Hirtella prancei Asprino & Amorim, 2016

Asprino, Renata Camargo & Amorim, André Márcio, 2016, A new species of Hirtella (Chrysobalanaceae), and redescription of a closely related taxon, from the Atlantic Forest, Brazil, Phytotaxa 265 (3), pp. 259-266 : 260-263

Hirtella prancei Asprino & Amorim , sp. nov.

Type:— BRAZIL. Bahia: Arataca, Parque Nacional da Serra das Lontras , acesso à serra pela roça do Sr. Cristóvão, coletada no começo da trilha para o Mirante II, 15º08’23’’S, 39º18’36’’W, 520 m, 16 December 2014, fl., R.C. Asprino & A.M. Amorim 117 (holotype CEPEC! , isotypes HUEFS! , K! , RB! ). ( Figs. 1A–K , 2A–I , 3 )

Hirtella prancei Asprino & Amorim is distinguished from H. santosii by its densely velutinous indumentum on the young branches and inflorescences (vs. densely hirsute to hirsute), stipules 6–10 mm long (vs. 2.5–6.5 mm), leaf blades 10.3–18 mm wide (vs. 4.2–9 cm), subcoriaceous (vs. subchartaceous to chartaceous), and eglandular (vs. with discoid glands at least on the abaxial surface), pendulous racemes (vs. erect), 18–40 cm long (vs. 4.5–12.5 cm) and bracteoles triangular to deltate and eglandular (vs. ovate to depressed ovate, bearing numerous glands on the margins).

Trees or treelets, 3–15 m tall; stems ca. 7 cm diam. at breast height; young branches yellowish brown, densely velutinous, becoming glabrescent with age, lenticels absent. Leaves alternate, distichous; stipules lateral, narrowly triangular, 6–10 mm long, late deciduous, eglandular; petiole thick, 6–10 mm long, velutinous when young, eglandular; leaf blade subcoriaceous, discolorous, widely elliptic to ovate, base obtuse to rounded or subcordate, apex acute to attenuate or acuminate, 17.5–32.5 × 10.3–18 cm, margins irregularly revolute, with 13–16 pairs of secondary veins, intersecondary veins sometimes present; abaxial surface with velutinous midvein, secondary to quaternary veins sparsely velutinous, eglandular, primary to quaternary veins prominent; adaxial surface with primary and secondary veins glabrescent, eglandular, midvein plane to impressed, secondary to quaternary veins deeply impressed, producing a strongly bullate surface. Inflorescence a single raceme with 30–70 flowers, pendulous, rachis greenish brown in vivo, yellowish brown in sicco, densely velutinous, 18–40 × 0.25–0.35 cm; bract 1, narrowly triangular to triangular, sericeous, (1.5–)2–4.5(–6) mm long, late deciduous, eglandular; pedicel thick, velutinous, (5.5–)7–9(–12) mm long, eglandular; bracteoles 1–2, triangular to deltate, sericeous, 1–2(–3) mm long, late deciduous, eglandular. Flowers 7–10 mm long; receptacle campanulate, slightly swollen on one side, greenish yellow in vivo, yellowish brown in sicco, exterior velutinous, interior glabrous except for deflexed hairs near throat; sepals 5, elliptic to oblong, 6–7 × 3–3.5 mm, velutinous abaxially, greenish yellow in vivo, yellowish brown in sicco, margin eglandular; petals 5, oblong to ovate, 5.5–6.5 × 3–3.5 mm, glabrous, pinkish; stamens 6–8, unilaterally inserted on disc, filaments 19.5–22.5 mm long, glabrous; anthers 0.8–1.0 mm long; staminodes opposite the stamens, filiform, 0.5–0.8 mm long; ovary inserted at mouth of receptacle, 1–1.5 × 0.5–1 mm, densely villous, unilocular, biovulate; style gynobasic, filiform, 22–24 mm long, hirsute up to 1/4 of its length, stigma truncate. Drupe fleshy, obovoid, (2.5–)3.5–3.6 × (1.5–) 1.9–2 cm, green when immature, dark purple when mature, calyx persistent, filaments sometimes persistent, epicarp sparsely hirsute, mesocarp fleshy, endocarp not seen.

Comments: — Hirtella prancei is morphologically similar to H. hebeclada and H. santosii ( Fig. 4A–G ), which also occur in the Brazilian Atlantic Forest domain. The three species are trees or treelets with dense indumentum (drying yellowish brown) covering the branches and rachis of the inflorescence, racemose inflorescences, and flowers 6–10 mm long. Hirtella prancei and H. santosii occur in sympatry in forests of southern Bahia, whereas H. hebeclada is widespread in forests from Minas Gerais to Rio Grande do Sul States. The occurrence of H. hebeclada in the state of Bahia may have been based on a few misidentified H. santosii specimens.

