Myrcia gaudichaudiana (O.Berg) M.F.Santos

Santos, Matheus F., 2025, Taxonomic monograph of Myrcia sect. Eugeniopsis (Myrciinae, Myrteae, Myrtaceae), an endemic clade of Eastern South America, Phytotaxa 703 (1), pp. 1-100 : 37-38

6. Myrcia gaudichaudiana (O.Berg) M.F.Santos (in Santos et al. 2019: 3) ( Figures 19 , 20 ).

≡ Eugeniopsis gaudichaudiana O. Berg (1857 –1859: 147). Marlierea gaudichaudiana (O.Berg) Loefgren & Everett (1919: 219) . Type: — Brazil, Rio de Janeiro, no date (fl.), Schüch 1035 (number 5878 is also presented in original labels) (lectotype W! [W0047995] designated by Santos et al. 2019; isolectotypes F! [876125], K! [K000330596], W! [W0047994]). Remaining syntype: — Brazil, Rio de Janeiro, 1830 (fl.), Gaudichaud-Beaupré s.n. (G! [G00301890]).

= Eugeniopsis schottiana O. Berg (1857 –1859: 148), syn. nov. Marlierea schottii D. Legrand (1962a: 33) . Myrcia schottii (D.Legrand) M.F.Santos (in Santos et al. 2019: 6). Type:— Brazil, Rio de Janeiro, 1837(?) (fl.), Schott 1083 (number 5866 is also cited in the original label) (lectotype W! [W0037061] designated by Santos et al. 2019; isolectotypes B†, K! [K000330595]).

Description:— Shrub to tree, 4 to 12 m high. Trichome reddish, simple or dibrachiate, 0.08–0.16 mm. Twig when young flattened and distally sulcate, puberulent, when mature greyish to stramineous (when dry), cylindrical, cortex slightly cracked; branching monopodial, internode 1.9–5.8 cm, node slender; cataphylls rarely present, deciduous; buds pubescent. Leaf concolorous, chartaceous, blade 5.0–11.9 × 2.0– 5.9 cm, elliptic to widely elliptic, oblong or ovate, apex acuminate to obtuse, base cuneate to obtuse (rarely rounded) or slightly attenuate, margin plane, secondary veins 2–8 mm apart, held at an angle of 65–70° relative to the midvein, marginal vein 0.5–3.0 mm from the margin, tertiary veins inconspicuous or sometimes barely conspicuous in both surfaces, areoles ca. 0.5–1.0 mm, pellucid dots conspicuous in the abaxial surface, 1–12 per mm 2; adaxial surface glabrous (except midvein), secondary veins plane to raised; abaxial surface glabrous (often puberulent), secondary veins plane to raised; petiole 4–8 × 1–2 mm, canaliculate, puberulent to glabrous. Inflorescence 4.5–10.0 × 2.0–6.0 cm, 20–45 flowers, axillar at subterminal (rarely terminal) nodes of the SGU (central bud developing a vegetative branch), one inflorescence per axillary bud, inflorescence pherophyll deciduous, opposite branching, three branching per node, rachis puberulent, first internode of central rachis 1–2 mm wide; bracts deciduous, not seen; bracteoles 1.2 × 0.2–0.4 mm, deciduous, lanceolate to ovate, concave or keeled, apex acuminate, base truncate, both surfaces puberulent. Flower bud 2.2–3.2 × 1.4–2.0 mm, clavate, corolla hidden or barely apparent before anthesis; hypanthium 0.8–1.7 mm extending above the summit of the ovary, not tearing at anthesis or with a small vertical rip (but not tearing the staminal ring), externally pubescent to puberulent, pellucid dots covering the whole surface; calyx 4–merous, lobes 0.6–1.4 × 0.8–1.8 mm, not fused, deciduous parallel to the hypanthium ring, depressed ovate to widely depressed ovate or ovate to very widely ovate, concave, apex rounded, both surfaces puberulent to glabrous; corolla 4–merous, petals white to cream, 1.2–2.4 × 0.8–2.0 mm, widely depressed ovate, very widely ovate or widely obovate to very widely obovate, plane, apex rounded, both surfaces puberulent to glabrous; staminal ring 0.2–0.4 mm wide, puberulent to glabrous, stamens 44–71(100), filament 1.6–4.4 mm long, anther 0.16–0.32 × 0.24–0.40 mm, gland at the apex; ovary 0.6–1.0 × 0.6–1.0 mm, obconic, style 3.6–7.2 mm long, subglabrate to glabrous, stigma punctiform. Fruit mature black, ca. 1.0 × 1.0 cm, globose, base rounded, glabrous, totally covered by pellucid dots, remnants of hypanthium and calyx present; seeds not seen.

Distribution and Habitat: — Myrcia gaudichaudiana is found from the states of Rio de Janeiro to Pernambuco, primarily within the Atlantic Forest domain from 17 to 750 m of elevation ( Figure 20 ). It typically inhabits rain forest, with occasional occurrences in flooded forests, seasonal forest (such as “mata de cipó”), and montane forests within Caatinga domain (“brejo”). It can be found in the understory or along forest edges.

