A revision of the genus Ocotea Aubl. (Lauraceae) in Madagascar and the Comoro Islands
Author
Werff, Henk Van Der
Missouri Botanical Garden, P. O. Box 299, St. Louis, MO, 63166 (USA)
henk.vanderwerff@mobot.org
text
Adansonia
2013
3
2013-12-31
35
2
235
279
http://dx.doi.org/10.5252/a2013n2a5
journal article
10.5252/a2013n2a5
93b27db0-ab0a-40d9-862c-1a5c68678186
1639-4798
5206484
18.
Ocotea ivohibensis
van der Werff
,
sp. nov.
(
Figs 8
,
9
)
Ocoteae trichanthae
similis, sed floribus sparse pubescentibus, foliis acuminatis, domatiis trichomatibus rubris ornatis recedit.
TYPUS. —
Madagascar
.
Fianarantsoa
,
Ivohibe
,
Réserve spéciale d’Ivohibe
,
22°29.8’S
,
46°57.3’E
,
1600 m
,
25.X.1997
, fl.,
Messmer
et al. 506
(
holo-
,
P
[
P00648795
]!
;
iso-
,
G
,
MO
[
2299151
])
.
PARATYPES
. —
Madagascar
.
Pic d’Ivohibe
,
1500-2000 m
,
5-11.XI.1924
, fl.,
Humbert
3332
(
MO
,
P
[
P01991805
],
TAN
)
;
Toliara
.
Betroka
,
Ivahona
,
Réserve
spéciale de
Kalambatritra
,
Andrianjafy
et al. 594
(
MO
,
P
,
TAN
)
;
Fianarantsoa
.
Iakora
,
Begogo
,
Bekora
, forêt de
Sahalava
,
Andrianjafy
et al. 770
(
MO
,
P
,
TAN
)
.
DISTRIBUTION. —
Ocotea ivohibensis
sp. nov.
is known from few collections from the Ivohibe massif and the special reserve Kalambatritra in south-central
Madagascar
between 1200 and
1600 m
altitude.
PHENOLOGY. — Flowers: October-November; fruits: June, August.
VERNACULAR NAMES. — Antafonana, Valotra, Varongi mainty.
DESCRIPTION
Tree,
12 m
.
Twigs terete, moderately to densely pubescent, the hairs short, erect, becoming glabrous with age. Terminal buds densely pubescent, the surface not visible. Leaves alternate, 4-10 ×
2-6 cm
, chartaceous, the upper surface sparsely pubescent or glabrous, lower surface moderately pubescent, the hairs erect, curly, denser along the major veins or glabrous except for some hairs along the major veins; the base acute to obtuse, the apex acute to acuminate, acumen to
1 cm
long; gland dots not visible on the leaves; lateral veins 2 to 5 pairs, impressed on the upper surface, raised on the lower surface, tertiary venation raised on the lower surface, immersed or impressed on the upper surface; domatia present in the axils of the basal 2-3 pairs of lateral veins, consisting of a depression largely covered by reddish hairs, the domatia visible as bumps on the upper surface. Petioles
4-7 mm
long, flat above, with a similar indument as the twigs. Inflorescences slender,
2-6 cm
long, racemose or with 1 or 2 cymes basally, few-flowered, moderately to sparsely pubescent, the hairs ascending to erect, in the axils of leaves or in the axils of deciduous bracts near the tips of the branches.Flowers greenish yellow,
3-4 mm
in diameter, the tepals half-erect, spreading in old flowers. Tepals 6, equal, sparsely pubescent outside, pubescent inside,
2 mm
long; stamens 9, all 4-celled,
c.
1 mm
long, glabrous; staminodia stipitiform, pubescent; two globose glands present at the base of the inner 3 stamens; pistil
1.5 mm
long, glabrous; receptacle deeply cup-shaped, glabrous inside. Fruit
1.3 cm
wide,
1 cm
high; cupule
1.6 cm
in diameter,
6 mm
high.
FIG. 8. — Distribution of
Ocotea glaberrima
van der Werff
,
sp. nov.
(
N
),
O. ivohibensis
van der Werff
,
sp. nov.
(
p
),
O. longipes
Kosterm.
(
l
) and
Ocotea macrocarpa
Kosterm.
(
Ì
).
REMARKS
Ocotea ivohibensis
sp. nov.
has been confused with
O. trichantha
Baker
from which it differs as follows:
Ocotea ivohibensis
sp. nov.
has sparsely pubescent flowers (densely pubescent in
O. trichantha
), domatia covered with reddish hairs (white hairs in
O. trichantha
), and the major veins slightly impressed on the upper leaf surface (immersed in
O. trichantha
). In the older collection made by
Humbert
the hairs covering the domatia have largely fallen off; leaf shape, venation and the sparse indument on the flowers allow identification as
O. ivohibensis
sp. nov.
The indument on the lower leaf surface of
O. ivohibensis
sp. nov.
is variable. Some specimens have a sparse indument of erect hairs on the lamina, others have only some hairs along the major veins or are glabrous with the exception of the domatia.