Hiraea mcvaughii 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 : 131-133

3. Hiraea mcvaughii C.E.Anderson , sp. nov. — Fig. 3 ; Map 5

Differt a H. reclinata laminae foliorum adaxaliter et abaxaliter pilos T-formes ferens; petalo postico margine apice dentato vel lacero-dentato et basi denticulato. — Type: McVaugh 15228 (holo MICH; iso MEXU, US), Mexico, Nayarit, Mirador de Aguila, c. 14 mi N of Tepic , 600 m, 8 July 1957 .

Etymology. The specific epithet honours Rogers McVaugh (1909–2009), foremost student of the flora of western Mexico, who collected the type.

Woody vine, shrub or twining shrub, or small tree to 3 m; stems sericeous when young, becoming glabrous. Leaves opposite. Laminas of the larger leaves 5–17.5 by 3–10 cm, elliptical to obovate, apex apiculate-mucronate, mucronate, or emarginate-mucronate, base truncate in smaller leaves to cordate or auriculate in larger ones, adaxially densely covered with subsessile to T-shaped hairs (stalk to 0.1 mm) when young, soon glabrous, abaxially tomentose when young, the vesture soon thinning, when mature with T-shaped hairs, stalks (0.05–) 0.1–0.2 mm long, trabecula 1–2 mm long, straight to wavy; margin with a few scattered glands c. 0.2 mm diam near apex or glands absent; costa slightly impressed adaxially and prominent abaxially, secondary veins not impressed adaxially and prominent abaxially. Petioles 5–11 by 1.2–2 mm, densely sericeous, with a pair of glands at apex, each gland 0.5–1 mm long. Stipules 1.5–4.5 mm long, borne near the base to the middle of the petiole. Inflorescences solitary axillary ternate cymes of 4-flowered umbels; umbel without a gland in the centre; inflorescence axis 0–3 mm long, bracts 1.5–2.5 mm long and wide; lateral peduncles borne on axes 0 – 4 mm long, subtended by bracts 1.5–2 mm long and wide; peduncles 1–12 mm long; bracts and bracteoles subtending pedicels 1.3–2 mm long and wide; pedicels (9–)12–26 by 0.4–0.5 mm, densely covered with sessile to T-shaped hairs (stalk to 0.1 mm); axes, abaxial surface of bracts and bracteoles densely sericeous. Sepals 2–2.5(–2.8) by 2–2.5 mm, triangular, adaxially glabrous, abaxially sericeous; anterior sepal eglandular, the lateral four biglandular, glands 1–2 mm long, or all sepals eglandular. Petals yellow, glabrous; lateral petals with the claw 2.5–3 mm long, limb of anterior-lateral petals 8–8.5 mm long and wide, orbicular, margin subentire to minutely denticulate, teeth to 0.1 mm long, or with a few larger teeth (to 0.3 mm) at apex, limb of posterior-lateral petals 7–8 mm long and wide, orbicular, margin irregularly denticulate or only at apex and otherwise subentire, teeth to 0.2(–0.4) mm long; posterior petal with the claw 3–4 mm long and thicker than that of lateral petals, limb 7–7.5 mm long and wide, orbicular, margin irregularly dentate to dentate-lacerate, teeth to 0.5–1.2 mm long, longest at apex. Stamens glabrous, filaments basally connate. Stamen opposite anterior sepal: filament 3.8–4.5 mm long, anther 1.1–1.3 mm long; stamens opposite anterior-lateral petals: filaments 3.5–4 mm long, anthers 0.9–1 mm long; stamens opposite anterior-lateral sepals: filaments 3.8–4.5 mm long, anthers 1–1.2 mm long; stamens opposite posterior-lateral petals: filaments 2.5–3 mm long, anthers 0.8–1 mm long; stamens opposite posterior-lateral sepals: filaments 3.5–4 mm long, anthers 0.9–1.1 mm long; stamen opposite posterior petal: filament 2–2.5(–3) mm long, anther 0.6–0.8 mm long. Styles incurved, glabrous, 4–4.5 by 0.4–0.5 mm; apex of anterior style extended into a spur 0.1–0.3 mm long; apex of posterior styles extended into a spur 0.05–0.1 mm long. Ovary 1–1.5 mm long, densely villous. Samara butterfly-shaped; lateral wings 3.2–3.3 by 2–2.3 cm; dorsal wing a crest c. 1.5 mm high, coarsely dentate; nut subspherical, 4–5 mm diam, areole 2–2.3 mm diam. Mature seed not seen.

