Revision of the Malagasy species of Homalium sect. Eumyriantheia Warb. (Salicaceae)
Author
Wendy L. Applequist
text
Candollea
2016
2016-03-14
71
1
33
60
journal article
10.15553/c2016v711a7
508bebc5-39aa-4f9c-b544-171e992dbbea
2235-3658
161516
2.
Homalium brevipedunculatum
Scott-Elliot
in J. Linn. Soc., Bot. 29: 21. 1891.
Typus
:
Madagascar
. Prov.
Toliara
:
Fort-Dauphin
,
V.18
??
, post-fl.,
Scott Elliot
2600
(
holo-
:
K
[
K000231468
] image seen;
iso-
:
P
[
P00375087
]!).
Tree
to
20 m
tall,
35 cm
dbh; large twigs dark gray to gray or dark brown; young twigs grayish to pale brown, glabrous (to sparsely or partially pubescent); stipules narrowly lanceolate or linear,
1.7-2 mm
, pubescent.
Leaves
subopposite to alternate especially proximally; petiole 3-12(-17) mm, glabrous or sparsely (to moderately) pubescent when young; blade obovate (narrowly or broadly obovate, elliptical), (3.7-)5.1-11 × 2.1- 5.8(-6.5) cm; base convex (cuneate, rounded); apex rounded to emarginate; margins usually somewhat revolute, occasionally minutely toothed then with 1-5 glands toward base of leaf, rarely more; abaxial surface sparsely pubescent on midrib (and blade), drying brown; adaxial surface glabrous, drying brown (green).
Inflorescences
racemose, lateral, sometimes mostly confined to distalmost portion of twigs, 1.5-4(-5.3) cm, densely (to moderately) short-pubescent; peduncle
0.3-0.8 cm
, sturdy; pedicel 1-2(-4) mm, densely pubescent; bracts broadly ovate (ovate), (1.4-)
2-3.8 mm
, densely pubescent; bracteoles ovate, sometimes apparently absent,
1.5-2.5 mm
, densely pubescent.
Flowers:
sepals (4-)5(-6), greenish-beige to whitish or yellowish, narrowly oblong (oblong-elliptical, oblanceolate) with acute apex,
4.5-7.5 mm
, abaxial surface densely to moderately pubescent (to sericeous), often slightly keeled at apex; calyx cup funnelform (becoming cylindrical), densely to moderately pubescent (to sericeous); sepal glands yellow, conspicuously elevated, 0.9-1.3 ×
0.9-1.3 mm
, the upper surface glabrous and wrinkled, with pubescence underneath on abaxial surface; petals greenish-white to white or yellowish-white, oblanceolate to narrowly obovate with a narrow base, acute to obtuse or rounded apex, 4.5-8.5 ×
1.8-3.2 mm
, slightly longer than or about equal to sepals, abaxial surface densely pubescent and often shallowly keeled, adaxial surface glabrous or rarely sparsely pubescent; filaments white to yellowish,
2.4-3.8 mm
, glabrous; anthers yellow,
0.3-0.4 mm
; ovary short-conical, long-pubescent to pilose; styles 3(-4), dark reddish green,
1.5-3.5 mm
, basally long-pubescent.
Seeds
probably 1 per fruit; mature seeds not seen.
Vernacular names. –
“Maranikoditra”
(Faliniaina et al. 37, Ramison et al. 139);
“Rohandriana”
(Service Forestier 6610, 7851)
.
Distribution, ecology and conservation status. –
Homalium brevipedunculatum
is native to littoral and low-elevation humid forests of southeastern
Madagascar
; it is reported primarily on sand, but occasionally on laterite. Fewer than ten distinct locations are known, most close to Fort-Dauphin; though these include some protected land, the remainder of its range is subject to ongoing forest loss, justifying a preliminary conservation status assessment of “Vulnerable” [VU B2ab(iii)] following IUCN Red List Categories and Criteria.
Notes. –
Homalium brevipedunculatum
most closely resembes, and co-occurs in part of its range with
H. nobile
; the latter species has sometimes very large leaves, (5.5-)6.5-18 × (3-)
4-9 cm
, with at least slight pubescence on the midribs, and petals
3.4-5 mm
broad. The other common littoral species with racemose inflorescences and densely pubescent perianth,
H. laxiflorum
, has broader and on average shorter sepals and petals with rounded apices, with the petals usually well exceeding the sepals; neither petals nor sepals are at all keeled, and their indument, though partly dense, is generally short.
