Studies of Malagasy Eugenia (Myrtaceae) - III: Seven new species of high conservation concern from the eastern littoral forests
Author
Snow, Neil
Herbarium Pacificum, B. P. Bishop Museum, 1525 Bernice Street, Honolulu, Hawaii 96825, USA
nsnow2@mt.gov
Author
Rabenantoandro, Johny
Rio Tinto / QIT Madagascar Minerals S. A., Villa 3 H Lot J, 169 Antananarivo, 101, MADAGASCAR; E-mails: johny. rabenantoandro @ riotinto. com;
johny.rabenantoandro@riotinto.com
Author
Randriatafika, Faly
Rio Tinto / QIT Madagascar Minerals S. A., Villa 3 H Lot J, 169 Antananarivo, 101, MADAGASCAR; E-mails: johny. rabenantoandro @ riotinto. com;
johny.rabenantoandro@riotinto.com
Author
Rabehevitra, David
Rio Tinto / QIT Madagascar Minerals S. A., Villa 3 H Lot J, 169 Antananarivo, 101, MADAGASCAR; E-mails: johny. rabenantoandro @ riotinto. com;
johny.rabenantoandro@riotinto.com
Author
Razafimamonjy, N. Darie
Department of Botany, University of Antananarivo, MADAGASCAR; E-mail: dariejosmail @ yahoo. com
Author
Cable, Stuart
Royal Botanic Gardens, Kew, Richmond, Surrey, UNITED KINGDOM; E-mail: s. cable @ kew. org
text
Phytotaxa
2012
2012-03-15
48
1
39
60
http://biotaxa.org/Phytotaxa/article/view/phytotaxa.48.1.7
journal article
10.11646/phytotaxa.48.1.7
1179-3163
4776766
Eugenia petrikensis
N. Snow & Randriat.
,
sp. nov.
(
Figs. 2
,
5
).
A congeneribis madagascariensibus combinatione characterum sequentium distinguitur: frutex
0.3–2 m
altus; petioli
3.5–4.5 mm
longi; folia
16.5–30 mm
longa,
10–17.5 mm
lata, elliptica, basi cuneata vel rotundata, apice obtuso; petala magentea ad marginem hyalina; stamina 20–30.
Type:
―
MADAGASCAR
. Prov.
Toliara
:
District Tolagnaro
; forêt
de Petriky
,
25°05’S
,
46°52’E
,
26 October 1989
,
N. Dumetz
812,
G. McPherson
&
R
.
Rabevohitra
(
holotype
MO! [sheet no. 3778658])
.
Shrubs
0.3–2 meters at flowering.
Branchlets
moderately to densely sericeous on emergence but becoming sparsely so to nearly glabrous (trichomes dibrachiate, dense, clear to ferrugineous that become whitish brown); oil glands not visible or only faint (becoming more prominent in age), occasional; internodes ca. 1.0–
1.2 cm
long.
Leaves
coriaceous, evenly distributed along branchlets, slightly discolorous, emerald green and slightly glossy above, citrine and matte below; venation brochidodromous. Stipules absent.
Petioles
3.0–
4.5 mm
, slightly sulcate above, eglandular but rugose-wrinkled throughout, glabrous, yellowish-green.
Leaf blades
1.6–3.0 x 1.0–
1.7 cm
, elliptic, base cuneate to rounded, margin somewhat revolute except near apex, laminar surface flat, apex and tip obtuse; adaxial surface sparsely sericeous towards base, oil glands absent, midvein slightly sulcate proximally but becoming flush distally; abaxial surface glabrous, oil glands absent, secondary veins invisible or faint with 4–5 veins arising on each side of midvein, sometimes slightly raised (dried material), intramarginal vein faint,
0.2–0.5 mm
from margin at laminar midpoint.
Inflorescence
axillary or ramiflorous, consisting of monads or 3–flowered cymes, solitary, paired or generally in fascicles (sometimes densely so).
Peduncles
(or pedicels, if flowers solitary)
2–5 mm
long, stiff, terete to compressed, medium green, glabrous or with a few scattered hairs. Anthopodia absent; metaxphylls mostly absent (present on one flower).
Bracteoles
0.5–0.7 mm
long, ca.
0.3 mm
wide at base, narrowly triangular to triangular, scalelike, spreading, stiff, sparsely hairy, persistent in flower.
Hypanthium
1.0–
1.5 mm
long,
1.3–1.5 mm
wide at apex at base of calyx lobes, obconic, glabrous, whitish to ivory or stramineous, oil glands common but small and inconspicuous, surface smooth, apex of ovary glabrous at base of style but villous towards staminal ring.
Calyx lobes
4,
1.4–1.8 mm
long, rounded to oblong, apex broadly rounded, glabrous, upper surface often magenta or cerise during anthesis and hyaline along margin, lower surface greenish.
