Poecilanthe fluminensis Meireles & H.C. Lima, 2013

Meireles, Jose Eduardo & Lima, Haroldo Cavalcante De, 2013, A new species of Poecilanthe (Leguminosae, Papilionoideae, Brongniartieae) from Southeastern Brazil, Phytotaxa 116 (2), pp. 57-60 : 57-59

Poecilanthe fluminensis Meireles & H.C. Lima , sp. nov. ( Figures 1 and 2 )

Differs from other Poecilanthe species by the combination of short petiolate (5–9 mm long) unifoliolate leaves and by its red calyx.

Type:— BRAZIL. Rio de Janeiro: Itatiaia, Parque Nacional do Itatiaia , 22 January 2008, fl., H. C. Lima 6854 (holotype RB!, isotypes B!, CEPEC!, K!, MBM!, MO!, NY!, SP!, SPF!, U!) .

Tree to 13 m tall; terminal branches brown; axillary bud inconspicuous; stipules 2–10 × 0.5–1 mm, oblonglinear, often persistent, glabrous. Leaves unifoliolate; petiole short, 5–9 mm long; leaflet 9.5–22.7 × 2.5–6.3 cm, narrowly elliptic, more rarely narrowly obovate, base acute; apex acuminate, rarely acute to obtuse, and mucronate; chartaceous to sub–coriaceous; discolor; midvein straight, secondary veins prominent; both faces glabrous on both faces. Inflorescence a panicle, axillary, terminal in position, or rarely cauliflorous; 3–7 cm long, tomentose; peduncle 0.5–2.8 cm long, sometimes presenting some small resting buds along its base; rachis 1.8–5.5 cm long; bract elliptic-ovate, 2.5–3 × 1.3–1.5 mm, outer face sparsely tomentose, caducous; floral bud 1.5–1.7 cm long, oblong-ovate, sub-falcate, 1.5–1.7 cm long, base sub-gibbous, apex acuminate and twisted, tomentose. Flowers 9–12 mm long; pedicel 1–2 mm long; bracteoles 1.5–2 × 1 mm long, ovate to slightly obovate, 1.5–2 × 1 mm, inserted at the base of the calyx, outer face tomentose, persistent, inner face glabrous. Calyx 4.5–5.5 mm long, red, tomentose externally, tube 4–4.5 mm long, teeth triangular, 0.7–1 mm long, inner face woolly; apex of the upper two acute, united but for the apical 0.1 mm long approximately; lateral teeth acute, lower tooth acuminate; hypanthium 0.5–1 mm long. Corolla violet; standard 8–10 × 6–8 mm, obovate, base attenuate, apex emarginated, claw 1–2 mm long; wings 9–10 × 3–4 mm, obovate, base distinctly auriculate on the vexillary margin, apex truncate or emarginate, claw 2–3 mm long; keel petals 6–7 × 3–3.5 mm, falcate, blade base slightly auriculate on the vexillary margin, apex obtuse, claw 2.5–3 mm long. Androecium monadelphous, 8–9 mm long, free portion of the filaments 1.8–3 mm; anthers strongly dimorphic, basifixed 1–1.6 mm long; dorsifixed 0.5–0.9 mm long. Gynoecium 8–10 mm long; stipe 1–2 mm long; ovary 5–7 mm long, glabrous to sparsely sericeous along the lower margin to the base of the style; style 1.5–2 mm long; stigma sub-capitate; ovules 4 per ovary. Fruit 12–23 × 2.8–5.5 cm, woody and explosively dehiscent, obovate to oblanceolate, stipe 4–10 mm long; margins plane, smooth; funicle anvil–shaped, flattened. Seeds 1–2 per fruit, broadly ovate–elliptic, sub–orbicular or orbicular, 18–22 × 16– 20 × 3–5 mm, testa coriaceous, glossy; hilum 1.5–2 mm, curved downward to the endocarp, not concealed, rim–aril present, one-lipped; hypocotyl-root lobe visible; lens, chalaza and raphe not visible.

Distribution and Ecology: —The new species is only known from Rio de Janeiro State, southeastern Brazil, in the municipalities of Itatiaia and Rio das Ostras, growing in montane and lowland forests, respectively. In both places, Poecilanthe fluminensis seems to grow along streams and wet areas.

Phenology:— Poecilanthe fluminensis has been found flowering in January and fruiting in February and July.

Etymology:— The species has been named after Rio de Janeiro State, southeastern Brazil, since it appears to be endemic to that region.

Additional specimens examined (paratype): — BRAZIL. Rio de Janeiro: Itatiaia , PARNA do Itatiaia, próximo as churrasqueiras, margem do rio Campo Belo , 29 February 2008, fr., J . E . Meireles et al.580 ( RB!, SPF!, CEPEC!, MBM!, K!, MO!, NY!); Rio das Ostras, Reserva Biológica União, Trilha 12, 17 July 1997, fr., P . P . de Oliveira 676 ( BHCB, ESA) .

Discussion: —This species is readily distinguished from the rest of the genus by the combination of its unifoliolate leaves with short petioles, and its red calyx, the latter being a unique feature in the genus. The affinities of Poecilanthe fluminensis to the other species are somewhat unclear. In spite of sharing unifoliolate leaves with the Amazonian species P. amazonica (Ducke 1922: 52) Ducke (1932: 734) and P. hostmannii ( Bentham 1860: 52) Amshoff (1939: 61) , the strongly dimorphic anthers (short anthers less than ¾ the size of the longer ones), auriculate on the vexillary margin wings, and seeds with a rim aril indicate a closer affinity with the extra-Amazonian group of Poecilanthe (Meireles 2007, Meireles & Tozzi 2007, 2008). Within the latter, however, the affinities of Poecilanthe fluminensis are less clear, since its morphology seems intermediate between the two groups of extra–Amazonian Poecilanthe species : the inconspicuous axillary buds, and flat pod margins from the P. parviflora Bentham (1860: 80) group and the purplish flower color, monadelphous androecium and ovary with sparse indumentum from the P. falcata (Velloso) Heringer (1952: 197) group.

Figures

FIGURE 1. Poecilanthe fluminensis. A. flowering branch; B. flower in lateral view; C. calyx inner surface; D. bract and bracteole abaxial surface; E. standard; F. wing; G. keel petal; H. dimorphic anthers; J. androecium; K. gynoecium; L. fruit; M. seed in lateral view. Branch and flowers (A-K) from H.C.Lima 6854, and fruit (L & M) from J.E.Meireles 580.

FIGURE 2. Poecilanthe fluminensis. A. bark; B. base of the unifoliolate leaves showing the long stipules; C. flower in lateral view; D. flowering branch; E. fruits.