Miconia aguilarii (Kriebel & Almeda) 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: COSTA RICA. Prov. Puntarenas: along gravel road to microwave tower above Golfito, 0.7 m above main road, 08°39’N, 83°11’W, 90 m, 15 September 1987, Croat 67598 (holotype: CAS!; isotype: MO).

Description: Suffrutescent herb or shrub (0.3–)0.4–2(–3) m tall, densely or laxly branched, bark brownish. Upper internodes(0.6–)1.1–5.8(–8.5) cm long, terete like the cauline nodes, nodal line absent. Indumentum on branchlets, petioles, adaxial base of leaf surfaces, primary and secondary leaf veins, inflorescence axes, bracts, bracteoles, and pedicels densely to copiously composed of brownish subsessile or thin stipitate dendritic trichomes (0.1–)0.2–0.3(–0.42) mm long with short axes and few-moderate number of terete arms, sparsely intermixed with caducous elongate smooth trichomes up to 3 mm long. Leaves of each pair somewhat unequal in size; the semiterete petioles 0.4–2.5(–5.85) cm long, adaxially canaliculate; larger blades (6.3–)11–23 × (3.4–)5–11.5 cm, smaller blades 2.5–10 × 1.7–7 cm, elliptic-ovate, the base attenuate to oblique and narrowly decurrent along the petiole, the margins ciliolate-denticulate, the apex acuminate, membranaceous to chartaceous; mature leaves (adaxial surface) glabrescent except for a few elongate smooth trichomes near the margins 0.5–1 mm long, the primary, secondary, tertiary and higher order veins glabrous; abaxial surface together with the tertiary and higher order veins with a sparse and caducous resinous indumentum of slightly furrowed more or less stalked glands 0.1–0.2 mm long; 5- or 7-(9-)plinerved, including the tenuous marginals, innermost pair of secondary veins diverging from the primary vein 0.5–2.8 cm slightly asymmetrically above the decurrent base, areolae 0.8–1.5 mm, adaxially the primary and secondary veins impressed, the tertiary and higher order veins slightly impressed, abaxially the primary and secondary veins elevated and terete, the tertiary and higher order veins slightly elevated. Inflorescences a pseudolateral dithyrsoid 2.25–6.95 cm long, including a peduncle (0.2–)0.4–1.5 cm long, the central flower of some dichasia and of the main axis occasionally aborted, divaricately branched, borne on the upper leafless nodes, the rachis green; bracts 0.6–0.75(–1.2) × 0.15–0.25 mm, spatulate to subulate, spreading and somewhat concave, on both surfaces the indumentum sparse and caducous, densely intermixed with resinous slightly furrowed more or less stalked glands 0.1–0.2 mm long; bracteoles 0.2–0.6 × 0.1–0.3 mm, subulate, spreading, on both surfaces the indumentum dense, sparsely intermixed with resinous-glandular trichomes similar to those of the bracts; both persistent in flower and commonly deciduous in fruit. Flowers 4-merous, the central flower of each dichasium sessile to subsessile, the rest on pedicels 0.25–0.5 mm long. Hypanthia at anthesis 1.7–1.85(–2.1) × 0.8–1.15 mm, free portion of hypanthium 0.95–1.15(–1.4) mm long, urceolate, bluntly 8-ribbed, green-whitish, caducously resinous with slightly furrowed more or less stalked glands 0.03–0.05(–0.1) mm long, inner surface and torus ridged, sparsely and caducously resinous-glandular with glands like those of the hypanthium exterior. Calyx open in bud and persistent in fruit, light green; tube 0.25–0.35 mm long, adaxially with the same indumentum as the inner torus, abaxially as the hypanthium; lobes 0.2–0.4 × 0.5–0.8(–0.99) mm, broadly triangular, the margin vaguely undulate, the apex bluntly acute, caducously resinous-glandular on both surfaces; exterior teeth (0.1–)0.2–0.25 mm long, bluntly triangular, inserted near the base of the calyx lobes and rarely equaling them, caducously resinous-glandular on both surfaces. Petals 0.65–0.85(–1.25) × 0.75–1 mm, obovate-oblong, with a minute projecting infra-apical tooth on the abaxial surface, the margin repand-undulate, the apex obtuse to slightly truncate, dull-greenish to white, densely and caducously papillose on both surfaces, reflexed at anthesis. Stamens 8; filaments 0.9–1.4 × 0.25 mm, light-green to white, glabrous; anther thecae 1.25–1.95 × 0.25–0.5 mm, linear-oblong and subulate, truncate-acuminate at the apex, opening by one dorsally inclined pore 0.11–0.15 mm in diameter, whitish to yellow at anthesis; connective yellow, its prolongation and appendage 0.25–0.35 mm long, the appendage deltoid-spatulate, bluntly acute to obtuse at the apex, densely and caducously gland-edged, also sparsely and minutely glandular toward the center and throughout the connective. Ovary 4-locular, completely inferior, 0.7–0.75 mm long at anthesis, the apical collar absent, the apex ca. 0.6 mm in diameter, somewhat depressed, deciduously glandular-puberulent; style 3.5–5.5 mm long, narrowed distally (i.e. tapering), white, glabrous; stigma capitellate at anthesis (truncate when dry). Berries mostly 3–5 × 2.5–3.5 mm when dry, globose and slightly oblate, initially white turning bright orange when ripe, hypanthium indumentum somewhat persistent at maturity. Seeds0.28–0.33 × 0.16–0.19 mm, ovoid, angled, light-brown; lateral and antiraphal symmetrical planes ovate, the highest point toward the chalazal side; raphal zone suboblong, nearly as large as the corpus of the seed, extending along its entire length, ve

