Myrcia costeira M.F. Santos (2015a: 165)

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

6. Myrcia costeira M.F. Santos (2015a: 165) ( Figures 3C, 3D, 3G , 14 and 20 )

Type:— BRAZIL. Paraná: mun. Guaraqueçaba, rio Murato , 7 December 1972 (fl.), Hatschbach 31837 (holotype MBM!, isotypes C!, K!, G!, NY!, SP!)

Tree 2–12 m high. Epidermal peeling present in immature parts; trichomes light brown (rarely ferruginous), 0.1–0.2 mm long. Twig when immature brownish or straw-like (when dry), flattened, keeled, puberulent or with scattered trichomes to glabrous; mature twig greyish (when dry), cylindrical, cortex slightly cracked, glabrescent to glabrous; branching monopodial or sympodial, 2–3 branches per node (rarely more), epidermal protrusion present at the nodes only when branching is sympodial, internode 1–3 cm long; cataphyll scale-like to foliaceous, 2–8 × 1–2 mm, present at all internodes (sometimes only at the basal one of a new branch), early deciduous, free, lanceolate or ovate, with scattered trichomes externally, glabrous internally; terminal node with central bud developed and lateral ones undeveloped or only one developed, puberulent or with scattered trichomes. Leaf concolorous, chartaceous, blade 2.1–5.4 × 0.9–2.7 cm, elliptic or obovate, apex acute to rounded, base cuneate or obtuse, margin sometimes slightly revolute at the base, secondary veins 2.0– 4.5 mm apart, held at an angle of 55–75° relative to the midvein, marginal vein 0.5–1.0 mm from the margin, tertiary veins slightly conspicuous to inconspicuous; adaxial surface glabrous, midvein sulcate in the first half and flat in the second half, secondary veins inconspicuous (rarely raised), pellucid dots conspicuous to inconspicuous, less than 5 to more than 15 per mm 2; abaxial surface with scattered trichomes when immature, glabrous at maturity, midvein raised, secondary veins inconspicuous (rarely slightly raised), pellucid dots conspicuous to inconspicuous, less than 5 to more than 15 per mm 2; petiole 2–5 × 1–2 mm, canaliculate, with scattered trichomes to glabrous when immature, glabrescent to glabrous at maturity. Inflorescence 2.0–5.5 × 1.0– 3.5 cm, corymbiform (rarely pyramidal), axillar at the terminal or subterminal nodes, terminal dichasia usually with three flowers, 10–40 flowers, rachis puberulent to glabrous, branching 1–6 times at the base (sometimes including vegetative branches), first internode of central rachis 1–2 mm wide, flattened, distal internodes flattened, opposite branching (rarely subopposite), 2–3 branches per node, epidermal protrusion present at nodes (usually absent in apical branches). Bract 0.6–1.2 × 0.4–0.8 mm, deciduous, lanceolate or ovate, concave, apex acuminate, base truncate, adaxial surface with scattered trichomes to glabrous, abaxial surface puberulent to glabrous. Pedicel 0–2.4 mm long, cylindrical, with scattered trichomes to glabrous. Bracteole 0.6–1.2 × 0.2–0.4 mm, deciduous, lanceolate or ovate, concave, apex acuminate, base truncate, adaxial and abaxial surfaces glabrous. Floral bud 2–4 × 1–2 mm, turbinate. Hypanthium extending 0.8–1.2 mm above the summit of the ovary, not tearing at anthesis, glabrous externally, pellucid dots conspicuous, glabrous internally; calyx 4–5–merous, lobes 0.4–1.2 × 0.8–2.0 mm, distinct from the hypanthium, deciduous, depressed ovate, concave, apex rounded, base truncate, externally with scattered trichomes to glabrous, internally puberulent to glabrous; corolla 5–merous, petals light brown to white, 1.0–2.2 × 1.2–2.4 mm, depressed ovate, widely depressed ovate or very widely ovate, concave, apex rounded, base truncate, externally and internally puberulent or with scattered trichomes to glabrous; staminal ring 0.2 mm wide, glabrous, 49–74 stamens, filament 1.8–4.4 mm long, glabrous, anther 0.24–0.48 × 0.24–0.40 mm, square, oblong or transversely oblong; ovary 0.8–1.0 × 0.8 mm, 2–locular, each locule with two ovules, style 5.0– 7.2 mm long, glabrous, stigma punctiform, papillose. Fruit green when immature, vinaceous at maturity, 4–10 × 4–10 mm, depressed globose or globose, base rounded, glabrous, remnants of calyx lobes present or not; seeds 1–3.

Distribution and Habitat:— Myrcia costeira occurs in restinga forest and lowland rainforest close to restinga areas ( Santos et al. 2015a). Myrcia costeira is distributed from the North coast of Rio Grande do Sul state to the central coast of São Paulo state ( Santos et al. 2015a) ( Figure 14 ).

Phenology:— Myrcia costeira flowers from October to December and fruits from November to February, from April to June and in August and September (mature fruits from April to June).

Conservation Status:— The Extent of Occurrence of Myrcia costeira is around 47,000 km 2, but the Area of Occupancy is small (52 km 2) and it is known to exist at about ten localities. The species occurs in coastal areas under strong anthropogenic impact and it is recorded from protected areas only in São Paulo state ( Santos et al. 2015a). Based on this, we agree with the classification of M. costeira as Vulnerable (VU, criteria B2a, biii; IUCN 2001) by Santos et al. (2015a).

