Erythroxylum umbrosum Costa-Lima & M.Alves, 2013

Costa-Lima, James Lucas Da & Alves, Marccus, 2013, A new species of Erythroxylum (Erythroxylaceae) from the Brazilian Atlantic Forest, Phytotaxa 141 (1), pp. 55-60 : 55-58

Erythroxylum umbrosum Costa-Lima & M.Alves , sp. nov. ( Fig. 1 )

It differs from Erythroxylum santosii Plowman (1987: 25) by the smaller stipules (0.4–1.2 mm vs. 3–4 mm long), larger pedicels (2.7–5 vs. 1.5–2 mm long), number and arrangement of bracteoles (bracteoles 2, distichous vs. numerous, spirally arranged), shape of calyx lobes (broadly triangular vs. lanceolate), and relationship of staminal cup × calyx lobes (longer vs. shorter).

Type:— BRAZIL. Pernambuco: Municipality Jaqueira, Reserva Particular do Patrimônio Natural de Frei Caneca , 8º42'34"S, 35º50'34"W, elevation c. 780 m, 30 January 2013 (fl, fr immature), J . L . Costa-Lima, B. S . Amorim, E. Pessoa, D. Araújo, S . N . Moreira & M. Chagas 870 (holotype UFP!, isotypes CEPEC!, F!, K!, NY!, RB!) .

Small trees, 3–7 m tall, c. 7 cm dbh. Bark brownish, longitudinally fissured. Branchlets 1.8–3 mm in diameter, reddish-brown to chestnut-brown in young branchlets, lenticels white to yellowish, elliptical. Cataphylls persistent, distributed on branches, similar to foliar stipules. Foliar stipules persistent, broadly triangular, 0.4– 1.2 mm long, non-striated, shortly 3–setose at apex, setae c. 0.1 mm long, the medial setae slender, blackish, colleters inconspicuous, margin entire. Leaves petiolate, persistent, chartaceous, opaque, adaxially dark green, abaxially pale green; leaf blades elliptical, 6.5–12.5 × 2.5–4.8 cm, base cuneate, apex slightly cuspidate, margin entire; the midrib slightly impressed on adaxial surface and prominent on abaxial surface, 7–10 secondary veins on each side arranged alternately, the secondary veins reticulate, usually not evident. Petiole 2–4× 1–1.8 mm, subterete, canaliculated adaxially. Flowers 1–3–(4) per node, white or greenish-white; pedicel 2.7–5 mm long, 5–angled; bracteoles 2, distichous, ovate, c. 0.1 mm long, non-striated, 1–setose, concave; calyx lobes broadly triangular, 0.6–1 × 0.5–0.7 mm, apex acute; petals oblong to obovate, 2.4–4 × 1.2–1.8 mm, concave, apex rounded, appendage ligulate, 2–lobed, 0.6–1.2mm long, auricles 0.4–0.8 mm long, margin erose; appendage between the auricles 0.4–0.9 mm long, apex erose; staminal cup 1.0– 1.5 mm long, 10–denticulate at margin. Brevistylous flowers: filaments 2.2–4 mm long, anthers 0.2–0.3× 0.4 mm; styles 1–1.3 mm long, free, stigma depressed-capitate, 0.4–0.5 mm long. Longistylous flowers: antipetalous filaments 0.7–1.1 mm long, antisepalous filaments 1.7–2 mm long, anthers 0.3–0.4 × 0.4 mm; styles 2.7–3.5 mm long, free, stigma depressed-capitate, 0.2–0.4 mm long; ovary obovoid, 1.2–1.8 × 1–1.4 mm, apex rounded. Drupe ellipsoid, 0.7–1.5 × 0.5–0.8 cm, endocarp cylindrical in cross-section, reddish to purplish when ripe, 1 fertile locule.

Distribution and habitat:— Erythroxylum umbrosum is known from the submontane Atlantic Forest in the states of Alagoas and Pernambuco, northeastern Brazil ( Fig. 2 ), 600–800 m elevation, on the Borborema Plateau. The Borborema Plateau is a series of massive metamorphic rocks that extends in a N–S direction from the state of Sergipe to Rio Grande do Norte, with great geomorphological and vegetational diversity ( Rodal et al. 2008). Several new species, some of them endemic to the area, have been recently described (e.g., Fischer et al. 1999, Chautems et al. 2000, Leme & Siqueira Filho 2006, Sales et al. 2006, Amorim & Alves 2012, Pessoa et al. 2012, Pontes 2012), including Erythroxylum pauferrense Plowman (1986: 193) [restricted to the northern portion of the Borborema Plateau] and E. simonis Plowman (1986: 189) [recorded from the “restingas” (coastal scrublands) and submontane semideciduous seasonal forests of northeastern Brazil].

