Over a century later and 400 kilometers apart: rediscovery of Bulbophyllum barbatum (Orchidaceae) in Diamantina, Minas Gerais, Brazil
Author
Menezes, Euler L. F.
0000-0002-1861-9552
Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento de Ciências Biológicas Rodovia MGT 367 - Km 583, nº 5.000, 39.100 - 000, Alto da Jacuba, Diamantina, MG, Brazil. & eulermenezes @ hotmail. com; https: // orcid. org / 0000 - 0002 - 1861 - 9552
eulermenezes@hotmail.com
Author
Giordani, Samuel C. O.
0000-0001-5542-2217
Universidade Federal dos Vales do Jequitinhonha e Mucuri, Departamento de Ciências Biológicas Rodovia MGT 367 - Km 583, nº 5.000, 39.100 - 000, Alto da Jacuba, Diamantina, MG, Brazil. & samuelgiordani @ gmail. com; https: // orcid. org / 0000 - 0001 - 5542 - 2217
samuelgiordani@gmail.com
Author
Rosim, Mauro S.
0000-0001-8669-5509
Independent researcher. & msrosim @ gmail. com; https: // orcid. org / 0000 - 0001 - 8669 - 5509
msrosim@gmail.com
Author
Gonella, Paulo M.
0000-0001-8332-5326
Universidade Federal de São João del-Rei, Campus Sete Lagoas, Departamento de Ciências Exatas e Biológicas, Rua Sétimo Moreira Martins 188, 35701 - 970, Sete Lagoas, MG, Brazil. & pmgonella @ gmail. com; https: // orcid. org / 0000 - 0001 - 8332 - 5326
pmgonella@gmail.com
text
Phytotaxa
2022
2022-02-24
536
2
175
182
journal article
20428
10.11646/phytotaxa.536.2.6
49d05b9f-7311-412b-9916-7666de5effb4
1179-3163
6257639
Bulbophyllum barbatum
Barbosa Rodrigues (1882: 119)
.—
Figures 1–3
Type
:—
BRAZIL
.
MINAS GERAIS
:
Parahybuna
,
Serra das Bicas
,
18 May 1879
,
J. Barbosa Rodrigues
s.n.
(lost).
Lectotype
(designated by
Smidt & Borba 2009a: 634
): Barbosa Rodrigues’ original drawing which appeared in his unpublished work “
Iconographie des Orchideés du Brésil
5: t. 251 fig. b”, deposited in the library of Jardim Botânico do
Rio de Janeiro
and reproduced in
Sprunger
et al.
(
1996
, v.1, t.377, fig. b.).
Description:
—
Herbs
small, epiphyte or occasionally rupicolous.
Roots
c.
0.5 mm
in diameter, slender, fasciculate.
Rhizome
3–4 mm
long, cylindrical, reptant, inconspicuous, brownish.
Pseudobulbs
11–14 mm
at the largest diameter and
7–9 mm
at the smallest, ovoid, compressed, coated with a very fine senescent bract, dark green, smooth and shiny when young, then yellowish-green, rugose and opaque, unifoliate.
Leaves
20–24 ×
12–14 mm
, ovate to elliptical, plane, glabrous, smooth, coriaceous, with salient midrib on the abaxial face and forming a longitudinal groove on the adaxial face, base constricted, apex acute, margins entire and slightly revolute, grayish-green when young, then yellowish-green.
Inflorescence
a raceme; scape
100–150 mm
long, 0.8–1.0 mm in diameter, cylindrical, thin, green tinged with purple, presenting 4 to 8 nodes with sterile bracts; sterile bracts 0.8–1.0 × c.
1 mm
, amplexicaul, margins entire, brownish; rachis
40–60 mm
long, thin, semi-upright to pendulous, 10–14 flowers arranged distichously, anthesis simultaneous; floral bracts 1.7 ×
0.8 mm
, patent, triangular, sepaloid, apex acute, margin entire, completely covering the pedicel+ovary and part of the dorsal sepal, purplish with vinaceous mid vein.
Flowers
pendent, membranaceous, jugae present, inconspicuous.
Pedicel
and ovary 1.3 ×
1.2 mm
, cylindrical, glabrous, brown, ovary obscure.
Sepals
navicular, trinerved, yellowish-green with longitudinal vinaceous spots, margins ciliated, trichomes linear, short, purple; dorsal sepal 5–6 ×
2.1–2.2 mm
, triangular, apex acute; lateral sepals 5–6 ×
2.4–2.6 mm
, free, triangular, slightly falcate, apex acute.
Petals
1.4–1.5 ×
0.4–0.5 mm
, inconspicuous, sessile, lanceolate to obovate, apex obtuse, veins inconspicuous, parallel to column, translucent white with minute vinaceous spots at base, margins ciliated, trichomes
0.9–1.1 mm
long.
Lip
4.8–4.9 ×
1.7–1.8 mm
, entire, yellowish-green with vinaceous stains, unguiculated, flat, linear-lanceolate, apex obtuse, with a longitudinal groove in the center which widens and deepens towards the base, margins densely ciliated, trichomes linear, dark purple,
0.1 mm
long at the base progressively longer towards the apex reaching up to
2 mm
.
Column
short, 2 ×
1.5 mm
, rhomboid, concave, glabrous, milky white with vinaceous spots on the back, with two dentiform stellids larger than the anther; column foot short, c.
0.4 mm
long; stigmatic cavity large, oval; anther cuculiform, base circular, apex acute and deflexed, yellow at the base and green at the apex, ciliated at the base near to the stigmatic cavity, trichomes linear; pollinia 4, overlapping, monomorphic, yellow.
