Eugenia canumana M.A.D.Souza & Sobral, 2022

Souza, Maria Anália Duarte De, Sobral, Marcos & Amorim, Gabriela, 2022, Six new species of Eugenia (Myrtaceae) from Amazonian Brazil, Phytotaxa 536 (3), pp. 197-212 : 199-200

1. Eugenia canumana M.A.D.Souza & Sobral , sp. nov.

Type:— BRAZIL. Amazonas: Maués , rio Abacaxis , igapó, 4°19’28” S, 58°37’ 56” W, 7 August 2015, A.S.S. Holanda, L.O. Demarchi, R. Braga-Neto, Y.O. Feitosa & A.T. Melo 814 (holotype INPA!, isotype HUFSJ!). Figure 1 .

Diagnosis:—This species is morphologically related to Eugenia laevis O. Berg (1855 –1856: 177; type image HAL 0081699) but differs by its twigs with cataphylls (versus devoid of cataphylls in E. laevis ), longer pedicels (8–16 mm vs. about 4 mm) and glabrous flowers (vs. minutely pilose); due to the presence of cataphylls it also vegetatively reminds E. brachyblastiflora Barrie et al. ( Barrie et al. 2016: 335; type images MO 6751836, MO 6751837), from which it differs by its shorter petioles (2.5–3 mm vs. 8–12 mm in E. brachyblastiflora ), smaller blades (42–78 × 19–40 mm vs. 70–160 x 40–80 mm) with acute apex (vs. acuminate in 5–12 mm) and less than 15 lateral veins (vs. 15–22), flowers with staminal ring to 1 mm in diameter (vs. about 4 mm) and smaller fruits (to 6 mm in diameter vs. 18–25 mm).

Description:—Tree (height not recorded). Plants glabrous. Twigs applanate, drying grey, slighlty longitudinally striate, with decussate triangular cataphylls 1–1.5 × 0.8–1 mm at their bases, these in 5 to 15 series, frequently deciduous (occasionally the cataphylls seem to proliferate very densely in an apparently tanatological way); internodes 20–25 × 1–2 mm. Leaves with petioles 2.5–3 × 1 mm, adaxially canaliculate and drying black; blades elliptic, 42–78 × 19–40 mm, 1.9–2.4 times longer than wide, drying dull brown or dull dark green, slightly discolorous, lighter abaxially; glandular dots 3–8/mm², perceptible and slightly raised on both sides and sometimes darker than the surface; base widely cuneate or cuneate; apex acute to widely acute; midvein adaxially impressed to somewhat plane; lateral veins 10–13 at each side, leaving the midvein at angles about 60°, more or less visible and slightly raised on both sides, the secondary lateral veins and higher order venation usually scarcely visible; intramarginal vein 1.2–3 from the margin, sometimes a second vein visible 0.2–0.3 mm from the margin, the margin itself visibly revolute and with a yellowish girdle to 0.2 mm wide. Inflorescences axillary or ramiflorous, fasciculiform, the axis to 3 × 1 mm, with 2–4 flowers, frequently with a series of triangular cataphylls as the twigs (sometimes also with the apparently tanatological condition of proliferation which occur there); bracts deltoid, to 0.5 × 0.3 mm, persisting at anthesis; pedicels 8–16 × 0.3–0.4 mm; bracteoles triangular, 0.7–0.8 × 0.5 mm, persisting after anthesis, with cilia to 0.1 mm; flower buds to 6 × 4 mm, the ovaries to 1.5 × 1 mm; sepals four, about the same size, hemispherical, 1.2–2 × 2 mm; petals not seen; stamens not seen; styles not seen; staminal ring to 1 mm in diameter; calyx tube absent; ovary with two internally glabrous locules and 14 to 15 ovules per locule. Fruits globose, 5–6 mm in diameter; seeds not examined.

Distribution, habitat and phenology:—presently known only from the municipalities of Borba and Maués, in the central-southern portion of the state of Amazonas, where it was collected in flooded forest (“igapó”); flowers were collected in April and fruits in August.

Affinities:—This species is morphologically related to the Central American Eugenia brachyblastiflora and E. laevis , with which it is compared in the diagnosis. Considering its fasciculiform inflorescences, it may be assigned to Eugenia section Umbellatae O. Berg (1855 –1856: 204), according to the sectional classification of Mazine et al. (2016; see also Mazine et al. 2018 for a more detailed treatment of section Umbellatae ).

Conservation status:—There are presently recorded respectively about 2,660 and 3,330 collections from the municipalities of Borba and Maués, with areas of respectively 44,200 km ² and 39,991 km ², resulting in 0.06 collection/ km² for Borba and 0.08 collection/km² for Maués, in both cases a poor sampling (see Material and Methods); so, the fact that only two collections of this species are presently known may not be taken as suggestive of its rarity. In the spite of any additional information of possible threats for the species, we suggest that this species be scored as DD (Data Deficient) according to IUCN conservation criteria ( IUCN 2019: 78).

Etymology:—The epithet is derived from river Canumã, where the type was collected.

Paratype:— BRAZIL. Amazonas : Borba , Rio Canumã, lugar Pataná, 2 April 1960, W. Rodrigues 1621 (INPA!) .

Figures

FIGURE 1. Eugenia canumana. Holotype (scale = 50 mm). Insert: detail of cataphylls at the base of one twig (scale = 10 mm).