AN UPDATED CHECKLIST AND KEY TO THE SPECIES OF BOLIVIAN BEGONIA, INCLUDING ONE NEW SPECIES
Author
Moonlight, Peter
Author
Fuentes, Alfredo F.
text
Edinburgh Journal of Botany
2022
2022-08-18
79
407
1
66
http://dx.doi.org/10.24823/ejb.2022.407
journal article
10.24823/EJB.2022.407
1747-0036
10553332
2.14.
Begonia galea Moonlight & A.Fuentes
,
sp. nov.
Begonia
galea
is unique among South American
Begonia
as the only species whose inflorescence is a scorpioid cyme with a terminal pistillate flower. –
Type:
Bolivia
,
La Paz Department
,
Prov. Franz Tamayo
, Santo Domingo,
arroyo San Pedro
,
14°47′53′′S
,
68°36′01′′W
,
1414 m
,
20 x 2006
,
A.F.
Fuentes,
M. Cornejo
,
E. Ticona
,
S. Sompero
&
C.
Cuqui
11158 (
holotype
E
[
E01004032
];
isotypes
BOLV
,
LPB
,
MO
[MO-2080523],
NOLS
,
US
[
US00966728
]).
Figure
.
Caulescent herb, lacking a tuber or rhizome, sometimes rooting from the lower nodes, terrestrial or epiphytic on the base of tree trunks.
Stem
erect,
20–60 cm
tall,
1.5–3 mm
in diameter, unbranched or branching at the base, internodes
8–60 mm
, glabrous, light green flushed red around the nodes.
Stipules
tardily deciduous, lanceolate, 3.5–9 ×
1–3 mm
, apex acuminate, aristate, glabrous, light green, margin entire, aciliate.
Leaves
alternate, basifixed;
petioles
joining blade at a slight angle,
4–15 mm
long, glabrous;
blades
asymmetrical, elliptic to oblanceolate, (30–)45–85(–115) ×
10–30 mm
, apex acuminate, base oblique, cordate on the broader side, basal lobe to
3 mm
, overlapping the petiole, cuneate on the narrower side, venation pinnate, with 3–6 secondary veins on the broader side, 2–4 secondary veins on the narrower side, upper surface dark green, very sparsely pilose, lower surface green, glabrous, margin irregularly dentate, ciliate.
Inflorescences
few, axillary, erect, arising close to the apex of the stem, a helicoid monochasial cyme, protandrous, c.4 staminate flowers developing before a terminal, pistillate flower;
peduncle
18–55 mm
long, glabrous, white flushed pink;
pedicels of staminate flowers
held vertically, sequentially shorter along the inflorescence with basal most flower held above the subsequent flowers in sequence, the basal-most pedicel to
12 mm
long, apical pedicel to
4 mm
long, glabrous, white flushed pink;
pedicels
of pistillate flowers
8–10 mm
long, glabrous, white flushed pink;
bracts
tardily deciduous, elliptic to ovate, 2–6 ×
1–5 mm
, apex acute to rounded, white, margin entire to lacerate, glabrous.
Staminate flowers
:
tepals
2, held horizontally, ovate, 8–10 ×
4–6 mm
, apex acute, margin entire, glabrous, white with a pink flush on outer surfaces;
stamens
8–10, fused at the base, held spreading horizontally, filaments
1.5–2 mm
long, anthers symmetrically basifixed, oblong,
1–1.5 mm
long, dehiscing via lateral slits, connectives extended to
1 mm
.
Figure.
Begonia
galea
Moonlight & A.
Fuentes
,
sp. nov.
A, Habit; B, staminate flower (front view);
C, stamen (front and side view); D, pistillate flower (front view); E, style and stigma (front view);
F, bracteole; G, stipule; H, fruit (side view). Drawn from
L. Cayola, G. Chive, I. Loza, M. Cornejo, E. Ticona & A.
Fuentes
2513 (MO [MO-2143708]) by Claire Banks.
