Borreria savannicola (Spermacoceae, Rubiaceae), a new species from savanna patches within the Caatinga, Ceará State, Brazil
Author
Souza, Elnatan Bezerra De
0000-0002-5222-4378
Universidade Estadual Vale do Acaraú, Curso de Ciências Biológicas, Av. da Universidade 850, 62040 - 370, Sobral, CE, Brazil & elbezsouza @ gmail. com; https: // orcid. org / 0000 - 0002 - 5222 - 4378
elbezsouza@gmail.com
Author
Nepomuceno, Álvaro
0000-0002-4643-8177
Universidade Estadual de Feira de Santana - UEFS, Programa de Pós-Graduação em Botânica - PPGBot, Feira de Santana, BA, Brazil & alvaronepomuceno 567 @ gmail. com; https: // orcid. org / 0000 - 0002 - 4643 - 8177
alvaronepomuceno567@gmail.com
Author
Da Costa Ribeiro, Maria Luiza R.
0000-0003-3994-5346
Universidade Estadual Vale do Acaraú, Curso de Ciências Biológicas, Av. da Universidade 850, 62040 - 370, Sobral, CE, Brazil & marialuizawetzel @ gmail. com; https: // orcid. org / 0000 - 0003 - 3994 - 5346
marialuizawetzel@gmail.com
Author
Miguel, Laila Mabel
0000-0002-9870-4983
Instituto de Botánica del Nordeste (IBONE-CONICET). Facultad de Ciencias Exactas y Naturales y Agrimensura (FACENA). Universidad Nacional del Nordeste (UNNE), Sargento Cabral 2131, c. c. 209, 3400, Corrientes, Argentina & lailammiguel @ yahoo. com. ar; https: // orcid. org / 0000 - 0002 - 9870 - 4983
lailammiguel@yahoo.com.ar
text
Phytotaxa
2022
2022-12-22
576
3
279
288
http://dx.doi.org/10.11646/phytotaxa.576.3.4
journal article
10.11646/phytotaxa.576.3.4
bdea20a5-363a-4d1e-82e9-642fe92af6ce
1179-3163
7471623
Borreria savannicola
E.B. Souza, Nepom. & L.M. Miguel
sp. nov.
Type
:—
BRAZIL
.
CEARÁ
:
Granja
,
03°11’11’’S
40°44’35’’W
,
50 m
,
21 June 2018
, fl., fr.,
E
.
B
. Souza 5313,
F
.
F
. Araújo,
E
.
K
.
S
. Brandão &
I
.
V
. Nepomuceno
(
Holotype
:
EAC
!, isotypes
CTES
!,
HUEFS
!,
HUVA
!). (
Figs. 1–5
)
.
Borreria savannicola
strongly resembles
Borreria scabiosoides
Cham. & Schltdl.
, but it differs in the erect habit (
vs.
decumbent), linear and papillose leaves (
vs.
narrowly elliptic to elliptic and without papillae), terminal glomerule with 4–6(–10) involucral bracts (
vs.
terminal glomerule with 4 involucral bracts), capsule
5–6 mm
long, obovoid (
vs.
capsule
2–5 mm
long, ellipsoid).
Herb to subshrub, erect, (20–)30–40(–100) cm tall; stem simple or with lateral branches, quadrangular to subquadrangular, glabrous, green–yellowish when dry. Leaves pseudo-verticillate, sessile, leaf blades (1.5–)3–5(–10.5) × (0.1–)0.2–0.5(–0.6) cm, linear, acute at apex, attenuate at base, chartaceous, densely papillose above, glabrous below, rarely with papillae on the main nerve abaxially, margins revolute, sometimes with 3 pairs of inconspicuous secondary veins; stipular sheaths (2–)
3–4 mm
long, glabrous, with (3–)5–6(–10) fimbriae; fimbriae
1–2.5 mm
long, glabrous and collector–tipped. Floral branches trichotomous, mostly with the central axis developed. Inflorescence terminal, sometimes 1 axillary, glomerules hemispherical; involucral bracts 4–6(–10), (1.5–)2–5(–7) × (0.1–)0.2–0.4(–0.5) cm, linear, abaxially puberulous or glabrous on the basal portion, the external pair as long as to three times larger than glomerule diameter. Flower subsessile, pedicel c.
