Merianthera calyptrata sp. nov. (Melastomataceae, Myrtales), a new candelabriform species from Minas Gerais, Brazil

Abstract

Merianthera is a genus of flowering plants with up to now seven species occurring in eastern Brazil, in the states of Bahia, Espírito Santo, and Minas Gerais. It belongs to the tribe Pyramieae (Melastomataceae), and can be recognized by its shrubby or treelet habit with caducous leaves, 5-merous flowers with a strongly zygomorphic androecium, the latter with dimorphic stamens bearing complex dorsal connective appendages, as well as an inferior ovary and capsular fruits. We describe here a new species of Merianthera from two collections and a photographic record, all from the same locality, an inselberg in the Municipality of Jacinto, in northeastern Minas Gerais. Its candelabriform habit, with a fistulose stem, and solitary, axillary or cauliflorous flowers are only shared with M. burlemarxii. However, M. calyptrata R.Goldenb., Bochorny & Fraga sp. nov. has at least three characters that are absent in M. burlemarxii and all other species in the genus: the total absence of both a peduncle and bracteoles, the calyptrate calyx and the fruits developing from inferior ovaries and dehiscing through longitudinal slits. The first character appears to be unknown in other species in the family.

Full text

European Journal of Taxonomy 888: 64–76 ISSN 2118-9773
https://doi.org/10.5852/ejt.2023.888.2209 www.europeanjournaloftaxonomy.eu
2023 · Goldenberg R. et al.
This work is licensed under a Creative Commons Attribution License (CC BY 4.0).
Research article
64
Merianthera calyptrata sp. nov. (Melastomataceae, Myrtales), a new
candelabriform species from Minas Gerais, Brazil
Renato GOLDENBERG 1,*, Thuane BOCHORNY 2, André Márcio AMORIM 3,
Juliana Klostermann ZIEMMER 4 & Claudio Nicoletti de FRAGA 5
1 Universidade Federal do Paraná, Departamento de Botânica, Caixa Postal 19031,
81531-970, Curitiba, Paraná, Brazil.
2,5 Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915,
22460-030, Rio de Janeiro, Rio de Janeiro, Brazil.
3 Universidade Estadual de Santa Cruz, Departamento de Ciências Biológicas,
Km 16 Rodovia Ilhéus–Itabuna s/n, 45662-900, Ilhéus, Bahia, Brazil.
4 Universidade Estadual de Campinas, Programa de Pós-Graduação em Biologia Vegetal,
Instituto de Biologia, Rua Monteiro Lobato 255,
13083-862, Cidade Universitária Zeferino Vaz, Campinas, São Paulo, Brazil.
* Corresponding author: rgolden@ufpr.br
2 Email: tbochorny@gmail.com
3 Email: amorim.uesc@gmail.com
4 Email: juliana.ziemmer@gmail.com
5 Email: cnfraga@jbrj.gov.br
Abstract. Merianthera is a genus of owering plants with up to now seven species occurring in eastern
Brazil, in the states of Bahia, Espírito Santo, and Minas Gerais. It belongs to the tribe Pyramieae
(Melastomataceae), and can be recognized by its shrubby or treelet habit with caducous leaves, 5-merous
owers with a strongly zygomorphic androecium, the latter with dimorphic stamens bearing complex
dorsal connective appendages, as well as an inferior ovary and capsular fruits. We describe here a new
species of Merianthera from two collections and a photographic record, all from the same locality, an
inselberg in the Municipality of Jacinto, in northeastern Minas Gerais. Its candelabriform habit, with a
stulose stem, and solitary, axillary or cauliorous owers are only shared with M. burlemarxii. However,
M. calyptrata R.Goldenb., Bochorny & Fraga sp. nov. has at least three characters that are absent in
M. burlemarxii and all other species in the genus: the total absence of both a peduncle and bracteoles,
the calyptrate calyx and the fruits developing from inferior ovaries and dehiscing through longitudinal
slits. The rst character appears to be unknown in other species in the family.
Keywords. Cambessedesieae, inselbergs, Pyramieae, xerophytic plants.
Goldenberg R., Bochorny T., Amorim A.M., Ziemmer J.K. & Fraga C.N. de 2023. Merianthera calyptrata sp. nov.
(Melastomataceae, Myrtales), a new candelabriform species from Minas Gerais, Brazil. European Journal of
Taxonomy 888: 64–76. https://doi.org/10.5852/ejt.2023.888.2209

