Myrciaria una Costa-Lima & E.C.O.Chagas, 2019

Costa-Lima, James Lucas Da & Chagas, Earl Celestino De Oliveira, 2019, Two new Myrciaria (Myrtaceae) from the Brazilian Atlantic Forest, Phytotaxa 399 (1), pp. 37-43 : 41-42

2. Myrciaria una Costa-Lima & E.C.O.Chagas , sp. nov. ( Figure 1F–I ).

Myrciaria una resembles M. cambuca , but differs being a treelet or tree (vs. small shrub) with longer internodes (3–6 vs. 0.8–2 cm long), longer (3.5–11.5 vs. 1.1–3.5 cm long), elliptic to elliptic-lanceolate (vs. ovate) leaf blades, a midrib covered by long trichomes on both surfaces (vs. only abaxially), secondary veins in 11–22 (vs. 8–12) pairs, visible on both surfaces (vs. only abaxially), inflorescences with up to 5 flowers (vs. with 2 flowers), papillose (vs. glabrous) bracteoles, ovate (vs. obovate) flower buds, bracts, calyx lobes, and petals verrucose (vs. non-verrucose) abaxially, and fruits purplish to blackish (vs. reddish) when ripe, pubescent (vs. glabrous).

Type: — BRAZIL. Alagoas: Mun. Ibateguara, Coimbra, Grota da Burra, 29 March 2011 (fl), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 10683 (holotype MAC – mounted on 2 sheets!, isotypes EAC, HUEFS, IPA, UFRN, W).

Treelets to trees, 4–7 m tall; bark exfoliating; branches hirsute to pubescent when young, pubescent to glabrescent when older, covered by long and, sometimes mixed with short trichomes, longer trichomes 1.8–2 mm long, hyaline to castaneous, shorter trichomes 0.1–0.2 mm long, hyaline to castaneous; internodes 3–6 cm long. Leaves opposite; petioles 1.5–2.5 mm long, hirsute to pubescent; leaf blades 3.5–11.5 × 1.3–5.1 cm, elliptic to elliptic-lanceolate, rarely obovate, membranaceous to chartaceous, visible glandular dots present on both surfaces, concolorous, sometimes shiny adaxially, glabrous adaxially, pubescent to glabrescent abaxially, covered by trichomes 1.8–2 mm long, hyaline or castaneous; base rounded; apex cuspidate, sometimes acuminate or caudate, rarely rounded, mucronate; margin recurved; the midrib prominent in a channel adaxially, prominent abaxially, covered by trichomes 1.5–2 mm long on both surfaces, hyaline or castaneous, the secondary veins 11–22 per side, alternately arranged, visible on both surfaces, the marginal vein 1–1.5 mm from the margin. Inflorescences cymose, axillary, 1–5-flowered, flowers subsessile; bracteoles fused at the base, rounded to ovate, 1–3 × 1.5–4 mm, verrucose and pilose abaxially, glabrous adaxially, margins ciliate; flower buds 4.5–5 × 2–2.5 mm, ovate, covered by trichomes 1–1.2 mm long, hyaline; calyx lobes 4, 4.5–5 × 2–2.5 mm long, ovate, verrucose and pilose abaxially, glabrous adaxially, caducous after the anthesis; calyx tube 1.5–2 mm long, glabrous; hypanthium extended 3–4 mm beyond the ovary, circumscissile at base, deciduous as a unit with the perianth, tomentose; petals 4, 2–3 × 2–2.5 mm, rounded to obovate, verrucose and sparsely covered by hyaline trichomes 0.2–0.3 mm long abaxially, glabrous adaxially, margins ciliate; stamens ca. 50, filaments 7–8 mm long, anthers 0.3–0.5 × 0.2–0.3 mm, elliptic, eglandular; staminal ring 1.5–2 mm diam., covered by hyaline trichomes; style 10–12 mm long, pubescent, covered by hyaline trichomes, stigma punctiform, papillose; ovary 2-locular, ovules 2 per locule. Fruits 1.8–2 cm diam., subglobose, pubescent with hyaline trichomes, purplish to blackish when ripe. Seeds 1–2, 5–6 mm diam., globose, creamy; embryo with cotyledons fleshy, connate, the radicle inconspicuous.

Etymology: —The epithet derives from the word “una ” in the Old Tupi language, which means black ( Barbosa 1951); it is used here because the species has purplish to blackish fruits when ripe, while the ripe fruits of most species of the genus are yellowish to reddish.

Distribution and habitat: — Myrciaria una is endemic to the Atlantic Forest domain and has been recorded in the states of Ceará, Pernambuco, Alagoas and Bahia, where it occurs in lowland and submontane forests, commonly in the subcanopy.

Conservation status: —Like Myrciaria cambuca , M. una has a large EOO in the Atlantic Forest of northeastern Brazil (slightly over 159,000 km 2), small AOO (i.e., 80 km 2) and occurs in discontinuous and highly fragmented environments. Thus, we chose to initially categorize this species as Endangered (EN) based on IUCN (2017) criteria B2ab(i, ii, iii). The main threats, in addition to the historical fragmentation of the coastal forests of northeastern Brazil, are urban expansion, sugar cane plantations, and extensive cattle ranching. Among the examined material and collection localities, only three subpopulations of Myrciaria una have been collected in protected areas: Estação Ecológica de Tapacurá (Pernambuco), Estação Ecológica de Murici and Reserva Biológica de Pedra Talhada (both in Alagoas).