1 mm
long; hypanthium
2.5–3 mm
long, pubescent in the upper portion; calyx 4–lobed, lobes (1–)
2–3.5 mm
long, narrowly triangular, pilose on the margin; corolla
5–6 mm
long, infundibuliform, white, external surface glabrous with papillae on the apex of the lobes, sparsely pilose inside the lobes, internal surface with a ring of moniliform hairs in the middle of the tube and scarce hairs on the lobes; stamens exserted, filaments
1.2–1.5 mm
long, anthers
1–1.5 mm
long, white; pollen grains 8–10 zonocolporate, oblatespheroidal, medium,
P
= 26.2–28.6 µm,
E
= 26.3–30.2 µm, short colpi (5–8 µm length) as ectoaperture, endocigulum as endoaperure, exine 1.3–1.5 µm high, tectate–perforate, uniformly spinulate; style
5–6 mm
long, stigma bilobed with papillae, nectariferous disk bipartite. Capsule (5–)6 ×
1.5–2 mm
, obovoid, pubescent on the upper portion, with longitudinal dehiscence splitting into two dehiscent valves. Seeds (1.5–)2.5–3 × 0.5–0.7(–1) mm, ellipsoid, brown, ventral surface with a longitudinal groove covered by a strophiole; exotesta reticulate-foveate.
Figures 2
to 4.
FIGURE 1.
Geographic location and AOO and EOO of
Borreria savannicola
.
FIGURE 2.
Borreria savannicola
.
A.
Vegetation of the locality.
B.
Stipule.
C.
Branch with glomerule and stipule.
D.–E.
Detail of the glomerule and insect landing on the glomerule.
F.
Glomerule with fruits, view from below.
G.
Glomerule with fruits, view from above. Photos: E.B. Souza.
FIGURE 3.
Borreria savannicola
.
A.
Floral branch.
B.
Stipular sheath.
C.
Flower.
D.
Opened corolla.
E.
Hypanthium, calyx, style, and stigma.
F.
Capsule.
G.
Seed in ventral view.
H.
Seed in dorsal view. Illustration: L. Simón.
FIGURE 4.
Microphotography of
Borreria savannicola
.
A–C.
Flower:
A.
Open bud.
B.
Open corolla.
C.
Detail of the stigma.
D– E.
Fruit:
D.
Capsule.
E.
Dehiscence valve in ventral view.
F–H.
Seed:
F.
Dorsal view.
G.
Ventral view.
H.
Detail of the exotestal.
I– M.
Pollengrain:
I.
Equatorialview.
J.
Polarview.
K.
Insideofpollengrain,detailofendoaperture.
L.
Exinebetweenectoaperture.
M.
Exine in polar view. Scale bars in each image.
Representative specimens examined (
paratypes
):
—
BRAZIL
.
Ceará
:
Granja
,
Parada
do km 35,
03°09’49’’S
,
40°46’32’’W
,
40 m
,
15 June 2022
, fl., fr.,
E
.
B
.
Souza
6443,
L
.
H
.
X.
Portela
,
J
.
G
.
Freitas
,
R
.
L
.
S
.
Medeiros
&
A
.
P
.
Sousa
(
HUVA
); margem da CE-362,
03°11’12’’S
,
40°44’48’’W
,
67 m
,
26 June 2019
, fl.,
E
.
B
.
Souza
5683
(
CTES
,
EAC
,
HUVA
);
Papagaios
,
03°11’11’’S
,
40°44’39’’W
,
58 m
,
26 June 2019
, fl.
Fr.
,
E
.
B
.
Souza
5709
(
CTES
,
EAC
,
HUVA
);
03°10’44’’S
,
40°45’17’’W
,
42 m
,
21 June 2018
, fl., fr.,
E
.
B
.
Souza
5328, 5341,
F
.
F
.
Araújo
,
E
.
K
.
S
.
Brandão
&
I
.
V
.
Nepomuceno
(
CTES
,
EAC
,
HUEFS
,
HUVA
); idem,
21 May 2015
, fl.,
E
.
B
.
Souza
3435, 3468
(
EAC
,
HUVA
); idem,
23 April 2015
, fl.,
E
.
B
.
Souza
et al. 3404, 3426
(
EAC
,
HUVA
)
.
Phenology:
—Specimens with flowers were collected in April, May, and June, and specimens with fruits in June.
