Inga teresensis F.C.P.Garcia & A.P.Chagas, 2021

Garcia, Flávia C. P., Chagas, Aline P. & Dutra, Valquíria F., 2021, Two new species of Inga (Fabaceae-mimosoid clade) from the Atlantic Forest, Brazil, Phytotaxa 521 (2), pp. 95-104 : 96-99

Inga teresensis F.C.P.Garcia & A.P.Chagas , sp. nov. Fig. 1

Type:— BRAZIL. Espírito Santo: Santa Teresa, Estação Biológica da Caixa D’agua, 17 April 1985 (fl.), W. Boone 384 (holotype: VIES!; isotypes: CEPEC, HUEFS, HRCB!, MBML!, RB!) .

Inga teresensis differs from I. cabelo T.D. Pennington (1997: 525) by its leaves, which have a narrower petiole and narrowly winged rachis, and filiform calyx lobes.

Shrubs, rarely scandent, 3−5 m tall. Young branches golden-hirsute, old branches glabrous, lenticellate. Stipules ca. 2 mm long, linear, hirsute, caducous. Petiole 0.7−2 cm long, narrowly winged, hirsute; appendix ca. 3 mm long, setose, caducous; rachis 1.3−2.5 cm long, hirsute, narrowly winged, wing of the apex ca. 2−4 mm wide; foliar nectaries stalked, stalk ca. 1.5 mm long, capitate to cylindric, to 0.2 mm diam.; pulvinule ca. 2 mm long; leaflets in 1–2 pairs, densely hirsute, 4.8−7.5 × 2.1−3.3 cm, obovate, apex acuminate, mucronate, base acute to obtuse, asymmetric, glandular trichomes sparsely present on young leaflets; venation eucamptodromous, midrib prominent on both surfaces, secondary veins in 7−8 pairs, convergent, ascending and arcuate, tertiary veins reticulate. Inflorescences solitary or fasciculate, axillary raceme 1−2 per axil; peduncle 2−5 cm long, cylindric, hirsute; floral rachis 3−6 cm long, hirsute; bracts ca. 2 mm long, triangular, caducous. Flowers pedicellate, pedicel to 4 mm long, hirsute, with scattered glandular trichomes; calyx open in bud, 4−5.5 mm long, tubular, hirsute, lobes 5, filiform, irregular; corolla 14.6−17.8 mm long, infundibuliform, membranaceous, hirsute, lobes 4−5, acute, irregular; androecium with ca. 37 stamens, ca. 3.5 cm long, staminal tube included to exserted, glabrous; ovary ca. 1.5 mm long, glabrous, style exceeding the stamens, stigma terminal, capitate. Legume 6−9.7 × 2−2.8 cm, straight, flat, margins narrow, villous.

Distribution and Habitat: — Inga teresensis has only been recorded in the municipality of Santa Teresa, in the state of Espírito Santo ( Fig. 2 ). This species occurs in clay soil, at 750−890 m elevation, in tropical lowland rain forest ( Veloso et al. 1991).

Phenology: —Flowers have been collected in April and October and fruits in August and September.

Conservation: — Inga teresensis , known from few collections made over 18 years in the municipality of Santa Teresa, has a restricted distribution (AOO = 12 km 2 and EOO = 0.43km 2) and occurs in two reserves: Reserva Biológica Augusto Ruschi and Parque Natural Municipal de São Lourenço. The municipality of Santa Teresa is in one of the regions where plant collecting has been greatest in Espírito Santo (Giaretta & Peixoto 201,; Ribeiro et al. 2014, Cardoso et al. 2018) and stands out for having many threatened species ( Dutra et al. 2019). The locations where I. teresensis was collected are in the urban region of Santa Teresa, which is threatened by fire, municipal roads, real estate development, and tourism ( IBAMA 2004). Considering the effort carried out in the last 10 years to collect I. teresensis and its occurrence restricted to small populations, we propose that this species be categorized as Critically Endangered (CR, criteria B1biii, iv + D).

Etymology: —The specific epithet “teresensis” refers to the municipality of Santa Teresa where the species was collected. “Teresense” is the name given to those born in Santa Teresa.

Paratypes: — Brazil. Espírito Santo: Santa Teresa, Reserva Biológica Augusto Ruschi, Casa da Pedra , right side, 28 August 2002 (fr.), R.R. Vervloet et al. 768 (HUEFS, MBML!, RB!, VIES!); Santo Antônio, property of the Bosa, 7 October 1998 (fl.), L. Kollmann et al. 716 (HUEFS, MBML!, RB!, VIES!); São Lourenço, 9 September 1998 (fr.), L. Kollmann et al. 496 (MBML!, RB!) .

