Duguetia sulcosa M.L.Bazante & M.Alves, 2017

Bazante, Márcio & Alves, Marccus, 2017, A new species of Duguetia (Annonaceae) from the Atlantic Forest of northeastern Brazil, Phytotaxa 314 (2), pp. 266-272 : 266-270

Duguetia sulcosa M.L.Bazante & M.Alves , sp. nov. ( Figs 1 , 2 , 3 )

Type:— BRAZIL. Pernambuco: Município de Jaqueira, Reserva Particular do Patrimônio Natural ( RPPN) Frei Caneca , Mata do Quengo , 08°42’53”S, 35°50’34”W, 680 m, 5 January 2016, Bazante et al. 334 (fl., fr.) (holotype: UFP; isotypes: INPA, RB) .

Duguetia sulcosa resembles Duguetia pauciflora (Rusby 1920: 18) Fries (1934: 103) but differs by the acumen of the leaves 2–5 mm long (vs. 10–30 mm long), sepals up to a third connate (vs. free), adaxial face of the inner petals reddish (vs. cream to yellowish), stigma glabrous (vs. sparsely covered with stellate trichomes) and areolas grooved (vs. not grooved).

Shrubs to trees, ca. 4 m tall. Young branches glabrous or covered with stellate scales. Leaves simple, entire, alternate, distichous, symmetrical, concolorous; petioles 6–8 × 3 mm, covered with lepidote-stellate trichomes, canaliculate; lamina narrowly elliptic, 10.0–14.5(17.0) × 3.0– 5.3 cm; base acute to obtuse, apex obtuse to acuminate (acumen 2–5 mm long), venation brochidodromous, upper and lower side slightly shiny, glabrous above, sparsely covered with stellate trichomes and lepidote-stellate trichomes 0.1(0.2) mm in diameter below, with 10–16 pairs of secondary veins, adaxial face with primary vein impressed, secondary veins flat to impressed, curved, loop-forming at right to obtuse angles, loops distinct, smallest distance between loops and margin 2–5 mm. Inflorescences terminal or leaf-opposed, 1–2–flowered. Pedicel 8 mm long, covered with lepidote-stellate trichomes. Upper bract arising halfway the pedicel, semi-amplectent, caducous, depressed ovoid, 4 × 3 mm, apex rounded, deciduous; outer side densely covered with lepidote-stellate trichomes, inner side pilose with lanuginose base. Flower buds subglobose, distinctly 3-ridged due to recurved edges of the sepals; densely covered with lepidote-stellate trichomes, 0.2–0.3 mm in diam. Flowers actinomorphic, cyclic, trimerous, dichlamydeous, bisexual. Sepals connate over 2–3 mm, valvate, ovate-triangular, 1.0–1.2 × 0.8–1.0 cm, greenish, deciduous; apex cuneate to slighty acuminate, outer side densely covered with lepidote-stellate trichomes, inner side glabrous. Petals biseriate, subequal, imbricate, yellowish, ovate to narrowly elliptic, 1.3–2.0 × 0.8–1.3 cm, free, with stellate trichomes and lepidote-stellate trichomes; base of the adaxial face of inner petals concave, grooved, reddish. Floral receptacle depressed ovoid with a slightly concave apex. Androecium depressed-triangular, 0.3 × 0.6–0.9 cm; stamens numerous, verticillate; anthers 1.0 × 0.2 mm, reddish; apex of connective discoid, 0.6–0.7 × 0.3–0.5 mm, papillate. Carpels free, narrowly ellipsoid, yellowish, 2.0 × 0.5 mm, ovary covered with stellate trichomes, one basal ovule, stigma elongate, glabrous. Fruits pseudosyncarpous, with base cream and apex green to brown in vivo, globose to subglobose, 1.7–2.0 cm in diameter; basal collar composed of 8–9 connate and sterile carpels, 2–4 mm in diameter, slightly protruding below the fruit, fertile carpels 15–20, obovoid, sessile, free, indehiscent, 0.5–0.8 × 0.7 cm, areoles 0.4–0.5 cm diameter, globose-pyramidal, smooth in vivo, verrucose in sicco, singly grooved, densely covered with lepidote-stellate trichomes; 4–6–angled, apiculate (apicule 1–2 mm long), straight to curved. Seeds obovoid to globose, 0.5 × 0.5 cm, smooth, brownish, aril absent, with ruminate endosperm.