GOLDENBERG R. et al., New Merianthera (Melastomataceae) from Brazil
65
Introduction
Melastomataceae Juss. is a subcosmopolitan family of owering plants with 173 genera and about 5860
species mainly distributed in tropical and subtropical regions and with a few species in temperate areas
(Ulloa Ulloa et al. 2022). Three subfamilies are presently recognized, Kibessioideae Naudin, Olisbeoideae
Burnett, and Melastomatoideae Ser. ex DC., the latter being the largest by far with 21 tribes (Penneys
et al. 2022). One of these tribes in Melastomatoideae, recently described as Cambessedesieae Bochorny,
Almeda, Michelang. & R.Goldenb. (Bochorny et al. 2019), is now assigned to Pyramieae Naudin, a
tribal name with priority (Bochorny et al. 2022). Its four genera (Bisglaziovia Cogn., Cambessedesia
DC., Huberia DC., and Merianthera Kuhlm.) with a total of 68 species are almost restricted to eastern
Brazil, except for four species of Huberia occurring in the Peruvian and Ecuadorian Andes (Bochorny
et al. 2022). Finally, the genus Merianthera had up to now seven species (Goldenberg et al. 2012), two
of which (M. eburnea R.Goldenb. & Fraga and M. sipolisii (Cogn.) Wurdack) are endemic to ʻCampos
Rupestresʼ in the Brazilian state of Minas Gerais, and ve are restricted to shrubby vegetation growing on
inselbergs in eastern Brazil, inside the Atlantic Forest domain; all ve occur in Espírito Santo, with three
species endemic to this state (M. bullata R.Goldenb., Fraga & A.P.Fontana, M. burlemarxii Wurdack, and
M. parvifolia R.Goldenb., Fraga & A.P.Fontana); the other two are also in Bahia (M. pulchra Kuhlm.) or
Minas Gerais (M. verrucosa R.Goldenb., Fraga & A.P.Fontana).
One of these species of Merianthera has a very striking set of morphological features, mostly
vegetative, but also reproductive (Wurdack 1984; Goldenberg et al. 2012). Plants of M. burlemarxii are
ʻcandelabriformʼ shrubs, i.e., with vegetative shoots that are curved upwards, each shoot thinner near
the base and distally thicker; the general aspect of the whole plant is that of a chandelier, with leaves
and owers crowded at the thick apices. These thick apices, in turn, are stulose, meaning that they are
hollow and transversally divided in chambers 1–11 mm high (Goldenberg et al. 2012). These hollow,
stulose stems have been suggested to be an adaptation for housing ant colonies, which are quite common
in the family (Michelangeli 2010), but no ants were found living in association with M. burlemarxii
(Ziemmer et al. 2017). An alternative explanation for this particular morphology is that it is actually a
xeromorphic adaptation related to the harsh conditions oered by the thin soils on the inselbergs, coupled
with a highly seasonal climate where these plants live (Ziemmer et al. 2017). During the wet season, at
least the apical portion of these stems is lled with water-accumulating tissues (aquiferous parenchyma),
which may dry up during the dry season and then leaving spaces for the stulae; the plates dividing the
dry stem in stulae are nodal medullary bundles, which are connected to the aquiferous parenchyma
above and below (Ziemmer et al. 2017). As for reproductive characters, this species is unique in having
depauperate cymes with a solitary, bibracteolate, pedicellate ower growing on top of a short peduncle
(Goldenberg et al. 2012).
It came to us as a surprise when a photo of a plant very similar to M. burlemarxii was posted in
February 2017 on ʻDetWebʼ, a Facebook group dedicated to identication of Brazilian plants
(https://www.facebook.com/groups/171157419593991). The very nice photos by Mr Reginaldo
Vasconcelos also showed that this plant had very distinctive leaves and, moreover, seemed to be
photographed in Minas Gerais, about 250 km from the nearest known population of M. burlemarxii in
Espírito Santo. With directions kindly provided by Mr Vasconcelos, we were able to return to what is
now the type locality, to locate plants of this species. It proved to be a new species with a distinctive set
of characters, mostly related to inorescences, ower calyx, and fruits, that we name and describe here.
Material and methods
The specimens have been deposited at the herbaria BHCB, MBML, UESC, UPCB, and RB (acronyms
follow Thiers, continuously updated), while additional duplicates will be sent to K, NY, and other herbaria
after the publication of this article. Morphological terminology follows Radford et al. (1974), while the

