Trichilia dazae T.D.Penn., 2016

Pennington, Terence D., 2016, Systematic Treatment Of American Trichilia (Meliaceae), Phytotaxa 259 (1), pp. 18-162 : 46-48

7. Trichilia dazae T.D.Penn. spec. nov. Type:— PERU. Amazonas, Prov. Bongará, San Carlos, February. 2007, fl., Pennington & Daza 18007 (holotype, K; isotype, MOL). Plate 2 , Map 10

Trichiliae tomentosae affinis sed ramis hornotinis glabris, foliis atque petiolis glabris, petalis roseis, filamentis staminorum in dimidio inferiore connatis differt.

MAP 10. Trichilia dazae T.D.Penn. Total distribution to 2010.

Young branches 6–10 mm diam., glabrous, smooth, brown, lenticellate and with prominent bud scale scars. New growth subtended by a small cluster of lanceolate pubescent bud scales 4–5 mm long. Leaves imparipinnate, petiole 8–9 cm long, semiterete, glabrous, rhachis 10–14.5 cm long, semiterete, glabrous; petiolule of lateral leaflets 1–1.5 mm long, petiolule of terminal leaflet 1–2 mm long. Leaflets opposite, 5–6 pairs, lateral leaflets 8.5 × 2.8–12 × 4.3 cm, lanceolate to elliptic lanceolate, apex long-acuminate, base asymmetric, acute to obtuse on one side and rounded on the other, lateral leaflets decrease slightly in size towards the leaf base; terminal leaflet 7.8 × 3–11.5 × 4.2 cm, elliptic, apex long-acuminate, base narrowly attenuate, chartaceous, leaves glabrous, finely glandular-punctate; venation eucamptodromous, midrib sunken on the upper surface, secondaries 9–13 pairs, ascending, slightly arcuate, parallel or slightly convergent, intersecondaries absent, tertiaries reticulate. Inflorescence axillary, clustered at the shoot apex, a slender pyramidal panicle with some cymose branches, 10–15 cm long, peduncle 6–8 cm long, lateral branches to 5 cm long, subglabrous; pedicel 2–3 mm long (above articulation); bracts 2–3 mm long, narrowly lanceolate, caducous. Flowers unisexual (plant dioecious). Male flowers only seen. Calyx 1–1.5 mm long, patelliform, sepals (4–)5(–6), free, ovate, aestivation open or slightly imbricate at the base, with scattered short indumentum outside, glabrous inside. Petals 5, 7–7.5 mm long, free, imbricate, oblong, apex acute to obtuse, minutely and sparsely puberulous outside in the upper half, with slightly coarser indumentum inside. Staminal tube 5–7 mm long, ca. 2 mm broad, cylindrical, filaments fused for ca. 1/3 their length, filament apex entire, rounded or truncate, glabrous below and coarsely pubescent in the upper half on both surfaces; anthers 10, ca. 1 mm long, lanceolate, dehiscent, with pollen, indumentum of sparse coarse hairs. Nectary an annulus around the base of the ovary. Ovary 1–1.5 mm long, ovoid, 3-locular, locules with 2 collateral ovules, pubescent, style 2–2.5 mm long, pubescent, style-head capitate. Capsule 1.2–1.5 cm long, 1.5–1.7 cm broad, 3-valved, globose to oblate, apex rounded, base truncate, smooth (wrinkled on drying), glabrous, drying dark brown with numerous pale lenticels, pericarp 1–2 mm thick. Seeds 3–6, 1–2 collateral in each valve, 7–8 mm long, slightly plano-convex, rounded at apex and base, with a free fleshy oily arillode covering the upper 1/3 to 1/2 of the seed. Embryo with plano-convex, collateral cotyledons, radicle apical, slightly exserted, endosperm absent.

Field Characters. Monopodial tree to 16 m high and 35 cm diam., with a crown of spreading or ascending branches. Bark smooth, grey or greyish-brown, twigs often massive, with a cluster of reddish bud scales. Leaves clustered at the branch tips, with reddish rhachis. Flowers without scent, petals deep pink outside and cream inside, staminal tube pale cream-coloured. Capsule ripening through dark green to dark brown, with many pale brown raised lenticels; interior of fruit valves cream-coloured, fruit glabrous. Seed black with a fleshy orange arillode. Flowering recorded in October and February, mature fruit October.

Distribution & Ecology. Known only from the environs of San Carlos, Bongará, Amazonas, Peru, where it is a component of seasonal wet evergreen montane forest, usually in disturbed areas, elevational range 1900–2150 m.

Collections Examined. PERU. Amazonas, Bongará, San Carlos (SW0579), Daza 44 (K, MOL), 5096 (K, MOL); Pennington & Daza 18006 (K, MOL), 18007 (K, MOL), 18402 (K, MOL).

Relationships.This species was first collected 30 years ago, but has remained unrecognized in the MOL herbarium among the collections of T. hirta . It is close to T. tomentosa (see discussion there) and there is some overlap in their geographical distribution. They are, however, ecologically distinct with T. tomentosa occuring in dry, seasonal, mostly deciduous forest on the western Pacific slopes of the Andes between 1350 m and 2550 m elevation, whereas the new species is found only in wet montane evergreen forest in the inter-Andean valleys several hundred kilometres to the east. They are easily distinguished in the field. Trichilia tomentosa is a small densely crowned tree with characteristic bark scaling in large irregular plates and the flowers have pale green petals, whereas T. dazae is a open-crowned monopodial tree with smooth bark and flowers with deep pink petals (outer surface only). In the herbarium the distinguishing characters of T. dazae are the glabrous leaves (pubescent to tomentose in T. tomentosa ), secondary veins 9–13 pairs (14–18(–22.5) in T. tomentosa ), and staminal filaments fused only in the lower half (fused for ½ to 2/ 3 in T. tomentosa ). Trichilia dazae is also morphologically close to T. multifoliola , a species known only from the high Andes of Bolivia. It differs from T. multifoliola in having fewer, larger leaflets which are glabrous, inflorescence a pyramidal panicle and in the larger flowers and capsule. The DNA analysis reported in this work confirms that T. tomentosa , T. dazae and T. multifoliola form a small clade of very closely related species, which are more distantly related to T. hirta .

Etymology. This species is named for Aniceto Daza Yomona , who first collected it in 1984. Aniceto Daza is the unsung hero of Peruvian Forest Botany, working in the Forest Herbarium of the Department of Forest Management, National Agrarian University, La Molina , Peru, for the past 40 years, where he has acquired an unrivalled knowledge of the Peruvian tree flora. His extensive herbarium collections in the MOL herbarium have been amassed from all corners of Peru and the fieldwork of many Peruvian and foreign botanists, including myself, would not have been possible without his organization and enthusiastic support. His ability to spot an unusual plant has resulted in the discovery of many new species, including the one described here.

Figures

PLATE 2.Trichilia dazaeT.D.Penn.A,habit withinflorescence;B, wholeflower;C, half flower&cross-section of ovary;D,infructescence; E, seed with arillode. (A–C, Pennington & Daza 18007; D, E, Daza 44).