Trichilia deminuta T.D.Penn., 2016

Pennington, Terence D., 2016, Systematic Treatment Of American Trichilia (Meliaceae), Phytotaxa 259 (1), pp. 18-162 : 127-129

67. Trichilia deminuta T.D.Penn. spec. nov. (sect. Moschoxylum ). Type:— COLOMBIA. Antióquia, Municipio San Luís, canyon of R. Claro, fl., March 1984, Cogollo 1473 (holotype MO). Plate 14 , Map 76

Trichiliae moschatae affinis sed inflorescentia valde reducta, corolla longiora cilíndrica, 4-lobata et staminibus 6 differt. MAP 76. Distribution of Trichilia deminuta T.D.Penn. Total distribution to 2010.

Young shoots finely appressed puberulous (basifixed hairs) at first, soon glabrous, grey-brown to dark brown, without lenticels, 6–8 mm diam. Bud scales absent. Leaves pinnate, with one of the ultimate pair of leaflets orientated to simulate a terminal leaflet, petiole 1.7–3 cm long, semiterete to slightly channelled, rhachis 4.5–6 cm long, semiterete; both glabrous; petiolule of lateral leaflets 5–7 mm long, petiolule of terminal leaflets up to 1.1 cm long. Leaflets alternate, (4–)5, 10–18.5 cm long, 4.5–6.5 cm broad, elliptic, apex acuminate, base narrowly attenuate or cuneate, coriaceous, glabrous, not glandular-punctate or -striate; venation eucamptodromous to brochidodromous, midrib slightly raised on the upper surface; secondaries 9–11, ascending, straight or arcuate, slightly convergent; intersecondaries well-developed, sometimes reaching to near the margin; tertiaries forming a lax reticulum. Inflorescence axillary, 0.75–2 cm long, a congested panicle, sparsely puberulous; pedicel ca. 0.5 mm long. Flowers unisexual (plant dioecious), male flowers only seen. Calyx ca. 1 mm long, shallowly cyathiform; with 4 shallow obtuse lobes, sparsely puberulous outside, glabrous inside. Petals (3–)4, 4.5–5mm long, ca. 1 mm broad, fused for 2/3–3/4 their length, valvate, remaining erect in open flower, apex ovate or triangular, acute, sparsely appressed puberulous on the free portion, otherwise +/- glabrous. Staminal tube ca. 3.5 mm long, ca. 1.5 mm broad, filaments completely fused, margin with 6 subulate teeth alternating with the anthers and ca. 3/4 their length, glabrous outside, pubescent in the throat; anthers 6, ca. 1 mm long, slender, glabrous. Nectary absent. Ovary ca. 0.75 mm long, conical, 3-locular, locules with 2 collateral ovules, densely strigose, style ca. 1 mm long, glabrous, style-head capitate, surmounted by 3 minute acute stigmatic lobes, Capsule (immature) ca. 2 cm long, 3-valved, broadly ovoid, apex obtuse, base rounded, densely sericeous. Seed not seen.

Field Characters. A small tree to 10 m high, with creamish-white flowers. Flowering recorded in March, July and October, young fruit in January.

Distribution & Ecology. Known only from a single locality in Antióquia, Colombia, where it is a tree of lowland rainforest between 300 m and 600 m elevation.

Collections Examined. COLOMBIA. Antióquia: Municipio San Luís, canyon of R. Claro, Cogollo 582 (MO), 810 (MO), 851 (MO), 1473 (MO); Cogollo & Borja 1219 (MO).

Relationships.The collections of this species had previously been assigned to T.moschata ,which is morphologically the most similar species. The foliage of both species is very similar, as is the general floral structure, but T. deminuta is clearly distinct in its tiny congested inflorescence not exceeding 2 cm long, and in the details of its floral structure. The flowers are longer and more narrowly cylindrical in outline, it has (3–)4 petals fused for more than ½ their length and with the petal apex remaining erect, and only 6 stamens (usually 5 reflexing petals and 8–10 stamens in T. moschata ).

The congested inflorescence also distinguishes T. deminuta from T. tuberculata and T. poeppigii . Trichilia tuberculata also differs in its much smaller flowers and T. poeppigii in its generally larger leaves with a winged petiole. The ITS analysis indicates a closer relationship with T. schomburgkii , a species which differs from it in its dimorphic leaflets.

Figures

PLATE 14. Trichilia deminuta T.D.Penn. A, habit with inflorescence; B, detail of leaf upper surface; C, detail of leaf undersurface; D, male whole flower; E, male half flower; F, cross-section of ovary; G, immature fruit. (A–F, Cogollo 1473; G, Cogollo & Borja 1219).