Rourea blanchetiana (Progel) Kuhlm., Arq. Inst. Biol. Veg. 1: 40. 1934.

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 blanchetiana (Progel) Kuhlm., Arq. Inst. Biol. Veg. 1: 40. 1934. Illustration: Progel (1877) and Schellenberg (1938)

Eichleria blanchetiana Progel, in Martius, Fl. Bras. 12(2): 518. 1877.

Type.

Brazil. Bahia: S. d. (fl., fr.), J. S. Blanchet 1050 (Lectotype: BR barcode BR 00000528168!, designated here; isolectotypes: G!, S!, W!).

Description.

Lianas: branchlets sparsely hirsute to hirsute, lenticels abundant, inconspicuous. Leaves 27-39-foliolate, loosely disposed; petiole 1.4-2.2 cm long, sparsely hirsute to hirsute, with glandular trichomes; rachis (8-)10-14.5 cm long, sparsely hirsute to hirsute, with glandular trichomes; leaflets subopposite to alternate, pulvinulus ca. 1 mm long; blade of the basal pair of leaflets 0.9-1.5 × 0.6-0.9 cm, orbicular or oblong, others 1.3-2.9 × 0.6-1 cm, oblong, the apical ones elliptic, membranaceous to subchartaceous, discolorous, abaxially glabrous, subglabrous or sparsely hirsute on the midvein, glaucous, adaxially glabrous, dull, base symmetric or slightly asymmetric, rounded or subcordate, obtuse in the apical leaflet, apex rounded, rarely truncate, obtuse in the apical leaflet, margin flat, glabrous; midvein abaxially slightly prominent, rarely prominent, adaxially slightly impressed, rarely impressed, secondary veins 5-7 pairs, abaxially slightly prominent or flat, adaxially flat, tertiary veins flat on both surfaces. Inflorescences in axillary cymes; bracts ca. 1 mm long; peduncle (2-) 3.5-6.7 cm long, densely hirsute, with glandular trichomes; rachis 0.5-2.2 cm long, densely hirsute, with glandular trichomes. Flowers congested apically; buds 3-6 × 2-3 mm, elliptic; pedicel 8-13 mm long, with glandular trichomes, 1-2 bracteoles located in the middle portion, deciduous; sepals 4-6 × 1-1.5 mm, chartaceous, lanceolate, outer surface hirsute, with glandular trichomes, inner surface subglabrous, margin ciliate; petals 9-14 × 2 mm, oblong or narrowly obovate, glabrous on both surfaces; stamens connate at base by ca. 1 mm, shorter series ca. 1 mm long, longer series ca. 2 mm long, with sparse glandular trichomes; ovary ca. 1.2 mm long, hirsute, style ca. 2.5 mm long, sparsely hirsute, subglabrous or glabrous only at the apex, stigma peltate, bilobate. Fruits 1.2 × 0.6-0.7 cm, colour not seen, outer surface sparsely hirsute, inner surface not seen, apex acuminate, style deciduous, calyx covering one third of the fruit; seeds ca. 1 × 0.4 cm, arillode colour not seen.

Distribution, habitat and phenology.

Most of the known specimens of R. blanchetiana are old collections with no precise locations. The most recently analysed specimen was collected in the municipality of Nilo Peçanha, which is located in southern Bahia (Fig. 3 ). Therefore, it seems that R. blanchetiana is a rare species and most likely restricted to the south portion of Bahia. This is a lianescent species growing on ombrophilous forests of the Atlantic domain. The specimen J. S. Blanchet s. n. (NY barcode NY00393553) was collected with flowers and fruits in August.

Specimens examined.

Brazil. Bahia: Locality unknown: Aug 1835 (fl., fr.), J. S. Blanchet s. n. (NY barcode NY00393553); s. d. (fl.), J. S. Blanchet s. n. (?) (P barcode P05487855). Nilo Peçanha, estrada a ca. 4 km da comunidade Quilombola de Jatimane na estrada para Ituberá, fazenda Outeiro do Chapeú, 13°40'06"S, 39°04'50"W, 14 Apr 2012 (st.), L. P. de Queiroz & F. H. F. Nascimento 15452 (HUEFS); Locality unknown, s. d. (fl.), J. S. Blanchet 297 (P barcode P05487854); s. d. (fl.), P. Salzmann s. n. (MO 1704495, P barcode P05487856).

Recognition and notes.

Rourea blanchetiana is easily recognised by the leaves with 27-39 leaflets, which are usually membranaceous, oblong and abaxially glaucous, aside from the flowers congested in the inflorescences, comparatively larger peduncle and petals 9-14 mm long. It is similar to R. discolor due to the leaflets abaxially glaucous and pedicel relatively long, but differs by the hirsute inflorescence rachis, elliptic flower buds and petals 9-14 mm long vs. glabrous or subglabrous inflorescence rachis, orbicular or ovate flower buds and petals (4-)6-8 mm long.

In the protologue of the basionym of Rourea blanchetiana from Flora Brasiliensis, the only specimen cited by Progel (1877) was Blanchet 1050, without indication of herbarium. Schellenberg (1938) inadvertently selected the lectotype from P. However, of the six specimens of R. blanchetiana , collected by Blanchet in P, none is annotated with number 1050. Specimens of Blanchet 1050 were found in BR, G, S and W and only the collection from G is fruiting, the rest, only flowering. Of these, the specimen from BR has an original label of "Herbarium Martii", identified as " Eichleria blanchetiana Prog. in Mart. fl. Br." and bears an attached pencil drawing containing floral details of the referred species. The characteristics of the branchlet of this specimen (number and shape of leaflets, inflorescence architecture and flower structures) and the detailed drawing match accurately with the illustration in Progel (1877, plate 116). In addition, considering that Progel worked in M and the original Flora Brasiliensis collection from M was sold to BR, then the specimen Blanchet 1050, deposited in the latter, seems the best candidate to be lectotype of R. blanchetiana , which is here proposed.

Rourea blanchetiana was originally described in Oxalidaceae ( Progel 1877). The author published the basionym under his new genus Eichleria , based on the similarity between Connaraceae and Oxalidaceae with respect to the imparipinate leaves and heterostylous flowers with apocarpous gynoecium. Kuhlmann (1934) firstly noticed this confusion and proposed the prompt combination after concluding that the species bear two ovules with marginal placentation, characteristic of Connaraceae . The close relationship between Connaraceae and Oxalidaceae has been confirmed by modern phylogenetic analyses and they form a monophyletic group within Oxalidales (APG IV 2016); Connaraceae differs morphologically from Oxalidaceae by the completely free carpels and follicular fruits.

Figures

Figure 3. Geographic distribution of Rourea bahiensis (circles), R. barbata (triangles) and R. blanchetiana (squares).