Cynometra cerebriformis 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 : 15-17

1. Cynometra cerebriformis Rados. sp. nov. Figures 4 , 5

Type.

BRAZIL. Pará: [Mun. Oriximiná] Rio Trombetas, near Cachoeira Porteira, 24 May 1974, [fl.], D. G. Campbell et al., P22338 (holotype US; isotype F, INPA, MO, NY).

Description.

Tree to 20 m tall; bark not seen; branchlets rough, lenticels prominent, bud scale scars partially encircling stems near base, new growth with short scattered pubescence, glabrous or nearly so at maturity. Stipules not seen. Leaves bifoliolate, pulvinate, axes glabrous or with sparse pubescence concentrated on adaxial surfaces; petioles 3.0-4.0 mm long, 1.0 mm wide, transversely corrugated; petiolules 0.5-1.0 mm long, 0.5 mm wide, transversely corrugated; leaflets appearing sessile, coriaceous, obelliptic to obovate, asymmetric, primary vein eccentric, proximal side 2.0-2.7 times wider than distal, 3.1-4.5 cm long, 1.1-1.9 cm wide, abaxial surface with scattered raised areas both surfaces glabrous, primary venation pinnate, secondary venation brochidodromous-eucamptodromous, 3-4 basal acrodromous veins, decurrent to primary vein, prominent abaxially, their course barely visible adaxially, tertiary venation difficult to discern on either surface even under magnification, margins entire, apex acute, usually short acuminate (acumen to 4.0 mm), retuse, mucronate, base oblique, acute, distal side narrowly cuneate with margin nearly parallel to midvein for 8.0-10.0 mm, proximal side convex, decurrent to petiolule, laminar glands absent. Inflorescence an axillary raceme, (1-)2 per axil, bracteate, axes ferrugino-pilose; peduncle 1.0-2.0 mm, rachis 2.0-5.0 mm long, flowers spirally arranged, 2-10 per raceme; pedicels 7.0-10.0 mm and filamentous in anthesis, to 18.0 mm and accrescent in fruit; bracts subtending individual flowers, scale-like, quickly deciduous, brown, broadly elliptical to deltoid, strongly convex 1.5-2.5 mm long, 1.0-1.5 mm wide, striate, abaxial surface pubescent, pubescence denser at base and along margins, glabrous adaxially; bracteoles not seen. Flowers bisexual, radially symmetric, pentamerous, delicate; hypanthium cupular, 0.7-1.0 mm deep, surrounding basal portion of ovary, fleshy, abaxial surface pubescent, adaxial surface glabrous; sepals 4, imbricate, reflexed, abaxial and adaxial sepals larger than lateral, greenish-white, petaloid, oblong to elliptic, apices acute to rounded, 3.0-4.0 mm long, 1.0-2.0 mm wide, pubescence on abaxial surface near apex, with faint parallel venation; petals 5, equal, white, crumpled texture, curving inwards, oblanceolate, 4.0-5.0 mm long, 1.0-1.5 mm wide, adaxial surface with minute appressed hairs, pinnate venation; stamens 10, filaments free, subequal, 7.0-8.5 mm long, anthers dorsifixed, versatile, longitudinal dehiscence, ellipsoid, to 1.0 mm long, glabrous; ovary centrally inserted, free, stipitate, obliquely elliptical, 2.5-3.0 mm long, 1.5-2.0 mm wide, tomentose, stipe 0.5 mm, style apical, 2.0-2.5 mm long, glabrous, eccentric, curving downwards, stigma capitate. Legume indehiscent, oblate, rugose, apiculate when immature, 14.2-17.5 mm long, 7.1-9.2 mm wide, 12.1-13.9 mm thick, valves pubescent, wall of pericarp up to 2.5 mm thick, brown. Seeds 1 per pod, filling locule, dark brown.

Distribution and ecology.

Currently, this species appears restricted to the Trombetas River Basin of Para State, Brazil. However, it is quite possible that the range is more extensive given that the species occurs in seasonally flooded forests and the genus is known for water dispersed fruits ( Ridley 1930, Clarke et al. 2001, Tomlinson 2016). Little else is known about this taxon.

Phenology.

Flowering specimens have been collected in May. Fruiting specimens have been collected in June and August.

Etymology.

Cynometra cerebriformis is named after the brain-like appearance of the mature fruit.

Additional specimens examined.

BRAZIL. Pará: Municipio Oriximiná: Rio Trombetas shore, Porteira cemetery, 3 Jun 1974 [im fr], D. G. Campbell et al. P22510 (INPA, NY, US); Margem direita do Rio Mapuera, entre as Cach[oeira] Paraiso Grande e Maracajá, Área do reservatório da 2a etapa, 00°58'S, 57°35'W, 12 Aug 1986 [im fr], C.A. Cid Ferreira et al. 7659 (INPA, NY); Rio Trombetas, river banks downriver from Cachoeira Porteira, N to NE bank (Between C.P. and IBDF Reverval - Lago do Jacaré), 17 Jun 1980 [fr], C. Davidson & G. Martinelli 10324 (INPA, NY, US); Rio Trombetas, margem esq. entre o Lago Jacaré e Cachoeira Porteira, 70 m alt., 17 Jun 1980 [fr], G. Martinelli 7016 (INPA, NY, RB).

Notes.

This taxon has been collected in the areas around Santarem and Oriximiná in Para, Brazil. Many of the specimens have been annotated by Adalea Sprada Tavares as Cynometra duckei ssp. trombetensis , but I can find no record of publication and several of the specimens thus annotated are assigned to different taxa in her unpublished thesis ( Sprada Tavares 1987). The available material of C. duckei is limited and only a few fruiting specimens exist. While a case can be made that C. duckei shares certain vegetative traits with C. cerebriformis (prominent lenticels, the smoothness of the adaxial surface of the leaflets), it also shares characteristics with several other taxa, including C. spruceana var. spruceana (long pedicels, leaflet shape) and C. marginata var. laevis (smooth leaflet surface, nearly sessile leaflets). In light of the characters separating C. cerebriformis from other taxa (see below), the author has opted to describe this taxon at the species level.

Cynometra cerebriformis differs from C. duckei primarily in the shape of the leaflets. Cynometra cerebriformis differs from C. spruceana var. spruceana in several ways. The leaflets of C. cerebriformis are generally smaller than those of C. spruceana var. spruceana and the surface is nearly smooth, while the secondary veins are quite obvious in C. spruceana . Cynometra cerebriformis also lacks the basal laminar gland present in C. spruceana and many other Cynometra taxa. Finally, the fruit of C. spruceana is approximately 1.5 ×-2.5× larger than the fruit of C. cerebriformis and the valves are smooth to slightly rugulose, lacking the strongly rugose surface of C. cerebriformis .

Cynometra cerebriformis differs from C. marginata var. laevis by having an acute leaflet base, short acumen and oblate rugose fruit; C. marginata var. laevis has an obtuse leaflet base, long acumen and a globose fruit with a prominent raised suture ridge.

Figures

Figure 4. Illustration of Cynometra cerebriformis. A Habit B bud with imbricate bracts C leaf base showing corrugated petiole and petiolule D inflorescence rachis showing bract scars on main axis and remnants of bracteoles on pedicels E flower F infructescence with single pod G bract H sepal I petal J longitudinal section of hypanthium and receptacle; sepals, petals and stamens removed. A-E, G-J Campbell et al. P 22338, US F G. Martinelli 7016, US.

Figure 5. Photograph of the holotype of Cynometra cerebriformis (Campbell et al. P 22338, US).