Myrcia insigniflora M.F.Santos (2014: 99)

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

9. Myrcia insigniflora M.F.Santos (2014: 99) ( Figures 4G , 6F, 6H , 27 and 28 )

≡ Marlierea glazioviana Kiaerskou (1893: 48) . Type:— BRAZIL. Rio de Janeiro: “ Serra da Estrella ”, 1 February 1880 (fl.), Glaziou 11998 (lectotype C [barcode C10015777]! designated by Mazine et al. (2014), isolectotypes C [barcode C10015778]!, G!, K!, LE!, P!, R!)

Tree 6–20 m high. Epidermal peeling present on immature parts; trichomes brown, 0.2–0.4 mm long. Twig when immature vinaceous (when dry), flattened, distally sulcate, pubescent or puberulent, not keeled; mature twig greyish (when dry), cylindrical, cortex smooth, glabrous; branching sympodial, 1–6 branches per node, epidermal protrusion present at the nodes, internode 10–20 cm long; cataphyll not seen, cataphyll scars present in all internodes; terminal node with central bud undeveloped, lateral ones developed, pubescent. Leaf concolorous, coriaceous, blade 30–53 × 9.3–18.5 cm, narrowly elliptic or narrowly oblong, apex acuminate to rounded, base attenuate, cuneate or obtuse, margin plane, secondary veins 10–20 mm apart, held at an angle of 45–70° relative to the midvein, two marginal veins, the first 4–7 mm and the second 1–2 mm from the margin, tertiary veins conspicuous; adaxial surface puberulent to glabrous when immature, glabrous at maturity, midvein sulcate at the base, then flattened to the apex, secondary veins raised, pellucid dots inconspicuous, less than 5 per mm 2; abaxial surface puberulent when immature, glabrescent at maturity, midvein raised, secondary veins raised, pellucid dots conspicuous to inconspicuous, less than 5 per mm 2; petiole 11–33 × 3–5 mm, semicylindrical to cylindrical, puberulent when immature, glabrescent to glabrous at maturity. Inflorescence 11.0–19.5 × 10 cm, pyramidal, axillar at the terminal node, terminal dichasia usually with three flowers, 17–70 flowers, rachis pubescent or puberulent, 2–3 branching at the base, first internode of central rachis 3–6 mm wide, flattened, distal internodes flattened, opposite branching, 2–3 branching per node, epidermal protrusion present at the nodes (sometimes absent in the apical branches). Bract 6–10 × 7 mm, deciduous, ovate to widely ovate, concave, apex acute or obtuse, base truncate, adaxial surface with scattered trichomes, abaxial surface puberulent. Pedicel 0–1.6 mm long, cylindrical, pubescent or puberulent. Bracteole 2.0–3.6 × 2.0– 3.2 mm, deciduous, triangular, ovate or widely ovate, concave, apex acute to rounded, base truncate, adaxial surface with scattered trichomes to glabrous, abaxial surface pubescent or puberulent. Floral bud 6–9 × 5–10 mm, obovate. Hypanthium 2–3 mm extending above the summit of the ovary, tearing vertically at anthesis, externally pubescent with strong epidermal peeling, pellucid dots inconspicuous (covered by the indumentum), internally glabrous; calyx 3–4–merous, lobes 2–5 × 4–7 mm, usually not clearly distinct from the hypanthium, splitting irregularly at anthesis, persistent, depressed ovate or widely depressed ovate in the bud (rarely triangular or narrowly triangular), concave, apex rounded (rarely acuminate), base truncate, externally pubescent, internally pubescent, puberulent to glabrous; corolla 3–4–merous, petals 2–5 × 2–5 mm, sometimes adnate after the anthesis forming a calyptra-like structure, very widely ovate, concave, apex rounded, base truncate, externally pubescent, puberulent to glabrous, internally puberulent to glabrous; staminal ring 1–2 mm wide, glabrous, stamens 200–350, filament 3–8 mm long, glabrous, anther 0.48–0.64 × 0.32–0.40 mm, oblong; ovary 1.2 × 2.8 mm, 2–locular, each locule with two ovules, style 5–6 mm long, glabrous, stigma punctiform, papillose. Fruit green when immature, mature fruit not seen, 21–26 × 25 mm, depressed globose or globose, base rounded, pubescent to glabrous, remnants of calyx lobes, stamens and style usually present; seed 1.

Distribution and Habitat:— Myrcia insigniflora has a narrow distribution in rainforest (Atlantic Forest domain), being found in the municipalities of Ubatuba (São Paulo state), Paraty and southernmost Rio de Janeiro (Rio de Janeiro state) ( Figure 28 ). The species shows high population density in Ubatuba. Myrcia insigniflora inhabits the forest understory close to the coastal line.

The locality “ Serra da Estrella ” (part of the current Serra dos Órgãos , Rio de Janeiro state) is described in the labels of type materials (P and R herbaria), but none additional specimens from this region were found in herbarium collections and field work. The distribution of Myrcia insigniflora seems to be restricted to lowland areas and we deduced that the locality in the type label is probably wrong. It agrees with other mistakes that have been found in Glaziou’s collection ( Rudd 1965, Wurdack 1970).

Phenology:— Myrcia insigniflora flowers in January, March and December and fruits in June, July and December (mature fruits were not seen).

Conservation Status:— The species is restricted to coastal forest areas, which are under strong pressure from the real estate development. Furthermore, the Area of Occupancy is smaller than 24 km 2 and it is recorded from less than 5 localities (only one in a protected area, the State Park of the Serra do Mar). Thus, Myrcia insigniflora is considered Endangered (EN, criteria B2a, biii; IUCN 2001).

