Aeschynomene veadeirana Silva, M. J. & Antunes, L. L. C., 2014

Silva, Marcos José Da & Antunes, Lorena Lana Camelo, 2014, An update of the Brazilian species of Aeschynomene sect. Ochopodium ser. Viscidulae including a new species and a new synonym, Phytotaxa 184 (1), pp. 31-38 : 32-34

Aeschynomene veadeirana Silva, M. J. & Antunes, L. L. C. , sp. nov. ( Fig. 1 )

It is similar to A. viscidula in its general aspect, but differs from it by having: stem and branches predominantly puberulous to sparsely hispidulous or glabrescent, leaflets preponderantly oblong with revolute, ciliate margins, apressed trichomes, base asymmetric-obtuse, wing petals obovate-falcate dorsally overlapping, and fruits pubescent, not reflexed or viscous.

Type: ___ BRAZIL. Goiás: Cavalcante , imediações do km 204, no lado esquerdo da estrada que leva a Teresina de Goiás, em campo úmido, 13º54,393’S, 47º22’48’ W, 1.278 m elev., 27 July 2014 (fl, fr), M. J . Silva , R. C . Sodré & R . D. Sartin 6127 (holotype: UFG!; isotype UB!, CEN!, RB!, SP!) .

Subshrub creeping or decumbent. Branches up to 2.9 m long, radiated from a taproot, puberulous and hispidulous or glabrescent, light green to opaque, cylindrical to angulated, slender; stipules 4–5 × 1–2 mm long, 6–8-ribbed, oval, acute at apex, base truncated, densely pubescent externally, ciliate; petiole 3–6 mm long, slender; rachis 0.6–1.5 cm long, both similar to the branches. Leaves 1.5–3 cm long, alternate, spiral; leaflets (–3 or 4) 5 (–7), 7–12 × 3–5 mm long, oblong or more rarely oblong-obovate, obtuse at apex, sometimes slightly mucronulate, base asymmetric-obtuse, margins ciliate and slightly revolute, pubescent on both surfaces, upper surface dark green, shiny, lower surface light green, opaque to canescent, trichomes denser on the lower surface; venation brochidodromous, primary and secondary veins prominent on the lower surface, midrib slightly excentric at the base. Racemes 8–16.5 mm long, axillary and terminal, with 6–13 flowers laxly distributed, slender, pubescent, sometimes slightly fractiflex; bracts 1.8–3 × 1.8–2 mm long, widely ovate, apex acute, base rounded to slightly cordate, margins hispid-serrated, densely pubescent externally, with conspicuous nerves; bracteoles 2.2–3 × 1–2 mm long, oval-elliptic, apex acute, similar to the bracts. Flowers 1–1.7 cm long, yellow petals, standard petal with a reddish basal spot, calyx slightly vinaceous, pedicel 2–6 mm long, pubescent, slender; calyx 4.9–5 × 2.5–3.2 mm, campanulate, pubescent externally, lobes triangular, subequal, margins hispid-ciliate; standard petal 11–13 × 11–12.5 mm, orbicular, slightly emarginated at apex, base obtuse, pubescent to shortly tomentose externally; wing petals 5–5.5 × 10–10.5 mm, obovate-falcate, glabrous, dorsally overlapping, apex rounded, base auriculate towards the claw, lamellate sculpture in the upper basal half; keel petals 4.9–5 × 2.5–3 mm, falcate, acute at apex, base similar to wing petals, glabrous; androecium consisting of 10 stamens, 7.9–8 mm long, monadelphous, staminal tube glabrous, portion free of filaments subequal, anthers oblong, base-fixed; ovary 9.8–10 × 1.8–2.9 mm, linear, densely tomentose; style discretely curved, glabrous, stigma punctiform. Fruits 1.5–2.5 cm long, 1–2 articulate, not reflexed; articles 4–6 × 3–4 mm, orbicular, joined by the isthmus, light green, maculate, pubescent, trichomes canescent, stipe 4–7 mm long, glabrescent. Seeds 4–6 × 3–4 mm, reniform, smooth, dark brown, hilum subapical.

Additional specimens examined (paratypes): — BRAZIL. Goiás: Cavalcante , GO 118, km 195, ca. 2 km a partir do Cruzeiro em direção a Teresina de Goiás, 13º56’9.4”S, 47º26’43.5’ W, 1.570 m elev., 6 September 2013 (fl, fr), M. J. Silva et al. 5305 ( UFG) , 5306 ( UFG), 5307 ( UFG), 5308 ( UFG), 5309 ( UFG), 5310 ( UFG), 5311 ( UFG), 5312 ( UFG), 5314 ( UFG), 5315 ( UFG), 5316 ( UFG), 5317 ( UFG), 5318 ( UFG); 12 October 2013 (fr), L. L. C. Antunes et al. 829 ( UFG) , 830 ( UFG), 831 ( UFG), 832 ( UFG), 833 ( UFG), 834 ( UFG), 835 ( UFG), 836 ( UFG), 837 ( UFG), 838 ( UFG), 839 ( UFG), 840 ( UFG); Cavalcante , imediações do km 204 da GO 118 , no lado esquerdo da estrada que leva a Teresina de Goiás, em campo úmido, 13º54,393’S, 47º22,48’W, 1.278 m elev., 27 July 2014 (fl, fr), M. J. Silva, R. C. Sodré & R. D. Sartin 6123 ( UFG), 6124 ( UFG), 6125 ( UFG), 6126 ( UFG), 6128 ( UFG), 6129 ( UFG), 6130 ( UFG) .