Pistillate flowers
:
bracteoles
3, tardily deciduous, ovate, 3–4 ×
3 mm
, apex obtuse, white, glabrous, margin lacerate, ciliate;
tepals
deciduous in fruit, 5, spreading, elliptic, 7–9 ×
2–3.5 mm
, apex acute, margin entire, glabrous, white with a pink flush on outer surfaces, loosely reticulate at the apex;
ovary body
ovoid, the base truncate, c.4 ×
3 mm
, glabrous, 3-winged, wings white flushed pink, the upper wing longer than the other two, semicircular, front edge truncate, apex acute, lower edge rounded, 10–12 ×
7–13 mm
, the lower two wings triangular to oblong, front edge truncate, apex obtuse, lower edge gently rounded to truncate 6–8 ×
5–6 mm
, 3-locular, placentas bifid, bearing ovules on both surfaces;
styles
3, yellow, free at base, c.
5 mm
long, bifid from around a third of their length, stigmatic papillae in a twice spirally-twisted band.
Fruiting pedicel
to
1 cm
long;
fruit
nutant, the base truncate, 6–9 ×
2–4 mm
, light brown, glabrous, wings same shape as in female flower, light brown, longest wing expanding to 10–12 ×
12–13 mm
, shorter two wings expanding to 6–8 ×
5–6 mm
.
Distribution and ecology
.
Begonia
galea
is known from six collections within
38 km
of each other within the Franz Tamayo and Bautista Saavedra Provinces of La Paz Department,
Bolivia
. This species has been collected from
1250 to 1500 m
within humid valleys in lower montane rain forest dominated by the palm
Dictyocaryum lamarckianum
H.Wendl.
Begonia
galea
has been collected flowering and fruiting in October.
Etymology
. The epithet
galea
is a Latin term referring to the helmets of Roman soldiers and gladiators; it emphasises the rounded appearance of the species’ fruits.
Proposed IUCN conservation category
. The known extent of occurrence (EOO) of
Begonia
galea
is
53 km
2
, which is sufficiently small for it to qualify as Critically Endangered (CR) under IUCN criteria (
IUCN Standards and Petitions Subcommittee, 2019
). Although its range falls partially in the Apolobamba protected area, these populations may be in decline due to intense human pressure (
Jones
et al.
, 2018
) from deforestation for agriculture (mainly coca plantations), gold mining and livestock (
Romero-Muñoz
et al
., 2019
). The same does not apply to the populations of Santo Domingo, an area currently unaffected by deforestation or major development projects that could threaten their conservation in the short term. However, considering the potential for gold mining in this entire region and the intensive mining activities in surrounding areas (
Revollo & Campanini, 2014
), it is possible that in the future these activities will expand and compromise the conservation of this species. We categorise
Begonia
galea
as Near Threatened (NT) under IUCN criteria (
IUCN Standards and Petitions Subcommittee, 2019
) because most of its range remains intact and we have no evidence for any decline in its population.
Additional specimens examined
.
BOLIVIA
.
La Paz Department
.
Franz Tamayo Province
: Región Madidi, Santo Domingo, sector Lechemayu, en la Parcela Permanente 49.
14°46′09′′S
,
68°37′11′′W
,
1475 m
,
19 viii 2010
,
A.F. Fuentes
,
P. Miranda
,
C. Miranda
,
L. Vaquiata
&
E. Segales
17037 (
LPB
);
Santo Domingo,
sector Tintaya
, parcela temporal 2,
14°47′09′′S
,
68°35′00′′W
,
1463 m
,
13 x 2006
,
A.F.
Fuentes,
M. Cornejo
,
E. Ticona
,
S. Sompero
&
C. Cuqui
10998 (
LPB
,
MO
[MO-2080525])
;
Región Madidi
,
Santo Domingo
,
sector arroyo Tintaya
,
14°47′43′′S
,
68°36′06′′W
,
1400 m
,
10 x 2006
,
L. Cayola
,
G. Chive
,
I. Loza
,
N
.