Phenology: —Flowers occurs from October (peak) to February, with immature fruits observed in March.

Conservation Status: —The species has an Extent of Occurrence of ca. 333,101 km 2 (threshold of Least Concern) and a small Area of Occupancy (52 km 2, threshold of Endangered) (sensu IUCN 2022). Myrcia gaudichaudiana is documented in over 10 localities (22 records) throughout its range, though only two of these are within Conservation Units. Many populations are in the northern Atlantic Forest, which faces significant environmental pressures (Fundação SOS Mata Atlântica & INPE 2022). Giving the conflicting data and limited information available, the species is preliminarily classified as Data Deficient (DD; IUCN 2022).

Taxonomy: — Myrcia gaudichaudiana is morphologically similar to Myrcia tenondeporan and Myrcia vellozoi , with overlaps in their circumscriptions. All three species share monopodial branching, typically elliptic leaf blades, and axillar inflorescence at terminal or subterminal nodes of the SGU. Myrcia gaudichaudiana is distinguished by its smaller leaf blade (compared to M. vellozoi ), its leaf apex (less prolonged than in M. tenondeporan and M. vellozoi ), glabrous or often puberulent leaves (versus glabrous to tomentose in M. vellozoi ), and flower bud size (larger than M. tenondeporan and generally smaller than M. vellozoi ). The distributions of M. gaudichaudiana and M. vellozoi overlap from Rio de Janeiro to Bahia states, but M. gaudichaudiana is found further norther, whereas M. gaudichaudiana and M. tenondeporan do not co-occur.

Myrcia schottii is here considered a synonym of M. gaudichaudiana due to absence of significant morphological differences between the type specimen of M. schottii (the only known collection) and the leaf and flower bud variations in M. gaudichaudiana . The primary distinguishing feature of M. schottii , a long internode and long inflorescence peduncle, is regarded as an atypical variation. The vernacular names “murta” or “murta-branca” have been recorded for the species in Pernambuco state.

Illustrations and images in previous works: — Berg (1857 –1859, as Eugeniopsis gaudichaudiana ), Fernandes et al. (2020, as Myrcia gaudichaudiana and M. schottii ).

Additional specimens examined: — BRAZIL. Unknown province /state, no date (fl.), J. B. E . Pohl s.n. ( K000330502 ). Alagoas: unknown municipality, 28 October 1980 (fl.), Andrade-Lima 80-9738 ( IPA); 28 October 1980 (fl.), Andrade-Lima 80-9755 ( IPA); 28 October 1980 (fl.), Andrade-Lima 80-9778 ( IPA). Bahia: Mun. Belmonte, 9 November 1967 (fl.), R. S . Pinheiro 401 ( CEPEC, MBM, MBML, SPF). Mun. Jequié , 20 October 1970 (fl.), T. S . Santos 1228 ( CEPEC, SPF); ibidem, 21 June 2004 (st.), G. E. L . Macedo 968 ( PEUFR). Espírito Santo: Mun. Linhares, 30 October 1991 (fl.), D. A . Folli 1466 ( K, RB, SPF, UEC). Pernambuco: unknown municipality, no date (fr.), G . Gardner s.n. ( K000018779 ). Mun.Bonito, no date (fl.), A. G . Silva 545 ( PEUFR). Mun.Cabo de Santo Agostinho , 29 January 1996 (st.), D. R . Siqueira 140 ( PEUFR). Mun. São Vicente Férrer, 30 October 1998 (fl.), E. M. N . Ferraz 494 ( PEUFR, RB). Mun. Sirinhaém , 1 November 1968 (fl.), D. P . Lima 12620 ( IPA). Rio de Janeiro: unknown municipality, 25 February 1826 (fl.), W. J . Burchell 2605 ( K). Mun. Duque de Caxias , 11 February 1939 (fr.), B . Lutz? ( R). Mun. Guapimirim, 25 March 1992 (fr.), S. V. A . Pessoa 613 ( BHCB, RB). Mun. Magé , 1883 (fl.), M . Palma s.n. ( R139896 ). Mun. Petrópolis, February 1938 (fl.), B . Lutz 1070 ( R); ibidem, February 1938 (fl.), B . Lutz 1054 ( R); ibidem, no date (fr.), D.Sucre 10760 ( RB); ibidem, 5 January 1950 (fl.), L. E . Mello-Filho 989 ( R); ibidem, 5 January 1950 (fl.), L. E . Mello-Filho 994 ( R) .

Figures

FIGURE 19. Representative specimens of Myrcia sect. Eugeniopsis: Myrcia gaudichaudiana (Folli 1466 [RB]).

FIGURE 20. Distribution of Myrcia gaudichaudiana (triangles) and Myrcia tenondeporan (circles). Solid lines represent the boundaries of South American countries and Brazilian states. The grayscale reflects elevation.