European Journal of Taxonomy 888: 64–76 (2023)
66
description of trichomes follows Wurdack (1986). Comparisons with currently recognized species of
Merianthera were based on analyses of herbarium specimens, including types, all listed in Goldenberg
et al. (2012).
For the SEM images, leaf fragments were mounted on aluminum stubs, coated with gold, and examined
using a scanning electron microscope Tescan Vega 3. The distribution map was generated in QGIS ver.
3.12 software (QGIS Development Team 2022) using layers available from IBGE (2022) and SISEMA
(2022). Geographical coordinates were obtained in the eld or from herbarium specimens. Conservation
status assessments follow IUCN Red List Categories and Criteria version 15.1 (IUCN 2022).
Results
Class Embryopsida Engler ex Pirani & J.Prado
Order Myrtales Reichenbach
Family Melastomataceae Juss.
Subfamily Melastomatoideae Ser. ex DC.
Genus Merianthera Kuhlm.
Arquivos do Instituto de Biologia Vegetal do Rio do Janeiro 1 (3): 231–233 (Kuhlmann 1935), here
amended.
Type species
Merianthera pulchra Kuhlm., Arquivos do Instituto de Biologia Vegetal do Rio do Janeiro 1 (3): 231–233
(Kuhlmann 1935).
Description (modied from Goldenberg et al. 2012)
Shrubs to treelets, sparsely to moderately glandulose-granulose. Leaves opposite, entire, acrodromous,
caducous. Inorescences terminal short panicles, depauperate few-owered cymes or reduced to
solitary owers; bracts absent, bracteoles absent or small, caducous. Flowers pedicellate, 5(–6)-merous;
hypanthium sometimes with a constriction above the ovary; calyx regularly or irregularly lobed, seldom
calyptrate and dehiscing through a transversal, circumscissile slit; petals free, obovate to elliptic; stamens
10(–12), glabrous, strongly zygomorphic and dimorphic, lament strongly attened, connective with one
basal (descending) and one apical, erect (ascending) portion, ascending portion always 2-lobed, lobes
curved backwards in the antesepalous stamens and not curved backwards in the antepetalous stamens,
anthers slightly dorsally arched, with a dorsal or apical pore in the antepetalous stamens and an apical
to slightly ventrally located pore in the antesepalous stamens. Ovary completely inferior, with a sterile,
apical stylar column, (3–)4–5-celled, the protruding placentae axillary; style curved at the apex, glabrous
or puberulous, stigma punctiform. Fruits costate, apically constricted or not, rupturing along the costae
when mature or seldom through (3–)4 regular, longitudinal slits; seeds many, pyramidal, testa rugulose.
Key to the species of Merianthera (modied from Goldenberg et al. 2012)
1. Stems hollow, stulose when dry; owers solitary, either on top of a short peduncle (then a 1-owered
strongly reduced cyme) or not .......................................................................................................... 2
– Stems solid when dry; owers in panicles or seldom in depauperate cymes with two or more
owers ............................................................................................................................................... 3
2. Leaves with an acuminate to abruptly acuminate apex; owers bibracteolate, borne on a short
peduncle; calyx not calyptrate, dehiscing through regular lobes ................ M. burlemarxii Wurdack
– Leaves with a rounded or obtuse apex; owers ebracteolate, not borne on a peduncle; calyx calyptrate,
dehiscing through a transversal, circumscissile slit ............................................................................
......................................................................M. calyptrata R.Goldenb., Bochorny & Fraga sp. nov.

