Alatococcus siqueirae Acev.-Rodr., 2012

Acevedo-Rodriguez, Pedro, 2012, Alatococcus, a new genus of Sapindaceae from Espirito Santo, Brazil, PhytoKeys 10, pp. 1-5 : 1-2

Alatococcus siqueirae Acev.-Rodr. sp. nov. Fig. 1

Type.

Brazil; Espirito Santo. Linhares, Povoaçao. Estrada Povaçao a Linhares, beira do rio; matas de cabrucas de cacao, mata de tabuleiro, 19°33'02"S, 39°50'40"W, 7 May 2011 (fl), G.S. Siqueira & L.F. Silva Magnago 639 (holotype US!; isotypes CVRD, K!, NY!, RB!). Fig. 1 .

Description.

Tree to 14-19 m tall. Branches terete, glabrous, grayish with lines of lenticels. Leaves paripinnate; petiole plus rachis 20-32 cm long, flattened adaxially, minutely lenticellate; petiolules 5-12 mm long, pulvinate; leaflets 8-12, elliptic, oblong or nearly oblanceolate, 14-20.5 × 6-7.5 cm, chartaceous, glabrous, the base obtuse, sometimes slightly asymmetrical, the apex obtuse to acute, the margins entire, midvein and secondary veins abaxially prominent, lighter.

Thyrses axillary, to 60 cm long, axes appressed-pubescent to glabrous; flowers in sub-cincinni; pedicels 2.5-3 mm long, articulate at base. Calyx abaxially glabrous; sepals ovate, ciliate, outer sepals ca. 2.5 mm long, inner sepals ca. 3 mm long; petals ca. 6 mm long, lanceolate, clawed at base, obtuse at apex, abaxially sericeous; appendage hood-shaped, ca. 2 mm long, with a bi-corniform crest and a wooly ligule; nectary asymmetrical-pentagonous (2 lobes per petal except for the anterior petal that has no lobes or only slightly developed ones), pubescent; stamens of unequal lengths, 1.5-2.5 mm long, filament flattened, lanose on lower half, anthers ellipsoid; pistillode trigonous, tricarpellate. Fruit of one, subglobose, well-developed, winged mericarp and two rudimentary mericarps; mericarp woody, 3.5-4 × 2.5-3 cm, asymmetrical with style in lateral position; wing surrounding its longitudinal circumference; seeds exarillate, subglobose, ca. 1.7 cm long; hilum elliptic, ca. 7 mm wide.

Pollen.

Pollen grains in Alatococcus siqueirae are isopolar, tricolporate, subspheroidal in equatorial view, trigonous in polar view, and with striate ornamentation ( Fig 2a-b ). Size as measured from 20 pollen grains using light microscopy is as follows: polar axis 20.11 µm (17.89-21.81µm); equatorial axis 19.16 µm (17.21-21.79 µm). Permanent pollen slides are deposited at Smithsonian’s pollen collection.

Vernacular names.

baratinha, pitomba do rio doce.

Distribution and ecology. Known only from Espirito Santo, Brazil, on tabuleiro, gallery and tall forests.

Specimen examined.

Brazil. Espirito Santo; Laranja da Terra, tall forest, 17 Dec 1992 (fr), Folli 1761 (K, US), Linhares, road from Linhares to Fazenda Maria Bonita, gallery forest, 19°26'18"S, 39°58'00"W, 26 Oct 2010 (fr), Folli 6734 (US).

Etymology.

The epithet honors Geovani Siqueira, curator of the CVRD herbarium, who collected flowering material of the new species, allowing the determination to the generic level.

Figures

Figure 1. Alatococcus siqueirae A Branch with detail of petiolules B Sub-cincinnus C Staminate flower bud D Staminate flower E Petal with appendage, adaxial and lateral views F Portion of staminate flower showing unilateral nectary disc and stamens, staminate flower with removed petal showing nectary disc, stamens and pistillode G Pistillode, top and lateral views H Fruit, two lateral views I Dissected fruit showing wing, locule, mesocarp and seed, seed basal view. A, H-I from Folli 1761 (K); B-G from Siqueira and Magnago 639 (US).

Figure 2. Pollen of Alatococcus siqueirae. A Equatorial view showing colpus and pore B Polar view showing three colpi and striate ornamentation. All from Siqueira & Magnago 639 (US).