Fruit
not seen.
FIGURE 1.
Distribution map of
Bulbophyllum barbatum
in Minas Gerais, SE Brazil.
Specimens examined:
—
BRAZIL
,
Minas Gerais
:
Diamantina
,
31 March 2020
, fl.,
E.L.F. Menezes
&
S.C.O. Giordani
206 (HDJF 7058)
;
ibid
,
05 April 2020
, fl.,
E.L.F. Menezes
223
(HDJF 7891)
;
ibid
,
29 March 2021
, fl.,
E.L.F. Menezes
&
S.C.O. Giordani
492
(BHCB 205936)
.
Distribution and habitat:
—The species was originally described based on material collected near Parahybuna, current Juiz de Fora, in southern
Minas Gerais
(
Fig. 1
), a region known as “Zona da Mata Mineira” due to its original forest cover (seasonal semideciduous forest), inserted in the Atlantic Rainforest domain. The protologue further adds “growing in the forests of Serra das Bicas, 608 meters above sea level” (
Barbosa Rodrigues 1882
). The “Serra das Bicas” likely refers to the current municipalities of Bicas or Maripá de Minas, east of Juiz de Fora. The habit is not mentioned in the protologue, but the species was assumed to be epiphyte (
Smidt 2020
).
The new populations were found in the municipality of
Diamantina
, over
400 km
to the northwest of the
type
location (
Fig. 1
), in small fragments of gallery forest (“capões de mata”) inserted in the
campos rupestres
vegetation at elevations from
1050 m
to
1270 m
. These new subpopulations were found only two kilometers apart and, while in one population all individuals were observed growing as epiphytes over unidentified tree hosts (
Fig. 3C, D
), in the other all individuals were growing as rupicolous (
Fig. 3A, B, E
) in quartzitic rock shaded by the surrounding trees. At both sites, the species was found syntopic with other
Orchidaceae
species, including two other
Bulbophyllum
species
,
B. carassense
Mota
et al.
(2009: 381
;
Fig. 3E
), and
B. plumosum
(
Barbosa Rodrigues 1877: 44
)
Cogniaux (1902: 614)
None
of these populations are within Protected Areas.
FIGURE 2.
Bulbophyllum barbatum
.
A
, habit.
B
, flower in front view with retracted lip.
C
, flower in front view with distended lip.
D
, flower in lateral view with floral bract.
E
, flower in dorsal view with floral bract.
F
, sepals in adaxial view, dorsal (left) and lateral (the two on the right).
G
, lip in adaxial view.
H
, dissected flower with sepals and lip removed, showing columns and petals in ventral (left) and dorsal (right) views.
I,
dissected flower with all sepals and petals removed, showing column in lateral view.
FIGURE 3.
Bulbophyllum barbatum
in situ
showing rupicolous growth (
A
,
B
,
E
) and epiphytic (
C
,
D
).
A,
vegetative organs.
B,
flowering individual.
C,
large epiphytic individual.
D,
inflorescence.
E,
individual of
B. barbatum
(right) growing syntopic with
B. carassence
(indicated by arrow).
Phenology
:—
Barbosa Rodrigues (1882)
reports flowering in May, while in the new records flowering was observed earlier, in March and April.
Preliminary conservation status:
—Critically Endangered—CR B2ab(iii).
Bulbophyllum barbatum
is likely to be extinct at the
type
location since it was not recollected in the region in the past 139 years. Similar to other regions of the Atlantic Rainforest, the region around the town of Juiz de Fora suffered from intense deforestation in the last centuries, with the conversion of the original forests into pastures and agricultural lands. The new populations were found in small montane forest fragments isolated among grasslands and rock outcrops of the
campos rupestres
, therefore a naturally fragmented habitat. Both new areas were used in the past for diamond panning and are currently not protected, lying close to the town of
Diamantina
and touristic attractions such as waterfalls, being susceptible to frequent anthropogenic fires. Only around 40 mature individuals were observed at each of the new subpopulations, which also makes the species susceptible to poaching and over-collection.
Taxonomic comments:
—
Bulbophyllum barbatum
was placed in
B
. sect.
Xiphizusa
(
Reichenbach 1852: 919
)
Cogniaux (1902: 607)
by Smidt (2007) based on the similar vegetative morphology to other species of the section (e.g. small discoid pseudobulbs, that are aggregated and unifoliate;
Figs. 2A
,
3A
). This section is a monophyletic group comprising 23 Neotropical species, centered in the
campos rupestres
of the mountains of east
Brazil
(Smidt
et al.
2007, 2011). Besides the aforementioned vegetative characteristics, the group is characterized by long scape with flowers arranged distichously in a thin rachis; lateral sepals usually united to form a synsepal (
B. barbatum
being one of the few exceptions); petals erect, with margins pilose; lip trilobed (the only exception being
B. barbatum
with lip entire); column foot with entire apex, shorter than column length (Smidt & Borba 2009;
Smidt
et al.
2011
).
The species is distinct from all other species of the section by the unique floral morphology, with sepals and petals with pilose margins (
Fig. 2F, H
), anther base pilose (
Fig. 2H, I
), petals lanceolate to obovate, and lip entire, densely pilose along the margin (
Fig. 2C, G
).
Although the
lectotype
of
B. barbatum
is an illustration rather than a specimen, it is not necessary to designate an epitype as the original illustration by Barbosa Rodrigues is very detailed and unambiguous, therefore not meeting the requirements of Article 9.9 of the Code (
Turland
et al.
2018
) for the designation of an epitype.