Chapi &
P. JØrgensen
2471 (
LPB
,
MO
[MO-2080524])
;
Región Madidi
,
Santo Domingo
,
sector arroyo Tintaya
,
14°46′45′′S
,
68°35′30′′W
,
1468 m
,
22 x 2006
,
L. Cayola
,
G. Chive
,
I. Loza
,
M. Cornejo
,
E. Ticona
& A.
Fuentes
2513 (
LPB
,
MO
[MO-2143708],
LPB
, US [US00966727])
.
Bautista Saavedra Province
:
Area Natural de Manejo Integrado Apolobamba
,
Tolapampa
, por la carretera
Charazani-Apolo
, sector loma
Callawaya
, parcela permanente 2,
15°04′32′′S
,
68°28′01′′W
,
1250 m
,
10 iv 2010
,
A.F.
Fuentes,
A. Escalante
,
R. Ticona
&
S. Quispe
15831 (
LPB
,
MO
[
MO-2773642
])
.
Notes
.
Begonia
galea
is unique among Andean
Begonia
in the structure of its inflorescence, a monochasial, scorpioid cyme that terminates in a pistillate flower. This structure is superficially reminiscent of the asymmetrical, thyrsoid inflorescences found in
Begonia
sect.
Pilderia
(Klotzsch) A.DC.
(see Moonlight & Jara-Muñoz, 2017). However, the inflorescence of
Begonia
galea
differs in that it is apical rather than terminal, and only has a single pistillate flower at the apex.
Begonia
galea
also lacks the characteristic glandular hairs found in all members of
Begonia
sect.
Pilderia
. We consider the inflorescence of
Begonia
galea
more likely to be a reduced form of the typical dichasial cyme found in most non-tuberous Andean species of
Begonia
, including
Begonia
sects.
Cyathocnemis
,
Hydristyles
and
Ruizopavonia
.
The sectional placement of
Begonia
galea
is difficult because the species has a unique inflorescence structure and otherwise falls between
Begonia
sects.
Cyathocnemis
and
Ruizopavonia
. These two sections have very similar flowers and fruits and differ primarily in their leaves, which are straight with pinnate venation in
Begonia
sect.
Ruizopavonia
and transverse with palmate-pinnate venation in
Begonia
sect.
Cyathocnemis
. The leaves of
Begonia
galea
are straight but have many fewer secondary veins than all Andean members of
Begonia
sect.
Ruizopavonia
. We suspect that
Begonia
galea
is a member of
Begonia
sect.
Cyathocnemis
with straight leaves, similar to
B. obtecticaulis
Irmsch.
(
Moonlight
et
al.
, 2018). The three bracteoles of
Begonia
galea
positioned directly beneath the ovary are consistent with this hypothesis, because this character state is frequent in
Begonia
sect.
Cyathocnemis
whereas members of
Begonia
sect.
Ruizopavonia
have two bracteoles that are usually spaced out from the base of the ovary. We therefore tentatively place
Begonia
galea
in
Begonia
sect.
Cyathocnemis
.
Identification notes
. When the plant is fertile, it is easy to identify
Begonia
galea
because of its unique inflorescence structure, which resembles the characteristic scorpioid cyme of members of the
Boraginaceae
. Sterile individuals may be confused with several species of Bolivian
Begonia
. The distichous, straight leaves of this species most resemble those of the Bolivian species of
Begonia
sect.
Ruizopavonia
, but unlike most Bolivian species in this section,
Begonia
galea
is entirely glabrous.
Begonia peruviana
A.DC.
is an often glabrous, Bolivian member of
Begonia
sect.
Ruizopavonia
and can be distinguished by its much more numerous and prominent secondary veins (
B. peruviana
has 8–12 veins on the broader side of the leaf lamina vs
3–6 in
B. galea
). Finally,
Begonia
galea
could be confused with either
B. comata
Kuntze
or
B. oblanceolata
Rusby
but has smaller (<
1 cm
long), tardily deciduous stipules that do not clasp the stem and leaves, with an irregularly serrate margin (vs persistent stipules,>
1 cm
long, that clasp the stem and leaves, with a denticulate or crenulate margin).