GOLDENBERG R. et al., New Merianthera (Melastomataceae) from Brazil
67
3. Calyx regularly lobed; style basally puberulous or granulose-glandulose ....................................... 4
– Calyx irregularly lobed; style glabrous ............................................................................................. 7
4. Leaves glabrous on abaxial surface; petals purple ........................................................................... 5
– Leaves with dense indumentum on abaxial surface; petals pink ...................................................... 6
5. Hypanthium weakly costate and smooth; calyx lobes lacking external teeth; style glandular-puberulous
on its basal half ........................................................... M. bullata R.Goldenb., Fraga & A.P.Fontana
– Hypanthium strongly costate and rugose; calyx lobes with distinct, thick external teeth; style granulose-
glandulose at the base .............................................M. verrucosa R.Goldenb., Fraga & A.P.Fontana
6. Leaves with strigulose abaxial surface, with curled, discrete trichomes ............................................
.............................................................................................................. M. sipolisii (Cogn.) Wurdack
– Leaves with lanate abaxial surface, with arachnoid-amorphous, matted trichomes ...........................
.........................................................................................................M. eburnea R.Goldenb. & Fraga
7. Leaves with petioles 12–29 mm long; panicles with more than 8 owers .......... M. pulchra Kuhlm.
– Leaves sessile or with petioles up to 9 mm long; depauperate racemes with up to 4(–5) owers,
reduced to triads, diads or sometimes single owers ..........................................................................
................................................................................M. parvifolia R.Goldenb., Fraga & A.P.Fontana
Merianthera calyptrata R.Goldenb., Bochorny & Fraga sp. nov.
urn:lsid:ipni.org:names:77324801-1
Figs 1–4
Diagnosis
Merianthera calyptrata sp. nov. diers from Merianthera burlemarxii by the acute or slightly cuneate
leaf base (vs obtuse to rounded in M. burlemarxii), rounded to seldom obtuse apex (vs acuminate or
abruptly acuminate), the solitary ower on a single, ebracteolate pedicel, borne directly on the stem,
i.e., not borne on a peduncle (vs solitary, bibracteolate, pedicellate ower borne on a short peduncle),
calyx closed in bud, calyptrate, dehiscing through a transversal, circumscissile slit that releases a single,
conical cap (vs open in bud, with ve regular sepals), fruits opening regularly through (3–)4 longitudinal
slits running from the apex to almost the base of the fruit (vs fruits opening irregularly, with no apparent
line of dehiscence, and the seeds are dispersed as the hypanthium and ovary walls decay and open; de
Goldenberg et al. 2012).
Etymology
The epithet refers to the owers with a calyptrate calyx, a unique feature of M. calyptrata sp. nov., and
otherwise unknown in the genus and tribe.
Material examined
Type
BRAZIL – Minas Gerais • Jacinto, Comunidade de Medeiros, “acesso a esquerda na MG-405 sentido
Jacinto - Jaguarão, propriedade do Sr. Augusto Chavier de Souza”; 16°15′25″ S, 40°4′27″ W; 30 Mar.
2022; Claudio N. de Fraga & Dayvid R. Couto 4144; holotype: RB[RB01463285]; isotypes: BHCB, K,
MBML, NY, UPCB.
Paratype
BRAZIL – Minas Gerais • Jacinto, “Inselbergs no lado esquerdo da MG 405, em direção sul”; 16°10′10″ S,
40°17′13″ W; 1 Feb. 2022; A.M. Amorim, F. Cabral & Y. Gouvea 11854; RB, UESC, UPCB.