Habitat and Distribution: Miconia aguilarii is known from the Pacific slope of Costa Rica and Panama, at 0–600(–950) m, where it grows in the understory of primary or secondary rain forest, and along banks of rocky streams. Among the collections studied, it has been considered locally common to occasional. In Costa Rica, it is widely distributed, ranging from the Nicoya Peninsula on the northern Pacific coast, through the central Pacific lowlands in El Rodeo Protected Ciudad Colón Zone, south to the Osa Peninsula. In Panama it is known from few collections in a region ranging from the Burica Peninsula south to Coiba Island, and at the border between Los Santos and Veraguas in the mountains of southern Azuero Peninsula.

Phenology: Collected in flower from January through March and from June through October; in fruit from July through February.

Etymology: The specific epithet honors Costa Rican botanist Reinaldo Aguilar, whose explorations of the Osa Peninsula have contributed much to our knowledge of that region's rich rain forest flora.

Taxonomy and Systematics: Miconia aguilarii was long overlooked and commonly determined as Ossaea quinquenervia or Clidemia quinquenervia, synonyms of what is here treated as Miconia quinquenervia. Within the Quinquenervia subclade both are part of a closely related group of species that includes M. reitziana. Within this subclade, M. aguilarii and M. quinquenervia are vegetatively very similar, especially in characters of pubescence (rusty-asperous indumentum mixed with simple trichomes) and leaves (margins ciliolate-denticulate, base decurrent on the petiole). Their inflorescence architecture is also identical. The consistent differences between these two species include flower merosity (4-merous in M. aguilarii vs. 5-merous in M. quinquenervia), exterior calyx teeth (not setose vs. setose), and the color of immature hypanthia (green-whitish vs. yellowish becoming bright pink). The most outstanding difference is the color of the mature berries (bright orange vs. purple-black) (Kriebel & Almeda 2009). In this study, additional specimens belonging to M. aguilarii were found among collections of M. quinquenervia received on loan, particularly from the Burica Peninsula in Chiriquí Province (Panama, Pacific side), a locality from which M. aguilarii had not been reported previously. Although M. quinquenervia is more widespread than M. aguilarii (ranging from Honduras south through Central America, to Colombia, Venezuela and Ecuador), its restriction to the Caribbean slopes of Central America is consistent with its reported distribution in Costa Rica and Panama, where it is also only known from the Caribbean slope (Kriebel & Almeda 2009). This species, which is common in the understory of tropical forests, appears to be tolerant of deep forest shade. Accordingly, it may flower when less than 1 m tall and consequently the labels on at least seven collections examined describe the habit as herbaceous. This is common among other species in the Octopleura clade, including M. reitziana, which is also apparently tolerant of deep shade and has been described as a suffrutescent herb. When rehydrated buds of immature flowers where examined, it was found that in at least four (A.C. Sanders et al. 17706, CAS!), the undeveloped stamens ranged from nine to 11. Further studies of flower development in M. aguilarii would clarify if these stamens are aborted before anthesis, or if the number of stamens is variable within the species. On mature flowers, the number of stamens was consistently eight. Conservation status:—Based on IUCN criteria (AOO), this species would be considered Endangered EN B2ab(iii). However, it occurs in many protected areas, warranting a status of Least Concern LC. In Costa Rica it is protected in the Cabo Blanco Absolute Reserve, Curú Wildlife Refuge, El Rodeo Protected Zone, and Carara, Manuel Antonio and Corcovado National Parks (Kriebel & Almeda 2009). In Panama it is only protected in the Coiba National Park.

Floras and Monographs

Miconia aguilarii (Kriebel & Almeda) Gamba & Almeda: [Article] Gamba Moreno, Diana & Almeda, Frank. 2014. Systematics of the clade of (Melastomataceae: Miconieae) in tropical America. Phytotaxa. 179 (1): 1--174.

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Distribution Map of Miconia aguilarii (image/jpeg)