Hiraea silvicola C.E.Anderson, 2016

Anderson, C., 2016, Circumscription and nomenclature of Hiraea barclayana, H. reclinata, and H. ternifolia (Malpighiaceae), and of seven species misassigned to them, Blumea 61 (2), pp. 125-146 : 137-138

6. Hiraea silvicola C.E.Anderson , sp. nov. — Fig. 6 ; Map 9

Differt a H. ternifolia foliis oppositis,stylis basi pubescentibus,et petalo postico late triangulari, c. 4 mm longo et lato. — Type: Lobo et al. 307 (holo MICH; iso MG), Brazil, Maranhão, Mpio. Santa Luzia, margens da estrada da Fazenda Cacique já próximo a ferrovia Carajás, 17 Mar. 1983.

Etymology. The specific epithet refers to the forest habitat.

Scandent shrub to 5 m; stems densely sericeous when young, becoming glabrous. Leaves opposite. Laminas of the larger leaves 6.5–17.5 by 3.5–12 cm, elliptical to obovate, apex obtuse- or emarginate-mucronate or sometimes apiculate, base acute to truncate, adaxially sericeous when very young, soon glabrous, abaxially velutinous, hairs V- or Y-shaped, stalk to 0.05 mm long, arms 0.1–0.2 mm long; margin with scattered glands 0.2–0.3 mm diam in distal 1/4–3/4 or only a few near apex or glands absent; costa and secondary veins not impressed adaxially, prominent abaxially. Petioles 7–15.5 by 1.5–2 mm, densely velutinous, with a pair of glands at apex to 1.5 mm below apex, each gland 0.7–1 mm long. Stipules 2–3 mm long, borne at middle to basal 1/4 of petiole. Inflorescences solitary axillary ternate cymes of 4-flowered umbels; umbel without a gland in the centre; inflorescence axis 0.5–1 mm long, bracts c. 1 mm long and wide; lateral peduncles sessile like the central one; peduncles 2– 5 mm long; bracts and bracteoles subtending pedicels 1–1.2 by 0.8–1 mm; pedicels 10–13 by c. 0.5 mm; axes, abaxial surface of bracts and bracteoles, and pedicels densely sericeous. Sepals 1.7–1.8 by c. 2 mm, broadly triangular, adaxially glabrous, abaxially sericeous; anterior sepal eglandular, the lateral four biglandular, glands c. 1.5 mm long. Petals yellow, glabrous; lateral petals with the claw 2–2.3 mm long, limb of anterior-lateral petals c. 6 mm long and wide, orbicular, margin subentire, limb of posterior-lateral petals c. 5.5 mm long and wide, orbicular, margin subentire; posterior petal with the claw c. 3 mm long and thicker than that of lateral petals, limb c. 4 mm long and wide, broadly triangular, margin glandular-digitate-fimbriate, fimbriae to 0.4(–0.5) mm long. Stamens glabrous, filaments basally connate. Stamen opposite anterior sepal: filament c. 2.5 mm long, anther c. 1.1 mm long; stamens opposite anterior-lateral petals: filaments c. 2.1 mm long, anthers c. 1.1 mm long; stamens opposite anterior-lateral sepals: filaments c. 2.5 mm long, anthers c. 1.1 mm long; stamens opposite posterior-lateral petals: filaments c. 2 mm long, anthers c. 0.9 mm long; stamens opposite posterior-lateral sepals: filaments c. 2.5 mm long, anthers c. 1 mm long; stamen opposite posterior petal: filament c. 1.6 mm long, anther c. 0.6 mm long. Styles incurved, 3–3.5 by c. 0.3 mm, anterior style with scattered hairs in the proximal 1/3–1/2, apex extended into a spur c. 0.2 mm long; posterior styles with scattered hairs in the proximal 1/4, apex extended into a spur c. 0.1 mm long. Ovary c. 1 mm long, densely villous. Mature samara not seen; immature samara butterfly-shaped, dorsal wing present.

Distribution — Brazil (Maranhão, Pará).

Habitat & Phenology — In forest; collected in flower in March, in young fruit in October.

Additional specimens examined. BRAZIL, Maranhão, Mpio.Grajaú, 52 km S of Arame, 78 km N of Grajaú along Hwy 006, S05°12' W46°12', Schatz et al. 928 ( MG, MICH) . Pará, Serra dos Carajás, Serra Norte , 5 km NE of AMZA Exploration Camp, c. S06° W50°15', Berg et al. 542 ( MICH) .

Note — Collections of H. silvicola were tentatively placed with H. ternifolia only because the laminas are abaxially persistently though finely velutinous. The hairs that compose the vesture range from sessile (V-shaped) to having a tiny stalk at most 0.05 mm long (Y-shaped); T-shaped hairs are absent. Hiraea silvicola also differs in its opposite phyllotaxy, leaves, and inflorescences. The laminas are adaxially sericeous when young and not bullate when mature. The inflorescence is a solitary ternate cyme with all umbels 4-flowered. In most species the lateral peduncles are usually borne on a rudimentary lateral axis, but in H. silvicola the peduncles are all sessile ( Fig. 6d ).

Figures

Map 9 Distribution of Hiraea silvicola C.E.Anderson.

Fig. 6 Hiraea silvicola C.E.Anderson.a. Flowering branch;b. detail of abaxial leaf surface;c.portion of petiole with gland and a pair of stipules;d. inflorescence; e. posterior petal; f. posterior-lateral petal; g. anterior-lateral petal; h. androecium, stamen fifth from right opposite posterior petal; i. gynoecium, anterior style in centre (all: Lobo et al. 307, MICH). — Scale bar: a = 4 cm; b = 2 mm; c–d = 8 mm; e–g = 6.7 mm; h–i = 2.7 mm. — Drawn by Karin Douthit.