Miconia cardenasiae Cárdenas & Burke & Michelangeli 2014, sp. nov.

Miconia cardenasiae Jan.M.Burke & Michelang., sp. nov. (Fig. 4)

Treelet, up to 4 m; young stems bluntly quadrangular, slightly alate on young stems; leaves lanceolate to elliptical, slightly coriaceous, mite domatia present as foliar pockets formed at base of secondary vein axils, up to 2 mm deep; peduncles quadrangular, slightly alate; flowers 5(–6)- merous; stigma capitate.

Type:— PERU. Pasco: Prov. Oxapampa, Dist. Huancabamba, Sector San Daniel, cercano a la laguna, ca. 0.5 km, 10˚26΄08˝ S, 75˚27΄29˝ W, 2366 m, 5 September 2006 (fl), L. Cárdenas, G. Castillo & J . Mateo 774 (holotype USM!, isotypes HOXA!, MO!).

Treelet, up to 4 m. Young stems bluntly quadrangular, white to beige, glabrous, internodes with 4 longitudinal ridges, slightly alate on young stems, nodal line present. Leaves isophyllous; petioles 0.45–0.75 cm long, glabrous, green; blade 8–12.5 × 2.3– 4.1 cm, lanceolate to elliptical, slightly coriaceous, base rounded to attenuate, asymmetrical, apex acuminate, margin serrulate, teeth 0.5–0.75 mm long, 1–3 mm apart; two pairs of secondary veins (including faint marginals), plinerved, diverging 0.25–0.45 cm above the base, asymmetrical, tertiary veins percurrent, arched at 70–80˚ from midvein, quaternary veins reticulate, veins slightly impressed on the adaxial surface and raised on the abaxial surface, brown; adaxial surface nitid, especially when young, glabrous on surface and veins; abaxial surface light green (drying brown), indument on the surface glabrous, veins glabrous, mite domatia present as foliar pockets formed at base of secondary vein axils, up to 2 mm deep. Inflorescences terminal, few-branched panicle, 5.5–6.8 cm long; peduncles quadrangular, slightly alate, brown, glabrous; bracts ca. 1 × 0.25 cm, oblong, caducous; bracteoles ca. 0.75 × 0.2 cm, linear, caducous before anthesis. Flowers with pedicel 1(–2.3) mm long, glabrous.. Hypanthia 1.5 mm long, urceolate, 1.4 mm wide at the torus, external indument sparse sessile glands, internal surface ridged, glabrous. Calyx open in bud; tube 0.25 mm long at anthesis; lobes ca. 0.4 × 0.4 mm, nearly vestigial, glabrous; teeth 0.5–0.6 × ca. 5 mm, long acuminate, glabrous. Petals 5–6, 1 × 0.8 mm, obovoid, erect, white at anthesis (drying yellow), granulose abaxially, base attenuate, apex slightly retuse, margin erose. Stamens diplostemonous, isomorphic, radially spreading at anthesis; filaments ca. 1 mm long, glabrous, white, with an inflection 3/4 of length; anthers incompletely 2-locular, thecae 0.5 × 0.4 mm, obovate, opening by 1 ventrally inclined pore, white at anthesis, connective prolonged 0.25 mm basally with bilobed ventral appendages and 1 short dorsal hump, glabrous. Ovary 3-locular, 2/3 inferior, the free portion projecting ca. 0.5 × ca. 1 mm, bluntly conical, glabrous; style 2.3–2.5 mm long, erect, white, glabrous; stigma capitate, 0.5–0.6 mm wide. Immature berries 2.3 mm long, globose, purple, calyx teeth persistent.

Distribution: — This species is known only from the type collection, in humid montane forest at 2366 m, in the department of Pasco, Oxapampa province, Peru.

Phenology: — Flowering in September.

Etymology: — The epithet is in homage to Lizeth A. Cárdenas, who has collected many exquisite Melastomataceae specimens from Oxapampa, Peru.

Conservation Status:— Miconia cardenasiae is only known only from one population inside the Yanachaga Chemillen National Park and thus should be considered as Data Deficient (DD) under IUCN criteria (2001). Based on its restricted distribution and habitat, following IUCN criteria (2001) as implemented in the IUCN guidelines (2011) we recommend that this species is considered Critically Endangered.

Discussion:— Miconia cardenasiae can be recognized by the short, stout petioles, glabrous leaves, and presence of pocket domatia. Miconia cardenasiae is most similar to Miconia opacifolia MacBride (1929: 184) and Miconia cremophylla Naudin (1850: 228). Miconia opacifolia has completely sessile leaves, while M. cardenasiae has short (<1 cm) petioles. Miconia cremophylla has similar leaf morphology, though the petioles are longer, and it lacks any pocket domatia.

Foliar mite domatia (acarodomatia) are not uncommon among tropical Melastomataceae (Goldenberg 2000, Almeda 2009, Larcher et al. 2012), but unlike ant domatia (Michelangeli 2010), have not been well documented, not even for other tropical plant families (Romero & Benson 2004). Foliar pocket domatia may provide shelter for beneficial mites that eat fungal spores; alternatively they may provide shelter for mite predators that help control insect or arthropod herbivory (Almeda 1989, Romero & Benson 2004). Within Miconieae, acarodomatia have been observed in a broad span of geographical and ecological zones, from Andean tropical montane forest (e.g., Miconia cookii Gleason (1933: 43), Miconia crocea (Desrousseaux 1797: 55) Naudin (1850: 245), Miconia media (Don 1823: 313) Naudin (1850: 244)), Brazilian cerrado (e.g. Miconia pusilliflora (de Candolle 1828: 194) Naudin (1850: 171), Miconia sellowiana Naudin (1850: 206)), to Central American cloud forest (e.g., Clidemia hammelii Almeda (1989: 140)). These domatia are expressed as either foliar pockets or hair tufts at vein axils. Moreover, there appears to be an ecological variation in their occurrence (Larcher et al. 2012). In Miconia cardenasiae, not all leaves on our specimen produce foliar pockets. This variation among leaves on a species bearing acarodomatia is not uncommon.