Ouratea roraimae Engl.
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Authority
Maguire, Bassett. 1989. The Botany of the Guayana Highland- Part XIII. Mem. New York Bot. Gard. 51: 1-127.
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Family
Ochnaceae
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Scientific Name
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Description
Species Description - Small tree or shrub. Leaves thick-coriaceous, oval, oblong-ovate or broadly ovate, rounded or obtuse to acute at apex, rounded to obtuse at base, 6-14 cm long, 3.5-8.5 cm wide, mainly entire except obsoletely crenulate toward the apical portion or extending basally with 5-6 crenulations per cm, upper and lower surface prominently nerved, the upper surface with numerous approximate lateral and intermediate nerves (1.5- 3 mm apart) widely spreading at a 10°-15° angle, tertiary venation areolate-alveolate, minutely reticulate and finer than that of the lateral or intermediate nerves, the nervation of the lower surface similar but more prominently elevated; petioles (4-)5-10 mm long. Inflorescence paniculate 7-25 cm long, 6-12 cm wide, with several (3-8) ascending, simple and many-flowered axes 4-15 cm long; pedicels 2-8(-11) mm long. Flower bud ovoid, obtuse, 5-7 mm long, 3 mm wide. Sepals oblong-lanceolate to lance-elliptic, obtusish,
Distribution and Ecology - Savanna and riparian woodlands of the Venezuelan Guayana, Guyana, and Roraima, Brazil, at 100-850 m elevations.
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Discussion
Specimens examined. VENEZUELA, territorio federal amazonas: Base of Esmeralda Ridge, Esmeralda, 100 m, 20 Oct 1928, Tate 276 (NY); hilltop wooded savanna, E slopes of Cerro Calentura (nr. headwaters of Cafio Parucito), ca. 5°56'N, 65''40'W, 110 m, 11 Apr 1974, Jangoux 10103 (VEN); Canaripo, 4°05'N, 66°50'W, 124 m, 2 Mar 1977, Steyermark, Redmond & Heny 113814 (VEN); Dept. Atabapo, sabana sobre arena blanca en los alrededores de la pista de aterrizaje, Canaripo, en la margen izquierda (sur) del bajo Rio Ventuari, a unos 20 k m al E de la confluencia con el Rio Orinoco, 4°03'N, 66°49'W, 98 m, 29 May 1978, Huber 1889 (VEN); Dept. Atures, sabana de arena blanca en la ribera N (derecha) del Rio Ventuari, frente al caserio de Canaripo, 4°09'N, 66^50'W, 100 m, 22 Aug 1978, Huber 2440, 2440A (VEN); Dept, Atabapo, sabanita a unos 10 k m al N E del Cerro Moriche, en la ribera E del medio Rio Ventuari, 4°48'N, 66°17'W, 120 m, 16 Feb 1979, Huber 3436 (VEN); Dept. Rio Negro, domo rocoso de gneiss granitoide en la ribera derecha del Rio Siapa medio, ca, 15 km al E de la Punta N del Cerro Aracamuni, 1*'41'N, 65''41'W, 350 m, 6 Feb 1981, Huber & Medina 5784 (NY, VEN). bolivar: Cerca del Puerto del Uaiparu, afluente del Ikabaru, Caroni, 700 m, 24 Oct 1946, Cardona 1892 (VEN); sabanetas del camino a las cabeceras del Rio Carun, Alto Paragua, 500 m, Feb 1948, Cardona 2447 (VEN), doubtful (with anthers more verruculose); Cerro Bolivar above Tunnel No, 5, 750 m, 25 Feb 1953, Maguire & Wurdack 34395 (MO, N Y , VEN); Chinese Slide on N lower slope of Cerro Bolivar, 300-400 m, 24 Oct 1953, Maguire, Wurdack & Bunting 35971 (NY, VEN); sabanas, Canaima, 26 Dec 1954, Quezada s.n. (VEN); savannas, E ridge, Cerro Bolivar, on principal ore body, vie. sect. 22, 625, 1 Dec 1957, B. Maguire 32658 (NY, VEN); Isla del Rio Hacha, regi6n de Canaima, ca. 600 m, subiendo el rio desde el Salto Hacha, ca. 6°15'N, 62°46'W, 200-500 m, 15 Feb 1964, Agostini 229 {NY, VEN); Rio Carrao, Isla frente al "Ucaima," 450 m, 12 Dec 1966, Rutkis 68 (VEN); region de Canaima, entre el hotel y el Salto Hacha, 6*'15'N, 62°47'W, 400 m, 18 Jun 1972, Steyermark 106366 (VEN); La Gran Sabana, wet savanna, Kavanayen, 1300 m, 3 Dec 1973, Davidse, Ramia & Montes 4802 (VEN); Canaima Lagoon nr. Avensa Camp, shore, quartz sand, 500 m, 6 Oct 1974, Ehrendorfer 74.10-6-1.2 (VEN); Canaima Lagoon, N and E of Avensa Camp, inundated varzea forest and remnants of gallery forest above high water line, quartz sand, ca. 500 m, 11 Oct 1974, Ehrendorfer 74.10.11-16 (VEN); Represa Guri, 7°46'N, 63°00'W, 250-350 m, 31 Mar 1981, Liesner & Gonzalez 11011 (MO, VEN).
The O. roraimae taxon is characterized by having an alveolate-areolate reticulation of the tertiary venation especially well developed on the lower leaf surface, a large much-branched panicle with elongate, simple, densely manyflowered lateral axes, relatively short pedicels, an elongate fmiting torus, and a gynophore usually longer than the ovary in anthesis. Specimens from the eastem portion of the Venezuelan Guayana in Estado Bolivar well show the above characters. Some specimens, however, from the Territorio Federal Amazonas in westem Venezuelan Guayana are doubtfully included with the specimens cited, but have the characteristic reticulate type of leaf venation of O. roraimae.