European Journal of Taxonomy 888: 64–76 (2023)
68
Description
Shrubs or treelets up to 2.5 m tall. Branches candelabriform, light brown at the very tip, becoming
reddish-brown to dark-vinose (blackish in dried specimens) below the leaf line, terete, each segment
is basally thin (0.4–0.6 mm diam.), becoming very thick at its apex (8–11 mm diam.), apparently solid
(but becoming hollowed in dried material, with stulae 2–5 mm high), the surface with the distinct leaf
scars sometimes topped by ower scars and always anked by two white lenticels (one at each side),
when young moderately to densely granulose-glandulose and glutinous, the minute, sessile, yellowish
glands (in dried specimens), partially covered with a layer of a viscous, shiny, yellowish substance.
Leaves isomorphic, with petioles 0.6–1 cm long; blade 4–7 × 1.5–3.5 cm, elliptic to spatulate, base acute
to slightly cuneate, apex rounded or seldom obtuse, chartaceous, discolorous both in fresh and dried
specimens, acrodromous nerves 3, distinctly suprabasal (distant 0.5–1.2 mm from the base), the laterals
sometimes joining the main nerve at the apex, but sometimes joining the leaf margins very near the leaf
apex before joining the main nerve and leaf apex, with an additional faint submarginal pair originating
near the leaf base and fading away about ½ to ⅔ of the blade length, main nerve, laterals, transversals
and reticulation plane or impressed on adaxial surface and prominent (main nerves) to plane (transversal
and reticulation) on abaxial surface, adaxial surface sparse to moderately granulose-glandulose and
glutinous (the sessile glands denser on the nerves and nearby surfaces), abaxial with dense vermiform,
usually eglandular trichomes 50–230 µm long (measurements from SEM images), mixed with the same
minute, sessile, yellowish glands 20–35 µm long (measurements from SEM images) found in young stems
and the adaxial leaf surface, the vermiform trichomes restricted to the areolae and absent on the nerves
and reticulation and the sessile glands present on both, the glutinous cover thin, i.e., not immersing the
vermiform trichomes. Flowers solitary, axillary or sometimes cauliorous (then from an axillary bud right
above a scar left by a caducous leaf), peduncles absent, ebracteate, ebracteolate; 5-merous, on pedicels 10–
19 mm long (the pedicel apex hard to distinguish from the tapering hypanthium base). Hypanthium 7–10 ×
5–7 mm, greenish brown in mature owers, conical, outside slightly costate-sulcate, strongly glutinous,
apparently moderately to densely glandulose-granulose below the glutinous layer, otherwise glabrous,
inside almost totally adhered to the ovary, except for a short, up to 1 mm long, glabrous projection, torus
glabrous. Calyx closed and yellowish-green in bud (contrasting with the darker hypanthium), dehiscent
through a transversal, circumscissile, clean slit that releases a single conical, yellowish-brown calyptra
11–15 × 6–8 mm, solid (i.e., the tip not hollowed as in Michelangeli & Goldenberg 2021), no evident
sepals nor external tooth, no tube remaining on the hypanthium, outside with the same indumentum
as the hypanthium, inside sparsely to moderately covered with minute, vermiform, both glandular and
eglandular trichomes, but the omnipresent sessile glands very sparse. Petals 21–24 × 14–15 mm, purple
in recently opened owers, lighter and pink in older owers, adaxial surface shortly papillose, otherwise
glabrous on both surfaces, deexed at anthesis, membranaceous, broadly elliptic, apex rounded or obtuse,
margins undulate, not revolute. Stamens 10, dimorphic; antesepalous with laments 16–18 mm long,
purple to pinkish (in older owers), connective purple to reddish, with light yellow to cream extremities,
prolonged ca 0.5 mm below the thecae, the ascending appendage 3.5–3.7 mm long, bilobed at the apex,
the descending appendage 2–2.3 mm long, narrowly triangular, acute apex, anthers whitish, 4–4.2 mm
long, straight; antepetalous with laments 10–11 mm long, purple to pinkish (in older owers), connective
light yellow to cream, 0.6–0.7 mm prolonged below the thecae, the ascending appendage 4.9–5.2 mm
long, straight, bilobed at the apex, the descending appendage ca. 1 mm long, blunt, anthers dark purple,
5–5.7 mm long, straight. Ovary 7–10 mm long, (3–)4-celled, stylar column almost absent, less than
1 mm long, glabrous; style 11–13 mm long, glandular-puberulous on its basal ⅔, straight with a strongly
curved apex, stigma punctiform. Fruits 12–20 × 8–15 mm (including pedicels), not constricted at the
apex, opening regularly through (3–)4 longitudinal, loculicidal slits running from the apex to near the
base of the fruit, these (3–)4 segments encompassing both the ovary wall and hypanthium; placentae
persistent. Seeds not seen.

