Myrcia foveolata ( Holst 2002: 145 ) M.F. Santos (2016b: 9)

Santos, Matheus F., Lucas, Eve & Sano, Paulo T., 2018, A taxonomic monograph of Myrcia sect. Sympodiomyrcia (Myrteae, Myrtaceae), Phytotaxa 380 (1), pp. 448-450 : 448-450

8. Myrcia foveolata ( Holst 2002: 145) M.F. Santos (2016b: 9) ( Figures 12 and 26 )

≡ Marlierea foveolata B.Holst. Type:— VENEZUELA. Amazonas: Departamento Atures , Sierra Maigualida, NW sector, small valley along an upper tibutary (sic) of Caño Iguana. 05°30’N 65°15’W, 2000 m, 28 February–3 March 1991 (fl.), Berry 4874 (holotype VEN [image!], isotypes MEXU [image!], MO!, SEL [image!])

Shrub to tree 2 m high. Epidermal peeling absent in immature parts; trichomes ferruginous or light brown, ca. 0.5 mm long. Twig when immature slightly flattened (when dry), not keeled, tomentose; mature twig greyish (when dry), cylindrical, cortex slightly cracked, glabrescent to glabrous; branching sympodial, 2–4 branches per node, epidermal protrusion present at the nodes, internodes 1.4–3.0 cm long; cataphyll not seen, cataphyll scars present at all internodes; bud at terminal node not seen. Leaf coriaceous, blade 1.8–3.3 × 1.3–2.6 cm, widely elliptic, circular or ovate to very widely ovate, apex obtuse or rounded, base truncate, retuse or cordate, margin plane or slightly revolute, secondary veins ca. 2 mm apart, held at an angle of 70° relative to the midvein, marginal vein ca. 1 mm from the margin, tertiary veins inconspicuous; adaxial surface tomentose when immature, glabrescent to glabrous at maturity, midvein flat along the entire length, secondary veins inconspicuous, pellucid dots conspicuous, more than 15 per mm 2; abaxial surface tomentose when immature, glabrescent at maturity, midvein raised, secondary veins inconspicuous (sometimes slightly raised), pellucid dots inconspicuous, from 5 to 15 per mm 2; petiole 1 × 2 mm, canaliculate to semicylindrical, tomentose when immature, glabrescent at maturity. Inflorescence 0.3–1.0 × 0.5–0.7 cm, reduced (only the terminal dichasia), axillar at the terminal node, 2–3 flowers, rachis tomentose, 1–2 branching at the base, first internode of central rachis 1.5 mm wide, cylindrical, distal internodes absents. Bract 2–5 × 0.2 mm, deciduous, linear or oblong, plane, apex acuminate or obtuse, base truncate, adaxial and abaxial surfaces tomentose. Pedicel absent. Bracteole 2.0–3.5 × 1.5 mm, deciduous, lanceolate, plane, apex acuminate, base truncate, adaxial and abaxial surfaces tomentose. Floral bud 3 × 2.5 mm, turbinate. Hypanthium 1 mm extending above the summit of the ovary, not tearing at anthesis (or slightly ruptured at the apex), externally tomentose, pellucid dots inconspicuous (covered by the indumentum), internally glabrous; calyx 3–5–merous, lobes 0.6–0.8 × 1.0– 1.2 mm, distinct from the hypanthium, deciduous, depressed ovate or widely depressed ovate, concave, apex rounded, base truncate, externally tomentose, internally puberulent; corolla 4–5–merous, petals 1.2–1.6 × 1.4–1.8 mm, depressed ovate or widely depressed ovate, concave, apex rounded, base truncate, externally puberulent to glabrous, internally glabrous; staminal ring 0.2 mm wide, glabrous, filament ca. 3 mm long, glabrous, anther 0.24–0.32 × 0.32–0.48 mm, square, oblong or transversely oblong; ovary 0.8 × 1.2 mm, 2–locular, each locule with two ovules, style 4 mm long, glabrous, stigma punctiform, papillose. Fruit colour not recorded, 4 × 5 mm (still immature), depressed globose, base rounded, glabrous, remnants of calyx lobes present; seeds not seen.

Distribution and Habitat:— Myrcia foveolata is only known from a few collections made above 2000 m in the Sierra Maigualida ( Venezuela, Guiana Highland), at the border of the Amazonas and Bolívar territories ( Holst 2002) ( Figure 12 ). Individuals occur alone or in small thickets along watercourses or in rocky areas with open vegetation ( Holst 2002).

Phenology:— Myrcia foveolata flowers in February. Specimens with fruits were collected in February and November (mature fruits were not seen).

Conservation Status:— Myrcia foveolata is known from a single locality within a difficult access area in the Guiana Highlands, first botanically surveyed in the 1980’s (Hubber 1995). The Extent of Occurrence (2 km 2) and Area of Occupancy (12 km 2) categorise Myrcia foveolata as Critically Endangered and Endangered, respectively. After balancing the lack of information available on this species with relatively high levels of protection in the Sierra Maigualida , Myrcia foveolata is here classified as Endangered (EN, criteria B2a, biii; IUCN 2001).

Discussion:— Myrcia foveolata is morphologically similar to Myrcia summa , sharing sympodial vegetative branching, secondary and tertiary venation inconspicuous on the adaxial leaf surface and a inflorescence in the terminal node. Myrcia foveolata differs in having a smaller leaf and shorter petiole, truncate, retuse or cordate leaf base and the inflorescence reduced to only one dichasium.

Available illustrations and images:— Holst (2002; as Marlierea foveolata ).

Additional specimens examined:— VENEZUELA. Amazonas: Dept. Atures, Sierra Maigualida, 2150 m, 5 ° 40’N, 65 ° 8’W, 24 November 1989 (fr), O.Hubber 13090 ( VEN!) . Bolívar: Distrito Cedeño , Sierra Maigualida, 2100 m, 5 ° 33’N, 65 ° 13’W, 18 November 1988 (fr), O.Hubber 12829 ( SEL!) . Total: 2 specimens .

Figures

FIGURE 12. Distribution of Myrcia attenuata (triangles), Myrcia foveolata (squares) and Myrcia summa (circles). Continuous lines represent South American country and Brazilian state boundaries. The grey gradient represents elevation.

FIGURE 26. Images of representative specimens of Myrcia sect. Sympodiomyrcia species: Myrcia foveolata (Hubber 13090 [SEL]).