Hirtella prancei differs from H. hebeclada by its densely velutinous indumentum on the young branches and inflorescences (vs. tomentose), stipules 6–10 mm long (vs. 3–7 mm), leaves 17.5–32.5 cm long (vs. 5.5–21 cm) and 10.3–18 cm wide (vs. 2.5–9 cm), with 13–16 pairs of secondary veins (vs. 8–11 pairs) and a strongly bullate adaxial surface (vs. not bullate), and inflorescences 18–40 cm long (vs. 6–20 cm) with 30–70 flowers (vs. 8–22 flowers).

Besides the features stated in the diagnosis, Hirtella prancei can also be distinguished from H. santosii by its usually longer leaves (17.5–32.5 cm vs. 8.5–21.5 cm), with 13–16 pairs of secondary veins (vs. 8–14 pairs), strongly bullate adaxial surface (vs. not bullate or slightly bullate) and revolute margin (vs. plane to slightly revolute), inflorescences with 30–70 flowers (vs. 12–36 flowers), and filaments 19.5–22.5 mm long (vs. 11–14 mm).

Etymology:— The specific epithet “ prancei ” is an honor to Sir Ghillean T. Prance, because of his relevant work on Chrysobalanaceae and other neotropical plant families.

Distribution and habitat:— Hirtella prancei is known only from a few collections from three localities in southern Bahia State, Brazil, where it grows in the understory of submontane and montane wet forest ( Fig. 3 ).

Conservation status:— The type locality is Serra das Lontras National Park, a protected area that comprises ca. 11,300 ha where there are at least two populations of Hirtella prancei . Nevertheless, H. prancei is considered Endangered (EN) according to the following IUCN (2012) criteria, combined with an analysis using GeoCAT ( Bachman et al. 2011): extent of occurrence less than 5,000 km 2, area of occupancy less than 500 km 2, with distribution in no more than five locations, and continuing decline in habitat area and quality (B1ab(iii) + B2ab(iii)).

Additional specimens examined (paratypes): — BRAZIL. Bahia: Arataca, Serra das Lontras , trilha para o Mirante II, 15º08’25’’S, 39º18’37’’W, 500 m, 05 April 2014, fr., R.C. Asprino et al. 61 (CEPEC!) . Ibidem, ca. de 7 km no ramal que liga o povoado de Itatingui à Serra das Lontras , 15º12’10’’S, 39º24’29’’W, 900 m, 13 September 2009, ste., A.M. Amorim et al. 7910 ( CEPEC!) . Ibidem, 10 October 2015, fr., A.M. Amorim et al. 9760 ( CEPEC! RB!) . Igrapiúna, assentamento Mirante , 13º54’20’’S, 39º20’59’’W, 18 December 2001, fl., D.M. Loureiro et al. 394 ( ALCB!, CEPEC!) . Ilhéus, Fazenda Attalea , Distrito de Castelo Novo, próximo ao Ribeirão do Choro , 100 m, 03 March 1995, fl., L.A. Mattos-Silva 3074 ( CEPEC!) .

Figures

FIGURE 1. Hirtella prancei. A—Branch with apical leaf and inflorescence; B—Detail of adaxial leaf surface; C—Basal leaf; D—Detail of abaxial leaf surface; E—Detail of petiole and stipule; F—Bract; G—Bracteole; H—Flower without petals; I—Longitudinal section of the flower without petals; J—Mature fruit; K—Isolated trichomes from leaf. (A–I, K based on R.C. Asprino 117 and J based on R.C. Asprino 61).

FIGURE 2. Hirtella prancei. A—Detail of stipules; B—Adaxial leaf surface (left) and inflorescence (right); C—Detail of adaxial leaf surface;D—Branch with leaves and inflorescences;E—Detail of abaxial leaf surface; F—Detailof leaf margin; G—Detail of inflorescence with old flowers; H—Mature fruit; I—View of the area where the type specimen was collected. Photos A–G, I by A.M. Amorim and H by R.C. Asprino.

FIGURE 3. Geographic distribution of Hirtella hebeclada (black triangles), H. prancei (black circles) and H. santosii (white squares).

FIGURE 4. Hirtella santosii. A—Detail of stipules; B—Detail of abaxial leaf surface; C—Detail of adaxial leaf surface; D—Buds and flowers at anthesis; E—Detail of leaf margin; F—Inflorescence; G—Branch with leaves and inflorescences. All photos by A.V. Popovkin.