Mouriri arborea Gardner 1843
Creators: name: Völtz, Rafael Rosenstock
name: Goldenberg, Renato
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Melastomataceae
Mouriri
Mouriri arborea

description: 1. Mouriri arborea Gardner (1843: t. 515).
Type:— BRAZIL. Rio de Janeiro: Organ Mountains. March 1841, [fl.], G. Gardner 5704 (holotype: BM001008151; isotypes: BR0000005208715, CAS0003600, E00285685, G00328336, GH00073007, K000329670, K000329671, NY00229532, NY00229533, NY00229534, NY00522635, P01168046, R![R000010531], W0070263, W0107081). (Fig.1–2)
= Mouriri sellowiana (O.Berg) Burret (1931: 150) ≡ Aulacocarpus sellowianus O. Berg (1857: 381). Type:— BRAZIL. Habitat in Brasilia, without date [fr.], F. Sellow s.n. (holotype: B, destroyed). Lectotype (designated here):—[Icon] Aulococarpus sellowianus O.Berg. Flora Brasiliensis 14(1): t. 40. 1857. (Fig.3). syn. nov.
= Mouriri megasperma Morley (1976: 254). Type:— BRAZIL. Espírito Santo: Norte do rio Doce, mata São Gabriel, September 1950 [fr.], J.N. Vieira 72 (holotype: MIN1001858; isotypes: RB! [RB00556714], RB! [RB00541515]). syn. nov.
= Mouriri petroniana Cogn. & Saldanha (1887: t. 5). Lectotype [designated by Morley 1976: 232]— BRAZIL. Rio de Janeiro: Serra da Nova Friburgo, February 3, 1883 [fl.], J. Saldanha 7058 (lectotype: BR000000520825; isolectotypes: BR00000520858, P01168048, R! [R000168367], R! [R000168367a]).
Description:—Canopy to understory tree or treelet. Bark light-brownish-gray, fissured-scaly, fissures shallow, short, parallel to oblique, ridges flattened, scales papyraceous, rectangular or irregular; slash with the outer bark grayishbrown, soft, laminate, the inner bark light-yellow to yellow, tangential section with longitudinal streaks. Stems with young shoots reddish-brown, terete. Petioles 1.5–10.0 mm long. Leaf blade chartaceous 7.0–18.5 × 2.5–6.1 cm, elliptic, elliptic-ovate or elliptic-oblong, apex long or short acuminate or acute, base acute, obtuse or rounded, glabrous on both surfaces, venation hyphodromous in vivo and in sicco, or sometimes obscure in sicco, midrib flat or slightly grooved on the adaxial surface, angular 2-winged or rarely 2-angled on the abaxial surface. Inflorescences axillary and/or in leafless nodes, 1–2 per side, 1–3(–5) flowers per peduncle, 4.7–11.0(–18.0) mm long to base of farthest pedicel measured along the axes with 2 internodes in that length. Bracts deciduous at anthesis. Pedicels 3.5–12 mm long. Flower bud with calyx lobes nearly completely fused with the corolla protruding through a small terminal opening, when fully developed 10.0–17.0 mm long, obovoid, the calyx bursting at anthesis irregularly into 2–3 pieces or regularly into 5 pieces, the pieces breaking away or not. Sepals 6.0– 9.5 mm long, oblong, apex rounded. Petals white to yellowish in vivo, 10.0–15.0 mm long, 7.6–10.0 mm wide, ovate to elliptic or widely elliptic, apex acute or acuminate. Filaments white in vivo, 7.0–15.0 mm long. Anthers yellow in vivo, 2.9–4.6 mm long, thecae 2.1–4.5 mm long, dehiscing through a short apical slit, gland 0.3–0.8 mm long, 2.0– 3.4 mm long from apex of anther when measured from center of gland, cauda 0.3–0.8 mm long from base of anther when measured from base of gland. Ovary 4–6-locular, free-basal placentation, ovules 4–6 per placenta, style 16–23 mm long. Fruits globose or subglobose, yellow to orange when ripe, 22.1–30.8 × 18.0– 34.7 mm, with a terminal circular scar 5.0– 10.5 mm diam. or crowned with some calyx lobes. Seeds 1–4(–5) per fruit, 12.8–23 × 12.9–19.4 mm, most of the seed surface brownish, smooth, hilum basal, rotund, 6.7–10.5 × 5.0– 9.2 mm.