Distribution and habitat:
—This species is known only from the municipality of Granja,
Ceará
. The geographic distribution of the species is associated with savanna enclaves amidst seasonally dry tropical forests in the Caatinga domain (
Nepomuceno
et al.
2021
), in the proximity of carnauba palms (
Copernicia prunifera
(Mill.) H.E.Moore
), in areas with clay-covered soils, subject to periodic flooding (
Figure 1
).
Etymology
:—The epithet is a reference to the habitat where the new species is found since its occurrence was associated with savanna enclaves in the middle of the Caatinga of northwestern
Ceará
(
Nepomuceno
et al.
2021
).
FIGURE 5.
Anatomical features. Stem:
A–C.
Borreria savannicola
.
A.
Showing stomata.
B.
Lamellar collenchyma.
C.
Vascular system respectively.
D–F.
Borreria scabiosoides
.
D.
Stipular colleter showing raphides.
E.
Stem with angular collenchyma.
F.
Vascular system with cambium. Leaf blade:
G–J.
Borreria savannicola
.
G.
Shows the midrib.
H.
Papillae.
I.
Phenolic idioblasts.
J.
Stomata.
L–O.
Borreria scabiosoides
.
L.
Showing the midrib.
M.
The stomata and substomatic chambers.
N.
The spongy parenchyma with braciform cells.
Arrow
= raphides,
LC
= lamellar collenchyma,
AC
= angular collenchyma,
PH
= phloem and
XY
= xylem, Bar = 100µm in
A
,
B
,
D
and
E
, 200 µm in
C
,
F
and
O
and 400 µm in
G
,
H
and
I
.
Preliminary conservation status
:—The species is known only from the
type
locality, being represented by only one population, which is not within any protected areas. According to the criteria used by the
IUCN (2022)
, the calculated area of occurrence is
1.401 km
² and the estimated occupancy area is
16.000 km
². Therefore, due to the species occurrence area being fragmented in relation to vegetation, mainly due to human interference and changing climatic conditions, and the number of mature individuals being below
250 in
the entire population, in addition to the low rate of mature individuals found, we classified the species as Critically Endangered (CR) (
Figure 1
).
Remarks:
—
Borreria savannicola
has an affinity with
B. scabiosoides
, being confused with it mainly by the morphological characteristics of the leaves, inflorescences, and flowers, besides the same habitat preference.
Among the other species of the genus,
B. savannicola
shares with
B. scabiosoides
the infundibuliform and white corolla, the bilobed stigma, the ellipsoid seed with a reticulate-foveate exotesta, and even the 8–10 zonocolporate, oblate–spheroidal pollen grains, with tectate–perforate, uniformly spinulate exine. Nevertheless, the new species differs mainly in erect habit, linear leaves, terminal glomerule with up to 10 involucral bracts, and obovoid capsule. These species also coincide in their habitat preference, growing in open areas that are permanently or periodically flooded.
B. scabiosoides
is widely distributed in the Americas, from
Cuba
to
Bolivia
and
Brazil
(
Cabral
et al.
2011
,
Miguel & Cabral 2013
).
Borreria savannicola
is anatomically distinct from
B. scabiosoides
by the presence of lamellar collenchyma in the stem (
Figure 5B
). On the other hand, the latter was characterized by angular collenchyma in the stem (
Figure 5E
)., a pattern also observed in
B. latifolia
and
B. orientalis
analyzed by
Zini
et al.
(2016)
. Another striking aspect of
Borreria savannicola
are the papillae on the adaxial surface of the leaves, a feature that was observed in
Galianthe palustris
(Cham. & Schltdl.) Cabaña Fader & E.L. Cabral
[=
B. palustris
] (
Zini
et al.
2016
).
Borreria savannicola
papillae have thick and ornamented cuticle and, according to
Dickson (2000)
, such characteristics can help to reduce the temperature, reflecting the radiation. Besides the papillae, idioblasts containing raphides and tannin were observed, these substances having two important functions in plants that grow in regions with high insolation levels, such as in the Caatinga biome: 1. protects from intense lighting, acting as a sunscreen, and 2. are unpalatable, creating a barrier to herbivory (
Rôças
et al.
1997
;
Barros & Soares 2013
). Other anatomical features that separate the two species can be seen in
Table 1
.