Macrosamanea kegelii (Meisn.) Kleinhoonte
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. & Grimes, James W. 1996. Silk tree, guanacaste, monkey's earring: a generic system for the synandrous Mimosaceae of the Americas. Part I. Abarema, Albizia, and allies. Mem. New York Bot. Gard. 74: 1-292.
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Family
Mimosaceae
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Scientific Name
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Type
"[Surinam:] ad ripas fl. Cassepoerkreek, m. Nov. 1845, legit [Hermann Aribert Heinrich] Kegel n. 1173." — Holotypus, NY (herb, meisner.)!; isotypus, GOET!
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Description
Species Description - Amply leafy, potentially arborescent riparian shrubs attaining 8(-?) m, the terete older branches gray, len- ticellate, the hornotinous ones and all lf-axes densely sordid-pilosulous with short ascending hairs, the thinly papery lfts remaining olivaceous when dry, sublustrous above, a little paler beneath, the fls disposed in short crowded pseudoracemes of few-fld umbelliform capitula arising either from knots on old branches or from lf-axils of slender hornotinous branchlets. Stipules erect, firm lanceolate 1.5-3 mm, dorsally glabrate and coarsely 3-6-nerved, tardily deciduous. Lf-formula v—viii/12—16; lf-stks 10-19 cm, shallowly or obscurely sulcate ventrally, the true petiole 6-12 mm, the longer interpinnal segments 23-35 mm; a depressed saucer-shaped or scutiform nectary 2-3.5 mm in long diameter shortly below first pair of pinnae, and progressively shorter ones between distal pairs of pinnae and lfts; pinna-pairs strongly decrescent proximally and less so distally (expanded lf-outline obovate), the rachis of longer ones (6.5-)7-12 cm, the interfoliolar segments about as long as greatest width of lft-blades, these subequilong except for a few abruptly decrescent proximally and for the longer, heteromorphic furthest pair; a pair of subulate or filiform paraphyllidia 0.3-0.9 mm at base of each pinna-rachis subcontiguous to pulvinus; lft-pulvinules transversely elliptic 0.4-0.5 x 1.2-1.6 mm; lfts at and near midrachis rhombic around an almost straight diagonal midrib, broadly cuneate at base, at apex triangular- or deltate-mucronulate, the basal and adaxial sides nearly straight, the distal side low-convex, the larger blades 21-28 x 5.5-9 mm, 2.3-3.1 times as long as wide; venation of midrib and 1 strong (sometimes few outer weak) intramarginal nerve produced well beyond mid blade, the midrib giving rise on each side to ±7-10 major and to several intercalated minor secondary nerves camptodrome well within the narrowly revolute margin, the tertiary venulation sinuous, all nerves sharply prominulous on both faces. Inflorescence little known, the primary axis apparently only 5-15 mm and the individual peduncles ±3-4 mm; rudimentary lf-stk subtending peduncles ±2 mm, charged ventrally with a homy nectary; capitula ±4-6-fld; bracts 1.5-2.5 mm, becoming dry, papery, few-nerved, lacking nectary, quickly deciduous; pedicels stout (0.5-) 1-2.5 mm; calyx cylindric, slightly widened distally, 14-20 x 3.5-6 mm, prominulously many-nerved, densely puberulent below middle but more thinly so toward the teeth, the tube 10-13.5 mm, the lance-ovate (often unequal) teeth 3-5.5 mm; corolla at least when young more densely silky-puberulent with paler hairs, 24-31 mm, the usually 5 lanceolate lobes 4—7 mm; androecium 4-5 cm, the staminal sheath included in the corolla, the filaments creamy-white with pink tips; style to 6 cm, well exerted from the stamens, white, the dilated stigma ±0.2 mm diam. Pods unknown.
Distribution and Ecology - On river and creek banks, below 200 m, apparently localized in NE Surinam and immediately adjacent French Guiana, on the Surinam, Maroni, and Tapa- honi rivers. — Map 52. — Fl. XI-XII.
Local Names and Uses - Water- tamarinde; kabanfo (Arawak).
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Discussion
When referring M. kegelii to his ser. Coriacea, Bentham remarked on the thin texture and pallid coloration of the foliage, which are reminiscent of some species of Zygia sect. Zygiopsis, and the relatively short androecial tube, at that time not otherwise known in the series. The species remains somewhat anomalous in Macrosamanea in two respects: the cauline inflorescence of shortly pedunculate few-flowered capitula, in which the peduncles are subtended by a rudimentary leaf-stalk and nectary, and the lack of nectary on the floral bracts. These two characters occur in species of Zygia, but coincide there with the small, short-calyxed Zygia flower. In proportionate lengths of calyx and corollas and in naked floral bracts M. kegelii is technically similar to the isolated M. macrocalyx, but differs significantly and obviously in leaf-formula, shape of leaflets, and cauliflory. The fruit of M. kegelii, when discovered, may contribute to our understanding of its affinities within Macrosamanea, which Kleinhoonte tentatively questioned, or to related zygioid genera.
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Common Names
Water- tamarinde, kabanfo
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Distribution
Suriname South America| French Guiana South America|