GOLDENBERG R. et al., New Merianthera (Melastomataceae) from Brazil
69
Fig. 1. Illustration of Merianthera calyptrata R.Goldenb., Bochorny & Fraga sp. nov. A. Fertile branch.
B. Detail of the branch showing leaf and ower scars plus two lenticels, each at one side of the leaf scar.
C. Branch tip with leaves, ower buds, an open ower and a fruit. D. Flower opening sequence, from
left to right: ower bud, with the calyptrate calyx still attached to the hypanthium; ower bud, with a
circumscissile dehiscence, but the calyptra still holding the petals together; and young ower, with the
calyptrate calyx falling from the petal tips. E. Petal, adaxial surface. F. Flower in longitudinal section
(calyx, petals and stamens removed) with detail of trichomes at the base of style. G. Antesepalous stamens,
from bud (left) and mature ower (right). H. Antepetalous stamens, from bud (right) and mature ower
(left). I. Antepetalous stamen, detail of the pore. From Fraga & Couto 4144 (all drawings). Drawn by
Diana Carneiro.

European Journal of Taxonomy 888: 64–76 (2023)
70
Fig. 2. Field photographs of Merianthera calyptrata R.Goldenb., Bochorny & Fraga sp. nov. A. Fertile
branch. B. Branch apex, longitudinal section showing the stulose structure of the stem, with the
chambers lled with parenchyma. C–E. Sequence of ower anthesis, showing the calyptrate calyx with
its circumscissile dehiscence. F. Flowers, frontal view. G. Stamens and style, lateral view. H. Old ower,
lateral view; this photo shows the single, ebracteolate ower and the absence of a peduncle. I. Mature
fruit. From: Fraga & Couto 4144 (A–H), Amorim et al. 11854 (I). Photos by C.N. Fraga (A–H) and
Y. Gouvea (I).

GOLDENBERG R. et al., New Merianthera (Melastomataceae) from Brazil
71
Distribution, habitat and phenology
Merianthera calyptrata sp. nov. has been recorded three times (two collections and one photo), all from
the same locality. The municipality of Jacinto lies on the Minas Gerais side of the border with Bahia, to the
south (right margin) of the Jequitinhonha River (Fig. 5). These plants grow on granitic inselbergs (Fig. 4),
right on the exposed surface, among other herbaceous, climbing, and shrubby species from genera that
are very common on inselbergs (Alcantarea (É.Morren ex Mez) Harms, Mandevilla Lindl., Piptadenia
Benth., Pseudobombax Dugand, Pleroma D.Don, and Stillingia Garden) in small vegetation clusters.
The climate in this region is highly seasonal, with a strong dry season in winter and a wet summer. The
plants were collected with very young ower buds (Amorim et al. 11854) and photographed with owers
(by Mr Reginaldo Vasconcelos) in February, then it was collected with open owers in March (Fraga &
Couto 4144), from the middle to the end of the rainy season; both collections had old, persistent, seedless
fruits from the previous season, which indicates that the fruits may be present all year long.
Preliminary conservation assessment
This species has been found in only two close locations at a single locality, both outside protected areas
and within private properties where cattle is raised. Vegetation on inselbergs is naturally fragmented, and
this fragmentation may be intensied by grazing. On the other hand, rock outcrops usually do not attract
much agricultural interest, and consequently, they have frequently been preserved from human impact
and have kept their refugial character (Porembski et al. 1998).
According to Guidelines for Using the IUCN Red List Categories and Criteria (IUCN 2022), it should
be considered Data Decient (DD) due to poor sampling. However, AOO of Merianthera calyptrata
sp. nov. is currently 8 km2, and its EOO cannot be dened. Although these gures are within limits for
Critically Endangered (CR), under the criterion B2 (AOO less than 10 km2), the number of locations is
greater than 1 and falls within the Endangered (EN) category.
We don’t have reliable information about continuing decline or extreme uctuations of populations of
this species, but two of the authors of this article made an intensive evaluation of this species in loco,
since they were in this place looking precisely for these plants. Due to its apparent rarity and restricted
endemic distribution and the fact that their populations are prone to the eects of stochastic events in the
near future, it seems prudent to include this species in the Vulnerable category [VU: D2].
Fig. 3. Merianthera calyptrata R.Goldenb., Bochorny & Fraga sp. nov., scanning electron micrographs of
the abaxial surface of the leaf. A. General view. B. Detail of the dense vermiform trichomes (arrow) mixed
with sessile glands (arrowhead). Scale bars: A = 200 µm; B = 100 µm. From A.M Amorim et al. 11854
(UPCB).

