Olax pseudaleioides subsp. sabulicola
Madagascar
Olax antsiranensis
O. thouarsii
A synoptic revision of Olax L. (Olacaceae) in Madagascar and the Comoro Islands
Rogers, Zachary S.
Malécot, Valéry
Sikes, Kendra G.
Adansonia
2006
3
28
1
71
100
492KB
Rogers & Malécot & Sikes, 2006
Rogers & Malécot & Sikes
2006
[294,494,1261,1287]
Magnoliopsida
Olacaceae
Olax
Plantae
Santalales
4
75
Tracheophyta
species
antsiranensis
sp. nov.
Z.S.Rogers, Malécot & Sikes, sp. nov.( Fig. 1)
“ Olax pseudaleioidessubsp. sabulicola” Capuron, Olacacées, Opiliacées et Santalacées arbustives ou arborescentes de Madagascar: 13 (1968), nomen inval. [ineffective publication]. Olax antsiranensis a O. thouarsii in laminis 1.5-4 (haud 5-12) cm longis (n.b.: bracteis interdum foliaceis!) plus minusve concoloribus et apicibus emarginatis (haud paginis abaxialibus glaucis et apicibus acutis acuminatis vel raro obtusis vel rotundatis), et ligulis petalorum 0-0.3 (haud 0.6-1) mm longis indumento pubescenti sparso (haud dense) praeditis, differt.
TYPUS. — Madagascar.Prov. Antsiranana, au Sud du Mont Raynaud, sur sables, [ 12°30’S, 49°27’E], 26.IV.1963, fl., Service Forestier (Capuron) 22719(holo-, P!; iso-, P- 00418010!, TEF!). PARATYPES. — Madagascar. Prov. Antsiranana, souspréfecture de Vohémar, commune rurale de Daraina, forêt de Bekaraoka, partie sud Andranostimaty, 13°11’S, 49°42’E, 130 m, 10.III.2003, fl., Gautier et al. 4305(G, INH!). — Ramena, Andavakoera, à 8 kmau Suddu village Andavakoera, forêt sèche sur sable, 12°20’53”S, 49°21’27”E, 50 m, 11.VIII.2004, imm. fr., Guittou et al. 75(K!, MO!). — Analabe forest, Fivondronana Vohémar, Fokontany Anjiabe, 13°04’14”S, 49°53’40”E, 26.II.2003, fl., Rabevohitraet al. 4554(K!, MO!, P!, TEF). — Fivondronana Diego II, Commune Ramena, Fokontany Andavakoera, forêt sèche d’Andranonankomba, Montagne des Français, 12°20’48”S, 49°21’28”E, 88 m, 7.IX.2004, fr., Randrianaivo et al. 1074(G!, MO!, P, TAN, TEF). — Same locality, 12°23’02”S, 49°20’12”E, 310 m, 28.III.2004, fl., Ratovoson et al. 735(MO!, P, TAN). — Tendrombohitr’Antsingy[= Montagne des Français], [ 12°22’S, 49°21’E], 26.XI.1958, fr., SF (Capuron) 20103(P!, TEF!). — SakaramySTF, forêt d’Analandriana, près de Sakoramy( Diégo-Suarez), [ 12°26’S, 49°16’E], 17.XII.1963, fr., SF (Capuron) 23017(P!, TEF!). — Ambongoabomassif, à l’Ouest de Diégo-Suarez, [ 12°15’S, 49°10’E], 26.I.1966, fr., SF (Capuron) 24442(P!, TEF!). — Vohémar, [ 13°22’S, 50°00’E], 14.X.1966, fr., SF (Capuron) 24867(P!, TEF!). DESCRIPTION Trees to 10 mtall. Branches glabrous; young branches 4-sided, winged; older branches terete, darker; bark cracked, exfoliating. Leaves alternate, distichous, elliptic or ovate, rarely obovate, 1.5- 4 cmlong, 9-23 mmwide, c. 2-2.5 times longer than wide; leaf blades chartaceous, glabrous, surfaces smooth, rarely slightly wrinkled, usually darker in color adaxially, base acute-cuneate (decurrent with petiole), margin slightly revolute, more obvious in lower half, apex apparently emarginate, sometimes with a short mucron in the sinus; midrib depressed or slightly raised adaxially, raised abaxially, glabrous; venation usually conspicuous on both surfaces, less pronounced abaxially, secondary veins c. 5 pairs per side; petioles 0-0.5 mmlong, c. 1 mmin diam., glabrous. Inflorescences racemose or pseudosolitary; axes 4-sided, c. 0.5 mmin diam., reaching 7 mmlong, proliferating with up to 5 flowers; floral pedicel 2.2-2.8 mmlong, c. 0.5 mmin diam. Flowers hermaphroditic, tubular, heterostylous; calyx cupuliform, green, 1-1.2 mmlong, semimembranous, glabrous, margin truncate; petals 5, white, oblong, 5.8-7.7 mmlong, glabrous adaxially; petal lobes c. 3 mmlong, 1.1-1.7 mmwide; petal ligule absent or up to 0.3 mmlong, sparsely puberulent or glabrous; free portion of filaments 1-2 mmlong; fertile stamens (5) 6 (7); anthers oblong, c. 1.5 × 0.7 mm, longitudinally dehiscent; staminodes 4 or 5, each bifid portion narrowly elliptic, c. 2 × 0.5 mm, membranous, glabrous, base thick, dark, articulate with filament; nectary disc annular, 0.1-0.2(-0.3) mm tall, glabrous; ovary ovoid-spheroid, c. 1.2 × 1 mm; style c. 0.4 mmin diam., articulate above ovary in immature fruit; long style not seen; short style 2.3-2.7 mmlong; stigma capitate, 3-lobed, 0.4- 0.6 mmin diam., papillate. Drupes transversely ellipsoid, uniformly depressed at both poles, 1.1-1.2 cmlong, 1.5-1.7 cmin diam., yellow, glabrous; accrescent calyx surrounding base of fruit, thin and chartaceous, 7-8 mmin diam., margin tearing irregularly into 4-8 lobes; stylar remnants c. 0.2 mmlong.