Notes: —Despite the absence of molecular data and a recent infrageneric classification, Inga teresensis belongs to section Vulpinae because of its hirsute indumentum, thin and elongate nectaries, and tubular calyx. It differs from other species of section Vulpinae by having only 1 or 2 pairs of leaflets, triangular bracts, pedicellate flowers, and filiform calyx lobes. Inga teresensis is similar to I. cabelo by the hirsute indumentum, stalked nectaries, obovate leaflets, and slender corolla tube. However, I. teresensis has leaves with 1 or 2 pairs of leaflets, a winged petiole and rachis, leaflets with a prominent midrib, inflorescences in a raceme with pedicellate flowers, and filiform calyx lobes, whereas I. cabelo has leaves with 3 or 4 pairs of leaflets, a commonly unwinged petiole and rachis, sunken midrib, inflorescences in lax spikes with sessile flowers, and acute calyx lobes.

Inga ciliata Presl (1834: 11) and Inga leptantha Benth. (1845: 603) , which are also in section Vulpinae , occur in the region where I. teresensis has been collected, but I. teresensis differs from both species by the presence of only 1 or 2 pairs of obovate leaflets with densely hirsute surfaces. Inga ciliata has 4–11 pairs of elliptic to lanceolate leaflets that are glabrous adaxially and glabrescent abaxially. Inga leptantha has (1)2–6 pairs of elliptic to narrowly lanceolate leaflets that are glabrous to glabrescent adaxially and hirsute abaxially. Additionally, I. teresensis has villous fruits (vs. hirsute fruits in I. ciliata and I. leptantha ). The main characters that help distinguish Inga teresensis , I. cabelo , I. ciliata , and I. leptantha are also listed in Table 1.

Identification key to the Inga species of sect. Vulpinae in the Brazilian Atlantic Forest

1. Leaf rachis winged .............................................................................................................................................................................2

- Leaf rachis unwinged or rarely winged in the superior portion of the pair of apical leaflets ............................................................8

2. Foliar nectary stalk> 3 mm long........................................................................................................................................................3

- Foliar nectary stalk to 2.5 mm long....................................................................................................................................................4

3. Stipule 4−8 mm long. Calyx lobes filiform; stamens pink.............................................................................................. Inga vulpina

- Stipule 11−20 mm long. Calyx lobes acute; stamens white ............................................................................................ Inga barbata

4. Leaflets densely hirsute. Inflorescence a raceme ......................................................................................................... Inga teresensis

- Leaflets glabrous to glabrescent on adaxial surface, glabrescent, hispid or hirsute on abaxial surface. Inflorescence a spike.........5

5. Leaflets 3.2−13 cm long. Bracts 1.5‒15 mm long, linear, filiform or lanceolate to elliptic ..............................................................6

- Leaflets 13−17.5 cm long. Bracts 13‒22 mm long, ovate........................................................................................... Inga platyptera

6. Branches hirsute. Bracts lanceolate to elliptic.............................................................................................................. Inga leptantha

- Branches hispid. Bracts linear or filiform ..........................................................................................................................................7

7. Leaflets in 2 pairs, hispid, apex rounded.............................................................................................................. Inga suborbicularis

- Leaflets in 4−11 pairs, glabrous on adaxial surface, glabrescent on abaxial surface, acute to attenuate .......................... Inga ciliata

8. Branches appressed-sericeous .................................................................................................................................... Inga ciatiformis

- Branches hirsute to hispid ..................................................................................................................................................................9

9. Foliar nectaries funnelform, cupuliform or cyathiform............................................................................................... Inga platyptera

- Foliar nectaries capitate to cylindrical..............................................................................................................................................10

10. Branches with golden brown indumentum. Leaflets glabrescent adaxially, sparsely hirsute abaxially on veins. Bracts 1.8–2.5 mm long.................................................................................................................................................................................... Inga cabelo

- Branches with dark brown indumentum. Leaflets hispid. Bracts 3–5.6 mm long ........................................................... Inga hispida

Figures

FIGURE 1. Inga teresensis. A. Flowering branch. B. Detail of the stipules, dorsal view. C. Leaf, detail of the adaxial surface. D. Detail of foliar nectary. E. Nectary profile. F. Detail of a bract, dorsal view. G. Flower (from W. Boone 384). H. Fruit (from R.R. Vervloet et al. 768).

FIGURE 2. Distribution map of Inga teresensis and Inga tripa. Legend (states): AL = Alagoas; BA = Bahia; CE = Ceará; ES = Espírito Santo; MG = Minas Gerais; PB = Paraíba; PE = Pernambuco; RN = Rio Grande do Norte; SE = Sergipe.