European Journal of Taxonomy 888: 64–76 (2023)
72
Fig. 4. Merianthera calyptrata R.Goldenb., Bochorny & Fraga sp. nov. in its habitat. A. Inselberg and
granitic outcrops where the plant can be found. B. Vegetation cluster growing on a cleft, on a granitic
outcrop, with M. calyptrata to the right and front, with owers. C. Three individuals with spreading
crowns, behind some Alcantarea (É.Morren ex Mez) Harms (Bromeliaceae). From Fraga & Couto 4144.
Photos by C.N. Fraga.

GOLDENBERG R. et al., New Merianthera (Melastomataceae) from Brazil
73
Discussion
Merianthera calyptrata sp. nov. is remarkably similar to Merianthera burlemarxii, which up to now is
known only from the state of Espírito Santo, and with the nearest population found at a distance of 250 km
from the former. Both have the remarkable ʻcandelabriformʼ habit (as explained in the Introduction),
with the same stulose stem (in dried material), and solitary, axillary or cauliorous owers. All other
species of Merianthera are regular shrubs with owers borne in cymose or paniculate inorescences (see
identication key above; Goldenberg et al. 2012). The dierences between the two species are listed in the
Diagnosis (see above). Among these, there are three characters that seem to be exclusive to M. calyptrata,
meaning that they are absent in M. burlemarxii and all other species in the genus, and sometimes absent
in the whole family: the absence of both a peduncle and bracteoles, the calyptrate calyx, and the fruits
from inferior ovaries and dehiscing through longitudinal slits.
The rst exclusive character in Merianthera calyptrata sp. nov. is the absence of a peduncle as well as a
pair of bracteoles below the ower. All species of Merianthera but M. burlemarxii have inorescences with
more than two owers, thus by denition have peduncles below the owers. However, M. burlemarxii has
solitary owers, but these are clearly reduced cymes, i.e., each grow on a short peduncle. The distinction
between peduncle and pedicel is marked by a clear articulation and the presence of a couple of caducous
bracteoles at the pedicel base / peduncle apex (Wurdack 1984; Goldenberg et al. 2012). The condition
found in M. calyptrata is remarkably dierent, with ependuculate and ebracteolate solitary owers,
and this character seems to be otherwise absent from the rest of the family (R.G. pers. obs.; F. Almeda
pers. com.): there are a few species in some groups (Henriettea DC. and Bellucia Raf. in Henrietteeae
Fig. 5. Distribution of Merianthera calyptrata R.Goldenb., Bochorny & Fraga sp. nov. and its closest
relative, Merianthera burlemarxii Wurdack. BA = Bahia; ES = Espírito Santo; MG = Minas Gerais.