Selected specimens examined:— BRAZIL. Bahia: Itamaraju, Goldenberg 3063 (UPCB); Porto Seguro, Thomas 11248 (RB); Wenceslau Guimarães, Bacci 288 (CEPEC). Espírito Santo: Cachoeiro do Itapemirim, Völtz 2889 (MBM); Conceição da Barra, Pereira 7760 (VIES); Domingos Martins, Folli 6745 (RB); Guarapari, Assis 789 (HUFU); João Neiva, Kollmann 10076 (UPCB); Linhares, Siqueira 1022 (CVRD); Piúma, Pirani 3504 (NY); Santa Leopoldina, Demuner 4076 (MBML); Santa Teresa, Demuner 439 (MBML); Serra, Botelho 69 (VIES); Venda Nova do Imigrante, Hatschbach 61519 (ESA); Vila Velha, Pereira 6246 (VIES). Rio de Janeiro: Duque de Caxias, Silva 75 (RB); Guapimirim, Völtz 2297 (MBM); Nova Friburgo, Glaziou 13860 (IAC); Portella, Portella 215 (RB); Rio de Janeiro, Ribeiro 2172 (US); Santa Maria Madalena, Marquete 2387 (RB!); Saquarema, Silva 544 (RB); Silva Jardim, Fernandes 219 (RB), Teresópolis, Freire de Carvalho 651 (RB). São Paulo: Ubatuba, Völtz 2439 (MBM).
Distribution and habitat: — Mouriri arborea is endemic to Brazil, occurring along the hills and mountains of the Atlantic Coast between 13° S and 23° S. It was previously known only from the state of Rio de Janeiro (Morley, 1976), but its distribution is expanded to Bahia, Espírito Santo, and São Paulo based on our work. Goldenberg (2009) did not mention M. arborea in São Paulo state, therefore we expand the distribution of this species further south. It is a component of the canopy layer in the Brazilian Atlantic Rain Forest and it is commonly found on clay soils within submontane to montane forests up to 1000 m elevation, along the Serra do Mar mountain system, as well as mountainous regions in Espírito Santo and Bahia. In the northern limit, M. arborea also grows in the undulating plains that are covered by lowland tropical forests, known as Tabuleiro forest, and in the woodland that is associated with sandy soils, called Mussununga forests (Fig. 4).
Conservation status:— Mouriri arborea has a relatively wide geographic distribution with an extent of occurrence (EOO) of 232,106.1 km ² and an area of occupancy (AOO) of 180 km ². According to the categories and criteria established by the IUCN (2012), the species would be classified as Least Concern (LC) due to its large extent of occurrence. However, it could also be considered Endangered (EN), since its area of occupancy is smaller than 500 km ², although only one criterion is met [EN B2b(iii)]. Field observations indicate that the populations in this species are sparse, and although some of them occur in protected areas, its natural environment is fragmented and threatened by deforestation (Laurance, 2009). Therefore, we recommend M. arborea as Near Threatened (NT) because it does not meet the criteria for more seriously threatened categories.
Nomenclatural and taxonomic notes:— Mouriri megasperma was described based on only one fruiting specimen, collected to the north of Rio Doce in the state of Espírito Santo, Brazil. Morley (1976) placed the new species doubtfully on the section Olisbeoides, in Mouriri subgenus Mouriri. Still according to Morley (1976), Mouriri megasperma differed from M. arborea (from Rio de Janeiro state) in having an acute leaf apex (vs. acuminate in M. arborea), 2-angled midrib on the abaxial surface of the leaf (vs. 2-winged), larger fruits with 5 seeds (vs. apparently 1-seeded), these larger than in the former, as well as differences in some leaf anatomical features. New collections (Siqueira 1022) from the same area of the type of M. megasperma make the separation between M. megasperma and M. arborea more difficult. Although Morley (1976) described M. megasperma as having an acute leaf apex, it is clear that the type material has leaves with both acute and short-acuminate apices. Most modern samples have a 2-winged midrib (Fig. 1C) on the abaxial surface, but a few samples have a 2-angled midrib. The specimens from the type locality of M. megasperma that have flower buds and flowers undoubtedly belong to M. arborea, with some differences only in the length of the thecae. At the same time, specimens with fruit show similarities in shape and in the terminal circular scar between what would be regarded as these two species (Fig. 2F–G). Morley (1976) stated that M. megasperma had 5-seeded fruits, while M. arborea had only one seed per fruit, but a new sample of M. arborea from southern Espírito Santo [Völtz et al. 2889] shows that the number of seeds in the fruits may vary from one to four in this species. Considering the lack of consistent diagnostic characters for M. megasperma, we here propose its synonymization under M. arborea.