Distribution and ecology: — Aeschynomene veadeirana appears to be endemic to the Chapada dos Veadeiros, and so far it has been found in the municipality of Cavalcante, where it grows in native pastures, near permanent streams, on clayey soils, around 1,570 m elev. In its habitat the species sends out branches up to 1.7 m in length and stands out against a background of native pasture due to the upward vivacious flowers with yellow petals. The region of Chapada dos Veadeiros comprises the Chapada dos Veadeiros National Park, the area where A. veadeirana was collected, which is priority for conservation due to the vegetation mosaic, multiple sources, and aquifers that have high species richness ( Munhoz & Felfili 2006). The specialists in the family Leguminosae Irwin & Barneby (1982) , Barneby (1991), and Lewis (1992) reported that Chamaecrista , Mimosa , and Aeschynomene , respectively, are genera with a high number of endemic species to that region. For instance, Lewis (1992) described A. simplicifolia G. P. Lewis and A. genistoides var. latifoliola G. P. Lewis , both endemic to the Chapada dos Veadeiros, and mentioned that this region has members of the family Leguminosae with peculiar morphological patterns.

Conservation status: — Aeschynomene veadeirana is known only in the Chapada dos Veadeiros region, a place that includes the Chapada dos Veadeiros National Park, an area officially protected, but with anthropogenic perturbation such as plant extraction, natural or accidental burning, and tourist visitation. Since the species grows in native pastures in an area less than 20,000 km 2, we suggest provisionally considering it vulnerable (VU) according to the IUCN red list criteria ( IUCN 2014).

Phenology: —The species has been collected with flowers and fruits from July to October.

Etymology: —The specific epithet “veadeirana” alludes to the Chapada dos Veadeiros, region where the species was collected.

Relationships and systematic position: — Aeschynomene veadeirana belongs to A. sect. Ochopodium because it has stipules not peltate, calyx campanulate, and fruits with articles joined by isthmus, compared with the series Viscidulae Rudd , which is herbaceous to suffrutescent, has habit prostrate to suberect, glabrous to indumented branches, hairs glandular or not, predominantly obovate leaflets, and small fruits with articles up to 5 mm in diameter ( Rudd 1955, 1959). This series is the largest one of Aeschynomene sect. Ochopodium in the Americas, comprising 15 species if we take into consideration the taxonomic treatments carried out by Rudd (1955) and Fernandes (1996), as well as the species A. sabulicola L. P. Queiroz & D. S. Cardoso described by Queiroz & Cardoso (2008) and A. veadeirana proposed here. In Brazil, 12 of these species grow in different habitats (check the key herein provided), but especially in the Cerrado biome.

Among the species of the series Viscidulae present in Brazil, A. viscidula Michx. is the most morphologically similar to A. veadeirana because both share prostrate, delicate, and radially branched stems, leaves with 3–9 leaflets and fruits with 1–4 articles. However, in A. veadeirana the stem is puberulous and hispidulous or glabrescent (vs. densely pubescent and hispid-glandular in A. viscidula ), the leaflets are predominantly oblong with asymmetricobtuse, revolute margins, and subcentric midrib (vs. oboval to widely oboval with cuneate base, not revolute margins, and excentric midrib), inflorescences 8–16.5 cm long usually with 6–13 flowers (vs. 4–7 cm, 2–4 flowers), flowers 1–1.7 cm long. (vs. 1–1.3 cm long), standard petal 11–13 mm long (vs. 5–7 mm long), wing petals dorsally overlapping (vs. not dorsally overlapping), and fruits not reflexed, pubescent and spotted (vs. reflexed, densely recovered by short hispid-viscous trichomes and without spots). Additionally, in A. viscidula the leaves may have 9 leaflets, whereas in A. veadeirana the leaves usually have 5, less frequently 3 or 4, and rarely 7 leaflets.

Another species of the series Viscidulae that resembles A. veadeirana is A. acapulcensis Rose , endemic to Mexico ( Rudd 1955). However, the latter has stipules with acuminate apex, leaflets obovate and glabrous on the upper surface, standard petal up to 7 mm long, and glabrous fruit with stipe 4–7 mm long.

Figures

FIGURE 1. Aeschynomene veadeirana. A. Flowering branch. B. Stipule. C. Leaflet. D. Leaflet, adaxial surface; E. Leaflet, abaxial surface, showing hispidous trichomes. F. Bracts, adaxial surface. G. Bracts, abaxial surface. H. Bracteoles, adaxial surface. I. Bracteoles, abaxial surface. J. Flower, frontal view. K. Calyx opened. L. Detail of the calyx margin. M. Standard petal. N. Detail of the abaxial surface of the standard petal; note the pilose trichomes. O. Wing petals. P. Keel petals. Q. Androecium. R. Anthers. S. Gynoecium. T. Fruit with calyx and staminal tube persistent. U. Fruit without staminal tube and calyx; note the stipe glabrescent. V. Seed, side view. Drawn by Cristiano Gualberto and Vinícius Yano from the holotype.