Trichilia watorikensis T.D.Penn., 2016

Pennington, Terence D., 2016, Systematic Treatment Of American Trichilia (Meliaceae), Phytotaxa 259 (1), pp. 18-162 : 144-147

80. Trichilia watorikensis T.D.Penn. , spec. nov. (sect. Moschoxylum ). Type:— BRAZIL. Amazonas, environs of Yanomami village of Watorketheri, close to the FUNAI PIN Demini on the old route of the abandoned BR 210 Perimetral Norte highway (km 211), fl., Aug. 1994, Milliken 2011 (holotype K, isotypes INPA n.v., MIRR n.v.). Plate 19 , Map 89

Trichilia gamopetalae affinis sed foliolis valde deminutis ad basin petioli desunt, et foliolis chartaceis, venatione tertiario obscuro, floribus minoribus, capsula ovoidea differt.

Young shoots rather stiffly pubescent with a mixture of appressed and erect basifixed hairs, eventually becoming glabrous; brown, with a few pale lenticels, 3–5 mm diam. Bud scales absent. Leaves pinnate, with a terminal leaflet or with one of the terminal pair orientated to simulate a terminal leaflet, petiole 3–7 cm long, rhachis 8–23 cm long, petiole semiterete, rhachis terete, both pubescent with a mixture of erect and spreading hairs; petiolule 1–1.5 mm long. Leaflets opposite or alternate, 9–16, 8.5–13 cm long, 2.5–4 cm broad, oblong or occasionally slightly oblanceolate or lanceolate, apex acuminate, base obtuse to rounded or slightly cordate, base of terminal leaflet often acute, chartaceous, upper surface pubescent along the midrib, lower surface with stiffly pubescent midrib and scattered hairs on the lamina, not glandular-punctate or -striate; venation brochidodromous to eucamptodromous, midrib slightly sunken on the upper surface; secondaries 15–17 pairs, widely spreading, +/- parallel and slightly arcuate, intersecondaries short or absent, tertiaries forming an obscure lax reticulum visible on the lower surface only. Inflorescence axillary, 12–20 cm long, a pyramidal panicle, lowest branches up to 4 cm long, densely golden-pubescent, pedicel 0–1 mm long. Flowers unisexual (plant dioecious). Calyx ca. 1 mm long, shallowly cyathiform, with 4 obscure obtuse lobes, pubescent outside, glabrous inside. Petals 4(–5), male ca. 4.5 mm long, female 5–5.5 mm long, both 1–1.5 mm broad, fused for ca. 2/3 of their length and remaining erect in open flower, valvate, apex lanceolate, apex acute, sericeous outside, glabrous inside. Staminal tube ca. 3 mm long in male, ca. 4 mm long in female, 1–1.5 mm broad, filaments completely fused, margin with 8 subulate teeth ca. 3/4 the length of the anthers and alternating with them, glabrous; anthers 8, ca. 1 mm long, oblong, glabrous; antherodes in female slender, shrunken, without pollen. Nectary absent. Ovary 1.5–2 mm long, ovoid, 3-locular, locules with 2 collateral ovules, densely pubescent; style ca. 0.5 mm long, stout, style-head capitate, ovary in male smaller, ca. 1 mm long, conical with style ca. 1.5 mm long and surmounted by a pointed style-head. Capsule ca. 2.1 × 1.4 cm, 3-valved, ovoid, slightly beaked and acute at the apex, base rounded, uniformly pubescent, pericarp ca. 0.5 mm thick. Seed solitary, ca. 1.4 cm diam., globose, completely enclosed by a thin fleshy arillode which is prolonged at the apex into a point, free apart from a thin line of attachment from micropyle to raphe; seed coat thin and membraneous. Embryo with plano-convex, free, collateral cotyledons, radicle apical, extending to the surface. Endosperm absent.

MAP 89. Distribution of Trichilia watorikensis T.D.Penn. Total distribution to 2010.

Field Characters. Tree to 20 m high and 15 cm stem diam., with greenish-white flowers. Flowering August and September, fruit maturing in March.

Distribution & Ecology. Known only from southern Guyana (upper Takutu-Upper Essequibo region) and northern Amazonian Brazil. A tree of lowland rain forest on non-flooded land, over brown sand, below 300 m elevation.

Collections Examined. GUYANA. Upper Takutu-Upper Essequibo region, Kwitaro Landing, on trail to Shea village (NW0258), D. Clark et al. 6231 (CAY, K, NY, US), 6232 (CAY, K, NY, US).

BRAZIL. Amazonas: Environs of Yanomani village of Watoriketheri, close to FUNAI PIN Demini on old route of abandoned BR 210 Perimetral Norte (km 211) (NW0162), Milliken 2011 (K); 0–3 km N of km 211 of Perimetral N Hwy, Pico Rondon (NW0162), Pipoly et al. 6691 (F, K, MO, US), 6875 (K), 6893 (K, US).

Relationships. Trichilia watorikensis is morphologically close to several other species which share the valvate corolla with petals fused into the upper half. Most of the species can be distinguished from T. watorikensis because they lack the coarse spreading indumentum of the very young shoots and inflorescence, e.g. T. elsae and T. poeppigii . However, a few species share a similar indumentum including T. gamopetala , T. magnifoliola and T. solitudinis .

Trichilia gamopetala differs in the presence of reduced basal scale-like leaflets near the base of the petiole, in its coriaceous leaflets with characteristic and prominent reticulate tertiary venation visible on both surfaces of the leaflets, and in its ellipsoid capsule.

Trichilia magnifoliola and T. solitudinis both differ from T. watorikensis in their fewer and much larger leaflets, and in other vegetative charcacters, such as the slightly winged petiole of T. solitudinis and the midrib of T. magnifoliola which is raised on the upper surface of the leaflet.

Another species which might be confused with T. watorikensis because of the similarity in leaflet shape and indumentum is T. pachypoda but the latter has a pair of reduced leaflets near the petiole base, petals free or fused only in the lower half, longer petiolules and a narrowly obovoid capsule.

Figures

PLATE 19. Trichilia watorikensis T.D.Penn. A, habit with male inflorescence; B, whole male flower; C, half male flower; D, female inflorescence; E, whole female flower; F, half female flower; G, cross-section of ovary; H, infructescence; I, seed. (A–C, D. Clarke et al. 6232; D–G, Milliken 2011; H, I, Pipoly et al. 6875).