Mouriri sellowiana was originally described as a Myrtaceae and placed in the genus Aulacocarpus O. Berg (1856: 345) by Otto Karl Berg in the Flora Brasiliensis (Berg, 1857), based on material collected by Friedrich Sellow in an unspecified locality in Brazil. Burret (1931: 150) transferred this species to Mouriri and added the information that the specimen was collected between Vitória and Bahia (nowadays city of Salvador). If this information is correct, Friedrich Sellow collected this specimen between November 1815, upon his arrival in Vitória, and March 1817, when he departed from Salvador (Urban, 1906; Moraes, 2009). Burret (1931) also highlighted the resemblance between M. sellowiana and M. petroniana (= M. arborea), and even questioned whether they could be considered conspecific. Unfortunately, the only known specimen of M. sellowiana was destroyed in World War II (Morley, 1976). As a result, the species is now only known from its original description and accompanying illustrations (Berg, 1857). Morley (1976) also agreed with Burret that the description and drawings are similar to M. arborea, but maintained M. sellowiana as a valid taxon, albeit listed as “species insufficiently known”. He also thought that M. sellowiana would be very close to M. megasperma, and argued that the leaves with an acute apex and larger fruits and seeds of the latter species would distinguish it from the former.
As we have previously discussed, we consider M. megasperma to be a synonym of M. arborea. After analyzing the most recent samples from presumably the same areas as the type of M. sellowiana (southern Bahia), we confirmed that M. sellowiana is the same species as M. arborea, supporting the hypothesis raised by previous authors. Generally, the calyx lobes from recent samples from South Bahia burst into five pieces at anthesis, resulting in fruits that are crowned with the persistent calyx (Fig. 2E), although some or all of the lobes may fall off, leaving a circular scar (Fig. 2F–G). The specimens from other regions show a calyx that bursts at anthesis irregularly into 2–3 pieces, the pieces breaking away or not (Fig. 2D). As a result, the fruit shows a circular scar at the apex (Fig. 2G). The number of seeds in each fruit in these specimens ranges from 1 to 4. The specimens with flowers from Bahia have shorter anthers and thecae than those from other regions, but this seems to be insufficient to recognize different taxa. After comparing herbarium specimens, original descriptions, and illustrations, we concluded that M. sellowiana should be synonymized under M. arborea. According to Art. 11.4 of ICN (Turland et al., 2017), the epithet arborea has a priority over sellowiana and megasperma, as the first one is the oldest legitimate name.
Since the original material of M. sellowiana was destroyed, a lectotypification is required according to Art. 9.3 and 9.4 of ICN (Turland et al., 2017). As long as no isotypes are known, the only original material remaining is an illustration associated with the protologue of Aulacocarpus sellowianus in Flora Brasiliensis (Berg, 1857). This illustration shows a fruiting branch, a cross-section of fruit, and three seeds depicted in different views. The fruits are 3–4-lobed according to the number of seeds and show a central hollow zone surrounded by a circular scar at the apex. In the description of the species Berg writes, “ disco profunde excavato reliquiisque sepalorum coronata ”, suggesting that fruits had remains of the sepals. In the cross-section of the fruit, there are four locules, each with one seed. These illustrations may have been drawn based on material seen by Berg, and it is likely from the original collection of the Sellow. In conclusion, we designated here the illustration of Aulacocarpus sellowianus from Flora Brasiliensis as a lectotype of Mouriri sellowiana (Fig. 1).
The name Aulacocarpus sellowianus was mentioned for the first time by Berg (1856). According to McVaugh (1956), this publication in Linnaea was a list of species that Otto Berg planned to be published after the publication of Flora Brasiliensis (Berg 1857), but it happened the other way. Despite being published before Berg (1857), Berg (1956) does not include descriptions for the species and consequently the names of new species cannot be considered valid, as stated in Art. 38.1 in the ICN (Turland et al., 2017). Therefore, since Berg (1857, in Flora Brasiliensis) has a description, it is regarded here as the valid publication for A. sellowianus.
description: Published as part of Völtz, Rafael Rosenstock & Goldenberg, Renato, 2024, A taxonomic notes on Mouriri (Olisbeoideae, Melastomataceae): Clarifying two little-known species from the Brazilian Atlantic Forest, with three new synonyms, pp. 247-258 in Phytotaxa 671 (3) on pages 248-253, DOI: 10.11646/phytotaxa.671.3.3, http://zenodo.org/record/14521459