Erythroxylum umbrosum inhabits the subcanopy of the forests, where it grows sympatrically with Erythroxylum citrifolium Saint-Hilaire (1829: 94) , E. mucronatum Bentham (1843: 372) , E. squamatum Swartz (1788: 75) , and E. subrotundum Saint-Hilaire (1829: 99) . It can be easily differentiated from other species in the area by the shorter stipules (<1.2 mm long).

Conservation status:— According to IUCN criteria (IUCN 2001), the conservation status of E. umbrosum can be regarded as Endangered (EN), based on criteria “B1” (extent of occurrence estimated to be <5,000 Km 2), “a” (high fragmentation and number of locations occurrence <five), and “b(iii)” (continuing decline, observed, inferred or projected in the area of occupancy, extent and/or quality of habitat). Erythroxylum umbrosum was found so far in two protected areas: “Reserva Biológica de Pedra Talhada” (state of Alagoas) and “Reserva Particular do Patrimônio Natural de Frei Caneca” (state of Pernambuco). Both are forest fragments highly threatened and surrounded by cattle farms and sugar cane plantations.

Etymology:— The epithet refers to the shaded areas in the forest subcanopy where the plant is found.

Additional specimens examined (paratypes):— BRAZIL. Alagoas: Mun. Quebrangulo, Reserva Biológica de Pedra Talhada , 9º14'39"S, 36º25'29"W, elevation c. 790 m, 24 April 2012 (fr), J . L . Costa-Lima et al. 667 ( CEPEC, F, NY, RB, UFP, UFRN); 9º14'29"S, 36º25'40"W, elevation c. 764 m, 19 December 2012 (bud), J . L . Costa-Lima et al. 846 ( RB, UFP, UFRN) . Pernambuco: Mun. Jaqueira, Reserva Particular do Patrimônio Natural de Frei Caneca, Mata do Quengo , 8º42'34"S, 35º50'34"W, elevation c. 780 m, 30 May 2012 (fl), J . L . Costa-Lima et al. 695 ( CEPEC, RB, UFP, UFRN); 8º43'28"S, 35º50'39"W, elevation c. 657 m, 29 January 2013 (fl), J . L . Costa-Lima et al. 860 ( CEPEC, NY, RB, UFP, UFRN); 8º42'34"S, 35º50'34"W, elevation c. 780 m, 30 January 2013 (fl), J . L . Costa-Lima et al. 872 ( CEPEC, NY, RB, UFP, UFRN) .

Discussion:— Erythroxylum umbrosum is characterized by having reduced, non-striated stipules that are shortly 3–setose at apex, a staminal cup longer than the calyx lobes, and endocarp with cylindrical crosssection. Among the Brazilian species of E. sect. Archerythroxylum having a staminal cup longer than the calyx lobes, E. umbrosum is the only one with a Brazilian extra-Amazonian distribution. The other species of the section with the same features occur in Central America, West Indies, the Andean region and Amazonia [e.g., E. coca Lamarck (1786: 393) , E. dillonii Plowman ex Jara-Muñoz (2011: 227) , E. leptoneurum Schulz (1907: 101) , E. novogranatense (D. Morris 1889: 5) Hieronymus (1895: 35) , and E. oxycarpum Schulz (1907: 90) ]. The presence of staminal cup longer than the calyx lobes is not exclusive to E. sect. Archerythroxylum and can be found in some species of 14 sections proposed by Schulz (1907).

The new species is similar to E. cuspidifolium Martius (1843: 359) [E. sect. Microphyllum Schulz (1907: 114) ] and E. santosii Plowman [E. sect. Archeryhroxylum], sharing the habit, general branching appearance, and leaf morphology. These two species differ from E. umbrosum by the length of the stipules (≥ 1.2 mm long), calyx lobes shape (lanceolate or ovate), and staminal cup shorter than the calyx lobes; in E. cuspidifolium the styles are connate in the longistylous flowers ( Table 1).

Erytroxylum umbrosum and the similar species discussed here are not found in sympatry. According to Loiola (2013), E. cuspidifolium can be found in the rainforests from southern Bahia to Rio Grande do Sul states, whereas E. santosii is restricted to the wet forest fragments in southern Bahia and known only from the type material.

Figures

FIGURE 1. Erythroxylum umbrosum. (A) General appearance of the branch. (B) Stipule, abaxial view. (C) Leaf, adaxial surface. (D) Brevistylous flower. (E) Longistylous flower, petals removed. (F) Drupe. (G) Cross-section of the drupe. A, B, C, and E from Costa- Lima et al. 870 (holotype); D from Costa-Lima et al. 872; F and G from Costa-Lima et al. 667; drawn by Regina Carvalho.

FIGURE 2. Geographic distribution of Erythroxylum umbrosum.