Distribution — Coastal regions of western Mexico (Colima, Guerrero, Jalisco, Michoacán, Nayarit and adjacent Sinaloa).

Habitat & Phenology — In tropical deciduous and subdeciduous forest, and roadside thickets; sea level to 600 m; collected in flower in February, May to August (one collection from December), in fruit in June to August.

Representative specimens. MEXICO, Colima, Mpio. Ixtlahuacán, brecha Ixtlahuacán-La Presa, 1 km NE de Ixtlahuacán, Santana & Cervantes 286 (IBUG, MICH). Guerrero, sea cliffs west of Acapulco, Clark 7178 (NY, US); Puerto Marqués, Acapulco, Sept. 1952, Ramírez C. s.n. (MEXU). Jalisco, Mpio. La Huerta, Estación de Biología de Chamela, 2 km SE sobre la carretera Puerto Vallarta-Barra de Navidad, Ayala 667 (CAS, MICH); Estación de Biología de Chamela, Bullock 1352 (MEXU, MICH, MO), 1585 (MICH, TEX); Mpio. La Huerta, km 56, carr. B. Navidad Pto. Vallarta, Bullock 1712 (CAS, MICH); Mpio. La Huerta, Los Angeles de Tenacatita, González & Gúzman 939 (MEXU); Mpio. La Huerta, Estación de Biología de Chamela, Magallanes 713 (MEXU, MICH), 2977 (MEXU, MICH, TEX). Michoacán, Mexican Hwy 200 between Playa Azul and Tecomán, Colima, 6 km W of Maruhuata, Miller & Téllez V. 3089 (MICH); trail from Atizupa to San Pedro N of Hwy 200, Murray & Johnson 1454 (MICH). Nayarit, Mpio.Tepic, Aguamilpa, 4 km antes La Presa, N21°40' W104°34', Flores F.1859 (MICH); Tres Marías Islands, María Magdalena, 28 June 1963, Grant s.n. (DS); W of Ingenio, Gregg 1039 (MO); Mirador de Aguila,c. 14 mi N of Tepic, McVaugh 15257 (MICH); Acaponeta, Rose 1507 (GH, NY, US). Sinaloa, Rosario, 26–29 July 1897, Rose s.n. ( US).

Note — Hiraea mcvaughii is a species of the coastal regions of western Mexico and not sympatric with H. barclayana , with which it was commonly placed, often as ‘ H. velutina ’. It is readily separated from H. barclayana and H. reclinata by the persistent abaxial laminar pubescence composed of T-shaped hairs. The dense abaxial vesture of the youngest leaves thins quickly, and mature laminas bear T-shaped hairs with straight to wavy trabecula. The hairs are never appressed, as in H. reclinata , nor predominantly Y-shaped, as in H. barclayana .

Figures

Map 5 Distribution of Hiraea mcvaughii C.E.Anderson.

Fig. 3 Hiraea mcvaughii C.E.Anderson. a. Flowering branch; b. large leaf, adaxial view; c. node to show epipetiolar stipules; d. large leaf, abaxial view, with detail showing vesture and marginal glands; e. enlargement of abaxial leaf surface to show reticulate venation; f. base of umbel; g. flower, posterior petal uppermost; h. flower with petals removed, anterior style at right; i. anther and portion of filament; j. samaras, abaxial view (above) and adaxial view (below) (from: a–c, f–i. McVaugh 15228, MICH; d–e, j. McVaugh 15257, MICH). — Scale bar: a–b = 4 cm; c, g = 8 mm; d = 4 cm (4 mm); e = 1.6 cm; f = 5.7 mm; h = 4 mm; i = 1.3 mm; j = 2.7 cm. — Drawn by Karin Douthit.