Miconia boekei (Wurdack) Gamba & Almeda

Description

Description Author and Date: Diana Gamba & Frank Almeda, modified from "Systematics of the Octopleura Clade of Miconia (Melastomataceae: Miconieae) in Tropical America". Gamba, D., Almeda, F. Phytotaxa 179(1): 1-174.

Type: ECUADOR. Prov. Azuay: Jesús María–Molleturo road, about 10 km from Guayas border, ca. 1100 m, 16 July 1977, Boeke & Loyola 2171 (holotype: US!; isotypes: MO!, NY-internet image!).

Description: Subshrub or shrub (1.5–)3–5 m tall, sparingly branched. Upper internodes compressed-rounded, (1–)5.7–8.4 cm long, cauline nodes terete, nodal line absent. Indumentum on branchlets, petioles, primary and secondary leaf veins abaxially, inflorescence axes, bracts, bracteoles, pedicels, hypanthia, calyx lobes abaxially, and exterior calyx teeth copiously covered with whitish elongate moderately roughened trichomes to 1 mm long, each trichome claviform and somewhat thickened, copiously intermixed with a whitish understory of single-tiered lepidote trichomes 0.15–0.23 mm in diameter with the radii nearly completely fused. Leaves of each pair typically equal in size; petiole 2–3 cm long, canaliculate and depressed adaxially, quadrate-grooved abaxially; blades 18–30 × 7–13 cm, elliptic, the base acute, the margin obscurely undulate-serrulate, the apex shortly to abruptly acuminate, chartaceous; mature leaves adaxially with surface and primary vein at first sparsely covered with the whitish lepidote general trichomes but soon becoming glabrous, the secondary, tertiary and higher order veins glabrous; abaxial surface, essentially glabrous with age, with caducous lepidote trichomes similar to those on the adaxial surface, the tertiary and higher order veins sparsely beset with short-stalked glands 0.1 mm long with thin-walled short heads to glabrescent; 5-plinerved, including the tenuous marginals, innermost pair of secondary veins diverging asymmetrically from the primary vein 1.5–3 cm above the base, areolae 0.5–0.7 mm, adaxially the primary and secondary veins slightly impressed, the tertiary and higher order veins flat, adaxially the primary and secondary veins elevated and terete toward the base, the tertiary and higher order veins flat. Inflorescences an axillary dithyrsoid 5–8 cm long, including a peduncle 0.5–1 cm long, occasionally the lateral branches of the dichasia with secund flowers, divaricately branched from the peduncle apex, paired among the upper leaves; bracts and bracteoles 1.5–2 × 1.8–2.2 mm, broadly ovate, the margins sparsely denticulate, acute to aristulate at the apex, concave, with conspicuous parallel venation, the indumentum caducous, the bracts somewhat spreading, the bracteoles erect, occasionally alternately positioned along the inflorescence branchlets, both persistent in fruit. Flowers 5-merous, subsessile or on pedicels 0.3–2 mm long. Hypanthia at anthesis 2.3–2.9 × 2–2.2 mm, free portion of hypanthium 0.9–1.2 mm long, subcylindric becoming globose in fruit, obscurely 10-ribbed, ridged on the inner surface, glabrous, the torus sparsely and minutely resinous-glandular adaxially. Calyx open in bud and persistent in fruit; tube 0.3–0.5 mm long, with the same vestiture as the torus adaxially and as the hypanthium abaxially; lobes 0.5–0.7 × 0.8–1 mm, oblong-triangular, the margin entire, the apex bluntly acute, glabrescent abaxially; exterior calyx teeth to 1 mm long at anthesis, conic-thick, inserted inframarginally and not projecting beyond the lobes. Petals 5–5.8 × 1.7–2.1 mm, oblong-lanceolate, the margin entire, the apex acute, cream to white, glabrous adaxially, abaxially with a copious squamate-stellate central band of lepidote trichomes with only partially fused radii, reflexed at anthesis but often appearing somewhat erect when dry. Stamens 10; filaments 2–2.5 × 0.25 mm, white, glabrous; anther thecae 1.5–2 × 0.5–0.7 mm, oblong, somewhat clavate and emarginate at the apex, opening by two dorsally inclined pores 0.15 mm in diameter; connective darker than the thecae when dry, its prolongation and appendage 0.3–0.5 mm long, the appendage deltoid to somewhat spatulate, obtuse-rounded at the apex, copiously gland-edged, the glands conspicuously stalked and rounded, the stalks linear to subulate to 0.2 mm long, the connective also somewhat prolonged and gland-edged but unappendaged ventro-basally. Ovary (6-) 7-locular, completely inferior, 1.4–1.7 mm long at anthesis, the apical collar absent, the apex 0.25 mm in diameter, truncate, sparsely glandular-granulose; style 6.5–7 mm long, narrowed distally (i.e. tapering), white, glabrous; stigma truncate to expanded truncate at anthesis. Berries 4–4.3 × 5–5.2 mm when dry, globose and slightly oblate, initially pale green, ripening orange, the hypanthial indumentum persistent at maturity. Seeds 0.43–0.48 × 0.17–0.2 mm, ovoid, angled, brownish; lateral and antiraphal planes ovate, the highest point toward the chalazal side; raphal zone sublinear, nearly as long as the seed, somewhat ventrally expanded toward the micropyle; appendage absent but a small protuberance may be present; individual cells elongate, anticlinal boundaries channeled, undulate, with ?- and U-type patterns; periclinal walls convex, low-domed to nearly flat, microrelief inconspicuously striate.

