Miconia bensparrei 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. Pichincha: Toáchi, Along-Santo Domingo road, at the confluence between Río Pilatón and Río Toáchi, 850 m, 9 September 1967, Sparre 18460 (holotype: S!). Nec Miconia sparrei Wurdack (1977: 245–246).

Description: Shrub 2.5–4 m tall, more or less erect and laxly branched, bark rusty-brown. Upper internodes [3.2–7.2(–17.4) cm long] and cauline nodes terete, nodal line absent. Indumentum on branchlets, petioles (when present), adaxial surface of young leaves, primary, secondary, tertiary and higher order veins abaxially, inflorescence axes, bracts, bracteoles, pedicels, hypanthia, and exterior calyx teeth densely to moderately composed of brownish-translucent dendritic trichomes 0.1–0.15 mm long with short axes and few-moderate number of terete arms. Leaves of each pair isophyllous; sessile or with an inconspicuous terete petiole 0.1–0.3 cm long; blades 13–27 × 7–13 cm, elliptic to slightly obovate-elliptic, the base rounded-cordate and amplexicaul, the margin distantly undulate-serrulate, the apex bluntly acute to obtuse, firm-chartaceous; mature leaves adaxially glabrescent, the primary, secondary, tertiary and higher order veins glabrous; abaxial surface glabrous, the indumentum caducous on the tertiary and higher order veins; 7- or 9-plinerved, including the tenuous marginals, innermost pair of secondary veins diverging symmetrically from the primary vein <1 cm above the base, areolae 0.5–1 mm, adaxially the primary and secondary veins impressed, the tertiary and higher order veins slightly impressed to flat, abaxially the primary and secondary veins elevated, canaliculate to terete, the tertiary and higher order veins slightly elevated. Inflorescencestypically an axillary and terminal dithyrsoid 19–26 cm long, including a terete peduncle 5–6.7 cm long, pendant, laxly and divaricately branched from the peduncle apex, paired or solitary in the upper leaf axils, the rachis brownish; bracts and bracteoles 1–1.2 × 0.3–0.5 mm, linear-subulate to oblong, the apex occasionally ciliate-aristate, green-reddish, the indumentum caducous on both surfaces, deciduous to subpersistent in immature fruit. Flowers 5-merous on pedicels 0.5–1 mm long. Hypanthia at anthesis 2.4–2.5 × 2.5–2.9 mm, free portion of hypanthium 1.4–1.5 mm long, subcylindric to campanulate, bluntly 10-ribbed, green, the indumentum caducous and becoming sparse, the dendritic trichomes with somewhat longer arms than on the rest of the plant, ridged on the inner surface, densely and minutely glandular, the glands rounded and sessile, the torus densely glandular-puberulent adaxially, the glands rounded-flattened and slightly furrowed. Calyx open in bud and persistent in fruit, white to green; tube 0.5–0.8 mm long, with the same vestiture as the torus adaxially and as the hypanthium abaxially; lobes 0.9–1 × 0.9–1 mm, depressed-rotund, the margin entire, the apex obtuse, glabrous on both surfaces; exterior calyx teeth 0.4–0.5 mm long, minute and bluntly triangular, inserted at the base of the calyx lobes and not projecting beyond them. Petals 5.1–7 × 2–2.3 mm, oblong-lanceolate, the margin entire, the apex bluntly acuminate, white but drying orange, glabrous on both surfaces, slightly spreading at anthesis. Stamens 10; filaments 2.3–2.6 × 0.25 mm, whitish, glabrous; anther thecae 2.2–2.8 × 0.45–0.55 mm, linear-lanceolate, bluntly acuminate at the apex, opening by one dorsally inclined pore 0.1 mm in diameter, white; connective darker than the thecae when dry, its prolongation and appendage 0.4–0.45 mm long, the appendage oblong to subulate, bluntly acute to obtuse at the apex, bearing conspicuous glandular trichomes at the apical edge, the glands with flattened rounded heads, slightly furrowed and minutely stalked, the stalks subulate. Ovary 5-locular, 1/2 to 2/3 inferior, 2–2.1 mm long at anthesis, the apical collar 0.1–0.2 × 0.4–0.5 mm, conic-truncate, densely to moderately glandular-puberulent; style 6–6.5 mm long, straight, moderately narrowed distally, white, glabrous; stigma expanded truncate to capitellate. Berries 6.5–7.5 × 7.5–8.5 mm when dry, globose and slightly oblate, first yellowish turning orange to red when ripe, the hypanthial indumentum somewhat persistent at maturity. Seeds 0.4–0.45 × 0.2–0.25 mm, ovoid, angled; lateral and antiraphal symmetrical planes ovate, the highest point toward the chalazal side; raphal zone suboblong, ca. 90 % the length of the seed, ventrally expanded toward the micropyle; appendage absent but a small protuberance present; individual cells elongate, some anticlinal boundaries channeled, others raised, undulate, with U-type patterns; periclinal walls flat, microrelief verrucose to somewhat striate.

Habitat and Distribution: This uncommon species occurs in primary or disturbed rainforests and cloud forests, on steep slopes or along streams in the northwestern foothills of the Ecuadorean Andes, with one record from southwestern Andean Colombia, at 850–2800 m. The single record from Colombia is from Reserva Natural La Planada, in the southwestern department of Nariño.

Phenology: Collected in flower from December through March, in May, and from July through September; in fruit in January, March, May and July.

Etymology: The specific epithet is dedicated to Benkt Sparre (1918–1986), a Swedish botanist and museum curator who collected the holotype of this species.

Taxonomy and Systematics: This species has brownish-asperous indumentum on vegetative and floral organs, 7- or 9-plinerved, elliptic to obelliptic leaves that are sessile and amplexicaul. It is strikingly similar to M. palenquensis, from which it differs in having larger flowers and different venation (5-plinerved in M. palenquensis). As noted under the discussion of M. palenquensis, these differences may not be taxonomically significant and as more collections of these two species come to light they may prove to be conspecific. Miconia bensparrei is also similar to M. variabilis in having 5-merous flowers and a dendritc indumentum but both flowers and trichomes are consistently smaller in M. variabilis. Miconia variabilis differs most notably from M. bensparrei in having petiolate leaves. Phylogenetically M. bensparrei is basal to a subclade containing M. albertobrenesii, M. boekei, and M. neomicrantha. The flowers of these four species have a similar oblong-lanceolate petal shape and ovoid-angled seeds but are different in vegetative and floral vestiture. The asperous-dendritic indumentum of this species is identical to that found in M. quinquenervia and its allies which may have led Wurdack (1978a) to suggest that the latter is a close relative. Indumentum characters, although very important taxonomically, can also be convergent and thus should be used in combination with other characters (like seeds and inflorescence architecture) to distinguish allied groupings within the Octopleura clade. Miconia incerta also seems close to M. bensparrei. It has the same vegetative indumentum and sessile-amplexicaul leaves, but M. bensparrei lacks the resinous-glands on the hypanthium. The seeds in M. incerta are also very different and its position within Octopleura is unclear at this time.

Conservation Status: Endangered EN B2ab(iii). It was considered Vulnerable in previous assessments (Cotton & Pitman 2004). Miconia bensparrei was thought to be endemic to Ecuador, where it is known from eight collections. It is not known from any protected area in Ecuador. It likely occurs in the Awá Indigenous Reserve, the Cotacachi-Cayapas and the Mache-Chindul Ecological Reserves but no collections are yet known from these protected sites. In Colombia it is protected in La Planada Natural Reserve. Apart from habitat destruction, no specific threats are known.

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