Petals
4, 3.0–4.1 x
2.1– 2.2 mm
, ovate, oil glands sparse, magenta but hyaline on margins. Staminal ring villous, diameter
1.5–1.8 mm
.
Stamens
20–30, in 1 or 2 series; filaments ca.
2–3 mm
long, whitish; anther sacs
0.7–0.9 mm
long, globose to cylindrical, dorsifixed, bearing a single apical gland, cream colored.
Style
ca.
3 mm
long, whitish, glabrous; stigma punctiform (scarcely if at all capitate). Locules 2; placentation axile, capitate, ovules 5–7 per placenta and radiating irregularly from placenta.
Fruit
(dimensions not measured) globose, glabrous, yellow at maturity, apex crowned by persistent calyx lobes.
Field characters:
―Shrubs up to 2 meters tall; flowers often ramiflorous in clusters and relatively small; hypanthium glabrous; calyx lobes sometimes with three relatively prominent veins; petals magenta; stamens relatively 30 or less. (
Fig. 5
).
Distribution:
―Known only from the eastern part of Petriky Forest (
Fig. 2
) and Ambinanibe Forest in
Toliara Province
in southeastern
Madagascar
. Ambinanibe Forest (not labeled in
Fig. 2
), only infrequently indicated on maps and from digital sources, is the highly fragmented area west of Tolagnaro, north of Lac Andriambe, an area of active mining operations.
Habitat and ecology:
―Growing in full sun (or more rarely in shade) in low forest on littoral sands from 0–10 meters elevation.
Phenology:
―Flowering late October to February; fruiting from December to March.
Etymology:
―The specific epithet is based on Petriky Forest (
Fig. 5
).
Vernacular name:—
Ropasy lahiny
.
Ropasy
is a contraction of
rotry
and
fasiky
, the former of which is a generic vernacular name used for species of
Eugenia
and
Syzygium
around Tolagnaro.
Fasiky
refers to sand; thus
ropasy
means “
Eugenia
that grows on sand”. When more than one species of a genus occurs locally a second name often is added for distinction, such as
lahiny
(male) or
vaviny
(female). The name
ropasy
is also used in Mandena (north of Tolagnaro) for
Eugenia arenicola
H. Perrier
, another species from littoral forests in the general region.
FIGURE 5.
Eugenia petrikensis
. Upper left: bark of main bole. Upper right: sessile to subsessile inflorescences. Lower left: emerging leaves with whitish indumentum. Lower right: mature leaves; abaxial (upper) and adaxial (lower) surfaces. (No voucher; photos by D. Rabehevitra).
Conservation status:
―The type gathering is in or near the eastern part of conservation zone P
1 in
Petriky Forest (
Fig. 2
; see also
Lowry
et al.
2008
). The
paratype
(
Fig. 5
) was from a non-protected and highly disturbed area. Although herbarium material of
Eugenia petrikensis
currently is known only from the type gathering, the species has been observed and photographed recently at Ambinanibe Forest (25°02’35’S,
46°56’04”E
) growing in full sun or rarely in shade. With an AOO of
18 km
2
, and 2 subpopulations, one in a protected area (Petriky),
E
.
petrikensis
is assigned a preliminary status of “Endangered” (EN: B2ab[iii]).
Discussion:
―
Eugenia petrikensis
may be more common than suggested by the known number of herbarium specimens. Its vegetative and floral morphologies most closely resemble those of
E. ardyceae
N. Snow (
Snow 2011
)
, which also occurs in the Tolagnaro region (
Fig. 2
). However, the pedicillate flowers with glabrous hypanthia of
R.
petrikensis
contrast with the sessile to subsessile flowers with sericeous-villous hypanthia of
E. ardyceae
. The dibrachiate trichomes of
E. ardyceae
on younger leaves are highly asymmetrical (i.e., arms of differing lengths [
Snow 2011
]), which contrast with the more symmetrical trichomes in the emerging foliage of
E. petrikensis
. The calyx lobes on the
type
specimen of
E. petrikensis
have 3 straight and equally-spaced vascular bundles that converge apically slightly inside of the margin (magnification required), but it is uncertain if this trait occurs in all specimens.The leaves, inflorescences, and flowers of
E. urschaiana
H. Perr. var.
urschiana
also somewhat resemble those of
E. petrikensis
(e.g.,
M. Ursch 17
, holo: P! [image seen]). However,
E. urschaiana
var.
urschiana
occurs ca.
1300 km
north of Tolagnaro at ca.
250 m
.
elevation in forests at or near Analamazaotra (
Perrier 1953a
, b) ("Analamazoatra" on herbarium label).
More detailed field surveys are urgently needed for this species.