Habitat and Distribution: Endemic to Ecuador where it is rare in primary or secondary cloud and premontane wet forests and disturbed sites throughout the western foothills of the Ecuadorean Andes, at 400–1100 m.

Phenology: Collected in flower and fruit in February, from June through July, and from September through October.

Etymology: The specific epithet is dedicated to the collector of the type, Jef D. Boeke, a molecular biologist and geneticist, currently at the Johns Hopkins University School of Medicine in Baltimore, Maryland, United States.

Taxonomy and Systematics: This species is readily recognized by the dense claviform-thickened vegetative indumentum that also covers the hypanthium and calyx, markedly asymmetrical plinervation, and conspicuous bracteoles that are occasionally present subalternately around the ultimate dichasial branching of the inflorescence. In the protologue, Wurdack suggested that it is closest is M. variabilis, a species with somewhat similar foliar plinervation and laxly reticulate and elevated foliar veins abaxially. Apart from the deflexed gland-edged dorso-basal staminal connective appendage and the conspicuous hypanthial ribs (synapomorphies for the entire Octopleura clade); these two species do not seem to have much else in common morphologically. Miconia boekei is sister to M. neomicrantha, a species with very different vegetative indumentum and overall general appearance. Another close relative is M. albertobrenesii, as noted by Wurdack (1978b), which differs in having shorter vegetative and floral indumentum, foliar areoles more densely arranged (0.2–0.3 mm in M. albertobrenesii vs. 0.5–0.7 mm), plinervation asymmetrical but less striking (0.6–1.2 cm vs. 1.5–3 cm), and different berry color at maturity (white vs. orange). Both M. albertobrenesii and M. boekii have a similar anther shape (rather clavate-emarginate) and ovaries that are occasionally 6-locular. Based on available collections, the northernmost occurrence of this species is in the southwest part of the Esmeraldas province. The southernmost is in the central-south of El Oro province. This distribution suggests that the range of this species is definitely centered in Ecuador, because the aforementioned points are far removed from the Colombian and Peruvian borders.

Conservation Status: Endangered EN B2ab(iii). It was considered Vulnerable in previous assessments (Cotton & Pitman 2004). In northern Ecuador, at least one population is protected inside the Reserva Ecológica Mache-Chindul (Esmeraldas). Three specimens are housed in Ecuadorian herbaria: Clark et al. 1960 (QCNE), Foster & Mitsui 13553 (QCA), Rubio & Alverson 510 (QCNE). Habitat destruction is the only known threat.

Map Distribution

View all records of Miconia boekei (Wurdack) Gamba & Almeda

Objects