Cynometra dwyerii Rados., 2019

Radosavljevic, Aleksandar, 2019, The rise of Cynometra (Leguminosae) and the fall of Maniltoa: a generic re-circumscription and the addition of 4 new species, PhytoKeys 127, pp. 1-37 : 17-19

2. Cynometra dwyerii Rados. sp. nov. Figures 6 , 7

Type.

PANAMA. Darién [now Comarca Emberá-Wounaan]: vicinity of Campamento Buena Vista, Río Chucunaque above confluence with Río Tuquesa, [08°23'N, 77°47'W] 5 July 1959, [fr.], W. L. Stern 941 (holotype US; isotype MO).

Description.

Tree to approximately 20 m tall; bark not seen; branchlets lenticelate, pubescent when young, becoming glabrous with age. Stipules not seen. Leaves bifoliolate, axes pubescent, transversely corrugated; petioles 4.5-5.5 mm long; petiolules 1.0-1.5 mm long, inconspicuous, leaflets appearing sessile; leaflets narrowly obovate to obovate, occasionally sub-trapeziform, strongly asymmetric, primary vein eccentric, proximal side 2.8-3.7 times wider than distal, 3.1-3.9 cm long, 1.4-1.9 cm wide, thin, abaxial surface sparsely pubescent, more so on midvein and major secondaries, adaxial surface with pubescence restricted primarily to midvein, occasional hairs scattered on lamina, primary venation pinnate, secondary venation brochidodromous-eucamptodromous, 2(-3) basal acrodromous veins, decurrent to primary, prominent abaxially, only slightly less so adaxially, tertiary venation visible on both surfaces at 10 × magnification, margins entire, apex acute, weakly acuminate (to 2.0 mm), retuse, mucronate, base oblique, acute, distal side narrowly cuneate, proximal side slightly concave to cuneate, decurrent to petiolule, laminar glands present, 3-6 per leaflet, arranged in a row approximately halfway between margin and midvein, restricted to distal portion of lamina, typically adjacent to tertiary veins, crateriform, less than 1.0 mm in diameter. Inflorescences not seen, position inferred as axillary from remnant of peduncle. Flowers not seen. Legume indehiscent, roughly globose, to 4.7 cm in diameter, surface of valves rugulose, wall of pericarp up to 3.0 mm thick, deep brown colour at maturity. Seeds 1 per pod, filling entire cavity, dark brown.

Distribution and ecology.

Known only from the type locality in the Darien Gap region of Panama; the area where the type was collected is primarily lowland moist tropical forest.

Phenology.

The type was collected with mature fruit in July.

Etymology.

The specific epithet honours the contributions of Dr. John Dwyer, who published the first monograph of the Neotropical species of Cynometra .

Note.

This species is known only from the type collection, however the combination of vegetative characters and fruit morphology make it clearly distinct from other Cynometra species. Superficially, this species resembles C. bauhiniifolia , given its small leaflets with prominent secondary venation. However, the pubescence and arrangement of laminar glands clearly distinguish it from other Neotropical species of Cynometra , which usually have just a single, basal laminar gland. In fact, the combination of bifoliolate leaves with small leaflets and several submarginal laminar glands is unique across the entire genus. When these characters are combined with the large, globose fruit, it is clear that this is a distinct species.

Additional specimens examined.

None.

Figures

Figure 6. Illustration of Cynometra dwyerii. A Leaf base (adaxial surface) showing corrugated petiole and pubescence along midrib B habit C leaf base (abaxial surface) showing basal acrodromous veins arising from leaflet pulvinus and laminar glands D leaflet apex (abaxial surface) E Dissected fruit, proximal surface F dissected fruit, distal surface G longitudinal section of fruit with single seed H reconstruction of fruit. A-H Stern et al. 941, US.

Figure 7. Photograph of the holotype of Cynometra dwyerii (Stern et al. 941, US).