Myrcia ascendens M.F. Santos (2015a: 160)

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

publication ID	https://doi.org/ 10.11646/phytotaxa.380.1.1
persistent identifier	https://treatment.plazi.org/id/03F887C9-FFE9-FF82-FF45-F94AFB8CFC5E
treatment provided by	Felipe
scientific name	Myrcia ascendens M.F. Santos (2015a: 160)
status

Treatment

1. Myrcia ascendens M.F. Santos (2015a: 160) View in CoL ( Figures 2H View FIGURE 2 , 4C, 4F View FIGURE 4 , 7C View FIGURE 7 , 9 View FIGURE 9 and 10 View FIGURE 10 )

Type:— BRAZIL. Bahia: mun. Mucugê, Serra de São Pedro, 17 December 1984 (fl.), Lewis CFCR 7074 (holotype SPF!, isotypes ALCB!, K!, NY!, RB!)

Shrub to tree, 1–3 m high, slender branches almost vertically inclined. Epidermal peeling absent in immature parts; trichomes brown to light brown, 0.1–0.3 mm long. Twig when immature greenish to brownish (when dry), flattened, keeled, pubescent or puberulent; mature twig greyish (when dry), cylindrical, cortex slightly cracked, glabrous; branching monopodial (rarely sympodial), 2–3 branches per node, epidermal protrusion absent at the nodes (present only when branching is sympodial), internode 0.2–1.0 cm long; cataphyll foliaceous, 1–2 × 1 mm, rarely present, early deciduous, free, lanceolate, externally puberulent, internally glabrous; terminal node with central bud developed, pubescent, lateral ones undeveloped. Leaf concolorous, chartaceous, blade 0.5–1.6 × 0.1–0.5 cm, narrowly elliptic or oblanceolate, apex acute to rounded, base narrowly cuneate or cuneate, margin revolute at the base, secondary veins ca. 1 mm apart, held at an angle of 45° relative to the midvein, marginal vein 0.2 mm from the margin, tertiary veins inconspicuous; adaxial surface with scattered trichomes when immature, glabrous at maturity, midvein flat along the entire length, secondary veins inconspicuous, pellucid dots conspicuous, more than 15 per mm 2; abaxial surface puberulent or with scattered trichomes when immature, glabrescent to glabrous at maturity, midvein raised, secondary veins inconspicuous (sometimes slightly raised), pellucid dots conspicuous, more than 15 per mm 2; petiole 1–3 × 1 mm, canaliculate to semicylindrical, puberulent or with scattered trichomes when immature, glabrous at maturity. Inflorescence 1–2 × 1–2 cm, umbelliform, axillar at the terminal or subterminal nodes, terminal dichasia usually with three flowers, 10–25 flowers, rachis puberulent, 1–2 branching at the base (sometimes with a central vegetative branch), first internode of central rachis 1 mm wide, flattened, distal internodes flattened, opposite branching, three times per node, epidermal protrusion at the node usually present. Bract 1.2–2.4 × 0.4–0.6 mm, deciduous, lanceolate or ovate, concave, apex acuminate, base truncate, adaxial and abaxial surfaces puberulent. Pedicel 0–0.6 mm long, cylindrical, puberulent. Bracteole 1.2 × 0.4 mm, deciduous, lanceolate, concave, apex acuminate, base truncate, adaxial and abaxial surfaces puberulent. Floral bud 2 × 1 mm, turbinate. Hypanthium extending 0.6–0.8 mm above the summit of the ovary, not tearing at anthesis, externally pubescent or puberulent, glabrescent towards the apex, conspicuous pellucid dots, internally glabrous; calyx 4–5–merous, lobes 0.6–1.0 × 0.6–1.0 mm, distinct from the hypanthium deciduous, depressed ovate, widely depressed ovate or ovate, concave, apex acute to rounded, base truncate, externally and internally puberulent; corolla 4–5–merous, petals white, 0.8–1.6 × 1.0– 1.4 mm, very widely ovate, concave, apex rounded, base truncate, externally and internally puberulent to glabrous; staminal ring 0.2 mm wide, glabrous (rarely with scattered trichomes), stamens ca. 32, filament 1.8–3.2 mm long, glabrous, anther 0.24–0.32 × 0.24–0.32 mm, square, oblong or transversely oblong; ovary 0.6–0.8 × 0.8 mm, 2–locular, each locule with 2–3 ovules, style 3.8 mm long, glabrous, stigma punctiform, papillose. Fruit green when immature, reddish to vinaceous at maturity, 4–5 × 4–6 mm, depressed globose or globose, base rounded, glabrescent to glabrous, remnants of calyx lobes present or not; seeds 1–2 (rarely 5).

Distribution and Habitat:— Myrcia ascendens is recorded only from the municipality of Mucugê in two localities: the “Parque Municipal de Mucugê” (a protected area) and the Serra de São Pedro ( Figure 10 View FIGURE 10 ). It inhabits rock outcrops close to watercourses.

Phenology:— Flowering specimens were collected in December and February. Specimens bearing fruits were collected in January and February (mature fruits in February).

Conservation Status:— The species is Critically Endangered (CR, criteria B2a, biii; IUCN 2001) according to Santos et al. (2015a). The Geocat analysis confirms this classification (area of occupancy of 8 km 2).

Discussion:— According to Santos et al. (2015a), Myrcia ascendens shares monopodial branching with Myrcia densa ( Figure 4F View FIGURE 4 ), also having keeled immature branches and inflorescences branching only once or twice at the base. Myrcia ascendens differs in its slender lateral branches inclined almost vertically (vs. thicker branches with inclination variable; Figure 2H View FIGURE 2 ), cataphyll scars rarely present (vs. present at least at the basal internode of the new branch; Figure 4C View FIGURE 4 ), internodes 0.2–1.0 cm long (vs. 0.5–4.5 cm), lateral veins 1 mm apart (vs. 1–3 mm) and marginal vein 0.2 mm from the margin (vs. 5–10 mm) ( Santos et al. 2015a). Narrow elliptic or oblanceolate leaf blades and umbelliform inflorescence are also typical of M. ascendens , although some overlap with M. densa ( Santos et al. 2015a) .

Available illustrations and images:— Santos et al. (2015a).

Additional specimens examined:— BRAZIL. Bahia: Mun. Mucugê, Parque Municipal de Mucugê , 925 m, 12 ° 59’59”S, 41°20’52”W, 12 February 2012 (fl, fr), M.F.Santos 829 (ALCB!, K!, NY!, RB!, SPF!) GoogleMaps ; ibidem, 925 m, 12 ° 59’59”S, 41 ° 20’52”W, 12 February 2012 (fr), M.F. Santos 830 (RB!, SPF!) GoogleMaps ; ibidem, 13 ° 0’0”S, 41 ° 20’52”W, 30 January 2003 (fr), T.C. Faustino 48 (BHCB!, HUEFS!, K!) GoogleMaps . Total: 3 specimens .