Eugenia paradisiaca Giaretta, 2021

Giaretta, Augusto, Lucas, Eve & Sano, Paulo Takeo, 2021, Taxonomic monograph of Eugenia sect. Schizocalomyrtus (Myrtaceae: Myrteae), a group within Eugenia with unusual flowers, Phytotaxa 524 (3), pp. 135-177 : 161-164

7. Eugenia paradisiaca Giaretta , sp. nov.

Type:— BRAZIL. Rio de Janeiro: Guapimirim, Estação Ecológica Estadual de Paraíso , Serra Queimada , Água Comprida , 22º26’/ 22º32’ S, 42º50’/ 42º56’ W, 21 November 1991, fl., H. C. de Lima et al. 4347 (holotype: RB! [00558771-2 sheets]; isotypes: CEPEC!, MBM, SPF!). ( Figure 17 ).

Eugenia paradisiaca is morphologically similar to Eugenia longohypanthiata (for alternative description see Berg (1856a: 320) under Schizocalyx pohlianus O.Berg ) but differs in having glabrous leaves (vs. leaves with sparse, abaxial pubescence near to the midvein), buds 9–11 × 8–9 mm (vs. 12–16.5 × 9–11 mm) with straight stamens (vs. curved), and the staminal whorl not splitting at anthesis (vs. deeply splitting at anthesis).

Trees ca. 12 m tall. Young leaves with appressed, brownish trichomes on the midvein and sparsely occurring on the abaxial surface, 0.2–0.4 mm long, adaxially glabrous to glabrescent. Leaves with petioles 11–17 × 1.5 mm; blades 6.5–13 × 3–5.5 cm, elliptic or sometimes obovate; bases cuneate or decurrent along the petiole; apices acuminate, 1–1.5 cm long, less often acute or obtuse; midvein sulcate adaxially; secondary veins 10–17 per side; marginal veins two, the innermost 1.5–5 mm from the margin, the outermost 0.5–1 mm from the margin. Inflorescence terminal, auxotelic, recovering of vegetative growth not observed; bracts 2 × 1.5 mm, oblong; rachis 3–21 mm long; 1–3 pairs of lateral axes emerging from the rachis, each lateral axis with a 3–flowered dichasial arrangement, middle flower sessile or with pedicel up to 30 mm long, lateral flowers with pedicels 5–25 × 0.5–0.8 mm, glabrous; lateral axes 18–42 mm long (to the first pair of bracteoles scar), flattened, glabrous; up to one rachis per axil; bracteoles not seens, deciduous before anthesis. Flower buds 9–11 × 8–9 mm, obovate, calyx lobes partially fused but free at the tip leaving an aperture of ca. 1 mm diameter, tearing regularly at anthesis in 4 lobes, 4–8 × 4–9 mm, glabrous outside; petals 7–12 × 7–10 mm, orbicular or spatulate; stamens straight in the bud, filaments up to 14 mm long, anthers 0.8–1.2 mm long; staminal whorls flat, 9–10 mm diameter, squared, not tearing at anthesis; style 6.5 mm long; ovary 2–locules, 14–19 ovules per locule. Fruit not seen.

Etymology:— The specific epithet is derivative from Latin ‘ paradisiacus ’ that means ‘from paradise’. It alludes to the type location, a protected area in the district of Paraíso, Rio de Janeiro, Brazil.

Distribution and habitat: — Eugenia paradisiaca is distributed in Southeastern Brazil (Rio de Janeiro), known from the Serra do Mar at elevations between 50 to 450 m ( Figure 18 ). Eugenia paradisiaca is known from forest on slopes adjacent to the coast, occurring within Ombrophilous Dense Forest in the Atlantic forest.

Phenology: —Flowers of Eugenia paradisiaca were collected in October and November ( Figure 6 ), the fruiting period is unknown.

Conservation status:— Eugenia paradisiaca is endemic to Rio de Janeiro, known from a well preserved protected area (APA de Petrópolis - Estação Ecológica de Paraíso), with a restricted AOO of 8 km ². Although some populations receive environmental protection, the species range is restricted, and Rio de Janeiro has lost ca. 80% of its original vegetation ( SOS Mata Atlântica 2017) and associated habitat. The last collection of Eugenia paradisiaca was made 26 years ago and tentatively re-collection was unsuccessful suggesting its rarity. Therefore, it is suggested that this species should be rated as Critically Endangered [CR B2ab(ii, iii, iv)].

Comments:— Although Eugenia paradisiaca was not sampled in a molecular phylogeny, the fused calyx that fits the homosepalous development pattern ( Giaretta et al. 2019b) and the inflorescence with a 3-flowered dichasial arrangement are in accordance with the current morphological circumscription of Eugenia sect. Schizocalomyrtus . Eugenia paradisiaca had been identified as Calycorectes martianus , however, examination of the type of the latter species indicates instead that it is a synonym of Eugenia acutata . Further examination concluded that Eugenia paradisiaca does not fit the diagnosis of any current species and is here newly described. This species is morphologically similar to Eugenia longohypanthiata but is distinguished by the characters provided in the diagnose.

Paratype: — BRAZIL. Rio de Janeiro: Magé, Estação Ecológica de Paraíso, área do Centro de Primatologia do Rio de Janeiro , alt. 200 m a.s.l., 22 October 1984, fl., H . C . de Lima et al. 2273 ( BHCB, CEPEC!, K!, NY, RB!) .

Figures

FIGURE 6. Frequency distribution (n) of flowering (black-line triangle) and fruiting (grey-filled triangle) stages based on herbarium material of Eugenia sect. Schizocalomyrtus.

FIGURE 17. Eugenia paradisiaca. A. Leaf branchlet with flowers. B. Inflorescence and flowers buds. (A: H.C. de Lima 4347; B: H.C. de Lima 2273).

FIGURE 18. Distribution of Eugenia paradisiaca.