Discussion:— Myrcia costeira is very similar to Myrcia bicarinata due to flattened and keeled immature twigs ( Figures 3D, 3G ) but differs in the presence of cataphyll scars at all internodes (vs. usually only at the basal internode of a new branch), leaf blades 2.1–5.4 cm long (vs. 4.5–9.4 cm long), venation usually inconspicuous on the abaxial surface (vs. usually conspicuous) and inflorescence with terminal dichasia bearing three flowers (vs. lateral flowers reduced) ( Santos et al. 2015a). Furthermore, Myrcia costeira occurs in restinga forests from Rio Grande do Sul to São Paulo, while M. bicarinata is distributed in inland semideciduous forests in central-southeastern Brazil (Distrito Federal, Minas Gerais, Rio de Janeiro and São Paulo states; Santos et al. 2015a). Previous works have treated specimens of M. costeira within M. bicarinata (e.g. Legrand 1961).

Available illustrations and images:— Legrand & Klein (1969; identified as Myrcia bicarinata ); Santos et al. (2015a).

Additional specimens examined:— BRAZIL. Rio Grande do Sul: Mun. Passo de Torres, February 1987 (fr), K.Hagelund s.n. (F 2078543!). Mun. Torres, May 1988 (fr), J.L.Waechter 2330 ( ICN!); ibidem, 28 December 1975 (fr), O.R.Camargo 657 (F!). Santa Catarina: Mun. Araquarí, 4 m, 12 June 1953 (fr), P.R.Reitz 782 (HBR!, US!). Mun. Barra do Sul, 5 m, 8 April 1953 (fr), P.R.Reitz 502 (C!, HBR!, PACA!, US!, W!). Mun. Florianópolis, Ilha de Santa Catarina, 11 December 1984 (st), J.Mattos 27184 (R!, RB!). Mun. Garopaba, 15 July 2006 (st), R.Hentschel s.n. (ICN 157993!). Mun. Sombrio, 10 m, 5 September 1959 (fr), P.R.Reitz 9056 ( HBR!); ibidem, 10 m, October 1959 (fl), P.R.Reitz 9324 (HBR!, US!). São Paulo: Mun. Cananéia, Ilha do Cardoso, 14 November 1979 (fl), D.A.Grande 346 (SP!, SPF!); ibidem, 24 January 2003 (st), E.J.Lucas 67 (K!); ibidem, 9 December 2003 (fl), E.R.Castro 313 ( HRCB!); ibidem, 10 May 1990 (fr), F.Barros 1848 (SP!, SPF!); ibidem, 13 June 1987 (fr), F.Barros 1368 ( SP!); ibidem, 300 m, 3 August 1990 (fr), P.Martuscelli 1066 ( SP!); Parque Estadual da Ilha do Cardoso , 26 June 2004 (fr), E.R.Castro 377 (HRCB!, SP!, W!); ibidem, 8 December 2002 (fl), F.F.Mazine 750 (BHCB!, ESA!, MBM!, RB!, SPF!, SPSF!); ibidem, 16 November 2012 (fl, fr), M.F.Santos 851 (K!, NY!, RB!, SP!, SPF!); ibidem, 24 November 1988 (fl), M.Kirizawa 2117 ( SP!); ibidem, 10 December 1987 (fl), M.Kirizawa 2023 ( SP!); ibidem, 12 November 2004 (fl), M.P.Sandrini s.n. (SPF 166672!); ibidem, 27 November 1990 (fl), M.Sugiyama 868 (MBM!, RB!, SP!); ibidem, 25 February 2003 (fr), V.C.Souza 29024 (ESA!, SPF!); ibidem, 5 m, 47 ° 54’75”S, 25 ° 3’88”W, 21 May 2006 (fr), V.G.Staggemeier 81 (HRCB!, MBM!, RB!). Mun. Iguape, Estação Ecológica Juréia-Itatins , 22 November 1990 (fl), E.L.M.Catharino 1541 (SP!, SPF!, SPSF!). Mun. Ilha Comprida , 3 June 2000 (fr), P.G.Carrasco 160 ( ESA!). Mun. Pariquera-Açu, Parque Estadual da Campina do Encantado , 28 May 1999 (fr), M.Sztutman 313 (ESA!, SP!, SPF!); Parque Estadual do Pariquera- Abaixo , 10 January 1999 (fr), J.R.L.Godoy 47 (SP!, SPSF!, UEC!). Mun. Santos, Distrito de Bertioga , 28 November 1989 (fl), Grupo B 22779 ( UEC!). Total: 29 specimens .

Figures

FIGURE 3. A. Detail of the leaf of Myrcia summa showing foveolate dots (Prance 29040 [RB]). B. Wax peeling (white) on the leaf of Myrcia rupestris (Santos 641 [SPF]). C. Wax peeling (white) on the leaf of Myrcia costeira (Santos 851 [SPF]). D. Keeled twig of Myrcia costeira (Santos 851 [SPF]). E. Keeled twig of Myrcia densa (Santos 643 [SPF]). F. Leafy cataphyll of Myrcia subcordata covering immature leaves (Rochelle 55 [SPF]). G. Leafy cataphyll (indicated) of Myrcia costeira (Santos 851 [SPF]). H. Scale-like cataphyll (indicated) of Myrcia subavenia (Santos 715 [SPF]). Scales:A=4 mm; B–H=1 cm.

FIGURE 14. Distribution of Myrcia bicarinata (squares) and Myrcia costeira (circles). Continuous lines represent South American country and Brazilian state boundaries. The grey gradient represents elevation.

FIGURE 20. Images of representative specimens of Myrcia sect. Sympodiomyrcia species: Myrcia costeira (isotype: Hatschbach 31837 [SP]).