Maytenus nemorosa Biral & Lombardi, 2015

Biral, Leonardo, Smidt, Eric De Camargo, Bolson, Mônica & Lombardi, Julio Antonio, 2015, A new species of Maytenus (Celastraceae) from the Brazilian Atlantic Forest, with evidence of molecular phylogeny, and two new synonyms for Maytenus floribunda, Phytotaxa 231 (1), pp. 53-62 : 57-60

Maytenus nemorosa Biral & Lombardi , sp.nov. ( Fig. 3 , 4 and 5 )

Similar to Maytenus gonoclada Mart. , according to the flowers and the type of inflorescence and sometimes the size and shape of leaves, but it is distinguished by the entire margin on leaves, and larger fruits (27–33 × 16–18 mm vs. 6–12 × 4–8 mm) with thicker pericarp walls (1.5–2.2 mm vs. 0.4–1.2 mm).

Type:— BRAZIL. Espírito Santo: Santa Teresa. Reserva Biológica Augusto Ruschi, em fragmento próximo à caixa d’água, 19º90’S, 40º54’W, 10 December 2012, Biral et al. 810 (holotype HRCB! [59268], isotypes, MBML!, NY!, UPCB!).

Tree, 8–25 m tall, 62.8–94.6 cm in diameter at breast height, glabrous; old twigs cylindrical, grayish; young twigs flattened, blackened to grayish, longitudinally ribbed, three to five ribs on each side. Leaves alternate, distichous; stipules 1 mm long, deltoid, base truncate, apex acute, caducous; petiole 3–10 mm long; blades 7.6–26.6 × 3.9–9.1 cm, oblong-elliptic, coriaceous, base cuneate, margin entire, revolute, apex acute, glabrous; venation brochidodromous, primary vein plane on adaxial face, prominule on abaxial face, secondary veins 7–9 pairs, obscure on both faces or slightly impressed on abaxial face. Inflorescences in cymes, simple, axillary, 2–7-flowered; peduncle 2–10 mm long; bracts acute, 2 mm long, margin irregular; pedicels 4–8 mm long. Flowers 5-merous, preforation imbricate, with the margins of petals overlapping each other in such a way that one petal is completely external and one petal completely internal; calyx gamosepalous at base, lobes 1 × 1 mm, ovate, margin sparsely ciliate; corolla dialypetalous; petals 2–3 × 1 mm, oblong, reflexed at anthesis, apex rounded, margin membranous, slightly undulate; stamens 5, alternate with petals, 2 mm long, filaments flattened, broadened at base, attenuated at apex, inserted on the margin of disk, erect and becoming reflexive at anthesis; anthers ovoid, yellow, dorsifixed, longitudinal dehiscence; intrastaminal disk 2 mm in diam., pentagonal, blackened when dry, margin slightly undulate; gynoecium 2-carpellate, ovary fused to disk, stigma capitate, subsessile. Fruit a loculicidal capsule, 27–33 × 16–18 mm, obovoid or spherical, slightly acuminate, style persisting or not, coriaceous pericarp, 1.5–2.2 mm width of wall pericarp, green when immature, yellow when mature and black when old, opening by 2 reflexed valves; seeds 1–3, 1.2–1.5 × 0.8–11 mm, oblong, wrinkled, completely surrounded by white aril.

Etymology: —The epithet refers to the habitat where the species has been found.

Distribution and ecology: — Maytenus nemorosa has been collected from Atlantic Forest communities between 500 and 1200 m elevation, mostly in the state of Espírito Santo, with a few collections in the states of Bahia and Rio de Janeiro.

Phenology: — Maytenus nemorosa has been collected with buds and flowers in November, and fruits in February, March, May to September, and December.

