Erythroxylum riparium T. Araujo & Amorim 2015, sp. nov.
Creators: name: Araújo, Thiago
name: Fiaschi, Pedro
name: Amorim, André M.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Erythroxylaceae
Erythroxylum
Erythroxylum riparium

description: Erythroxylum riparium T. Araújo & Amorim sp. nov.
Type:— BRAZIL. Bahia: Itacaré, Reserva Particular do Patrimônio Natural Capitão, 14°19’12’’S, 39°03’44”W, 21 April 2013 (fl, fr), T. Araújo & C. Pessoa 211 (Holotype CEPEC!, Isotype HUEFS!). Figures 1A–K, 2 & 3A–H.
Erythroxylum riparium is similar to E. ectinocalyx and E. santosii, by its general branching appearance, non-striate stipules, and staminal cup shorter than the calyx lobes. It can be distinguished by having branchlets intensely dotted with elliptic, often united, lenticels, leaf blades with undulate margin, two bracteoles per flower, petal appendages 4-lobed, and brevistylous flowers with connate styles vs. branchlets with few scattered lenticels, leaf blades with plane margins, three bracteoles per flower, petal appendages 2-lobed, and brevistylous flowers with free styles.
Shrubs 1–2.5 m tall, branchlets light-brown to grayish-brown, densely dotted with yellowish to light-brown elliptic lenticels, these often united. Cataphylls persistent, scattered along branches and branchlets. Stipules similar to cataphylls, persistent, 1–2 × 1–1.5 mm, triangular, non-striated, margin entire, apex rounded, 3-setulose, setae ca. 0.8 mm long. Leaves persistent, petiolate, membranous to papery, shiny, adaxially dark green, abaxially pale green. Leaf blades 5–13 × 2–5 cm, elliptic, cuneate at base, margins undulate, acute to attenuate at apex; midrib slightly impressed adaxially and prominent abaxially, secondary veins 8–12 per side, reticulation inconspicuous. Petioles 0.5–1.5 mm long, terete, adaxially canaliculate. Flowers 1–3 per node, in the axils of petioles or cataphylls; pedicel 4–6 (–9) mm long, 5-angled, bracteoles 2, persistent, 0.7–1 mm long, lanceolate, non-striate, margins erose; calyx lobes greenish, lanceolate or narrowly triangular, 3–4.5 × 1–1.5 mm, acute to acuminate at apex; petals white, oblong, 3–4 × 1–1.5 mm, rounded at apex, appendages ligulate, 4-lobed, 1.5–2 mm long; staminal cup 1/3 to 1/2 the length of calyx lobes, 0.7–1.5 mm long, 10-crenulate at margin; ovary ovoid, 2–2.5 mm long, rounded to acute at apex. Brevistylous flowers: filaments ca. 2.8 mm long, anthers ca. 0.5 × 0.4 mm, styles 3, ca. 1.5 mm long, one of which is connate to two others for ca. 0.5 mm, and the latter two further connate for ca. 0.4 mm. Longistylous flowers: antesepalous filaments 0.8–1 mm long, antepetalous filaments 1.5–2 mm long, anthers ca. 0.5 × 0.4 mm; styles 3, 2.5–3 mm long, two of which are connate for 2–2.5 mm, with a third style connate with other two for 1.5–2 mm, stigmas depressed-capitate; Drupes oblong to elliptic, 8–12 mm long, reddish to purplish when ripe, with one fertile locule.
Distribution and habitat:— Erythroxylum riparium is known from a single population in a protected private reserve of Atlantic Forest in Southern Bahia State, Brazil (Fig. 2). This species inhabits the forest subcanopy, where it grows on clayey soils along river banks (Fig 3 H).
Etymology:—The specific epithet refers to the riparian environments where these plants are found.
Additional specimens examined (paratypes):— BRAZIL. Bahia: Itacaré, Reserva Particular do Patrimônio Natural Capitão, 14°19’12’’S 39°03’44”W, 21 April 2013 (fr immature), T. Araújo & C. Pessoa 208 (CEPEC). Ibidem, 12 February 2011 (fl), T. Araújo, J.L. Paixão & C. Vivas 42 (CEPEC). Ibidem, 12 December 2014 (fl, fr), A.M. Amorim et al. 8907 (CEPEC, HUEFS, RB, HCE). Ibidem, 24 January 2015 (fl, fr), A.M. Amorim et al. 9048 (CEPEC, F, HUEFS, NY, RB).
Notes: — Erythroxylum riparium is here assigned to Erythroxylum sect. Microphyllum Schulz (1907: 114), because it shares with remaining species of this section the non-striated stipules and longistylous flowers with partially connate styles. As referred in the diagnosis the new species is morphologically similar to E. ectinocalyx Martius (1843: 355) and E. santosii Plowman (1987: 25) (see Table 1). These three species have a similar general branching appearance, non-striate stipules, and staminal cup shorter than the calyx lobes. However, Erythroxylum riparium can be distinguished by having branchlets intensely dotted with elliptic lenticels, leaf blades with undulate margin, two bracteoles per flower, petal appendages 4-lobed, and brevistylous flowers with connate styles.
description: Published as part of Araújo, Thiago, Fiaschi, Pedro & Amorim, André M., 2015, Erythroxylum riparium (Erythroxylaceae), a new species from the Brazilian Atlantic Forest, pp. 75-80 in Phytotaxa 230 (1) on pages 75-79, DOI: 10.11646/phytotaxa.230.1.7, http://zenodo.org/record/13632249