Matayba ayangannensis Acev.-Rodr.,, 2011
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|Matayba ayangannensis Acev.-Rodr.,|
Frutex 2.5 metralis; foliis 4-6 foliolatis; foliolis alternis vel sub oppositus, discolores, ellipticus, apice rotundatis retusisque; calyce tomentelli, petalis obovatis.
Guyana. Cuyuni-Mazaruni. Mt. Ayanganna, S.S. Tillet, C.L. Tillet, & R. Boyan 45080 (holotype: NY!; isotypes: MO!, US!).
Shrub to 2.5 m tall. Stems glabrous, striate. Leaves paripinnate; petiole plus rachis 2-6.5 cm long, slightly flattened adaxially, striate, puberulent; petiolules ca. 5 mm long, pulvinate at base; leaflets (4) 6, 2.5-4.5 × 1.2-2.3 cm, opposite or sub-opposite, obovate, oblanceolate or nearly elliptic, rigidly coriaceous, brittle, discolorous (abaxial surface drying brownish), adaxially glabrous, abaxially puberulent, especially along midvein, the base obtuse, symmetrical, the apex emarginate or less often rounded, the margins entire, slightly revolute; abaxially the midvein prominent, secondary and tertiary veins inconspicuous, reticulate. Thyrses 8-18 cm long, axillary, on distal portion of branches, paniculate, with ferruginous-pubescent and slightly angled axes. Flowers in simple dichasia; pedicels ca. 2 mm long, pubescent. Calyx brownish yellow, ferruginous-pubescent, ca. 1 mm long, the lobes 0.5-0.7 mm long, ovate; petals ca. 2 mm long, yellowish white, obovate, emarginate at apex, lanose mostly along margins; appendages 2, ca. 1 mm long, sericeous-tomentose, supra basal; disc glabrous, pulvinate; stamens 2-2.5 mm long, the filaments lanose on lower half; ovary tomentulose, the style subcapitate. Capsules not known.
Distribution and ecology.
Known only from the type collection in Guyana, in low forest.
Matayba ayangannensis looks vegetatively similar to Matayba yutajensis Steyerm., as both species are shrubs and have leaflets with retuse apex and reticulate venation; however, Matayba ayangannensis differs from the latter by its leaves with (4) 6, discolorous, brittle leaflets that are 2.5-4.5 cm long (vs. 2(4), concolorous, coriaceous, 10-18 cm long), and by its ferruginous-pubescent calyx, ca. 1 mm long (vs. glabrous or sparsely strigose at base and ca. 3.5 mm long).
The epithet refers to Mt. Ayanganna where the type collection was made.
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