A new generic system for the pantropical Caesalpinia group (Leguminosae)
Author
Gagnon, Edeline
https://orcid.org/0000-0003-3212-9688
Institut de recherche en biologie vegetale and Departement de sciences biologiques, Universite de Montreal, H 1 X 2 B 2, Montreal, Quebec, Canada
edeline.gagnon@gmail.com
Author
Bruneau, Anne
Institut de recherche en biologie vegetale and Departement de sciences biologiques, Universite de Montreal, H 1 X 2 B 2, Montreal, Quebec, Canada
Author
Hughes, Colin E.
Department of Systematic and Evolutionary Botany, University of Zuerich, 8008, Zuerich, Switzerland
Author
de Queiroz, Luciano Paganucci
Universidade Estadual de Feira de Santana, BR 116, Km 03, Campus Universitario, Feira de Santana 44031 - 460, Bahia, Brasil
Author
Lewis, Gwilym P.
Comparative Plant and Fungal Biology Department, Royal Botanic Gardens, Kew, Richmond, Surrey, TW 9 3 AB, United Kingdom
text
PhytoKeys
2016
2016-10-12
71
1
160
http://dx.doi.org/10.3897/phytokeys.71.9203
journal article
http://dx.doi.org/10.3897/phytokeys.71.9203
1314-2003-71-1
FFA8FF9AFFEAFFDABA68757DFF9EFF8B
160340
13
.
Biancaea Tod., Nuovi Gen. Sp. Orto Palermo: 21. 1860, descr. emended E. Gagnon & G. P. Lewis
Figs 20G-J
, 22
Campecia
Adans. 1763; no type species designated, and no species names ever published in this genus. It is thus not possible to apply this name which is rejected against
Biancaea
.
Caesalpinia sect. Sappania
DC. 1825.
Diagnosis.
Biancaea
is closely related to
Mezoneuron
, differing principally in its fruit, a coriaceous, laterally compressed, wingless, dehiscent pod (except
Biancaea decapetala
, which has somewhat inflated, boat-shaped pods, often with a narrow wing or ridge along the upper suture). In contrast,
Mezoneuron
has chartaceous, coriaceous or ligneous pods, which are also laterally compressed, but indehiscent, and with a wing along the upper suture. In addition, the ovary of
Biancaea
species always has a velvety indumentum (vs. glabrous to pubescent in
Mezoneuron
).
Type
.
Biancaea scandens
Tod. ≡
Biancaea decapetala
(Roth) Deg.
Emended description.
Lianas, climbing or trailing shrubs (1-3 m), or small trees (2.5-10 m), armed with short, slightly recurved prickles, scattered along the branches; young shoots pubescent or glabrescent. Stipules lanceolate-oblong to broadly-ovate, sometimes amplexicaul at base, 3-4 mm to 4.5 cm long, caducous or sub-persistent to persistent. Leaves alternate (except in
Biancaea oppositifolia
), bipinnate, ending with a pair of pinnae, rachis pubescent (glabrous in
Biancaea oppositifolia
), armed with pairs of prickles at the base of each pinna, sometimes also scattered on the rachis; pinnae in 4-19 opposite to alternate pairs; leaflets opposite to alternate, in 5-20 pairs per pinna, blade membranous, eglandular, glabrous to pubescent, 10-35
x
4-15 mm (4-10
x
1.5-4.5 cm in
Biancaea oppositifolia
), oblong-elliptic, apex acute, obtuse, rounded to emarginate, base asymmetric. Inflorescences erect, showy, terminal or axillary racemes or panicles; rachis eglandular, pubescent, unarmed or with a few scattered prickles, mainly near the base; bracts ovate-lanceolate, acuminate, 2-8 mm long, caducous. Flowers bisexual, zygomorphic; calyx with a short hypanthium and 5 sepals, the lower sepal cucullate and covering the other 4 in bud, sepals pubescent (except in
Biancaea sappan
), caducous, but the hypanthium persisting as a calyx ring around the pedicel as fruits mature; petals 5, free, yellow to white, eglandular, the claws pubescent; the median petal smaller than the other 4, and inrolled towards the centre, lateral petals oblong, obovate to spathulate, 4-10
x
2-8 mm; stamens 10, filaments densely pubescent (most evident at the base), eglandular, 10-15 mm long; ovary densely velutinous. Fruit a coriaceous, glabrous, eglandular, oblong-elliptic to obovate, dehiscent, wingless, laterally compressed (but somewhat inflated and often with a narrow wing along the upper suture in
Biancaea decaptala
), 4.5-10
x
2-4 cm, 2-8-seeded pod, usually much broader at the rounded to truncate apex, which terminates in a sharp beak. Seeds flat, elliptic, ovoid to orbicular, c. 2 cm in diameter, black or brown.
Geographic
distribution.
A genus of six species widespread across southern Asia, from India, to Myanmar (Burma), Thailand, Cambodia, Vietnam, south China, Japan, the Philippines, and the Malay Peninsula and Archipelago, one species endemic to Sabah (near Sandakan).
Biancaea decapetala
, native to Asia, has been widely introduced across the tropics as a hedge plant or ornamental and is considered to be invasive in South Africa and Hawaii.
Habitat.
Primary forest and forest margins, grasslands, scrub vegetation, riverine habitats, secondary thickets and clearings. From the coast to mountain slopes.
Etymology.
Unknown.
Notes.
Based on the study of
Gagnon et al. (2013)
,
Molinari-Novoa et al. (2016)
provided some, but not all, of the required nomenclatural transfers to the genus
Biancaea
. Furthermore, they did not emend the description of the genus, as provided here.
References.
Hattink (1974)
;
Vidal and Hul Thol (1976)
;
Jansen (2005)
;
Brummitt et al. (2007)
;
Chen et al. (2010a)
;
Molinari-Novoa et al. (2016)
.
Figure 22.
Biancaea decapetala
(Roth) O. Deg.
A
flowering branchlet and foliage
B, C
leaflets viewed from above and below, respectively
D
flower with parts separated, and centre of flower enlarged
E
calyx three views
F
lateral petal
G
median petal
H
stamen
I
anther
J
gynoecium
K
fruits
L
seed.
A
from
Rutherford-Smith
11062
B, C
from
White
2478
D-J
from
Chase
4564
K
,
L
from
Myre
2528. Drawn by D. Erasmus, originally published in
Flora Zambesiaca
, vol. 3 part 2, page 182, figure 3.2.39 (2007).