A new Madagascan species of Hancea Seem. (Euphorbiaceae)
Author
McPHERSON, Gordon
text
Adansonia
2012
3
2012-06-30
34
1
71
75
http://dx.doi.org/10.5252/a2012n1a8
journal article
10.5252/a2012n1a8
1639-4798
4599314
Hancea inhospita
McPherson
,
sp. nov.
(
Fig. 1
)
Ab ceteris speciebus madagascariensibus cognitis foliis ovatis vel ellipticis domatiis nullis differt.Ab
H. spinulosa
laminis foliorum apice late acuminatis vel aliquando obtusis (nec anguste acuminatis), nervis in axillis domatiis non instructis, stipulis brevibus (
1-2 mm
contra
3-5 mm
), floribus staminatis bracteis brevibus (
1 mm
contra
1.5-3 mm
) et staminibus paucioribus (45-50 contra 80-90) distinguenda.
TYPUS. —
Madagascar
. Prov.
Toamasina
,
Ambatovy
,
NE
of
Moramanga
, low, dense forest on lateritic soils,
18°51’12”S
,
48°18’48”E
,
1100 m
,
26.II.1998
, fl., fr.,
McPherson 17461
(holo-,
MO
! [#5888427]; iso-,
K
,
MO
!,
P
,
TAN
)
.
PARATYPI
. —
Madagascar
.
Prov.
Toamasina
, parc national
de Zahamena, NW
de la rivière
Moango
,
17°33’57”S
,
48°53’58”E
,
740 m
,
24.X.2000
, fl., fr.,
Randriamanarivo
17
(
MO
,
P
,
TAN
)
. —
Ambatovy
, forêt
d’Analamay Sud
,
18°48’18”S
,
48°19’48”E
,
1220 m
,
18.XII.2004
, fl.,
Andriamahefarivo
47
(
MO
,
P
,
TAN
)
;
idem
,
18°48’25”S
,
48°20’43”E
,
1095 m
,
9.X.2007
, fl., fr.,
Bernard
602
(
MO
,
P
,
TAN
)
;
idem
,
18°49’25”S
,
48°20’04”E
,
1068 m
,
31.III.2005
, fr.,
Rakotovao
1701
(
MO
,
TAN
)
;
idem
,
18°49’58”S
,
48°19’46”E
,
1061 m
,
11.III.2005
, fr.,
Rakotovao
1614
(
MO
,
P
,
TAN
)
;
idem
,
18°50’53”S
,
48°18’29”E
,
1124 m
,
12.X.2005
, fl.,
Razanatsoa
67
(
MO
,
P
,
TAN
)
;
idem
,
18°51’07”S
,
48°17’49”E
,
1109 m
,
16.II.2005
, fl., fr.,
Rakotovao
1183
(
MO
,
P
,
TAN
)
;
idem
,
18°51’22”S
,
48°18’34”E
,
1141 m
,
2.III.2005
, fl.,
Rakotovao
1461
(
MO
,
TAN
)
;
idem
,
18°51’24”S
,
48°17’41”E
,
1000 m
,
6.III.1997
, fl.,
Rakotomalaza
1258
(
MO
,
P
,
TEF
)
;
idem
,
18°51’34”S
,
48°18’25”E
,
1050 m
,
27.II.1997
, fl.,
Rakotomalaza
1196
(
MO
,
P
,
TEF
)
. —
Prov.
Fianarantsoa
,
Farafangana
, forêt
de Manombo
,
23°10’12”S
,
47°42’50”E
,
21 m
,
24.III.2004
, fl.,
Ludovic
672
(
MO
,
P
,
TAN
)
. —
Prov.Tulear
,
Fort-Dauphin
, forêt
d’Ivohibe
,
24°34’14”S
,
047°12’04”E
,
265 m
,
28.XI.2005
, fr.,
Razakamalala
2438
(
MO
,
P
,
TAN
)
;
idem
,
24°33’52”S
,
47°11’43”E
,
386 m
,
XI.2005
, fl.,
Razakamalala
2446
(
MO
,
P
,
TAN
)
.
