Tetrameranthus guianensis Westra & Maas, 2012

Westra, Lubbert Y. T. & Maas, Paul J. M., 2012, Tetrameranthus (Annonaceae) revisited including a new species, PhytoKeys 12, pp. 1-21 : 9-10

Tetrameranthus guianensis Westra & Maas sp. nov. Fig. 3A-C Map 1

Latin.

A speciebus ceteris hujus generis pilis stellatis vel simplicibus validis et monocarpiis rugosis in statu sicco distinctus.

Type.

Sabatier & Gonzalez 5387 (holotype CAY; isotype L), French Guiana, Savane-roche Virginie, Parcelle SRV2, 4°11'N, 52°9'W, 18 March 2008.

Description.

Tree, 8-25 m tall, 10-25 cm diam., slash yellow-orange (Mori et al. 23521); young twigs and petioles densely covered with brownish, stellate and simple hairs>0.5 mm long. Leaves:petioles 5-10 mm long, 3-4 mm diam., more or less thickened toward the base; lamina narrowly obovate to obovate-elliptic, 14-26 by 5-10 cm (index 2.4-2.9), chartaceous, shiny green above in vivo, dark brown above and pale brown below in sicco, rather densely covered mainly on large veins to rather sparsely covered with stellate hairs>0.5 mm long or glabrous elsewhere above, densely covered with stellate hairs on large veins, rather densely to sparsely so or almost glabrous elsewhere below, base acute to attenuate, apex abruptly acuminate (acumen 2-12 mm long), primary vein impressed above, secondary veins 14-19 on either side of primary vein, impressed above, loop-forming, shortest distance between loops and margin 1-3 mm, or not loop-forming, tertiary veins impressed above, percurrent to reticulate. Inflorescences 1-flowered, only seen in postfloral and fruiting stages, peduncles c. 10 mm long, c. 3 mm diam., fruiting peduncles to c. 5 mm diam., pedicels c. 20 mm long, c. 3 mm diam., fruiting pedicels to c. 5 mm diam., peduncles and pedicels densely covered with brownish, stellate and simple hairs; sepals not seen; petals whitish (fide collectore) in vivo, estimated to be c. 35 by 40 mm; stamens not seen. Monocarps 7-15, ellipsoid to fusiform, yellowish green to yellowish orange in vivo, pale brown in sicco, 35-60 by 20-30 mm, apex obtuse, rounded, or bluntly pointed, with or without weak oblique constriction, wall shriveled in sicco. Seeds 1-3 per monocarp, 25-30 by 15-20 by 15 mm.

Distribution.

French Guiana and the adjacent Brazilian state of Amapá.

Habitat and ecology.

In forests. At an elevation of c. 100 m. Flowering recorded in December; fruiting recorded in March, July, and December.

Notes.

Tetrameranthus guianensis is the first species of the genus reported from the Guianas. It is distinct from other species of Tetrameranthus by a dense cover of coarse stellate and simple hairs on all vegetative parts. Like the Ecuadorian Tetrameranthus globuliferus , it has shriveled fruit walls in dry condition.

As no complete flowers were available in herbarium material, description of floral characters is based in part on field observations of a single living flower at distance. The collector, D. Sabatier, has informed us that an attempt to collect that flower which was high up in a large tree and out of reach had failed. Sabatier (pers. comm.) notices 5 scars per whorl on the receptacle (compare Figure 3A ) implying that we have a 5-merous flower here! This definitely requires confirmation from further collections, though.

Two sterile collections, namely Mori et al. 23521, 23674, also from French Guiana, seem to come quite near this species, differing mainly in the leaf shape (obovate-elliptic, rather than narrowly obovate), and the less dense and more coarse indument of stellate hairs of comparable size. It concerns trees of 8 m, 10 cm diam., and 15 m, 12 cm diam., respectively, from non-flooded moist forest. More material, and more complete in particular, is needed here.

Additional specimens examined.

French Guiana. Sinnamary River, above Petit Saut, between Crique Plomb and Crique Tigre, 500 m above Saut Tigre in area to be inundated by waters of Petit Saut Dam, Mori et al. 23521 (CAY, NY, U), Mori et al. 23674 (CAY, NY, U); Rivière Grand Inini, Basin of Maroni River, Arbre II-59, 3°40'N, 53°50'W, Sabatier & Prévost 3084 (CAY, P, U); Savane-roche Virginie, Parcelle SRV2, 4°11'N, 52°9'W, Sabatier 5784 (CAY, WAG). Brazil. Amapá: Rio Araguari, upland plant, Pires et al. 51490 (MG).

Figures

Map 1. Distribution of Tetrameranthus duckei R. E. Fr. (●), Tetrameranthus guianensis Westra & Maas (■), and Tetrameranthus pachycarpus Westra (□).

Figure 3. Tetrameranthus guianensis Westra & Maas A Single-flowered inflorescence after shedding of perianth and stamens B A twig C Ripe fruit, also sectioned to show seed. Tetrameranthus globuliferus Westra D, E Twig with inflorescences (Perez C. & Santillan 4404, QCA) F, G Flower seen from the side and from above (same). A-C Photos by D. Sabatier, D-G Photos by A. J. Perez C.