Discussion:— The species has a peculiar morphology among the species of Myrcia sect. Sympodiomyrcia , due to the big leaves and flower features, which includes: obovate flower bud; hypanthium tearing at anthesis; calyx lobes almost indistinct from hypanthium tissue and persistent after anthesis; petals usually keeping totally adhered to each other and forming a pseudo-calyptra after anthesis; and stamens persistent (but dry) (Figures, 6F, 6H). The collection Peixoto 4177 (MO) has some flowers with a hypanthium that does not tear at the anthesis and calyx lobes distinct from the hypanthium tissue, showing transition to the typical flower morphology of the group. Beyond the flower features, Myrcia insigniflora has typical characters of M. sect. Sympodiomyrcia, as sympodial vegetative branching ( Figure 4G ), presence of cataphylls (in all internodes) and inflorescence with sympodial basal branching and opposite apical branching.

Available illustrations and images:— Kiaerskou (1893; as Marlierea glazioviana ).

Additional specimens examined:— BRAZIL. Rio de Janeiro: unknown municipality, 1880 (fl), Glaziou 109..? (G!). Mun. Paraty , 25 October 2006 (st), M.C.Souza 445 ( RB!) ; ibidem, 14 December 1988 (fl), M. Nadruz 457 (CEPEC!, RB!, SPF!) ; ibidem, 23 ° 19’50”S, 44 ° 38’22”W, 10 July 2008 (fr), R. Marquete 4193 (BHCB!, IBGE!, RB!) ; ibidem, 29 June 1995 (fr), M.D. Campos 56 ( RB!) ; ibidem, 460 m, 1 July 1993 (fr), R. Marquete 1155 ( RB!) . Mun. Rio de Janeiro, Jacarépagua , 22 January 1987 (fl), A.L.Peixoto 4177 ( MO!) . São Paulo: Mun. Ubatuba , 13 January 1993 (fl), M.A.Assis 83 (BHCB!, HRCB!, UEC!) ; ibidem, 5 September 2002 (st), K. Matsumoto 799 ( UEC!) ; Parque Estadual da Serra do Mar–Núcleo Picinguaba , 20 January 2001 (fl), A.Lobão 514 ( SPF!) ; ibidem, 7 May 2006 (st), M.C.R. Campos 253 ( ESA!) ; ibidem, 62 m, 23 ° 21’26”S, 44 ° 52’3”W, 22 March 2011 (fl), M.F. Santos 682 (K!, RB!, SPF!) ; ibidem, 17 December 1992 (fl, fr), M. Sanchez 361 (RB!, UEC!) ; ibidem, 17 December 1993 (fl), M. Sanchez 46 ( HRCB!) ; ibidem, 21 May 1993 (fr), M. Sanchez 31336 ( UEC!) ; ibidem, 100 m, 23 ° 22’S, 44 ° 48’W, 5 February 1997 (fl), M. Sanchez 718 ( UEC!) . Total: 16 specimens .

Figures

FIGURE 4. A. Myrcia plusiantha, with cataphylls (arrow indicating the scar) present at all internodes; note sympodial branching (Santos 705 [SPF]). B. Myrcia nitida, with cataphylls (arrow indicating the scar) present only at the basal internode of a new branch; note monopodial branching (Harley CFCR 4530 [SPF]) C. Myrcia ascendens, without cataphyll—they are rarely formed in this species; note monopodial branching (Santos 829 [SPF]). D. Sympodial branching of Myrcia mutabilis (Santos 716 [SPF]). E. Monopodial branching of Myrcia rupestris (Santos 640 [SPF]). F. Monopodial branching of Myrcia ascendens (Santos 829 [SPF]). G. Bifid vegetative bud in Myrcia insigniflora (Santos 682 [SPF]). H. Leaf of Myrcia subcordata against light showing the venation (Santos 681 [SPF]). Scales: A, D and F=2 cm; C and H=1 cm.

FIGURE 6. A. Myrcia lenheirensis, three terminal dichasia with only the central flower (Forzza 3692 [SPF]). B. Myrcia bicarinata, terminal dichasia with aborted lateral flowers (indicated) (Heringer 623 [IBGE]). C. Flowers of Myrcia nitida, one flower (right) with bracteole in the regular position (indicated), and the other (left) with one “migrant” bracteole at the hypanthium (indicated) (Lombardi 4532 [SPF]). D. Turbinate flower bud of Myrcia subcordata (Messias 5 [RB]). E. Clavate flower bud of Myrcia bicolor (Carvalho 6829 [SPF]). F. Obovate flower bud of Myrcia insigniflora (Assis 83 [BHCB]). G. Cross section of flower of Myrcia subcordata after anthesis, showing the hypanthium (indicated) not torn and internally glabrous, and the narrow staminal ring above (Santos 842 [SPF]). H. Flower of Myrcia insigniflora after anthesis, with the hypanthium tearing vertically, adnate petals (indicated) and persistent (but dry) stamens (Santos 682 [SPF]). Scales: A, C, D, G and H=2 mm; B and E=1mm; F=3 mm.

FIGURE 27. Images of representative specimens of Myrcia sect. Sympodiomyrcia species: Myrcia insigniflora (Santos 682 [SPF]).

FIGURE 28. Distribution of Myrcia insigniflora (squares), Myrcia mutabilis (circles) and Myrcia truncata (triangles). Continuous lines represent South American country and Brazilian state boundaries. The grey gradient represents elevation.