Enlarging the monotypic Monocarpieae (Annonaceae, Malmeoideae): recognition of a second genus from Vietnam informed by morphology and molecular phylogenetics
Author
Chaowasku, Tanawat
Author
Damthongdee, Anissara
Author
Jongsook, Hathaichanok
Author
Ngo, Dung T.
Author
Le, Hung T.
Author
Tran, Duc M.
Author
Suddee, Somran
text
Candollea
2018
2018-11-23
73
2
261
275
journal article
28564
10.15553/c2018v732a11
a6c2daaa-106b-4373-9e9b-22b88fa2276e
2559368
Leoheo domatiophorus
Chaowasku, D.T. Ngo & H.T. Le,
spec. nova
(
Fig. 2C–H, 3A, 4A, 5–7
).
Holotypus
:
VIETNAM
.
Prov. Thua Thien-Hue
:
Nam Đông Distr
.,
19.III.2009
, fl.,
HUAF collectors
2009-0 3-19
-ND
(
CMUB
!; iso-:
G
!,
P
!).
Leoheo domatiophorus Chaowasku, D.T. Ngo
ð H.T. Le differs from species of the genus
Monocarpia Miq.
by the lack of intramarginal leaf veins and by having axillary inflorescences, leaf domatia, longitudinal ridges on the monocarp surface, and subsessile monocarps with a stout stipe.
Medium-sized (to large)
trees
, 15–25(–30) m tall; young
twigs
puberulous with appressed hairs.
Petiole
5 – 8 mm long, grooved on upper surface, both sides puberulous with appressed hairs;
leaf
blade elliptic, 9.1– 22.8 × 3.1– 6.5 cm, both surfaces glabrous, base cuneate, apex caudate-acuminate; midrib raised and puberulous with appressed hairs on lower surface, sunken (becoming less so toward apex) and puberulous with appressed and erect hairs (more sparsely so toward apex) on upper surface; secondary veins 11–12 per side, angle with midrib at middle part of leaf blade 40°– 50°.
Flower(s)
in a 1- to 2-flowered axillary inflorescence, bisexual; peduncle 7–10 mm long (up to 17 mm long and 6–8 mm thick in fruit), indumentum puberulous-tomentose with erect hairs, bract(s) often leaf-like, placed at top of peduncle, often caducous; pedicel 2–2.5 cm long (6–7 mm thick in fruit), tomentose with erect hairs, bracts ovate, generally 2 per pedicel, one placed at ± midpoint of pedicel, another near pedicel base, often caducous.
Sepals
triangular-ovate, 8–11 × 7–8 mm, both surfaces and margin tomentose with erect hairs. Outer
petals
obovate, 5.8–6.2 × 1.8–2.1 cm, both surfaces and margin puberuloustomentose with erect hairs, apex obtuse-rounded; inner petals elliptic-obovate, 5.9–6.1 × 2–2.3 cm, indumentum similar to that of outer petals, apex obtuse. Torus volcano-shaped with a slightly sunken apex, glabrous.
Stamens
70–76 per flower, c. 2 mm long, connective truncate, covering thecae.
Carpels
3–4 per flower, 4.5–6 mm long; stigmas ± peltate and irregularly lobed (5–6 lobes); ovaries villous with appressed hairs; ovules 15–17 per ovary, lateral, biseriate.
Monocarp(s)
1– 4 per fruit, subsessile (with a stout stipe), cylindrical, 5.5–7.5 × 3–3.5 cm, pericarp c. 3 mm thick, hardened when dry, surface shallowly coarsely rugose-verrucose with 7–8 longitudinal ridges (some ridges running to only midpoint of monocarps, whereas some forming loops with others), indumentum short-tomentose (often more sparsely so or almost glabrous on ridges), apex not apiculate.
Seeds
9–17 per monocarp, flattened-ellipsoid to flattened-ovoid, 1.7–2.1 × 1– 1.2 cm, more flattened for in-between seeds, surface pitted and slightly rugose, raphe slightly raised with a slight groove in the middle, endosperm ruminations spiniform.
Etymology.
– The specific epithet
domatiophorus
is a masculine adjective in first and second declensions, referring to “domatia” on the lower leaf surface.
