Miconia garagoana Humberto Mend., Ariza-Cortés & L. Carvajal, 2024

Mendoza-Cifuentes, Humberto, Ariza-Cortés, William & Carvajal Rojas, Lyndon, 2024, Miconia garagoana - Melastomataceae: A new rheophytic species from the eastern Andes of Colombia, PhytoKeys 247, pp. 145-154 : 145-154

Miconia garagoana Humberto Mend., Ariza-Cortés & L. Carvajal sp. nov.

Figs 1 , 2

Diagnosis.

Rheophytic shrubs with stellate-lepidote trichomes in distal branches and inflorescences; leaves linear-elliptic, 3 - nerved or 3 - slightly plinerved, length-to-width ratio is greater than 5.5: 1; terminal inflorescences with 1-9 (- 14) flowers, flowers 4 - merous (rarely 5 - merous), anthers oblong-subulate with a ventrally oriented pore, ovary 2 - locular, fruits bluish-green with large and relatively few sedes. Similar to Miconia riparia Triana but differs in the indumentum of stellate-lepidote trichomes (vs. indumentum of pinoid trichomes in M. riparia ), flowers predominantly 4 - merous (vs. 5 - merous). Also similar to Miconia rheophytica Posada-Herrera & Almeda , but the latter has branches with dense indumentum of dendritic ferruginous trichomes, ciliate leaf margins, dichasial axillary inflorescences, 5 - merous flowers and 3 - locular ovary.

Type.

Colombia. • Boyacá: Municipio de Garagoa, vereda Ciénega Valvanera, Reserva Privada El Secreto , en borde de Quebrada; 2100 m elev.; 5 ° 7 ' 29 " N, 73 ° 16 ' 42 " W; 12 Apr 2016 (fl); W. Ariza-Cortés et al. 4855 (holotype: UDBC!; isotypes: JBB!, COL! [Branches with inflorescences and fruits were deposited in the supplementary spirit collection - Anthoteca UDBC]) .

Description.

Shrub 30–250 cm tall, rheophytic; foliage dense; external bark smooth and whitish; primary branches sympodial, plagiotropic; young branches quadrangular, flattened and slightly channeled, older branches becoming oblong-terete and exfoliating in thin flakes; apical buds with dense indument of stellate-lepidote trichomes (type 38 of Wurdack 1986); internodes 0.9–3.5 cm long, 1.7–3.3 mm wide. Leaves decussate, isophyllous; petiole 5–17 mm long, slightly channeled adaxially, glabrous; blade 40–85 × 7–17 mm, linear-elliptic, apex and base acute, margin entire, revolute and denticulate toward apex, adaxial surface green, shiny (fresh material) and glabrous, in mature leaves yellow, abaxial surface clear pale green, with sparse stellate-lepidote trichomes especially along the middle vein; venation with one pair of secondary veins accompanying the middle vein, nerved or slightly plinerved to 1–3 mm, 22–34 pairs of tertiary veins lateral to the middle vein, 1–3 mm apart in the middle, central vein raised on both surfaces, tertiary veins blurred on the lower side. Inflorescence 2.5–5 cm long, paniculate, sparsely branched, terminal, sessile or with a peduncle 5–20 mm long, with a sparse to dense indument of stellate-lepidote trichomes (type 38); 1-9 (- 14) flowers, sessiles; central axis with 1–5 branching nodes; branch apices regularly with one flower; basal nodes with linear bracts 2–5 mm long, distal nodes with linear-subulate bracts 1.7–4.4 mm long; flower supported by two linear-triangular bracteoles 0.7–1 mm long. Flowers 4 - merous, rarely 5 - merous, diplostemonous. Hypanthium 2.3–2.4 × 1.7–2 mm, obconical, externally with dense indument of stellate-lepidote trichomes (type 39) ca. 0.09 mm diameter; internally glabrous and slightly ribbed; free thalamus of ovary ca. 0.9 mm long. Calyx lobed, externally with indument similar to the hypanthium; tube ca. 0.2 mm long; lobes 0.2–0.3 × 1.2–1.3 mm, wide triangular; dorsal teeth 0.55–0.6 mm long, triangular and exceeding the lobe length. Corolla patent; petals 2.9–3.2 × 1.4–1.7 mm, spatulate, apex rounded, white, glabrous. Stamens isomorphic, glabrous, white; filaments 3.3–3.7 mm long; anthers 1.8–2.1 × 0.4 × 0.6 mm, oblong-subulate, with a ventrally oriented pore ca. 0.2 mm diameter; basal connective with two little ventral lobules 0.2–0.35 mm long. Ovary 1.6–1.7 mm long, 2 - locular, basal part fused to the hypanthium ca. 1 mm long, apical part free of the hypanthium ca. 0.6 mm long, rounded, glabrous; style 5–6.1 mm long, cylindric; stigma 0.3–0.4 mm diameter, punctiform. Fruit 15–18 × 8–15 mm, pyriform, slightly ribbed, bluish-green when ripe, with 12–18 seeds. Seeds 1.3–2 × 1.2–1.5 mm, ovoid and angled, antiraphal portion symmetrical and ovate; testa smooth, shiny, light yellow.

Phenology.

In Santander, flowering was recorded in November, while in Boyacá flowering was observed between February and July. Fruiting occurred between April and August. At least in the Boyacá locality, active flowering and fruiting events are presumed to occur for most of the year.

Habitat and distribution.

Miconia garagoana is endemic to Colombia in the North of the Eastern Cordillera. This species has been recorded in the departments of Boyacá and Santander, within relatively undisturbed Andean forests at altitudes ranging from 2000 to 2200 meters above sea level (Fig. 3 ). It is a rheophytic plant, which grows exclusively along the banks of streams and rivers, typically on slopes characterized by moderate to steep inclinations (Fig. 4 ).

Etymology.

The specific epithet refers to the municipality of Garagoa in the department of Boyacá, where the majority of individuals of the species have been observed.

Conservation status.

M. garagoana is found in remnants of riparian vegetation along rivers and streams in Andean humid forests, typically within a matrix of pastures designated for livestock grazing (Fig. 4 ). Considering its limited area of occupancy AOO = 8 km 2, recorded only in two locations, it is proposed as Critically Endangered (CR), according to criteria B 2 a of IUCN (2012, 2017).

Specimens examined (Paratypes).

Colombia • Santander: Municipio de Gambita, Cueva de Choco , creciendo en borde de quebrada en el interior de la caverna; 2176 m elev.; 05 ° 54 ' 7.17 " N, 72 ° 20 ' 22.73 " W; 01 Nov 2018 (fl); H. Mendoza 21578 ( JBB, UDBC) .

Figures

Figure 1. Miconia garagoana Humberto Mend., W. Ariza & L. Carvajal A flowering branch B leaf seen from the underside C flower in lateral view D longitudinal cut of the ovary-hypanthium E dorsal tooth of calyx F petals G, H, I stamens in different views J ripe friut. Illustration based on W. Ariza-Cortés et al. 4855 (UDBC).

Figure 2. Miconia garagoana Humberto Mend., W. Ariza & L. Carvajal A, B different views of flowering branch C leaf variation D branch with flowers and fruits E seeds. All photos by Lindon Carvajal and William Ariza.

Figure 3. Distribution of Miconia garagoana Humberto Mend., W. Ariza & L. Carvajal in northern South America.

Figure 4. Miconia garagoana Humberto Mend., W. Ariza & L. Carvajal A Andean forests in the area of origin B habitat C – F different views of growth habit. All photos by Lindon Carvajal and William Ariza.