Rabenantoandro et al. 954
from Mahabo (
23°10’20”S
47°42’23”E
; MO) has flowers like those of
H. brevipedunculatum
, with narrow petals, and the leaf midribs are virtually glabrous, but the leaves are very large as is typical of
H. nobile
. Both species are known from Mahabo. It is suggested to be a hybrid between those species.
Additional material examined
. –
Madagascar
. Prov.
Fianarantsoa
:
S of
Farafangana
, near village of
Mahabo
,
23°10’51”S
47°42’29”E
,
30 m
,
5.XI.2001
, fl.,
McPherson
&
Rabenantoandro
18358
(
MO
,
P
)
;
Fkt. Nosy
ala,
forêt d’Analazaha
,
23°10’13”S
47°43’27”E
,
22 m
,
26.VIII.2003
, fl.,
Rabehevitra et al.
558
(
P
).
Prov.
Toliara
:
Fort-Dauphin
, fl.,
Cloisel
125
(
P
); forêt sur la route de
Ste Luce
, partie S,
24°46’S
47°09’E
,
0-10 m
,
23.III.1989
, post-fl.,
Dumetz
631
(
MO
,
P
)
;
Fkt. Sainte Luce
,
24°46’41”S
47°10’04”E
,
17.XII.2000
, fl. and post-fl.,
Faliniaina
et al. 37
(
MO
)
;
Bemangidy
forest, ca.
3 km
E of
Antsotso
, along RN 12a,
24°34’05”S
47°12’38”E
,
100 m
,
10.II.2006
, post-fl.,
Lowry
et al. 6756
(
MO
,
P
)
;
Ste. Luce
region,
Manafiafy
,
24°47’S
47°10’E
,
25 m
,
19.X.1989
, fl.,
McPherson
et al. 14168
(
MO
,
P
)
;
few km NW of
Manantenina
,
forêt d’Analalava
,
24°13’S
47°21’E
,
40 m
,
28.X.1989
, fl.,
McPherson
14274
(
MO
,
P
)
;
N of town near village of
Ste. Luce
(
Manafiafy
), forest NW of village,
24°47’S
47°10’E
,
20 m
,
16.I.1990
, post-fl.,
McPherson
et al. 14808
(
MO
,
P
)
;
Taolagnaro
, forêt M 7,
24°57’31”S
47°00’02”E
,
0-10 m
,
6.X.2000
, fl.,
Rabenantoandro
et al. 333
(
MO
,
P
)
;
Fkt. Sainte Luce
, forêt sublittorale de S8,
Hova
site minier,
24°46’29”S
49°08’57”E
,
6 m
,
4.XI.2003
, fl.,
Rabenantoandro
&
Ramisy
1540
(
MO
,
P
)
;
Fkt. Sainte Luce
, forêt
d’Analavinaky
, à l’W du village
d’Ambandrika
,
24°46’30”S
47°09’00”E
,
21 m
,
24.XI.2009
, fl.,
Rakotovao
4736
(
MO
)
;
sentier reliant
Ampasy et Iaboakoho
village,
24°35’57”S
47°09’31”E
,
29.XI.2009
, fl.,
Rakotovao
et al. 4909
(
MO
)
;
forêt
d’Ambavarano
,
24°57’32”S
47°02’07”E
,
7 m
,
11.XII.2006
, fl,
Ramison
et al. 139
(
MO
)
;
Ste. Luce
, fkt.
Manafiafy
, forêt de
Manafiafy
,
24°46’08”S
47°10’14”E
,
21 m
,
30.XI.2002
, fl.,
Randrianaivo
et al. 865
(
MO
,
P
)
;
Antsotso
, forêt d’Ivohibe,
24°56’46”S
47°19’54”E
,
386 m
,
XI.2005
, fl.,
Razakamalala
et al. 2458
(
MO
,
P
)
;
Iaboko,
Antsotso
Avaratra
,
24°34’35”S
47°12’28”E
,
25 m
,
13.XII.2007
, fl.,
Razakamalala
et al. 4025
(
MO
,
P
)
;
N of Ft. Dauphin on road to
Ste. Luce
, block S-9 of QUIT-FER,
24°47’S
47°11’E
,
15 m
,
12.XI.1990
, fl.,
Schatz et al.
2999
(
MO
,
P
)
;
Mandena
,
19.XII.1952
, post-fl.,
Service Forestier
6610
(
P
)
;
Mandena
,
3.XI.1953
, fl.,
Service Forestier
7851
(
P
)
;
Vinanibe
, à l’W de
Fort-Dauphin
,
7.XII.1968
, fl.,
Service Forestier
28619
(
P
[2 sheets]).