Taxon Details: Swartzia humboldtiana Cuello
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Family:
Fabaceae (Magnoliophyta)
Fabaceae (Magnoliophyta)
Scientific Name:
Swartzia humboldtiana Cuello
Swartzia humboldtiana Cuello
Accepted Name:
This name is currently accepted.
This name is currently accepted.
Description:
Author: Benjamin M. Torke
Type: Venezuela, Amazonas: Caño Monomi, tributary of the Rio Casiquiare, 2 Nov 1962 (fl), V. Vareschi 7793 (Holotype: VEN).
Description: Small tree; young branchlets 1.5-3.8 mm thick, glabrescent, sometimes sparsely strigulose at nodes. Leaves unifoliolate, with a distinct articulation between petiole and pulvinule; stipules 0.3-0.6 x 0.2-0.4 mm, triangular, glabrescent; petioles, excluding petiolule, 2.9-7 mm, pulvinate for basal two thirds to all of length, longitudinally bi-ridged to narrowly marginate adaxially, caniculate between ridges, stipellate at apex, glabrous; stipels 0.4-0.9 mm, rigid, subulate to narrowly triangular, glabrous; petiolules 1.9-3.8 mm, glabrous; leaflet blades 2.6-3.1 x as long as wide, 8.4-12.6 x 3.1-4.7 cm, ovate, shallowly cordate to truncate at base, caudo-acuminate at apex, glabrous, acumen 1.3-1.9 cm long, rounded at tip, venation inconspicuous, midrib and other venation weakly raised to immersed on both surfaces, secondary veins ca. 10-12 on each side of midrib, most initially ascending at 20-30°, fairly straight then forming a loose submarginal vein in the distal half of leaflet. Inflorescences simple racemes, borne from coeval leaf axils or terminal, ca. 5--15-flowered; axes 4.1-10.3 cm; bracts 0.7-1.8 x 0.4-1 mm, triangular to triangular-lanceolate, glabrescent, sometimes thinly strigulose abaxially; pedicels 11.1-13.3 mm, dorso-ventrally compressed, somewhat dilated apically, glabrous; bracteoles 0.5-1.1 mm long, opposite to strongly subopposite, inserted at center or in distal half of pedicel, but well below its apex, triangular-lanceolate, glabrescent; flower buds 8.2-9.4 x 5.7-7.1 mm, elliptic, umbonate, glabrous. Calyx glabrous; segments 3, ca. 7.4-10 x 4.2-7.4 mm, subequal, oblong-elliptic, recurved. Corolla monopetalous or occasionally dipetalous; petal seen only in immature condition, glabrous; claw ca. 2-3 mm; limb ca. 1.6 cm wide, oblate-orbicular, the base cordate in bud, probably truncate when mature. Stamens glabrous, dimorphic; larger stamens 5, abaxial, filaments ca. 15-16 mm, dorso-ventrally compressed, tapering at apex, anthers ca. 1.7-1.8 x 1-1.2 mm, elliptic in outline; smaller stamens ca. 90, filaments 5-9.2 mm, anthers 0.7-1.3 x 0.6-0.8 mm, elliptic in outline. Gynoecium glabrous; stipe ca. 13 mm; ovary ca. 8.3 x 2.2 mm, inequilaterally arcuate-elliptic in outline, laterally compressed, locule glabrous, ovules ca. 8; style ca. 1.7-1.8 mm, oblique-terminal, arcuate, narrowly conical; stigma punctiform. Fruits not seen.
Common names: No common names have been recorded.
Distribution: Swartzia humboldtiana is known only from the type specimen collected along a tributary of the Casiquiare River in southern Venezuela.
Ecology: On the type specimen label, Vareschi reported that the species was a rare component of the riverine vegetation. The tributary from which the collection was made is a black water stream; it drains a large area of white sands. Nothing else is known about the species' ecology.
Phenology: The single collection was made from a flowering individual in November.
Taxonomic notes: The initial assertion of a close relationships with S. stipellata (=S. anomala) by Cuello (2001), and the subsequent placement of S. humboldtiana in section Unifoliolatae by Torke and Mansano (2009) were not supported by subsequent examination of the type material at VEN. Bracteolate pedicels, the form of the ovary and the overall proportions of the gynoecium all indicate that S. humboldtiana should be placed in section Recurvae, where it is morphologically aligned with S. klugii, another unifoliolate member of the section found in Amazonian Peru, Ecuador and Colombia. Swartzia humboldtiana can be easily distinguished from S. klugii by its cordate- to tuncate-based (versus acute- to obtuse-based) leaflets, with less ascending, more inconspicuous secondary veins, glabrous (versus strigulose-lepidote), longer pedicels, larger flower parts, and proportionately more elongate ovary.
Uses: No uses have been recorded.
Etymology: The epithet was chosen by Cuello (2001) to honor the German naturalist and explorer Alexander von Humboldt, who in 1800 explored and charted the Casiquiare River, a distributary of the upper Orinoco River that forms a canal connecting its drainage to that of the Rio Negro.
Conservation status: The conservation status of S. humboldtiana is unknown. The single collection was made in a remote part of the central Casiquiare River system in 1962. The fact that subsequent expeditions in the region have failed to document the species suggests that it is rare, and perhaps highly localized in its occurrence. The drainage of the Caño Monomi, where the species was collected, lies within a largely intact Amazonian wilderness, however, most of the drainage is not included within the limits of protected areas in the region.
