Myrcia mucugensis Sobral (2010: 142)

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-FFCB-FFAD-FF45-FD8CFB91FE56
treatment provided by	Felipe
scientific name	Myrcia mucugensis Sobral (2010: 142)
status

Treatment

11. Myrcia mucugensis Sobral (2010: 142) View in CoL ( Figures 2E View FIGURE 2 , 5F View FIGURE 5 , 7B View FIGURE 7 , 30 View FIGURE 30 and 31 View FIGURE 31 )

Type:— BRAZIL, Bahia: ca. 7 km de Mucugê, ca. 1000m altit, 9 November 1988 (fl.), Kral 75641 (holotype SP!, isotypes BHCB [image!], K!, MBM!)

Shrub 1–2 m high. Epidermal peeling absent in immature parts; trichomes ferruginous to light brown, 0.1–0.5 mm long. Twig when immature flattened, keeled, tomentose; mature twig greyish (when dry), cylindrical, cortex cracked, glabrescent to glabrous; branching monopodial (rarely sympodial), 2–3 branches per node (rarely more than three), epidermal protrusion absent at the nodes (present only when branching is sympodial), internode 0.2–0.8 cm long; cataphyll not seen, cataphyll scars rarely present; terminal node with central bud developed, tomentose, lateral ones undeveloped. Leaf concolorous, coriaceous, blade 0.5–1.5 × 0.2–0.7 cm, ovate, apex acute to rounded, base truncate or retuse, margin strongly revolute, secondary veins, marginal and tertiary inconspicuous; adaxial surface tomentose when immature, glabrescent to glabrous at maturity, midvein flat along entire length, pellucid dots inconspicuous, less than 5 per mm 2; abaxial surface tomentose when immature, tomentose to glabrescent at maturity, midvein raised, pellucid dots inconspicuous, less than 5 per mm 2; petiole 0–1 × 1 mm, canaliculate, tomentose when immature, glabrescent at maturity. Inflorescence 1.0–1.5 × 0.5 cm, umbelliform, axillar at the terminal or subterminal nodes, terminal dichasia usually with three flowers, 3–9 flowers, rachis tomentose, 1–2 branching at the base (rarely more than two branching with a central vegetative branch), first internode of central rachis 1–2 mm wide, semicylindrical to flattened and keeled, distal internodes flattened, opposite branching, three branching per node, epidermal protrusion present at the nodes. Bract 2.8–4.0 × 1.2–2.8 mm, deciduous, ovate, concave, apex acute, base truncate or retuse, margin revolute, adaxial and abaxial surfaces tomentose. Pedicel absent. Bracteole 1.6 × 0.6 mm, deciduous, lanceolate, concave, apex acuminate, base truncate, adaxial and abaxial surfaces tomentose. Floral bud 2 × 1.5 mm, turbinate. Hypanthium 0.8 mm extending above the summit of the ovary, not tearing at anthesis, externally tomentose, pellucid dots inconspicuous, internally glabrous; calyx 4–5–merous, lobes 0.4–0.8 × 0.6–1.6 mm, distinct from the hypanthium, deciduous, depressed ovate or widely ovate, concave, apex rounded, base truncate, externally and internally minutely tomentose; corolla 4–merous, petals white, 1.0–1.4 × 1.2–1.4 mm, widely depressed ovate or widely ovate, concave, apex rounded, base truncate, externally puberulent to glabrous, internally glabrous; staminal ring 0.2 mm wide, glabrous, stamens ca. 50, filament 2.4–3.4 mm long, glabrous, anther 0.24–0.32 × 0.32–0.40 mm, square or transversely oblong; ovary 0.6 × 0.8 mm, 2–locular, each locule with two ovules, style 4.4 mm long, glabrous, stigma punctiform, papillose. Fruit green when immature, reddish to vinaceous at maturity, 5–6 × 5 mm, depressed globose or globose, base rounded, glabrescent to glabrous, remnants of calyx lobes present or not; seeds 1–3.

Distribution and Habitat:— Myrcia mucugensis occurs in campo rupestre close to the city of Mucugê (Bahia state), in the Chapada Diamantina (Caatinga domain) ( Figure 30 View FIGURE 30 ). It inhabits rocky outcrops and patches of sandy soils.

Phenology:— Specimens in flower were collected in November and with fruits in January and February (mature fruits in February).

Conservation Status:— The species is only known from few records (one in a protected area, the “Parque Municipal de Mucugê”) close to the city of Mucugê, totalling an Area of Occupancy of 8 km 2. Due to the restricted distribution and usual anthropogenic impacts on campo rupestre vegetation ( Drummond et al. 2005; especially fire in the region), Myrcia mucugensis is classified as Endangered (EN, criteria B2a, biii; IUCN 2001).

Discussion:— Myrcia mucugensis is morphologically similar to Myrcia densa , sharing monopodial vegetative branching ( Figure 7B View FIGURE 7 ), keeled immature twig and the inflorescence with only 1–2 branching at the base. It differs in its small, sessile leaves with truncate or retuse bases and revolute margins, and the umbelliform inflorescence ( Figure 5F View FIGURE 5 ). Furthermore, the species undergoes almost continuous growth and cataphylls are rarely present.

Available illustrations and images:— Sobral (2010).

Additional specimens examined:— BRAZIL. Bahia: Mun. Mucugê , 990 m, 12 ° 59’47,5”S, 41 ° 21’49,1”W, 11 February 2012 (fr), M.F.Santos 823 (ALCB!, K!, NY!, RB!, SPF!) GoogleMaps ; ibidem, 850 m, 12 ° 59’0”S, 41 ° 21’0”W, 25 January 1980 (fr), R.M. Harley 20619 (K!, SPF!) GoogleMaps ; Parque Municipal de Mucugê , 995 m, 12 ° 59’48, 9”S, 41 ° 21’19,6”W, 11 February 2012 (fr), M.F.Santos 825 (BHCB!, K!, RB!, SPF!) GoogleMaps . Total: 3 specimens .