Myrciaria cambuca Costa-Lima & E. C. O. Chagas 2019, sp. nov.
Creators: name: Costa-Lima, James Lucas Da
name: Chagas, Earl Celestino De Oliveira
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Myrciaria
Myrciaria cambuca

description: 1. Myrciaria cambuca Costa-Lima & E.C.O.Chagas, sp. nov. (Figure 1A–E).   
 Myrciaria cambuca is similar to M. tenella (De Candolle 1828: 272) Berg (1856: 328), but differs by the young branches with tomentose to hirsute (vs. pubescent to puberulent) indumentum, with longer trichomes 2–3 (vs. 0.1–0.2) mm long, leaf blades ovate (vs. elliptic), rounded (vs. acute to cuneate) at base, recurved (vs. revolute) at margin, and pilose (vs. glabrous) abaxially, inflorescences with 2 (vs. 3) flowers, and calyx lobes and petals pilose (vs. glabrous) abaxially.   
 Type: — BRAZIL. Alagoas: Mun. Maceió, Serra da Saudinha, Fazenda Cela, 20 October 2007 (fl, fr), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] 60 (holotype MAC!, isotypes ASE, CEPEC, HUEFS, IPA, JPB, UFRN, W).   
Small shrubs, 0.5–1.5(–3) m tall; bark exfoliating; branches pilose to hirsute when young, pilose when older, covered by short and long trichomes, longer trichomes 2–3 mm long, castaneous, shorter trichomes 0.1–0.2 mm long, hyaline to castaneous; internodes 0.8–2 cm long. Leaves opposite; petioles 1.5–2 mm long, hirsute to pilose; leaf blades 1.1– 3.5 × 0.6–1.5 cm, ovate, membranaceous to chartaceous, visible glandular dots present on both surfaces, concolorous, glabrescent to glabrous adaxially, strigose abaxially, covered by trichomes 2–3 mm long, castaneous; base rounded; apex acuminate and mucronate; margin recurved; the midrib prominent in a channel adaxially, prominent abaxially, covered by trichomes 2–3 mm long, castaneous, the secondary veins 8–12 per side, alternately arranged, visible on adaxial surface, the marginal vein 0.5–1 mm from the margin. Inflorescences cymose, axillary, 2-flowered, flowers subsessile; bracteoles fused at the base, rounded to ovate, ca. 1 × 1 mm, pubescent to glabrous, margins ciliate; flower buds 2.2–3 × 0.8–1 mm, obovate, covered by trichomes 0.3–0.5 mm long, hyaline; calyx lobes 4, 1.5–2 × 1.8–2 mm, rounded, pilose abaxially, glabrous adaxially, caducous after the anthesis; calyx tube 1–1.5 mm long, glabrous; hypanthium extended 2–3 mm beyond the ovary, circumscissile at the base and deciduous as a unit with the perianth, pilose; petals 4, 1.5–2 × 0.8–1 mm, obovate, sparsely covered by hyaline trichomes 0.2–0.3 mm long abaxially, glabrous adaxially, margins ciliate; stamens ca. 50, filaments 5–6 mm long, anthers 0.1–0.2 × 0.05–0.1 mm, elliptic, eglandular; staminal ring ca. 2 mm diam., covered by hyaline trichomes; style 6–8 mm long, pubescent, covered by hyaline trichomes, stigma punctiform, papillose; ovary 2-locular, ovules 2 per locule. Fruits 1–1.5 cm diam., subglobose, glabrous, reddish when ripe. Seeds 1–2, 5–6 mm diam., globose, creamy; embryo with cotyledons fleshy, connate, the radicle inconspicuous.  
 Etymology: —The epithet refers to a common name of this species, “cambucá,” which is also applied to other Myrtaceae that occur in coastal areas of northeastern Brazil.   
 Distribution and habitat: — Myrciaria cambuca is endemic to the Brazilian Atlantic Forest and occurs in coastal forests from the state of Paraíba to Espírito Santo. This species is common in the subcanopy of restinga forest and lowland semideciduous seasonal forest, but also grows in open vegetation, such as tabuleiro savanna, but in the shade.   
 Conservation status: —Despite the large EOO on the coast of eastern Brazil (slighlty over 136,000 km 2), the known AOO of Myrciaria cambuca is small (i.e., 120 km 2), especially because this species occurs in discontinuous and highly fragmented areas. Considering the small AOO, we opted for initially categorizing this species as Endangered (EN) based on IUCN (2017) criteria B2ab(i, ii, iii). Myrciaria cambuca occurs in historically degraded areas, where some of the first places in Brazil were urbanized since its colonization. Currently, urban expansion in the country continues and is one of the main threats to this species, along with the cultivation of monocultures, such as sugarcane plantations, and the invasion of alien species in coastal environments, such as the palm tree Elaeis guineensis Jacquin (1763: 280). Some subpopulations of Myrciaria cambuca were found in protected areas: Reserva Particular do Patrimônio Natural (here referred to as RPPN) Sabiá and RPPN Santa Rita (both in Alagoas), RPPN Estação Vera Cruz (in Bahia), and RPPN Fazenda Tabatinga (in Pernambuco).   
