Oxandra saxicola Maas & Junikka, 2016

Junikka, L., Maas, P. J. M., Maas-van de Kamer, H. & Westra, L. Y. Th., 2016, Revision of Oxandra (Annonaceae), Blumea 61 (3), pp. 215-266 : 251-253

21. Oxandra saxicola Maas & Junikka , sp. nov. — Plate 2c–e; Map 10

Floribus subsessilibus (saepe in axillis foliorum delapsorum apparentibus), monocarpiis globosis 20–25 mm in diametro metientibus differt. — Typus: Parada 944 ( WAG 3 sheets; iso MO), Bolivia, Santa Cruz, German Busch , 500 m from El Carmen Viejo, 165 m, 13 May 2008.

Tree or shrub, 0.5–12 m tall, 20–50 cm diam; young twigs densely lenticellate, sparsely ( Bolivia) to densely ( Brazil) covered with erect hairs, soon glabrous. Leaves: petiole 2–4 mm long, c. 1 mm diam; lamina narrowly elliptic to ovate, 5–10 by 2.5–5 cm (leaf index 1.6–2.5), coriaceous, not verruculose, shiny and green above, pale glaucous green below, glabrous (Bolivian material) to sparsely covered with appressed hairs (Brazilian material) above, sparsely covered with appressed hairs to glabrous (Bolivian material) or rather densely to sparsely covered with erect hairs (Brazilian material) below, base obtuse to cordate, apex obtuse to bluntly acute, primary vein slightly raised to flat above, secondary veins distinct, 10–12 on either side of primary vein, raised above, angle of secondary veins with primary vein 40–70°, smallest distance between loops and margin 1–3 mm, tertiary veins strongly raised above and below, reticulate. Flowers solitary, often on leafless branchlets; pedicels 0.5–1 mm long, c. 1 mm diam, fruiting pedicels c. 3 mm long, c. 2 mm diam, rather densely covered with appressed hairs; bracts 5–7, broadly ovate 1–2.5 mm long, lowest bract sparsely covered with appressed hairs to glabrous, the other bracts densely covered with appressed, whitish hairs; flower buds subglobose; sepals broadly ovate-triangular, 2–2.5 by 1.5–3 mm, outer side densely covered with appressed, whitish hairs ( Brazil) to glabrous ( Bolivia); petals yellowish white to greenish white in vivo, narrowly elliptic, 5–7 by 1–3 mm, outer side glabrous; stamens c. 20, 2.5–3 mm long, apex of connective ovate to depressed ovate; carpels 5–10. Monocarps 1–3, green to yellow, maturing yellow to red in vivo, blackish brown in sicco, somewhat glaucous when young, subglobose, 20–25 by 20– 25 mm, glabrous, apex rounded, wall c. 3 mm thick, stipes absent. Seed subglobose, 13–25 by 10–15 mm, brown, surface transversely striate, ruminations peg-shaped to lamellate in 4 parts.

Distribution — Bolivia (Santa Cruz), Brazil (Bahia, Goiás, Mato Grosso do Sul, Tocantins).

Habitat & Ecology — In ‘bosque seco chiquitano’, in ‘vegetación saxícola’ ( Bolivia) and: cerrado, on rocky soil, also in deciduous rainforest on rocky soil ( Brazil). At elevations of 100– 800 m. Flowering: February, May, October, November; fruiting: March to May, October to January .

Vernacular name — Brazil: Mejo-de-porco (Ratter et al. 7327).

Field observations — Flores muy aromáticas ( Parada 944, 969, Bolivia); flores con olor de limão ( Pereira & Amaral 326, Brazil).

Selection of other specimens studied. BOLIVIA, Santa Cruz, Prov. Chiquitos, Concesión Don Mario, c. 125 km NE of San José de Chiquitos, 450 m, Mamani et al. 1408 (MO); Angel Sandoval, 9 km de Santo Corazón, sobre el camino a Santiago de Chiquitos, 263 m, Wood et al. 25096 (K, UB); German Busch, Carmén Rivero Torre, 0.5 km de la carretera entrando hacia El Carmén Viejo, 120 m, Wood & Villarroel 25544 (K, L, UB). – BRAZIL, Bahia, Paulo Alfonso, Estação Ecológica Raso de Catarina (Mata da Pororoca), 715 m, Moraes et al. 102 (MO, U); Campo Formoso, Orlandi 379 (HUEFS, MG, RB). Goiás, Mun. Nova Roma, saída da cidade em direção a laciara Fazenda Cachoeira, 710 m, Alvarenga et al. 1292 (CEN); Mun. Posse, Rodovia Brasília-Fortaleza, 220 km de Formosa, Belém & Mendes 116 (IAN, MG);Mun.Minaçu,right bank of Rio Tocantins, Bucci & Verano 1579A, 1580A (UB); Porto Real, Burchell 8464 (K); Mun. Monte Alegre, Fazenda Nica, 565 m, Fonseca et al. 2987 (IBGE); Mun. Guarani de Goiás, 800 m, Pereira & Alvarenga 2999 (IBGE); Mun. São Domingos, km 34 da estrada Guaraní de Goiás /Terra Ronca, 600 m, Pereira & Alvarenga 3288 (RB); Mun. Mambaí, Vale do Rio Paranã, tributary of Lower Rio Tocantins, left margin of Rio Vermelho, affluent of Rio Corrente, Pereira & Alvarenga 3641 (IBGE, MG); Mun. Cavalcante, Bahia Morro Branco (Rio Tocantins), vila Veneno, 320 m, Pereira-Silva et al. 5664 (CEN); 18 km from Alto de Paraíso de Goiás on the road to Nova Roma, Ratter et al. 7327 (K); Mun. Colinas do Sul, Serra da Mesa (Grande Lago), 350 m, Walter et al. 3583 (CEN, UFG). Mato Grosso do Sul, Dois Irmãos do Buriti, Fazenda Taruana, 260 m, Solórzano 215 (UB). Tocantins, Mun.Aguiarnópolis, Patio da Ferrovia Norte e Sul, 155 m, Pereira & Amaral 326 (CEN); Mun. Taguatinga de Tocantins, Azuis, Rio Sobrado, Pereira 3467 (IBGE); Mun. Paranã, Fazenda São João, 342 m, Sevilha et al. 3779 (CEN).

Notes — Oxandra saxicola resembles O. reticulata by its leaf shape and size and leaf reticulation, but can be told apart by subsessile flowers (flowering pedicels 0.5–1 mm long vs 3–4 mm long), a higher number of bracts (5–7 vs 1–2) and globose, large, thick-walled monocarps instead of ellipsoid, thin-walled monocarps.

A peculiarity of this species is the fact that flowers are often produced in leafless condition.

The Brazilian collections look quite similar to the Bolivian specimens aberrant, however, in having a different indument of young twigs and leaves and hairy (instead of glabrous) sepals.