Rourea amazonica (Baker) Radlk.
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Authority
Forero, Enrique. 1976. A revision of the American species of Rourea subgenus Rourea (Conaraceae). Mem. New York Bot. Gard. 26 (1): 1-119.
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Family
Connaraceae
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Scientific Name
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Description
Species Description - Scandent shrub, shrub or small tree; branchlets terete, glabrous or puberulous. Leaves 1-2-jugate, rarely unifoliolate; petiole 1.5-3.5 cm long, glabrous; rachis 1-10 cm long, glabrous. Leaflets 6-31 cm long, 3-15 cm broad, elliptic or obovate, chartaceous, glabrous above and below, the apex sharply or gradually acuminate, the base attenuate or obtuse; petiolule 0.2-0.5 cm long; venation reticulate, diffuse, plane above, prominulous (midrib prominent) below; lateral veins 6-7 pairs, ascending, anastomosing diffusely near margin. Inflorescence paniculate, pseudoterminal, the rachilla 4-13 cm long, puberulous; bracts 0.1-0.15 cm long, triangular, minutely puberulous. Pedicels articulate, very short or 0.1-0.4 cm long, puberulous; sepals 0.3-0.4 cm long, 0.1-0.2 cm broad, oblong-lanceolate, oblong-elliptic or ovate-oblong, densely to sparsely puberulous without, puberulous within; petals 0.5 cm long, 0.1-0.2 cm broad, glabrous, free; stamens 10; anthers globose. Fruit 1-1.2 cm long, 0.3-0.5 cm wide, glabrous, recurved, the apex villous; calyx in fruit 0.5-0.6 cm long, lanceolate-elliptic, densely or sparsely puberulous, the margin ciliate. Seed 0.6-1 cm long, 0.3-0.4 cm wide; arilloid 0.2-0.3 cm long; testa under arilloid smooth.
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Discussion
Rourea glabra var amazonica Baker in Martius, Fl. Brasil. 14(2): 182. 1871, pro parte. Lectotype examined (M). Brazil, Rio Negro, “in sylvis Yapurensibus.” Martius s.n. fr. w/o date. (Lectotype selected by Schellenberg, 1938). Rourea amazonica Huber, Bol. Mus. Goeldi 5: 373. 1909. Holotype examined (MG). Fragment and photograph of holotype examined (F). Brazil, Amazonas, Rio Negro, Paraná do Adaucá a W de Faro. A. Ducke 8659 fr. 7 Sep 1907. Isotype examined (RB). The variability found in R. amazonica is not surprising, given its wide area of distribution. Its distinction from the closely related and very similar R. puberula is often difficult. The pictorialized scatter-diagram in Fig. 24 shows the correlation between maximum leaflet length, maximum inflorescence length, length of the pedicel and density of indumentum on the calyx in R. puberula and R. amazonica. None of these characters, when taken separately, is absolutely diagnostic; the values for one species overlap with those of the other so that there is no clearcut discontinuity between them. But when these characters (especially leaflet length and inflorescence length) are used in combination, as shown in the pictorialized scatter-diagram, the two species can be readily separated. Rourea amazonica is a species with considerable biological diversity, as can be seen from the scatter-diagram in Fig. 24. The following forms can be distinguished when the material available is examined closely, and after the different characters are plotted in the scatter-diagram. These forms are best left unnamed until the species becomes better known throughout its range: (a) The populations from western Amazonia (Dept. Loreto, Perú), characterized by the sessile or very short-pedicellate flowers and fruits, the large leaflets of which the terminal one is usually obovate, the sharply and abbreviately acuminate apex of the leaflets, the usually long inflorescence, and the densely puberulous calyx. (b) The populations from south-central Amazonia, characterized by the elliptic, smaller leaflets with gradually and usually long-acuminate apex of the leaflets, the sparsely puberulous calyx, the long inflorescence, and the longer pedicel and peduncle (0.3-0.5 cm long). This variant approaches R. puberula mainly in the size of the leaflets and in the length of pedicels and peduncles. (c) The reason for not recognizing the above forms as formal infra-specific taxa is the large number of intermediate variants found throughout the range of the genus. One of these intermediates is the type of the species (Martius s.n. from the area of the Rio Negro in Brazil), which has long pedicels and a sparsely pubescent calyx. Poeppig 2332, Tessmann 4030 and Williams 4091, from Perú, differ from the form growing in that country only in the smaller size of the leaflets. Tessmann 4053 and Woytkowsky 6278 differ in the longer pedicels. Williams 15293, from Amazonian Venezuela, approaches the Peruvian populations in the shape of the terminal leaflet and in the sharp and short-acuminate apex of the leaflets, but resembles the other form in the long peduncle and in the sparsely puberulous calvx.
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Distribution
Distribution. In the Brazilian states of Amazonas, Acre and Territory of Rondônia and adjacent Bolivia, in the territory of Amazonas in Venezuela, and in Dept. Loreto in Perú. Occurring in forests, river margins and edge of forest.
Brazil South America| Bolivia South America| Venezuela South America| Peru South America|