Additional specimens examined:— BRAZIL. Pernambuco: Jaqueira, RPPN Frei Caneca, Mata do Quengo , 3 September 2013, fr., Melo et al. 1204 ( UFP) ; 30 January 2013, fl., Amorim et al. 1769 ( UFP) ; 8 October 2000, fr., Siqueira-Filho 1096 ( UFP). Alagoas: São José da Laje, Mata da Chaminé , 6 May 2003, fl., Oliveira & Grillo 1372 ( UFP) ; Viçosa, Fazenda Mata Verde , 14 May 2010, fl., Chagas-Mota & Bastos 7773 ( MAC) ; fr., Chagas-Mota & Bastos 7753 ( MAC) ; Quebrangulo, Reserva Biológica Pedra Talhada, Pedra D’Água , 7 October 2010, fr., Chagas-Mota 9011 ( MAC) .

Distribution and Ecology:— Duguetia sulcosa is endemic to the Brazilian Atlantic Forest, reported so far for the states of Pernambuco and Alagoas. The new species is found in submontane forest (sensu Veloso et al. 1991), to which several other species are restricted, such as Eugenia submontana Amorim & Alves (2015: 209) ( Myrtaceae ), Specklinia integripetala Pessoa & Barros (2014: 129) ( Orchidaceae ) and Turnera pernambucensis Urban (1883: 133) ( Passifloraceae ) ( Zelenski et al. 2016). The climate of the areas is considered tropical wet and dry (Aw sensu Köppen), with an annual average precipitation of 1.250 –1.500 mm /year (data from the headquarters of Usina Colônia), elevation from 600–780 m, and annual temperatures 18–30 °C (LAMEPE/ITEP; MMA, 2006). Specimens of Duguetia sulcosa are found in shady areas of the forest fragments, with elevated humidity and rich soil with high deposition of plant litter ( Nusbaumer et al. 2015, Melo et al. 2016).

The species was observed flowering from January to May and fruiting from January to December.

Conservation status:— Following the IUCN (2001) criteria, this species is considered endangered (EN): B2+(biv). All specimens known in the field were found close to each other and on the edges of the forest fragments.

Etymology:— The species name refers to the grooves present in the fertile carpels, a unique character that differentiates it from the most closely related taxa in the genus.

Morphological affinities: — Maas et al. (2003) organised all 93 species of Duguetia currently recognised in ten clusters obtained by basic cluster analysis (UPGMA) based on 42 morphological characters. Each cluster is formed by a set of species grouped by morphological characters. Duguetia sulcosa would fit morphologically among the species placed in cluster 1, which is recognised by Maas et al. (2003) by the small number of carpels. Among them, the new species is morphologically similar to D. pauciflora Rusby (1920: 18) and D. inconspicua (Sagot 1881: 135) , due to the chartaceous, narrowly elliptic lamina, stellate and lepidote-stellate trichomes, yellowish flowers and 6–20 fertile carpels of the fruits.

Duguetia sulcosa and D. inconspicua are distinguished from D. pauciflora by the characters detailed in Table 1. It is important to emphasize that the new species described here is the first record for northeastern Brazil of a taxon that fits in cluster 1 sensu Maas et al. (2003). The species of this cluster share a small number of fertile carpels in the fruits, and most of them occur in the Amazon forest ( Guyana, Suriname, French Guiana, Venezuela and Brazilian Amazon - Amapá, Amazonas and Pará), representing a case of Amazonian-Atlantic Forest disjunction.

Figures

FIGURE 1. Distribution of Duguetia sulcosa in the Jaqueira (PE), Quebrangulo, São José da Laje and Viçosa (AL).

FIGURE 2. A–O. Duguetia sulcosa. A–B. Habit. C. Abaxial surface of a leaf, detail. D–F. Flower buds. D. Side view. E. Top view. F. Trichomes. G. Mature flower without some petals and sepals. H. Bottom view of the sepals showing connate portion. I. Adaxial face of inner petal. J. Longitudinal section of floral receptacle. K. Stamen. L. Carpel. M. Fertile carpel. N. Fruit. O. Longitudinal section of fruit.

FIGURE 3. A–F. Duguetia sulcosa. A. Immature flower. B. Mature flower with one petal removed to show reddish stamens. C. Connate sepals. D. Mature fruit with floral bud. E–F. Mature fruits. (B from Amorim 1769; A, C, D, E, and F from the Bazante 334, the type specimen).