Eugenia pipensis A. R. Lourenço & B. S. Amorim, 2013

Lourenço, Ana Raquel Lima, Amorim, Bruno S. & Alves, Marccus, 2013, Eugenia pipensis, a new species of Eugenia sect. Umbellatae (Myrtaceae) from northeastern Brazil, Phytotaxa 104 (1), pp. 30-34 : 31-33

Eugenia pipensis A. R. Lourenço & B. S. Amorim , sp. nov. ( Figs. 1 , 2 )

Type:— Brazil. Rio Grande do Norte, Mun. Tibau do Sul, Praia da Pipa , Restinga de dunas, 06º13'43.7"S, 35º03'31.7"W, 7 April 2012, fl., fr., A. R. Lourenço 436 (holotype: UFP!; isotypes: JPB!, K!, NY!) .

Tree up to 6m tall, inflorescence a fascicle on foliate or defoliate nodes, closely related to E. astringens but differing in having the calyx lobes 2.5 to 3 mm long and glandulose-verruculose fruits.

Trees 5–6 m tall, glabrous; bark dark brown, no exfoliating rhytidome. Leaf blade elliptic or obelliptic, 6.8– 8.6 × 3.7–4.5 cm, glabrous on both surfaces, chartaceous, discolored, densely covered with oil glands visible on the abaxial surface; apex obtuse, subacute or shortly rounded acuminate, base cuneate; midvein prominent or slightly raised above, prominent below; lateral veins visible on both surfaces, 6–8 pairs, marginal vein 2–4 mm from the margin. Petiole 7–11 mm long, glabrous. Inflorescence a fascicle on foliate or defoliate nodes, sometimes more than one arising from the same point, each fascicle with 1–3 pairs of flowers, rachis up to 4 mm long; floral bracts deltoid, up to 1 mm long, deciduous; pedicels 4–6 mm long; bracteoles deltoid, free, ciliate, 1.6–2 × 1.6–2 mm, persistent. Flower bud not seen; hypanthium not prolonged beyond the ovary, glabrous; sepals slightly unequal, rounded, 2.5 × 3 mm, apex rounded to truncate; petals not seen, mostly deciduous after anthesis; filaments 3–7 mm long, anthers 0.5–1 mm long; staminal disk 3 mm diam., glabrous; style not seen, mostly deciduous after anthesis; ovary glabrous internally, bilocular, 10–14 ovules per locule. Fruit elliptical or slightly elliptical, 12–16 × 10–13 mm, glandulose-verruculose, dark purple to black at maturity with persistent calyx; seeds 1, 10– 12 mm diam., coriaceous coat; embryo “c” shaped, flattened, cotyledons fully fused.

E. pipensis is morphologically related to Eugenia astringens Cambessédes (1833:361) and they resemble each other in vegetative and reproductive gestalt (bracts and bracteoles). E. astringens is distributed along the Atlantic coastal forest of Brazil (Sobral et al. 2012) and the plasticity of its morphological characters overlaps with some morphological characters of E. pipensis , which is restricted to the northern limit of the Atlantic Forest. The species differ in diagnostic reproductive characters as the length of the calyx lobes that are up to 1mm long, and fruit surface that is smooth, in E. astringens ( Legrand & Klein 1969; Amorim & Alves 2011; Sousa & Morim 2008; Lourenço & Barbosa 2012; Sobral et al. 2012b) and 2.5 to 3 mm long and glanduloseverruculose, respectively, in E. pipensis . Considering Berg (1856) and Mazine (2006), E. pipensis fits the circumscription of Eugenia sect. Umbellatae .

Distribution, habitat and phenology — Eugenia pipensis is known only from the state of Rio Grande do Norte, northeastern Brazil. It was found in vegetation locally called “restinga” which is open to dense forest on quaternary sandy marine sediments in coastal plains, common along the Brazilian coast and considered an ecosystem associated with the Brazilian Atlantic coastal forest ( Stehmann et al. 2009). The area has an open forest physiognomy with widely spread, 3–5 m tall trees and shrubs, and is extremely at risk of further disturbance related to urban expansion.

Conservation status —Following the IUCN criteria, Eugenia pipensis is considered critically endangered (CR), based on criteria A4 (an observed population reduction in the past and future) and D (very small or restricted population <50 mature individuals).

Etymology —The epithet refers to the locality where the species was found, Pipa Beach in the state of Rio Grande do Norte in northeastern Brazil.

Additional specimens examined — BRAZIL. Rio Grande do Norte: Tibau do Sul, Praia de Pipa, Atlantic Rain Forest , Restinga Forest , 06º13'43.7"S, 35º03'31.7"W, 27 september 2011, fr., A. R. Lourenço, M. Alves, A. Alves-Araújo & A.A.M. Araújo 422 (UFP); Ibid. 25 july 2011, fr., M. Alves & S. Heald 11-003 (UFP) .

Figures

FIGURE. 1. A–D. Eugenia pipensis. A. Fruiting branch. B. Detail of fasciculate inflorescences. C. Detail of flower. D. Cross section of ovary. Illustration by Regina Carvalho, based on A. R. Lourenço 436 (UFP).

FIGURE. 2. A–D. Eugenia pipensis. A. Flowering branch. B. Fruiting branch. C. Detail of fasciculate inflorescences. D. Detail of immature fruit. Ana Raquel Lourenço, based on A. R. Lourenço 436 (UFP) (A–C) and A.R. Lourenço et al. 422 (UFP) (D).