European Journal of Taxonomy 888: 64–76 (2023)
74
Penneys, Michelang., Judd & Almeda, or Mouriri Aubl. in Olisbeoideae Burnett, for instance) with a
condition similar to M. burlemarxii, where solitary owers apparently evolved from depauperate cymes,
but these always have even a small peduncle, and always a pair of bracteoles at the base of the pedicel,
even though sometimes the bracteoles are very early caducous.
The second exclusive character is the calyptrate calyx that gives this species its name. All other species in
the genus have either an open calyx dehiscing through regular lobes (Merianthera bullata, M. burlemarxii,
M. eburnea, M. sipolisii, M. verrucosa) or the calyx is closed in bud and dehisces through irregular lobes
in M. parvifolia and M. pulchra, but never through a circumscissile slit that releases a single calyptra.
While absent from Merianthera and other genera in the tribe Pyramieae (Bochorny et al. 2019), this
dehiscence mode can be found in at least ve dierent tribes of Melastomataceae: Cyphostyleae Gleason,
Henrietteeae, Merianieae Triana, Pyxidantheae Griseb., and in at least four unrelated clades of Miconieae
DC. (Michelangeli et al.2011; Judd et al. 2022).
The third character that is exclusive to Merianthera calyptrata sp. nov. is related to the fruits. In all other
species of Merianthera, the fruits apparently lack a dehiscence region, and “the seeds are dispersed
after the hypanthium and ovary walls decay and open (“cápsula rompente” or “rupturing capsule” sensu
Baumgratz 1985), and the seeds are released through the gaps left by the falling irregular hypanthium
pieces” (Goldenberg et al. 2012). The same mechanism is found in some species of Huberia (also in
the tribe Pyramieae; Bochorny et al. 2019, 2022), and in Allomaieta Gleason and Alloneuron Pilger
(both in the tribe Cyphostyleae; Michelangeli et al. 2011). All these species in Merianthera, Huberia,
Allomaieta and Alloneuron have an inferior ovary, and this dehiscence mechanism has been interpreted
as a consequence of the ovary position (Goldenberg et al. 2012). Most Melastomataceae with inferior
ovaries have eshy fruits, while most species with dry fruits have superior ovaries (Clausing et al. 2000,
but see Michelangeli et al. 2011 for exceptions); in the latter case, the dry fruits from superior ovaries
usually release the seeds from apical slits on the mature ovaries, but they do not have the hypanthium
tearing along clear lines, like the ones found in M. calyptrata. This condition where the hypanthium
tears along clear lines may also be found in Microlicia D.Don (tribe Lavoisiereae DC.) and Wurdastom
B.Walln. (Cyphostyleae).
In conclusion, it is remarkable that at least three macromorphological characters occur in this species
and are absent in the other members of the genus and tribe. Moreover, at least one of them is apparently
lacking in the close to 6000 species in the entire family. If not of great consequence, this at least makes
Merianthera calyptrata sp. nov. one of the easiest recognizable new species described in Melastomataceae
in the recent past. Another aspect is that, despite the recent revision and the small size of the genus,
the taxonomy of Merianthera still needs some attention, as is the case for the whole inselberg’s ora
in southeastern Bahia, northeastern Minas Gerais and western Espírito Santo, where these species are
endemic. Plants heretofore determined as M. burlemarxii, for instance, seem to actually belong to two
dierent morphological groups (see Goldenberg et al. 2012), but a satisfactory resolution of their status
still will require more collections and more detailed studies. Since these inselbergs are frequently dicult
to reach and consequently poorly collected, it is expected that more species of Merianthera might come
to light in the near future.
Acknowledgements
We thank Mr Reginaldo Vasconcelos for nding the plant and posting photos of it in DetWeb / Facebook,
and then providing us with the locality where this plant was sighted. We also thank Diana Carneiro for
the drawings, Yuri Gouvea for the photo of the fruit, and Frank Almeda and Fabián Michelangeli for their
reviews on a previous version of this manuscript. AMA, RG and CNF receive grants from CNPq / Brazil
(AMA and RG as “Produtividade em Pesquisa”, respectively #312404/2018-2 and # 310912/2021-0;
CNF as “Edital Universal”, #422191/2021-3). TB and CNF receive grants from “Fundação de Amparo

GOLDENBERG R. et al., New Merianthera (Melastomataceae) from Brazil
75
à Pesquisa do Estado do Rio do Janeiro”, FAPERJ / Brazil (respectively “Pós-doutorado nota 10”,
E-26/204.271/2021, and “Jovem Cientista do Nosso Estado”, #201280/2022). JKZ receives a PhD grant
from CAPES / Brazil (#88887.373597/2019-00).
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Manuscript received: 9 November 2022
Manuscript accepted: 24 February 2023
Published on: 9 August 2023
Topic editor: Frederik Leliaert
Desk editor: Radka Rosenbaumová
Printed versions of all papers are also deposited in the libraries of the institutes that are members of the
EJT consortium: Muséum national d’histoire naturelle, Paris, France; Meise Botanic Garden, Belgium;
Royal Museum for Central Africa, Tervuren, Belgium; Royal Belgian Institute of Natural Sciences,
Brussels, Belgium; Natural History Museum of Denmark, Copenhagen, Denmark; Naturalis Biodiversity
Center, Leiden, the Netherlands; Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain; Leibniz
Institute for the Analysis of Biodiversity Change, Bonn – Hamburg, Germany; National Museum of the
Czech Republic, Prague, Czech Republic.