Sacoglottis guianensis Benth.
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Authority
Cuatrecasas, José. 1961. A taxonomic revision of the Humiriaceae. Contr. U. S. Natl. Herb. 35: 25-214. pl. 1-24.
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Family
Humiriaceae
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Scientific Name
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Type
Type: Bob. Schomburgk 574; paratype: Rich. Schomburgk 842, British Guiana.
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Description
Description - Large or medium-size tree with minutely hirtellous-puberulous or glabrous terminal branches. Leaves coriaceous, firm. Petiole 4-12 mm. long, minutely puberulous or glabrous, sulcate above. Blade elliptic, ovate-elliptic, subovatc or oblong-ovate, rounded, obtuse or cuneate at base, narrowed, acuminate or cuspidate at apex, slightly scrrate-crenate or subentire at margin; 5-15 cm. long, 3-6 cm. broad; above nitid, glabrous with flat midrib, lateral nerves and veins little or not conspicuous; beneath scattered, appressed, minute hairs or more frequently glabrous, midrib thick, eminent, secondary nerves 10-12 pairs, little ascendent more or less prominulous, near the margin arcuate-anastomosate, minor nerves finely reticulate slightly prominulous. Inflorescences axillary, cymose-paniculate, shorter than flowers, dichotomous, peduncle and branchlets shortly hirtellous-pubescent. Bracts amplcctant, ovate-triangular, ciliate, 0.5-1 mm. long, persistent. Pedicels very short, (0.1-0.2 mm. long), glabrous, articulate with 1-3 mm. long peduncles or sessile on pilose or glabrate terminal branchlets. Sepals ovate-rotundate 6-7 mm. long, puberulous and minutely ciliate. Petals greenish, rather thick, linear or oblong-lanceolate, subacute, glabrous or puberulous, 3-4.5 mm, long, 1.5 mm. broad at base. Stamens 10, filaments complanate, thickened, about lower half connate, 2.5 and 3 mm. long, alternating. Anthers ovate-lanceolate, 1 mm. long, thecae elliptic about 0.4 mm. long, connective thick, trigonous-lanceolate. Disk annular, membranous, denticulate, 0.5-0.6 mm. high. Ovary globose, glabrous, 5-locular, cells uniovulate. Style 2-3 mm. long, erect, glabrous. Stigma subcapitate, 5-lobate. Drupe ellipsoid-oblong, attenuate at base, subacute or subobtuse at apex, 15-30 mm. long, 9-12 mm. in diameter (most typical 30X10 mm.); exocarp smooth compact, resinous, 1-1.5 mm. thick; endocarp woody, smooth or very slightly bullate and furrowed, narrow-oblong, acute at both ends, resinous-lacunose, usually 1-seeded, rarely with 2 or 3 seeds.
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Discussion
S. guianensis is a widespread polymorphous species throughout tropical South America, and includes varieties difficult to distinguish and often mistaken for closely related species. The lack of complete material for every collection or tree and the fact that the existing herbarium specimens only bear flowers or fruit make it difficult to establish correlations between flowering and fruiting characters and the constancy of them. Through his extensive knowledge of the Amazonian flora, Ducke was the first to point out the existence of several varieties and forms among the supposed S. guianensis populations. Study of abundant material with special attention given to the fruit as a taxonomic character has made it possible to consider two new species segregated from the former broader concept of S. guianensis. A few varieties remain in this species with somewhat artificial characters due to the lack of fruiting material. For the same reason the typification of the species cannot be free from error because the Schomburgk collections are flowering specimens lacking fruit, which in fact are key characters. Schomburgk 842, 571, and 574, coincide so much that they seem to belong to one and the same collection; they agree completely with fruiting collections (as for example the Melinon from French Guiana) having elongated fruit; 1 therefore do not hesitate to consider the oblong fruit the characteristic trait of S. guianensis. The typical form of this species has pubescent-hirtellous branches and glabrous petals, but the pubescence of the branchlets is lacking in some varieties, and the petals become more or less puberulous in others. The length and thickness of the fruit show some variation, but the elongate, acutish or subobtuse drupe is the main character of the species and distinguishes it from the newly segregated S. cydonioides and S. mattogrossensis. From the latter one it is furthermore distinguished by its more rigid and thicker, not conspicuously reticulate leaves.