Erythroxylum angelicae Loiola, 2013

Loiola, Maria Iracema Bezerra, 2013, A new species of Erythroxylum (Erythroxylaceae) from the Brazilian semiarid region, Phytotaxa 150 (1), pp. 61-64 : 61-64

Erythroxylum angelicae Loiola , sp. nov. ( Fig. 1A–G )

A new species characterized by persistent cataphylls, non-striated, long-triangular, palleaceous; stipules non-striated, 3– setulose; flowers subsessile, calyx lobes triangular, and styles free.

Type:— BRAZIL. Ceará: Novo Oriente, Baixa Fria, Planalto da Ibiapaba , 760 m, 8 November 1990, (fl), F. S . Araújo 209 (holotype EAC 19335 A, isotypes EAC 19335 B, RB) .

Shrubs. Branches ascending, relatively short and straight, 1–2.5 mm diam., grayish to dark brown (when young), longitudinally finely striate, without distinct lenticels. Short shoots absent. Cataphylls alternate or congested along the shoots (in number of 5-7, the inferior shorter than superior), persistent, long-triangular, 2– 6 mm long, non-striated, palleaceous. Foliar stipules persistent, narrowly triangular, 1.7–4 mm long, rounded apex, non-striated, membranaceous, 3–setulose, keels sub-alate, margin entire; setae deciduous, 1–1.5 mm long,presenting colleters. Leaves persistent, short-petiolate; petioles subterete, 1–1.5 mm long, narrowly canaliculate adaxially; leaf blades ovate, 2.3–5.2 × 0.9–2.1 cm, acuminate to acute at apex, acute at base, margin entire, membranaceous, discolorous, adaxially dark green, abaxially pale green; the midrib impressed adaxially, prominent abaxially, 8–10 secondary nerves on each side, the veinlets reticulate, conspicuous on both surfaces. Buds rounded, 2–2.2 × 1.7–2 mm. Pedicels inconspicuous, less than 1 mm long. Flowers 1–3 per node, in axils of leaves or cataphylls, 2–2.5 mm long. Bracteoles 1, ca. 1 mm long, 1–setulose, keel subalate, non-striated, triangular, concave, margin entire. Calyx divided half its length, with triangular lobes, 1– 1.2 × 0.6–0.8 mm, longer than the staminal cup. Petals oblong, 1.8–2 × 0.7–0.8 mm, concave, rounded at apex, bilobate. Staminal cup 0.5–0.7 mm long, the margin 10-denticulate. Brachystylous flowers not seen. Dolichostylous flowers: antesepalous filaments 0.5–0.6 mm long, antepetalous filaments 0.8–1 mm long, anthers oblong, ca. 0.5 × 0.5 mm; ovary obovoid to oblong, 0.8–1 × 0.7–0.8 mm, styles free, 1–1.4 mm long, stigmas depressed-capitate. Drupe not seen.

Etymology:— Erythroxylum angelicae honours Professor Maria Angélica Figueiredo (1939-2012) of the Federal University of Ceará, Brazil, for her valuable studies of the flora and phytogeography of Ceará.

Additional specimen examined (paratype):— BRAZIL. Ceará, Novo Oriente, Estrondo, Planalto da Ibiapaba , 8 November 1990 (fl), F . S . Araújo 208 (EAC).

Distribution:— This species has so far been observed only on the Ibiapaba plateau, in the municipality of Novo Oriente (approx. 5º 32' 04" S, 40º 46' 26" W), Ceará state, northeastern Brazil. It deserves mentioning that field trips were conducted in this area some time ago (ca. 3 years ago), but the species was not found. Recently, there were no field trips in that area and, therefore, few samples of this species were analyzed.

Habitat and ecology:— Grows in “Carrasco” vegetation type, at 760 m elevation. According to Araújo et al. (1999), the “Carrasco” is a dense, shruby and deciduous type of vegetation, covering quartz-sandy soils, between altitudes of 700 and 900 m, on the Ibiapaba and Araripe plateaus, in the Brazilian semiarid domain. The two collections, both with flowers, were gathered in November. The characteristics of fruits (drupes) are unknown.

Conservation status:— Considering that only two samples collected in the area during the study of the “Carrasco” vegetation ( Araújo et al. 1999) and few individuals of Erythroxylum angelicae have been observed at the site, this species was considered rare. However, based on IUCN (2001) criteria, the conservation status of this species is Data Deficient (DD).

Discussion:— In a preliminary list of Erythroxylum species form Ceará state, I identified both specimens of this new species as Erythroxylum laetevierens O.E. Schulz (1907: 42) of section Rhabdophyllum , due to the general aspect of the branches, leaf morphology, and geographical distribution (both species are sympatric). However, closed observations of this collections show that Erythroxylum angelicae belongs to section Archerythroxylum , based on its non-striate stipules and triangular calyx lobes.

Erythroxylum angelicae superficially resembles several other species encountered in northeastern Brazil, such as Erythroxylum vacciniifolium Martius (1840: 387) , also of sect. Archerythroxylum ; differing by the length of setae (1-1.5 mm long in E. angelicae vs. 0.6-0.8 mm in E. vaccinifolium ), length of pedicels (inconspicuous, less 1 mm long vs. 2-5mm) and shape of calyx lobes (triangular vs. lanceolate). The new species is also similar, in general branching appearance and leaf morphology, to E. tenue Plowman (1987: 35) of sect. Rhabdophhylum; however, this last species have striated stipules. Other characters that distinguish E. angelicae from these morphologically related species are presented in Table 1.

Erytroxylum angelicae and the similar species discussed here are not found in sympatry. E. vacciniifolium is reported from savanna formations (cerrado) and savanna-steppe vegetation (caatinga) in the west-portion of Brazil ( Loiola 2013) and E. tenue is recorded from the coastal forest in southern Bahia ( Plowman 1987).

Figures

FIGURE 1. Erythroxylum angelicae. A. General appearance of a flowering branch. B. Leaf. C. Stipule, frontal view. D. Cataphyll. E. Detail of a branch showing stipules and flowers. F. Dolichostylous flower (a petals removed). G. Petals. (All from the F. S. Araújo 209 A EAC; drawn by Francisco Átila Leles Magalhães).