Trichilia primogenita W.A. Palacios

Pennington, Terence D., 2016, Systematic Treatment Of American Trichilia (Meliaceae), Phytotaxa 259 (1), pp. 18-162 : 111-113

56. Trichilia primogenita W.A. Palacios (sect. Moschoxylum ), Novon. 4: 155, fig. 1 (1994). Type:— ECUADOR. Esmeraldas, road Lita to San Lorenzo, fl., May 1987, van der Werff, Dodson & Palacios 9502 (holotype, QCNE; isotypes, AAU, K, MO). Plate 12 , Map 63

Young shoots minutely appressed puberulous (basifixed hairs), soon glabrous, becoming dark brown, scaling and slightly suberous, 5–10 mm diam., usually with a few large raised lenticels. Bud scales absent. Leaves pinnate, usually with 1 leaflet orientated to simulate a terminal leaflet, petiole 8–15.5 cm long, rhachis 11–24 cm long, petiole and rhachis semiterete, glabrous; petiolule 0.3–1.2 cm long, swollen towards the base, not channelled. Leaflets alternate, 5–7, lateral leaflets 15–25 cm long, 5.5–11 cm broad, ultimate leaflet up to 29 x 14 cm, broadly elliptic to obovate, apex narrowly acuminate, base narrowly cuneate or acute, subcoriaceous, glabrous, obscurely glandular-punctate and -striate; venation eucamptodromous or sometimes brochidodromous in the upper 1/3, midrib flat or slightly rounded on the upper surface; secondaries 17–21 pairs, ascending, straight or only slightly arcuate, parallel; intersecondaries absent; tertiaries oblique, obscure. Inflorescence axillary and clustered at the shoot apex in the axils of undeveloped leaves, male 15–25 cm long, a many-flowered pyramidal panicle, lateral branches up to 8 cm long, ascending, indumentum of sparse minute appressed hairs, female inflorescence 5–10 cm long, little branched; pedicel ca. 1.5 mm long. Flowers unisexual (plant dioecious). Calyx 0.5–1 mm long, 2–2.5 mm broad, patelliform, obscurely and obtusely 4–5-lobed, with some sparse minute appressed hairs on the outside. Petals 4–5, 3–4 mm long, ca. 1.5 mm wide, free or some fused near the base, valvate, finally reflexing, with sparse minute appressed hairs outside, glabrous inside. Staminal tube ca. 2 mm long, ca. 2 mm broad, filaments completely fused, margin with slender filamentous appendages alternating with the anthers and ca. 1/2 their length, alternate filaments slightly shorter, glabrous outside, glabrous or with scattered hairs inside in the throat; anthers 8, ca. 1.25 mm long, oblong, apex acute, glabrous; antherodes in female ca. 0.75 mm long, without pollen. Nectary absent. Ovary ca. 2 mm long, ovoid (pistillode in male ca. 1 mm long, conical), 3- locular, locules with 2 collateral ovules, densely and shortly pubescent; style ca. 1 mm long (ca. 0.5 mm long in male), glabrous, style-head small, discoid with slightly obtuse apex. Fruit unknown.

MAP 63. Distribution of Trichilia primogenita W.A.Palacios. Total distribution to 2010.

Field Characters.Tree to 20 m high and 80 cm diam., flowers fragrant with a greenish-cream corolla and staminal tube. Flowering recorded in February and May to June.

Distribution & Ecology. Known only from wet evergreen lower montane forest between 600 m and 1200 m

elevation on the Pacific slopes of the Andes in NW Ecuador. Presumably also present in SW Colombia, though I have seen no material.

Collections Examined. ECUADOR. Carchi: Tulcan, Awá Ethnic Reserve, Parroquia Chical (NW0178), C. Aulestia et al. 1185 (MO, NY); Grijalva et al. 457 (M)), 488 (K), 493 (K, NY); Cantón Tulcan, Parroquia Dobar Donoso, sector Sabalera, Awá Reserve (NW0178), Tipaz et al. 1418 (K), 1433 (K). Esmeraldas: near Lita (NW0078), van der Werff et al. 9502 (MO, NY).

Local Names and Uses. Chalde, naranja, pichalde. The timber is used for construction and the branch wood for fuel.

Relationships. The morphology of this species is closest to the Amazonian T. tenuifructa , and their floral structure is very similar. Trichilia primogenita differs vegetatively in having much larger leaflets with the midrib flat or only slightly rounded on the upper surface (sharply raised in T. tenuifructa ), and in having 17–21 more or less straight and parallel secondary veins (9–12 pairs, arcuate and slightly convergent in T. tenuifructa ). The fruit of T. primogenita has yet to be collected.

It is also close to T. poeppigii but differs in the slightly smaller flowers with free, subglabrous, finally reflexing petals (petals fused for ½–3/4 of their length, densely appressed puberulous, erect in T. poeppigii ). In addition there are also some vegetative differences. The petiole of T. primogenita is semiterete, while that of T. poeppigii is narrowly winged. All collections of this species seen by me are from lower montane rain forest between 600 m and 1200 m elevation, whereas T. poeppigii is exclusively lowland (both in its Pacific and Amazonian distribution), and not recorded higher than 400 m elevation.

Note. Vargas et al. 509 (K, QCNE) collected in Cañar, Ecuador, has a similar floral structure to T. primogenita but differs in the presence of a pair of reduced basal leaflets and in the indumentum of erect hairs on young parts and inflorescences.

Figures

PLATE 12. Trichilia primogenita W.A.Palacios.A, habit; B, detail of leaf upper surface; C, detail of leaf undersurface; D, shoot apex with inflorescence; E, whole flower; F, half flower; G, cross-section of ovary. (A–C, Tipaz et al. 1433; D–G, C.Aulestia & Grijalva 1185).