Allophylastrum frutescens Acev.-Rodr., 2011

Acevedo-Rodriguez, Pedro, 2011, Allophylastrum: a new genus of Sapindaceae from northern South America, PhytoKeys 5, pp. 39-43 : 39-41

Allophylastrum frutescens Acev.-Rodr. sp. nov. Fig. 1

Latin.

Frutex vel arbor parva; folia trifoliolata; foliola chartacea, elliptica, margine serrato; flores apetali, monocarpus ellipsoideus, glabrus.

Type.

Brazil. Roraima, Sema Ecological Station, Ilha de Maracá, 3°22'N, 61°25'W, E.S. Silva & J. Lima 5828 (holotype NY!, isotypes INPA, K!-2, U-2!).

Description.

Shrub or small tree to 7 m tall. Branches terete, glabrous, brown with grayish lineate lenticels. Leaves trifoliolate; petioles flattened-canaliculate adaxially, 1.6-4.5 cm long, minutely puberulent; leaflets elliptic, 6-10.8 × 1.3-3.4 cm (the lateral ones smaller), chartaceous, the base cuneate on distal leaflets, obtuse-acute and asymmetrical on lateral ones, the apex acute to acuminate, the margins serrate. Flowers axillary, solitary or in short (1-2 cm long), axillary racemes; pedicels 8-10 mm long; sepals 4, concave, obovate, rounded at apex, puberulent, ca. 2 mm long; disc cupular, glabrous, with sub-fimbriate margin; filaments glabrous, 4-5 mm long; pistillode ca. 0.4 mm long; pistillate flowers unknown. Monocarps ellipsoid, divaricate, glabrous, 1-1.2 cm long; exocarp red, fleshy and thin; endocarp subwoody. Seed obovoid, ca. 1 cm long, with papery testa.

Pollen.

Pollen grains in Allophylastrum frutescens are subglobose in equatorial view and obtusely 4- or 5-angled in polar view, 4-5-porate, with rugulate ornamentation ( Fig. 2a-d ). Size as measured from 20 pollen grains using light microscopy varies from 24.57-31.96 µm long by 21.86-28.10 µm wide. Generally, Sapindaceae pollen is 3-aperturate or less often 2- or 4-aperturate ( Acevedo-Rodríguez et al. 2011). Therefore, this is the first time a 5-aperturate pollen is reported for the family. Allophylastrum pollen resembles that of Allophylus by being porate and having a rugulate ornamentation ( Acevedo-Rodríguez et al. 2011); however the shape and the number of apertures is quite distinctive from that of Allophylus , where the pollen is triangular in polar view, oblate in equatorial view, and triporate.

Distribution and ecology.

Known only from Brazil (Roraima) and Guyana, on terra firme forest.

Specimens examined.

Guyana: Without locality, M.R. Schomburgk 505 (B), R.H. Schomburgk 336 (BM, K, NY, W). Brazil. Roraima, Mun. Boa Vista, road to Santa Rosa, secondary forest, J. Lima 812 (INPA, K).

Note.

The above cited collections by Schomburgk were studied by L.A.T. Radlkofer (1829-1927) but wrongly identified as Allophylus edulis (St. Hil.) Hieron. ex Niederlein, a vegetatively similar species.

Figures

Figure 1. Allophylastrum frutescens. A Flowering branch B Detail of branch with leaf subtending a single flower, detail of a raceme C Pre-anthesis staminate flower and l. s. of same D Detail of staminate flower nectary disc, stamens, and pistillode E Staminate flower at anthesis, showing nectary disc and stamens F l. s. of staminate flower G Stamen, frontal and lateral views H Pistillode I Fruiting branch J Fruit with two monocarps and detail of monocarp insertion K Fruit showing fully developed monocarp with seed, and an undeveloped monocarp L Embryo, lateral and frontal views. A-H from Silva and Lima 5828 (NY); I-L from Lima 812 (NY).

Figure 2. Pollen of Allophylastrum frutescens. A Equatorial view showing pore B Oblique polar view of 4 - angular grain showing 2 pores C Oblique equatorial view of a 5 - angular grain showing 3 pores D Polar view of 5 - angualr grain (top), oblique equatorial views of a 5 - angular grain showing 3 pores. All from R. H. Schomburgk 336 (W).