Hornschuchia mellosilvae L.Vilela & J.C.Lopes, 2021

Lopes, Jenifer De Carvalho, Vilela, Lucas & Johnson, David M., 2021, Hornschuchia mellosilvae (Annonaceae) a new species endemic to the Brazilian Atlantic Forest, Phytotaxa 520 (3), pp. 273-278 : 274-276

Hornschuchia mellosilvae L.Vilela & J.C.Lopes sp. nov.

TYPE: BRAZIL. Bahia: Almadina, Rodovia de Almadina para Ibitupã ca. 20 km . Fazenda São Roque , ca. 10 km da entrada do ramal à esquerda, 14º38’27”S, 39º42’47”W, 12.III.2005, P. Fiaschi et al. 2784 (Hototype: SPF! [bc] SPF00168936 ; Isotypes: CEPEC! [bc] CEPEC00104268 , NY! [bc] NY01282018 ) . Figs. 1 , 2 .

Hornchuchia mellosilvae is similar to Hornschuchia mediterranea but differs in petal length 9–24 mm (vs. 6–9 mm long),10 stamens (vs. 3–6),4 carpels (vs. 5–8), and oblong monocarp with an acute apex (vs. globose to ellipsoid with a rounded apex).

Shrub or treelet. Twigs glabrous. Leaves chartaceous to subcoriaceous, petiole 2–7 mm long; lamina 6–11.6 × 2.4–5.3 cm, narrowly elliptic to elliptic or lanceolate; abaxial and adaxial surfaces glabrous; base cuneate to acute or obtuse, apex acuminate to acute or obtuse; primary vein impressed adaxially and raised abaxially, secondary veins 8–12, angle between primary and secondary veins 50–60°. Inflorescence solitary; supra-axillary or terminal or ramiflorous, flower white. Pedicel 2–4 mm long; flower buds 5–7 × 2–3 mm, conical, densely to sparsely covered by simple, straight, adpressed and yellowish trichomes. Calyx with sepals completely connate, cupuliform, densely covered by simple, straight, adpressed and yellowish trichomes, 3–8 × 2–5 mm. Corolla with linear petals, free, outer petals (9–)20–24 × (1.5–) 2–3 mm, inner petals ca. 15 × 3 mm, densely covered by simple, straight, adpressed and yellowish trichomes; stamens 10, ca. 4 × 0.5 mm; carpels 4, ca. 5.5 × 1 mm, densely covered by simple, straight, adpressed and yellowish trichomes. Fruit with 1 monocarp, subsessile, oblong with acute apex, rugose, 20–24 × 9–12 mm, glabrous, green in vivo. Seeds 4, oblong-flattened, 15–18 × 8 mm, with aril.

Distribution and Habitat:— Hornschuchia mellosilvae occurs in Southern Bahia state, Brazil. It inhabits the semideciduous seasonal forest ( Gouvêa et al. 1976, Thomas & Barbosa 2008).

Conservation status:— Hornschuchia mellosilvae is known from only two specimens, and the last collection was made 15 years ago. It has an EOO of 0 km 2 and an AOO of 32 km 2. The region where it occurs has been suffering a continued decline of its original vegetation due to anthropic pressure ( Landau et al. 2008, Mori & Silva 1979). The conservation status is categorized as Endangered, EN B2ab(iii), according to IUCN Red List Categories and Criteria (2012).

Etymology:— Hornschuchia mellosilvae is named after Renato Mello-Silva (1961–2020), a Brazilian botanist who studied Annonaceae for 30 years and contributed to the knowledge of the species of Hornschuchia ( Johnson & Mello-Silva 1993, Mello-Silva et al. 2021).

Phenology:—Flowering from March to April and fruiting in March.

Notes:— Hornschuchia lianarum , H. mediterranea and H. mellosilvae are sympatric species, occurring together in the municipality of Antônio Cardoso, and endemic to Southern Bahia. The three species occur in the interior semideciduous seasonal forest ( Gouvea et al. 1976, Thomas & Barbosa 2008). Hornschuchia lianarum is distinguished from the other two by the cylindrical flower bud (flower bud is globose to ovoid or conical in H. mediterranea and conical in H. mellosilvae ). Hornchuchia mellosilvae differs from H. mediterranea by the petal length (9–24 mm vs. 6–9 mm); number of stamens (10 vs. 3–6) and number of carpels, (4 vs. 5–8); and by its monocarp (oblong with acute apex, 20–24 × 9–12 mm, glabrous vs. globose to ellipsoid with rounded apex, 6–11 × 3–9 mm, densely covered with trichomes).

Additional specimens examined:— BRAZIL, Bahia, Antônio Cardoso, 20 km de Feira de Santana, na BR-116, Fazenda Sossego , 14.IV.1995, E. Mello 1143 ( SPF! [bc] SPF00146918 , SPF00133100 ) .

Figures

FIGURE 1. Hornschuchia mellosilvae. A. Branch with flowers; B. Leaf adaxial surface; C. Ramiflorous floral bud; D. Flower; E. Carpel; F. Stamen; G. Monocarp. (A, C Mello 1143; B, D–G Fiaschi 2784).

FIGURE 2. Distribution map of Hornschuchia mellosilvae (black dots). BA, Bahia state, MG, Minas Gerais state, the Southern portion of Bahia borders Espírito Santo state. Shape file of the Brazilian political division was downloaded from http://www.forest-gis.com/ download-de-shapefiles/.