Habitat and phenology.
– Occurring in (edges of) evergreen forests, disturbed evergreen forests, or edges of secondarforests adjacent to the primary ones; on a steep hillside or near a stream at 270–350 m. Flowering material collected in March. Fruiting material collected in July.
Fig. 3. –
Inflorescence position of
Leoheo
Chaowasku
(
A
) and
Monocarpia
Miq.
(
B
).
A.
Axillary inflorescences/infructescences of
Leoheo domatiophorus
Chaowasku, D.T. Ngo & H.T. Le
;
B
. Terminal inflorescence of
Monocarpia
kalimantanensis
Kessler.
[
A:
HUAF collectors 2009-0 3-19-ND
, CMUB;
B
:
Sidiyasa et al. 3469
, L] [Photos:
A:
D.T. Ngo;
B:
Arbainsyah]
Fig. 4. – Lower leaf surface of
Leoheo
Chaowasku
(
A
) and
Monocarpia
Miq.
(
B
).
A.
Leoheo
domatiophorus
Chaowasku, D.T. Ngo & H.T. Le
, with a hairy domatium;
B.
Monocarpia maingayi
(Hook. f. & Thomson) I.M. Turner, without domatia. [
A:
Chaowasku 131
, CMUB;
B:
Promchua 18
, CMUB]
Fig. 5. –
Reproductive organs of
Leoheo
domatiophorus
Chaowasku, D.T. Ngo & H.T. Le
:
A.
Flower with petals and stamens removed;
B.
Flower with petals, stamens, and carpels removed, back view, showing outer side of sepals;
C
. Same as (
B
), but on another side,
showing a volcano-shaped torus and inner side of sepals;
D
. Inner side of an outer petal;
E
. Outer side of an outer petal;
F
. Inner side of an inner petal;
G
. Outer side of an inner petal;
H
. Stamen, abaxial side;
I.
Stamen, adaxial side;
J
. Carpels, showing enlarged and irregularly lobed stigmas;
K.
Fruit, showing longitudinal ridges on monocarp surface;
L
. Seed, lateral view, showing a raphe;
M.
Seed, lateral view, showing a pitteand slightly rugose surface;
N.
Cross section of a seed, showing spiniform endosperm ruminations.
[
A–J:
HUAF collectors 2009-0 3-19-ND
, CMUB;
K:
Chaowasku 131
, CMUB;
L–N:
Chaowasku 165
, CMUB] [Drawing: A. Damthongdee]
Fig. 6
. –
Leoheo
domatiophorus
Chaowasku, D.T. Ngo & H.T. Le
, showing habit with inflorescences and flowers.
[
HUAF collectors 2009-0 3-19-ND
,CMUB] [Drawing: A. Damthongdee]
Conservation status. –
Leoheo domatiophorus
grows in lowland rainforests of Nam Đông (where part of Bach Ma National Park is located) and A Luoi Districts of Thua Thien-Hue Province (
Fig. 7
), and has also been observed in the adjacent Quang Tri and Quang Nam Provinces as well. This habitat has been continuously destroyed for
Acacia
Mill.
cultivation and other kinds of deforesting land use. Furthermore, only a small part of the habitat of
L. domatiophorus
is protected in the Bach Ma National Park. Due to its restricted range in threatened lowland rainforests of central Vietnam, the new species qualifies as “Vulnerable” [VU B2ab(iii)] using the IUCN Red List Categories and Criteria (
IUCN, 2012
).
Paratypi.
–
VIETNAM. Prov. Thua Thien-Hue:
Nam Đông Distr., 16°08'N 107°37'E, VII.2014, ster.,
Chaowasku 129
(CMUB); A Luoi Distr., 16°01'N 107°31'E, VII.2014, ster.,
Chaowasku 130
(CMUB);
ibid. loco,
VII.2014, fr.,
Chaowasku 131
(CMUB); Nam Đông Distr., 16°08'N 107°37'E, VII.2016, fr.,
Chaowasku 165
(CMUB);
ibid. loco,
VII.2016, ster.,
Chaowasku 166
(CMUB).