Aspidosperma rizzoanum Scudeler & A.C.D.Castello, 2018

Scudeler, Ana Laura, Castello, Ana Carolina Devides, Pereira, Andreza Stephanie De Souza & Koch, Ingrid, 2018, A new species of Aspidosperma (Apocynaceae) from the Brazilian Cerrado, Phytotaxa 333 (1), pp. 117-123 : 118-120

publication ID

https://doi.org/ 10.11646/phytotaxa.333.1.9

persistent identifier

https://treatment.plazi.org/id/03A687BA-FFAA-FF93-FF6B-CD09FD7AD11F

treatment provided by

Felipe

scientific name

Aspidosperma rizzoanum Scudeler & A.C.D.Castello
status

sp. nov.

Aspidosperma rizzoanum Scudeler & A.C.D.Castello View in CoL , sp. nov. ( Figures 1 − 2 View FIGURE 1 View FIGURE 2 )

Aspidosperma rizzoanum is characterized by the discolorous and glabrous leaves, glabrous ovary, and by the follicles with ferruginous pilosity and with more than one parallel rib.

Type: — BRAZIL. Goiás: Alto Paraíso de Goiás, Fazenda São Bento, 14º09’29’’S, 47º36’45’’W, 1200 m, 28 October 2005 (fl.), J.R.R. Pinto & E. Lenza 345 (holotype: UB!).

Description: —Trees 2 − 5 m high. Branches cylindrical, not suberous, lenticellate, glabrescent to glabrous, cataphylls 1 mm long, deltoid, pilose; latex whitish. Leaves simple, alternate, congested, rarely arranged along the branches; petioles (0.8–) 1–1.8 cm long, flattened, striated, glabrescent to glabrous; blade 4–8.7(–11) × (2.3–) 3.2–4.5 cm, chartaceous to subcoriaceous, elliptic, obovate or ovate, apex rounded or acute, base cuneate or oblique, margin lighter than the rest of the blade, discolorous, venation eucamptodromous, adaxial surface dull, glabrous, dark green, primary vein immersed or flat, secondary veins flat, abaxial surface dull, glabrous, light green, primary vein prominent, secondary veins prominulous, 14–20 pairs. Inflorescences 3–4.5 cm long, axillary, corymbiform cyme, glabrescent. Flower buds with corolla lobes not twisted. Flowers 6 − 7 mm long; pedicellate, pedicel 0.9 mm long, glabrescent. Calyx 0.6–0.7 mm long, green, glabrous externally and internally, ciliate margin; lobes 5, 0.6–0.7 × 0.3–0.4 mm, equal, deltoid, apex acute. Corolla 5 mm long, tubular, beige; tube 3 mm long, glabrescent externally, pubescent below the anthers internally, glabrous above; lobes 5, 1.8 − 2 × 0.9 − 1 mm, erect, triangular, apex rounded to acute, glabrous externally, glabrescent internally. Stamens 5, 2.8 mm long, included; filaments adnate to the corolla tube, 0.3–0.4 mm long, anthers 0.7 × 0.4 mm, free from each other and from the style-head, ovate, base cordiform, apex acute. Carpels 2, 1.6 mm long; ovary 0.55 × 0.4 mm, ovate, apex acute, glabrous; style 1 mm long; style-head 0.15 × 0.2 mm, main body obovate with apex truncate, with 2 pubescent apical appendages, ca. 0.2 mm long. Follicles 3.8 − 4.3 × 2 − 2.55 cm, 2 or 1 by abortion, flat, circular to pyriform, stipitate, stipe 1.05 cm long, slightly mucronate, with more than one parallel rib, lenticellate, light brown to ferruginous, pilose. Seeds 3.2 × 2.45 cm, ovate; seminal nucleus central.

Etymology: —The specific epithet is a tribute to Professor José Ângelo Rizzo, an important collector of the Goiás and Tocantins flora, and Coordinator of the “Flora of Goiás and Tocantins ” project. Professor Rizzo made it possible to study the Aspidosperma species that occur in these states.

Distribution and habitat: — Aspidosperma rizzoanum occurs in Goiás and Tocantins states, mostly in “Cerrados rupestres”, between 712 − 1600 m ( Figure 3 View FIGURE 3 ).

Phenology: —Flowers in October, fruits from March to May.

Conservation status: — Aspidosperma rizzoanum has an AOO of 44 km 2 and an EOO of 6,689.037 km 2. Considering the IUCN guidelines (IUCN 2016), species with AOO smaller than 100 km 2 are evaluated as endangered, and vulnerable with EOO smaller than 20,000 km 2. Aspidosperma rizzoanum has a low number of occurrences, but almost all were collected in a conservation unit area, the Chapada dos Veadeiros National Park (Goiás state).

Paratypes: — BRAZIL. Goiás: Alto Paraíso de Goiás, Chapada dos Veadeiros, 7 km de Alto Paraíso/Teresina de Goiás, 25 May 1994, fr., M.A. Silva et al. 2071 (UEC!). Alto Paraíso de Goiás, Chapada dos Veadeiros, ca. 20 km by road N of Alto Paraíso, 03 March 1973, fr., W.R. Anderson et al. 6225 (MBM!, NY!, RB!, UB!). Alto Paraíso de Goiás, Chapada dos Veadeiros, ca. 6 − 7 km E of Alto Paraíso on road to Nova Roma, 07 March 1973, fr., W.R. Anderson et al. 6527 (NY!, RB!, UB!). Cavalcante, Chapada dos Veadeiros, 31 May 1994, fr., S. Bridgewater et al. S 233 (UB!, UFG!). Teresina de Goiás, Chapada dos Veadeiros, 13 km by road S of Terezina, 16 March 1973, fr., W.R. Anderson et al. 7270 (NY!, RB!, UB!). Tocantins: Arraias, Estrada vicinal no trevo de Arraias para Campos Belos (TO-050), 08 March 2015, fr., R.C. Forzza et al. 8680 (UEC!, UPCB!).

Discussion: — Aspidosperma rizzoanum belongs to Aspidosperma subgenus Aspidosperma (1996: 206) section Aspidosperma Marcondes-Ferreira (1996: 207) , characterized by species with alternate and congested leaves, and buds protected by cataphylls [except A. macrocarpon Martius & Zuccarini (1824: 136) and A. verbascifolium Müller Argoviensis (1860: 46) ], ( Marcondes-Ferreira & Kinoshita 1996). Aspidosperma rizzoanum is similar to A. subincanum Martius (1838: 82) since both have discolorous leaves, with secondary veins that bifurcate near the edge of the blade, follicles with lenticels and apparent midrib. Aspidosperma rizzoanum can be distinguished from A. subincanum by the glabrous ovary (vs. pilose), and the follicles with ferruginous pilosity (vs. beige pilosity), a conspicuous midrib and two parallel ribs (vs. absence of parallel ribs) ( Figures 1 − 2 View FIGURE 1 View FIGURE 2 ). This species can also be distinguished from Aspidosperma macrocarpon , A. melanocalyx Müller Argoviensis (1860: 52) , A. nobile Müller Argoviensis (1860: 44) , A. tomentosum Martius & Zuccarini (1824: 135) and A. subincanum , that occur in the Cerrado of Goiás and Tocantins states, by the following features presented in the key and the Table 1.

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