 Paratypes: — BRAZIL. Alagoas: Mun. Coruripe, Usina Coruripe, Fazenda Capiatã, 22 March 2011 (fl), E. C. O. Chagas, M. C. S. Mota [as Chagas-Mota] & W. T. C. C. Santos 10443 (MAC!); ibidem, estrada para a fazenda Capiatã, 10º03’21’’S, 36º16’09’’W, 110 m, 10 April 2012 (fl bud), J. E. Q. Faria & V. G. Staggemeier 2605 (HUFSJ, RB!, UB); ibidem, 10 April 2012 (fl bud, fr), J. E. Q. Faria & V. G. Staggemeier 2608 (HUFSJ, RB!, UB); ibidem, Fazenda Capiatã A, 10º12’56’’S, 36º17’56’’W, 15 June 2013 (fl), R. P. Lyra-Lemos et al. 13626 (MAC!); ibidem, Mata Rio das Pedras, 25 September 1999 (fl bud, fl, fr), A. M. Amorim et al. 3116 (HUEFS!, MAC!); Mun. Marechal Deodoro, APA de Santa Rita, 5 May 2005 (fl bud), R. P. Lyra-Lemos et al. 8897 (MAC!); Mun. Paripueira, RPPN Sabiá, 29 August 2009 (fl), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] & V. G. Ramalho 5224 (MAC!); Mun. São Miguel dos Campos, Mata da Fábrica CIMPOR, 21 August 2007 (st), I. A. Bayma 982 (MAC!); Mun. Teotônio Vilela, Fazenda dos Pacheco, 20 July 2012 (fr), I. A. Bayma & R. C. Pinto 2404 (MAC!); ibidem, Usina Seresta, Madeiras, 3 October 2009 (st), E. C. O. Chagas & M. C. S. Mota [as Chagas-Mota] & V. G. Ramalho 5928 (MAC!). Bahia: Mun. Itamaraju, ca. 5 km a W de Itamaraju, 20 September 1978 (fl), S. Mori et al. 10733 (CEPEC!, NY!, RB!); Mun. Itanagra, road from Itanagra to Subaúma, 8 km W of Itanagra, 50 m, 27 May 1981 (fl bud), S. A. Mori & B. M. Boom 14127 (CEPEC!, NY – 2 sheets!); Mun. Porto Seguro, Monte Pascual [sic], 3 October 1966 (fl), R. P. Belém & R. S. Pinheiro 2707 (CEPEC!); ibidem, estrada que liga Eunápolis a Porto Seguro, RPPN Estação Vera Cruz, 16º25’9’’S, 39º12’8’’W, 50–100 m, 13 October 2006 (fr), A. M. Amorim et al. 6455 (BHCB, CEPEC!, NY!, RB!). Espírito Santo: Mun. São Mateus, km 6 da Rodovia BR-381, ligando São Mateus a Nova Venécia, 4 December 1994 (fr), J. R. Pirani et al. 3354 (SPF).   
 Paraíba: Mun. Serraria, Fazenda Serrote, 17 April 1953 (fl), L. P. Xavier s.n. (JPB 1719!, RB 374976!); Mun. João Pessoa, Mangabeira, Jacuapé, 14 May 1993 (fl bud, fl), O. T. Moura 996 (JPB!, RB!); ibidem, 7 July 1993 (fr), O. T. Moura 1029 (JPB!, RB!); ibidem, mata ciliar do Rio Cabelo, 47 m, 12 May 2011 (fr), L. A. Pereira & E. C. O. Chagas 244 (JPB!); Mun. Santa Rita, Reserva Legal do Pau Brasil, Usina Miriri, 13 May 2011 (fr), P. C. Gadelha Neto et al. 2937 (JPB!). Pernambuco: Mun. Goiana, RPPN Fazenda Tabatinga, 7º36’17’’S, 34º49’05’’W, 10 m, 25 May 2009 (fr), B. S. Amorim & A. Alves-Araújo 456 (RB!, SPF, UFP); ibidem, 7º36’22’’S, 34º49’14’’W, 15 August 2010 (fr), B. S. Amorim 670 (ASE, UFP); Mun. Igarassu, Mata de Macacos, 7º46’44’’S, 35º00’22’’W, 53 m, 14 March 2009 (fr), B. S. Amorim et al. 438 (HUEFS!, UFP!); Mun. Recife, Jardim Botânico do Recife, 8º4’43.16’’S, 34º58’7.54’’W, 19 April 2010 (fr), B. S. Amorim 649 (MAC!, RB!, UFP); Mun. Sirinhaém, Mata de Jindaí, 11 February 2004 (fl, fr), M. Oliveira & A. A. Grilo 1542 (IPA, MAC!, RB!, UFP!); Mun. Tamandaré, Rio Formoso, 28 May 2009 (fr), B. S. Amorim & A. Alves-Araújo 462 (NY!, UFP!). Sergipe: Mun. Estância, Povoado Fonte Nova, 11º10’18’’S, 37º28’52’’W, 17 September 2010 (st), C. Calazans et al. 312 (ASE); Mun. Itaporanga d’Ajuda, 6 May 2014 (st), M. L. G. C. Tavares 37 (ASE); ibidem, Mata Rio Fundo, 11º04’29’’S, 37º19’44’’W, 1 March 2016 (fl), J. P. Santana 490 (ASE); ibidem, Fazenda Trapsa, 28 February 2011 (fl), J. P. Souza-Alves 29286 (ASE); Mun. Santa Luzia do Itanhi [Santa Luzia do Itanhy], ca. 2 km do distrito de Crasto, 9 October 1993 (fr), S. C. Sant’Ana et al. 421 (ASE, CEPEC!, NY!); ibidem, 15 September 1995 (fl), M. F. Landim et al. 628 (ASE, UB); Mun. Salgado, Sítio Gameleiro, 10 March 1982 (fl), E. Carneiro 314 (ASE); ibidem, Sítio Sr. do Bonfim, 13 April 1983 (fl), E. Carneiro 673 (ASE); Mun. São Cristóvão, 26 May 1999 (fl), A. Cruz & E. Santos 104 (ASE, MAC!).   
