'57.8"S, 40°25'17.8"W, 18 Mar 2001 (fr.), W. W. Thomas et al. 12351 (CEPEC, NY, RB, SPF). Espírito Santo: Reserva Natural Vale, estrada Fruta de arara, 1 Jun 2001 (fl.), D. A. Folli 3940 (CVRD, ESA); Reserva Natural Vale, estrada Braúna Preta, 12 Apr 2002 (fr.), D. A. Folli 4352 (CVRD, ESA); Linhares. 5 km S, 5 Aug 1983 (fr.), G. Hatschbach 46735 (CEPEC, MBM); Floresta Atlântica de Tabuleiro, área com corte seletivo, em regeneração, 19.4000S, 39.9722W, 3 Oct 2000 (fr.), O. J. Pereira et al. 6541 (VIES).

Recognition and notes.

Rourea tenuis is recognised by leaves 5-7-foliolate, leaflets usually elliptic or ovate, abaxially hirsute and inflorescences in thyrses or panicles with glandular trichomes.

Forero (1976) included Rourea tenuis in Rourea subgen. R. sect. Multifoliolatae mainly due to the long staminal tube, reduced inflorescences and leaflets hairy. Aside from that, this species does not resemble other members of the section in overall similarity of leaves: in R. tenuis , the number of leaflets is reduced and they are usually relatively larger, with elliptic or ovate shape (vs. oblong, narrowly elliptic or narrowly ovate) (Fig. 1C ). Forero (1976) firstly noticed that R. tenuis could be a borderline species between those of R. subgen. R. sect. Multifoliolatae with those from the Amazon, then suggested that the morphological limits of the section should be re-evaluated ( Forero et al. 1984). The present study, therefore, considers that the circumscription of the whole group should be tested using molecular and phylogenetic approaches.

Figures

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

Figure 11. Geographic distribution of Rourea macrocalyx (circles), R. prostrata (triangles) and R. tenuis (squares).

Figure 12. Rourea tenuis, flowering branchlet (photo by Thiago Flores).