Additional specimens examined: — BRAZIL. Bahia: Wenceslau Guimarães. Ca. 3 km W of Nova Esperança, W edge of Reserva Estadual Wenceslau Guimarães, 500–600 m, 13º36’S, 39º43’W, 14 May 1992, Thomas et al. 9320 (NY). Espírito Santo: Domingos Martins. Córrego do Cavalo, 19 October 1985, Hatschbach & Zelma 49964 (MBM). Espírito Santo: Santa Leopoldina. Rio das Farinhas, propriedade de Antônio Carlos Barata, 728 m, 20º07’312’’S, 40º36’556’’W, 15 March 2007, Fontana 3035 (MBML, RB). Espírito Santo: Santa Teresa, Parque Natural Municipal de São Lourenço, 05 July 2003, Cruz et al. 88 (HRCB, MBML). Espírito Santo: Santa Teresa, cabeceira do rio Bonito, terreno da Aeronáutica, Radar, 1030 m, 12 June 2001, Kollmann 3912 (HRCB, MBML). Espírito Santo: Santa Teresa, Reserva Biológica Nova Lombardia, 700 m, 5 February 1985, Peixoto et al. 3502 (MO). Espírito Santo: Santa Teresa, Reserva Biológica Augusto Ruschi, trilha da cachoeira a partir da Sede Nova, 19 August 2003, Rossini et al. 466 (HRCB, MBML). Rio de Janeiro: Itatiaia, Parque Nacional de Itatiaia, trilha do hotel Simon para o Três Picos, 1200 m, 22º15–28’S, 44º34–54’W, 7 December 1995, Braga 3067 (RB). Rio de Janeiro: Teresópolis. Matas do Rio Paquerer próx. ao Km 2 da estrada para a barragem, 1140 m, 4 April 2004, Pardo 402 (HRCB, RB).

Comments:— The most remarkable characteristics of Maytenus nemorosa are the large fruits and the pericarp with thick walls (see description and table 2). Apart from M. megalocarpa , no other known species have such large fruits or a pericarp with thick walls. Maytenus megalocarpa differs from M. nemorosa by having a delayed dehiscence fruit not opening by two reflexed valves, as commonly seen for the genus, and possessing four larger seeds ( Groppo et al. 2014). Additionally, the young twigs of M. nemorosa are strongly flattened with longitudinal ribs and large (7.6–26.6 × 3.9–9.1 cm), predominantly oblong leaves that are useful characters to identify M. nemorosa from other Maytenus species. Only one collection with flowers was found at this moment for the species. We credit this fact to height of most specimens, which makes it difficult to see the flowers, due to the very small size of them.

Maytenus nemorosa is morphologically similar to Maytenus gonoclada and the relationships between them are corroborated by phylogenetic analysis. The main morphological differences between the species are presented in table 2.

Maytenus floribunda Reissek , in Martius (1861: 16). Type: — BRAZIL. Goiás: ad Crixas, May 1819, Pohl 1775 (holotype W! [0047062], isotypes BR!, LE)

= Maytenus cardenasii Rusby (1927: 290) . syn. nov. Type: — BOLIVIA. Beni: San Rafael, near Reyes, 1000 feet, 29 Out 1921, Cardenas 1379 (holotype NY! [00337408], isotypes BKL!, GH!, K!).

= Maytenus erythrocarpa Rusby (1927: 290) . syn. nov. Type: — BOLIVIA. Beni: near Rurrenabaque, 1000 feet, 1 Dec 1921, Cardenas 1737 (holotype NY! [00337413], isotypes BKL!, K!, MICH!, US!).

Maytenus floribunda is easily identified from other Maytenus by the presence of carinate young twigs, chartaceous leaves with a crenate margin and, mainly, ascendant secondary veins, in addition to multifloral fascicles and the fruits opening by two coriaceous valves. Rusby (1927) described M. cardenasii and M. erythrocarpa based on two collections of Martin Cardenas from Beni province, Bolivia. The unique commentary provided by the author superficially relates the two new species to each other (“Species [ M. cardenasii ] near M. erythrocarpa”, Rusby 1927, p. 290 ). By examining many collections, including the holotypes, and the original descriptions of M. cardenasii and M. erythrocarpa¸ we conclude that the morphological characters overlap each other, like the slender branchlets, size and shape of leaves, serrate margins and number of secondary veins, and therefore they belong to a single taxon. However, these characters are also the same used to identify M. floribunda . In this way, M. cardenasii and M. erythrocarpa are indistinguishable from M. floribunda and we thus propose them to be synonyms.

Maytenus floribunda has a wide distribution in South America occurring in seventeen Brazilian states ( Lombardi et al. 2015), as well as the countries of Colombia, Guyana, Suriname, French Guyana and Bolivia. Maytenus floribunda occurs in numerous habitats including deciduous and semi-deciduous seasonal forests, riparian forests, limestone outcrops, savannas (including the Cerrado formation), Terra Firme forests in the Amazon basin, and more rarely in the Atlantic Forest, from an elevation of 250 m to 1400 m.

Figures

FIGURE 3. Maytenus nemorosa. Habit, with an opened fruit exposing one seed and aril [Rossini et al. 466 (HRCB)].

FIGURE 4. Maytenus nemorosa. Flower in detail [Pardo et al. 402 (HRCB)].

FIGURE 5. Maytenus nemorosa. Inflorescence [Pardo et al. 402 (HRCB)].