 Discussion: — Myrciaria cambuca presents morphological affinities with Myrciaria tenella, especially because these species inhabit the same coastal environments and have a shrubby habit and small leaf blades. Features that differentiate them are listed in the diagnosis. Myrciaria cambuca can also be confused with Myrciaria glomerata Berg (1857: 365), which occurs in semideciduous seasonal forests in the states of Minas Gerais and Pará (Sobral 2006, BFG 2015), especially because of the type of indumentum on the branches and leaves, and the conspicuous secondary veins. However, M. cambuca is a small shrub (vs. tree) with shorter leaf blades (1.1–3.5 vs. 6–10.8 cm long) that are ovate (vs. elliptic to elliptic-lanceolate), rounded (vs. attenuate) at base, recurved (vs. revolute) at margin, glabrous (vs. glabrescent) adaxially and pilose (vs. tomentose) abaxially, inflorescences with 2 flowers (vs. more than 3 flowers), and glabrous (vs. pilose) mature fruits.   
 Most of the specimens of Myrciaria cambuca have been identified as M. ferruginea, with which it shares only the axillary flowers in glomerulate arrangements, and leaf blades apiculate at the apex (see Berg 1859: 597). Myrciaria cambuca can be distinguished for its patent branches (vs. erect in M. ferruginea), pilose to hirsute (vs. dense ferruginoustomentose), petiole 1.5–2 mm long (vs. leaves sessile), leaf blades membranaceous to chartaceous (vs. coriaceous [as rigidis]), ovate (vs. oblong), acuminate (vs. acute to truncate) at apex, rounded (vs. truncate) at base, concolor (vs. discolor), green (vs. canescent-green) adaxially, glabrous (vs. puberulous) adaxially, strigose (vs. glabrescent) abaxially, venation visible until 3 rd –4 th order (vs. inconspicuous), and midrib hirsute to pilose (vs. dense tomentose).   
 The type of Myrciaria ferruginea is a specimen of the collection Sellow s.n. at the herbarium of the Botanischer Garten und Botanisches Museum Berlin-Dahlem (B) and was destroyed in the World War II. No duplicates of this collection were found in any other herbaria so far and, in accordance with Article 9.8 of the International Code of Nomenclature for algae, fungi, and plants (Turland et al. 2018), a neotype for M. ferruginea needs to be designated. Furthermore, unfortunately, when the first author analyzed the collection of Myrtaceae at the Field Museum of Natural History (F), no Myrtaceae negatives were found in their Berlin Negatives collection. If there were any available, a negative of the type of M. ferruginea could have been used to confirm that other Myrciaria specimens are taxonomically congruent with the type specimen. In the 1980s, M. Sobral wrote in the label of the specimen Santos 1521 at CEPEC that this was the neotype of Myrciaria ferruginea, but this has not been published and, in addition, this specimen does not match the protologue (i.e., Berg 1859). Even so, the name M. ferruginea has been widely applied to Myrciaria species with rusty indumentum, especially from the Atlantic Forest, including the material of the new species described here.
description: Published as part of Costa-Lima, James Lucas Da & Chagas, Earl Celestino De Oliveira, 2019, Two new Myrciaria (Myrtaceae) from the Brazilian Atlantic Forest, pp. 37-43 in Phytotaxa 399 (1) on pages 38-40, DOI: 10.11646/phytotaxa.399.1.4, http://zenodo.org/record/13712950