Paratypes: — BRAZIL. Alagoas: Mun. Flexeiras, Fazenda São João , 16 August 1968 (fl), M. T. Monteiro 22702 ( HST!, IPA) ; Mun. Ibateguara, Alto Guzerá, margem da estrada, 16 December 2003 (fl), M. Oliveira & A. A. Grilo 1495 ( IPA, MAC!, RB!) ; ibidem, Mata da Cobra , 8 April 2003 (fl), M. Oliveira & A. A. Grilo 1349 ( IPA, MAC!, RB!, UFRN!) ; ibidem, 29 March 2011 (fl, fr), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 10689 ( MAC!) ; Mun. Mar Vermelho, Fazenda Canadá, 8 May 2009 (fl), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] et al. 3587 ( MAC!) ; ibidem, 29 January 2010 (st), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 7336 ( MAC!) ; Mun. Murici, [Estação Ecológica de Murici], Serra do Ouro , 17 April 2009 (fl, fr), E. C. O. Chagas, M. C. S. Mota [as Chagas-Mota] & A. I. L. Pinheiro 2702 ( MAC!) ; Mun. Palmeira dos Índios, Serra das Pias, Fazenda Fortaleza, 27 March 2009 (fl), E. C. O. Chagas, M. C. S. Mota [as Chagas-Mota] & S. P. Gomes 2379 ( MAC – 2 sheets!) ; ibidem, 20 May 2009 (fr), S. P. Gomes s.n. ( MAC 40008 !) ; ibidem, 18 October 2009 (fl, fr), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 6305 ( MAC – 2 sheets!) ; ibidem, 18 October 2009 (fr), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 6327 ( MAC!) ; Mun. Quebrangulo, Reserva Biológica Pedra Talhada, Pedra D’Água, 7 October 2010 (fr), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 8991 ( MAC!) ; ibidem, trilha após Pedra Talhada, 24 April 2012 (fl), B. S. Amorim et al. 1513 ( JPB!, MO, NY!, UFP) ; ibidem, 24 April 2012 (fr), B. S. Amorim et al. 1515 ( JPB!, NY!, UFP) ; Mun. Viçosa, Fazenda Jussara, 28 January 2010 (st), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 7087 ( MAC!) ; ibidem, 25 November 2010 (st), E. C. O. Chagas, M. C. S. Mota [as Chagas-Mota] & J. M. Ferreira 9604 ( MAC!) . Bahia: Mun. Esplanada, Algodão , 120 m, 22 May 2013 (st), A. V. Popovkin & J. C. Mendes 1439 ( HUEFS!) . Ceará: Mun. Guaramiranga, Serra de Baturité , Morro Alto Redondo, 10 August 1993 (fl), M. R. L. Oliveira 60 ( EAC, RB!) ; ibidem, Sítio Cana Brava, 27 November 1993 (st), M. R. L. Oliveira s.n. ( EAC 23086 !) ; ibidem, 7 January 1994 (st), M. R. L. Oliveira s.n. ( EAC 21160 !) . Pernambuco: Mun. Bezerros, Parque Ecológico Serra Negra, 12 June 2009 (fl), B. S. Amorim et al. 483 ( RB!, UFP) ; Mun. Paudalho, Aldeia, Mata km 17, 7º54’31’’S, 35º2’49’’W, 26 July 2010 (fl), B. S. Amorim et al. 660 ( UFP, UNIP) ; Mun. Recife, Mata de Macacos , 19 June 1950 (fl), C. G. Leal & O. A. Silva 107 ( RB!) ; ibidem, Dois Irmãos, Macacos, 19 June 1950 (fl), Andrade-Lima 50515 ( IPA) ; Mun. São Lourenço da Mata, Estação Ecológica de Tapacurá, Mata do Camucim , 17 November 2010 (fl), B. S. Amorim et al. 687 ( UFP!) .

Discussion: — Myrciaria una is morphologically similar to M. cambuca (described above), especially for the indumentum on the branches and leaves, and the conspicuous secondary and tertiary veins. Features that separate them are provided in the diagnosis. In addition, these species do not co-occur— M. una inhabits areas of forest with more humidity and shade, as compared to M. cambuca –, although they both grow in coastal forests.

Myrciaria una can also be confused with M. glomerata , but its leaf blades are rounded (vs. attenuate) at base, recurved (vs. revolute) at margins, glabrous (vs. glabrescent) adaxially, and pubescent (vs. tomentose) abaxially, with venation visible to the 3 rd –4 th order (vs. inconspicuous), the midrib hirsute to pubescent (vs. dense tomentose), and bracts, calyx lobes, and petals verrucose (vs. non-verrucose) abaxially. Some specimens of M. una have been identified as M. ferruginea , but can be distinguished by many of the characteristics presented in the discussion concerning M. cambuca . Other specimens were treated by Amorim & Alves (2012) as M. glazioviana ( Kiaerskou 1893: 180) G.M.Barroso ex Sobral (2006: 137) , a species that is native in the Southeast Region of Brazil ( Sobral 2006), with thick branches (vs. slender in M. una ), tomentose (vs. hirsute to pubescent), longer leaf blades (8–12 vs. 3.5–11.5 cm long), auriculate (vs. rounded) at base, revolute (vs. recurved) at margins, with more than 30 (vs. 11–22) secondary veins per side, and yellowish (vs. purplish to blackish) fruits when ripe.

Figures

FIGURE 1. Myrciaria cambuca. A. Flowering branch, in sicco (scale: 2 cm). B. Habit. C. Inflorescences arrangement. D. Flowers at anthesis. E. Mature fruits. Myrciaria una. F. Flowering branch, in sicco (scale: 5 cm). G. Flowering branch, in vivo. H. Inflorescences arrangement. I. Fruits, with detail of the mature fruit.All photographs by the authors.