DESCRIPTION
Small tree
2-8 m
; diameter at breast height up to
12 cm
; young twigs glabrous,often resinous near tips; stipules subulate,
1.5-2 mm
long, caducous. Leaves opposite to subopposite and unequal, or alternate. Blades elliptic-oblong to occasionally ovate,the smaller 1.4-6.5 ×
0.9-2.8 cm
, the larger 2.3-16×
1.2-4.5 cm
, somewhat coriaceous, obtuse to broadly cuneate at the base, typically rather broadly acuminate at the apex but sometimes merely acute or even obtuse (most often in smallest leaves); midrib raised on both surfaces, usually pubescent abaxially with erect hairs more than
0.5 mm
long, but sometimes glabrate or glabrous;secondary veins8-12on each side of the midrib, domatia absent; both surfaces without glandular granules or embedded circular glands, glabrous except for the midrib abaxially.Shorter petioles
2-25 mm
, the longer
4-43 mm
, narrowly canaliculate, pulvinate at both ends, often pubescent abaxially like the midrib but sometimes glabrate or glabrous.
FIG. 1.—
Hancea inhospita
McPherson
,
sp. nov.
: fruiting branchlets,
McPherson 17461
, holo-, MO.
Plants monoecious or (apparently) dioecious. Staminate inflorescences racemiform, axillary,
2-5 cm
long, resinous-scurfy, flowers solitary along the axis or in groups of 2-3, bracts up to
1 mm
long, quickly caducous, pedicels
1-1.5 mm
; buds
1.5-2 mm
in diameter; sepals 3-4,
1.5-2.5 mm
long; stamens
45-50 in
number. Pistillate inflorescences axillary; peduncle
2-7 cm
long, bearing a single terminal flower; pedicel
c
.
1 mm
; calyx of five subulate sepals
1-3 mm
long; styles not seen. Fruit
c
.
6 mm
high,
9-10 mm
in diameter, minutely papillate-granular and puberulent-glabrate, spinulose, each sixth of the capsule bearing one spinule up to
2 mm
long.
DISTRIBUTION AND ECOLOGY
Hancea inhospita
sp. nov.
is endemic to the humid evergreen forests of eastern
Madagascar
on lateritic soils or sand at recorded elevations from
21 to 1220m
(
Fig. 2
).
REMARKS
The new species differs in leaf shape and apex from
Hancea capuronii
(Leandri) S.E.C.Sierra, Kulju & Welzen
, which is the only Madagascan species having obovate to oblanceolate leaves with obtuse apices. From the four other Madagascan species known,
H. inhospita
is easily distinguished by its lack of leaf domatia. It most closely resembles
H. spinulosa
but differs in having leaves with shorter and broader tips, in lacking leaf domatia entirely, and in having shorter stipules (
1-2 mm
vs
3-5 mm
), shorter staminate bracts (
1 mm
vs
2-3 mm
) and fewer stamens per staminate flower (45-50 vs
c
. 100).
E TYMOLOGY
The specific epithet, meaning “not providing shelter”, was suggested by the fact that
Hancea inhospita
can be most readily separated from its congeners with similar leaves by its lack of domatia in the axils of the leaf veins.
KEY TO
HANCEA
SEEM. IN
MADAGASCAR
1. Leaves obovate to oblanceolate, the apex obtuse ............................................................ ....................................................
H. capuronii
(Leandri) S.E.C.Sierra, Kulju & Welzen
— Leaves ovate or elliptic, the apex acuminate or acute, rarely obtuse ............................. 2
2. Twigs densely pubescent ...............
H. acuminata
(Baill.) S.E.C.Sierra, Kulju & Welzen
— Twigs glabrous or obscurely puberulent ...................................................................... 3
3. Domatia present in axils of leaf veins .......................................................................... 4
— Domatia absent .........................................................
H. inhospita
McPherson
,
sp. nov.
4. Fruit less than
10 mm
in diameter (excluding spinules); spinules up to
4 mm
long, 6-
c.
24 in
number .............................
H. spinulosa
(McPherson) S.E.C.Sierra, Kulju & Welzen
— Fruit more than
15 mm
in diameter (excluding spines); spines
5-15 mm
long, more than
25 in
number ............................................................................................................. 5
5. Leaf apex long-acuminate; petiole not canaliculate; known only from Ampasindava Peninsula ..............................................................................................................
H.
sp. 1
— Leaf apex shortly and broadly acuminate; petiole canaliculate, at least distally; known only from the summit of Mt. Vohimarangitra .................................................
H.
sp. 2