Author: Benjamin M. Torke
Type: Venezuela, Amazonas: Caño Monomi, tributary of the Rio Casiquiare, 2 Nov 1962 (fl), V. Vareschi 7793 (Holotype: VEN).
Description: Small tree; young branchlets 1.5-3.8 mm thick, glabrescent, sometimes sparsely strigulose at nodes. Leaves unifoliolate, with a distinct articulation between petiole and pulvinule; stipules 0.3-0.6 x 0.2-0.4 mm, triangular, glabrescent; petioles, excluding petiolule, 2.9-7 mm, pulvinate for basal two thirds to all of length, longitudinally bi-ridged to narrowly marginate adaxially, caniculate between ridges, stipellate at apex, glabrous; stipels 0.4-0.9 mm, rigid, subulate to narrowly triangular, glabrous; petiolules 1.9-3.8 mm, glabrous; leaflet blades 2.6-3.1 x as long as wide, 8.4-12.6 x 3.1-4.7 cm, ovate, shallowly cordate to truncate at base, caudo-acuminate at apex, glabrous, acumen 1.3-1.9 cm long, rounded at tip, venation inconspicuous, midrib and other venation weakly raised to immersed on both surfaces, secondary veins ca. 10-12 on each side of midrib, most initially ascending at 20-30°, fairly straight then forming a loose submarginal vein in the distal half of leaflet. Inflorescences simple racemes, borne from coeval leaf axils or terminal, ca. 5--15-flowered; axes 4.1-10.3 cm; bracts 0.7-1.8 x 0.4-1 mm, triangular to triangular-lanceolate, glabrescent, sometimes thinly strigulose abaxially; pedicels 11.1-13.3 mm, dorso-ventrally compressed, somewhat dilated apically, glabrous; bracteoles 0.5-1.1 mm long, opposite to strongly subopposite, inserted at center or in distal half of pedicel, but well below its apex, triangular-lanceolate, glabrescent; flower buds 8.2-9.4 x 5.7-7.1 mm, elliptic, umbonate, glabrous. Calyx glabrous; segments 3, ca. 7.4-10 x 4.2-7.4 mm, subequal, oblong-elliptic, recurved. Corolla monopetalous or occasionally dipetalous; petal seen only in immature condition, glabrous; claw ca. 2-3 mm; limb ca. 1.6 cm wide, oblate-orbicular, the base cordate in bud, probably truncate when mature. Stamens glabrous, dimorphic; larger stamens 5, abaxial, filaments ca. 15-16 mm, dorso-ventrally compressed, tapering at apex, anthers ca. 1.7-1.8 x 1-1.2 mm, elliptic in outline; smaller stamens ca. 90, filaments 5-9.2 mm, anthers 0.7-1.3 x 0.6-0.8 mm, elliptic in outline. Gynoecium glabrous; stipe ca. 13 mm; ovary ca. 8.3 x 2.2 mm, inequilaterally arcuate-elliptic in outline, laterally compressed, locule glabrous, ovules ca. 8; style ca. 1.7-1.8 mm, oblique-terminal, arcuate, narrowly conical; stigma punctiform. Fruits not seen.
Common names: No common names have been recorded.
Distribution: Swartzia humboldtiana is known only from the type specimen collected along a tributary of the Casiquiare River in southern Venezuela.
Ecology: On the type specimen label, Vareschi reported that the species was a rare component of the riverine vegetation. The tributary from which the collection was made is a black water stream; it drains a large area of white sands. Nothing else is known about the species' ecology.
Phenology: The single collection was made from a flowering individual in November.
Taxonomic notes: The initial assertion of a close relationships with S. stipellata (=S. anomala) by Cuello (2001), and the subsequent placement of S. humboldtiana in section Unifoliolatae by Torke and Mansano (2009) were not supported by subsequent examination of the type material at VEN. Bracteolate pedicels, the form of the ovary and the overall proportions of the gynoecium all indicate that S. humboldtiana should be placed in section Recurvae, where it is morphologically aligned with S. klugii, another unifoliolate member of the section found in Amazonian Peru, Ecuador and Colombia. Swartzia humboldtiana can be easily distinguished from S. klugii by its cordate- to tuncate-based (versus acute- to obtuse-based) leaflets, with less ascending, more inconspicuous secondary veins, glabrous (versus strigulose-lepidote), longer pedicels, larger flower parts, and proportionately more elongate ovary.
Uses: No uses have been recorded.
Etymology: The epithet was chosen by Cuello (2001) to honor the German naturalist and explorer Alexander von Humboldt, who in 1800 explored and charted the Casiquiare River, a distributary of the upper Orinoco River that forms a canal connecting its drainage to that of the Rio Negro.
Conservation status: The conservation status of S. humboldtiana is unknown. The single collection was made in a remote part of the central Casiquiare River system in 1962. The fact that subsequent expeditions in the region have failed to document the species suggests that it is rare, and perhaps highly localized in its occurrence. The drainage of the Caño Monomi, where the species was collected, lies within a largely intact Amazonian wilderness, however, most of the drainage is not included within the limits of protected areas in the region.