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
6.
Denisophytum R. Vig., Notul. Syst. (Paris) 13(4): 349. 1948, descr. emended E. Gagnon & G. P. Lewis
Figs 11G-I
, 12
Diagnosis.
Denisophytum
is closely related to
Tara
(Fig.
3
), but differs in having flowers with a lower cucullate sepal with an entire margin (vs. a lower cucullate sepal with a pectinate margin), and dehiscent, coriaceous, laterally compressed pods (except for
Denisophytum madagascariense
which has inflated fruits) (vs. indehiscent, somewhat fleshy, coriaceous pods that are slightly turgid). Morphologically, species of
Denisophytum
are most likely to be confused with those of
Caesalpinia
s.s., but no reliable diagnostic characters have been found to differentiate these two genera. The corolla of
Denisophytum
species is consistently yellow and the flowers are bee pollinated, whereas
Caesalpinia
s.s. species display a wide range of flower colour (yellow, orange, red, green and white) and pollination syndromes (chiropterophily, ornitophily, psychophily and mellitophily).
Type
.
Denisophytum madagascariense
R. Vig.
Emended description.
Shrubs to small trees, 0.5-2 (-5) m tall, armed with straight or curved, deflexed prickles, scattered along shoots and also in pairs at the petiole base (except
Denisophytum madagascariense
which is unarmed); young twigs glabrous to pubescent, eglandular. Stipules either minute or foliaceous and conspicuous, caducous (persistent in
Denisophytum stuckertii
). Leaves alternate, bipinnate, ending with a pair of pinnae; petiole and rachis glabrous and eglandular, with membranous or spinulose stipels at the insertions of pinnae on the leaf rachis, occasionally also at the insertion of the leaflets on the pinnae; pinnae opposite, in 1-6 pairs per leaf; leaflets opposite, in 2-10 (-11) pairs per pinna, elliptic, obovate to orbicular, with a rounded, acuminate or emarginate apex, c. 2-25
x
3-12 mm, leaflet blades glabrous to pubescent, eglandular. Inflorescence a terminal or axillary raceme; bracts caducous (acuminate and filiform in
Denisophytum stuckertii
). Flowers bisexual, zygomorphic; calyx a short hypanthium with 5 sepals, c. 4-10 mm long, eglandular, glabrous to finely pubescent, lower sepal cucullate and covering the other 4 sepals in bud, all sepals caducous, leaving a persistent free hypanthium ring on the pedicel as the fruit develops; petals 5, free, yellow, the median petal sometimes with red markings on the inner face of the blade, c. 5-10 mm long, obovate, petal claw almost absent (present in
Denisophytum madagascariense
); stamens 10, free, filaments pubescent and eglandular (8-11 mm long in
Denisophytum madagascariense
), anthers dorsifixed, glabrous to pubescent; ovary glabrous. Fruits coriaceous, oblong-elliptic, laterally compressed (but inflated in
Denisophytum madagascariense
), glabrous, eglandular pods with a tapering, sharp beak, 18-49
x
5-15 mm, elastically dehiscent, with twisting valves. Seeds ovoid, laterally compressed.
Geographic distribution.
Denisophytum
comprises nine taxa in eight species, found across North America, South America and Africa, including Madagascar, a classical highly disjunct trans-continental distribution typical of lineages occupying the succulent biome sensu
Schrire et al. (2005)
. Three species are distributed in Mexico, Florida, and the Caribbean, one species is endemic to Paraguay and Argentina, one is endemic to northern Madagascar, and the other three occur in northern Kenya, Somalia and Arabia. An evaluation of species limits is needed in this group.
Habitat.
Low deciduous seasonally dry tropical woodland or scrubland, also in open pineland or coastal plains and foothills. Species in Madagascar and Africa grow in limestone soils.
Etymology.
There is no indication of the etymology of
Denisophytum
in the posthumous publication of the generic name. Nevertheless, it is quite likely that the author,
Rene
Viguier, had intended to honour his friend and collaborator, Marcel Denis, a botanist with expertise in the genus
Euphorbia
in Madagascar. Sadly, M. Denis passed away prematurely at the age of 33 in 1929 (
Allorge and Allorge 1930
).
References
.
Britton and Rose (1930)
;
Burkart (1936
: 84-86);
Viguier (1949)
;
Roti-Michelozzi (1957)
;
Brenan (1967)
;
Capuron (1967)
;
Thulin (1983
: 16-18;
1993
: 344-347);
Ulibarri (1996)
;
Du Puy and Rabevohitra (2002)
;
Barreto
Valdes
(2013)
.
Figure 12.
Denisophytum stuckertii
(Hassl.) E. Gagnon & G. P. Lewis.
A
foliage and inflorescences
B
median leaflet undersurface
C
stipule
D
leaf rachis spines
E
bract
F
calyx opened out
G
median petal
H
lateral petal
I
stamen
J
gynoecium
K
stigma
L
developing ovary
M
infructescence,
N
single fruit valve after dehiscence.
A, B, D-K
from
Renvoize et al.
3538
C, M
from
Venturi
7697
L
from
Ruiz et al.
10488c
N
from
Aguilar
241. Drawn by Eleanor Catherine.