Deguelia decorticans R.A. Camargo & A.M.G. Azevedo, 2014

Camargo, Rodrigo A. & Tozzi, Ana Maria G. A., 2014, A new species of Deguelia (Leguminosae, Papilionoideae) from the Brazilian Amazon Basin, Phytotaxa 184 (3), pp. 160-164 : 161

Deguelia decorticans R.A. Camargo & A.M.G. Azevedo , sp. nov. ( Fig. 1 )

Species haec ab Deguelia duckeana A.M.G. Azevedo differt cortice decidua, stipellis praesentibus, foliolis, pedicellis et pistillis longioribus, bracteis et bracteolis lanceolatis (vs. ovatis).

Type: — BRAZIL. Amazonas : Humaitá, BR-230 (Rodovia Transamazônica), a 115 km de Humaitá, Reserva Indígena dos Tenharim, 6º 58’ S, 62º 08’ W, 13 April 1985, C. A. C . Ferreira 5444 (holotype INPA!; isotypes HRCB!, K!) .

Scandent shrub to liana. Stems more or less sinuous, when young fissured with double indument, rufous, dense bristly and sparsely villous, then glabrescent with the bark peeling off in older stems, external layer grayish brown, internal layers cream to reddish brown. Stipules caducous. Leaves imparipinnate, 9–11 leaflets; petiole 6.9–15.7 cm long and rachis 10.3–19.8 cm long, both striate, densely rufous-bristly and sparsely villous; leaflets (7.5–)11.2–15.3 x (2.8–) 3.4–6.8 cm, proximal pair usually smaller, narrowly elliptic to elliptic, apical oblanceolate to obovate, apex long-acuminate to cuspidate, base rounded, ventrally glabrous (except for small trichomes present on the midrib, very sparse), dorsally rufous-sericeous and hirsute on the midrib; petiolules 3.2–5.3 mm long; stipels 1.5–2.4 mm long, usually persistent, linear-triangular. Inflorescence pseudoracemose, (16.8–) 21.1–43.2 cm long, 1–2 per node, densely rufous-bristly (with trichomes sometimes retrorse) and with sparse villous trichomes, sometimes dense at the base and becoming less frequent towards the apex; brachyblasts terete, 5–12 on first 10 cm, 11–24 on subsequent 10 cm; bracts 2.1–3.1 x 0.7–0.8 mm, lanceolate, dorsally tomentose, long trichomes sometimes present, bracteoles 1.5–2.1 x 0.5–0.7 mm, lanceolate, dorsally tomentose; pedicel 0.8–1.3 cm long, dense bristly. Calyx 5 dentate, dorsally rufoustomentose; vexillary teeth almost totally united, 0.6–1.2 mm long, depressed ovate; carenal teeth 0.8–1.4 mm long, shallowly triangular, central tooth slightly longer. Corolla purple, lilac or pink; standard 1–1.2 x 1–1.2 cm, oblate to orbicular, apex emarginated, base slightly truncate, dorsally sericeous; wings 0.8–1.3 x 0.2–0.3 cm, oblong-spatulate, with sparse trichomes present at the base, dorsally; keel petals 0.9–1.2 x 0.3–0.5 cm, ovate-falcate, dense sericeous at the apex, dorsally. Stamens 7.4–11.2 mm long, pseudomonadelphous (vexillary stamen is free at the tube base but connate higher up with the reminder), glabrous; anthers 0.7–1.1 x 0.5–0.7 mm, oblong to elliptic. Ovary 6.5–7.8 mm long, rufous-sericeous, style 3.6–4.4 mm long, slightly curved, stigma short. Legume unknown.

Distribution and habitat: — only three Brazilian collections are known, one from southeastern Amazonas state, the second from southwestern Pará state, and a third collection from Rondônia state. It occurs in “terra firme” forests, altered forest borders or “capoeiras” with clay soils.

Etymology: — referring to the stem layers from which the bark peels off.

Additional specimens examined (paratypes): — BRAZIL. Pará: Itaituba , BR-163 (Estrada Santarém-Cuiabá), km 1109, 6º 50’ S, 55º 30’ W, 14 April 1983, M. N . da Silva et al. 12 ( INPA!) . Rondônia, Porto Velho, ao longo da BR- 364, 4 km W de Jaci Paraná, Ramal 500 m ao Sul , 14 April 2012, M. F . Simon et al. 1483 ( RB!, CEN) .

Taxonomic notes: — This species is similar to Deguelia rariflora (Mart. ex Bentham 1860: 98) G. P. Lewis & Acev. -Rodr. in Acevedo-Rodríguez & Strong (2012: 422) and Deguelia duckena A.M.G. Azevedo in Tozzi (1994: 48), as they share flowers with conserved morphology, differing mainly in size, which we suggest to be a species complex. The new species, hereafter named Deguelia decorticans , can be distinguished by the peeling off the bark, the presence of stipels (character more usual in the trees of this genus), narrower, longer leaflets, pedicel size, and bract/ bracteoles shape ( Table 1). Additionally, the latter can be distinguished by the combination of types and distribution of their double indumentum, composed of short and long trichomes, presented on the lower surface of the leaflets: sericeous in D. decorticans , with hirsute trichomes densely distributed on the midrib, especially towards the proximal half, becoming sparse towards the apex and along the secondary veins; sericeous in D. duckeana , with sparse, long adpressed trichomes on the midrib and leaflet blade (that sometimes are dense only on the secondary veins); and pilose (short and erect intermixed with long and curved trichomes, feeling velutinous to the touch) in D. rariflora , with dense pilose (long and curved trichomes) on the midrib and secondary veins, becoming sparse near the apex. The type material may contain misused information on the label about the habit, referring it as a treelet and here it was interpreted as a scandent shrub, once this collection clearly shows sinuous branches.

Figures

FIGURE 1. A. Flowering branch. B. Stipels and rachis showing double indumentum. C. Bracteole. D. Calyx, ventral view. E. Petals, ventral view (standard, wings and keel petals). F. Pedicel and pistil. G. Staminal tube, longitudinally opened. Scale bars A: 4 cm; B: 4 mm; C: 1 mm; D–G: 2 mm. A: drawn from M.N. da Silva 12 et al. (INPA); B: drawn from C.A.C. Ferreira 5444 (HRCB); C–G: C.A.C. Ferreira 5444 (INPA).