REMARKS The flowers of Olax antsiranensishave 5 petals, (5) 6 (7) stamens, 4 or 5 staminodes, and a weakly accrescent calyx in fruit. Olax antsiranensisis distinguished from O. thouarsiiby its 1.5-4 (vs. 5- 12) cm long leaves, the more or less concolorous leaf blade with an emarginate apex (vs. abaxially glaucous blade with an acute, acuminate, or rarely obtuse or rounded apex), and by the 0-0.3 (vs. 0.6-1) mm long, sparsely (vs. densely) pubescent petal ligule. Please note that leaves of O. thouarsiishould not be confused with its foliose bracts (see species no. 8 for further discussion). The placement of this taxon was not addressed in the Flore( Cavaco & Keraudren 1955a) because no collections were available at that time. Capuron (1968)collected Olax antsiranensison five occasions, considering it to be a subspecies of O. thouarsii(though he regarded O. pseudaleioidesto be the correct name for the species). We believe that O. antsiranensisdeserves recognition at the rank of species.
DISTRIBUTION AND PHENOLOGY Olax antsiranensisoccurs in a few dry forest fragments in northern Madagascarnear Diégo-Suarez and Vohémar from 0 to 310 melevation (Fig. 11). The species grows on sand, calcareous limestone, and lateritic soil on basaltic rock. It flowers February through April and fruits from August to January.
VERNACULAR NAME Kombimba ( Ratovoson et al. 735); Sarinkombimba ( Guittou et al. 75). FIG. 1. — Olax antsiranensisZ.S.Rogers, Malécot & Sikes: A, flowering branch; B, flower (two petals, two stamens and two staminodes removed); C, fruit. A, Service Forestier 22719(type); B, Rabevohitra 4554; C, Service Forestier 20103. Scale bars: A, 1 cm; B, 3 mm; C, 4 mm. USE “Fakaboka” ( Ratovoson et al. 735). In Malagasy, Fakaboka means the plant is used by sorcerers to curse people (F. Ratovoson pers. comm.). CONSERVATION STATUS Olax antsiranensisgrows in one protected area (Sakaramy). The EOO of the species is 1400 km 2, a figure which easily meets the requirements of B 1 inthe EN category (i.e. EOO < 5000 km2). AOO for the species is 600 km 2(grid cell size 10 × 10 km) and does not quite qualify as EN in the B2 category (i.e. AOO < 500 km2). Therefore, the spe- cies is assigned a provisional conservation status of Vulnerable (VU B1ab + 2ab).
1963-04-26
TEF
Sud du Mont Raynaud
Madagascar
-12.5
Antsiranana
1293
49.45
4
75
1
Antsiranana
2003-03-10
INH
de Vohemar & de Daraina & de Bekaraoka
Madagascar
130
-13.183333
Andranostimaty
1291
49.7
Prov.
4
75
1
Antsiranana
paratype
2004-08-11
MO
Madagascar
Ramena
50
-12.348055
Sud
21
49.3575
Andavakoera
4
75
1
paratype
2003-02-26
2004-09-07
2003-02-26
MO, TEF, TAN
Fivondronana Diego II & Commune Ramena & Fokontany Andavakoera & d'Andranonankomba
Madagascar
Analabe forest
88
5
76
-12.383889
Fokontany Anjiabe
21
49.336666
Fivondronana Vohemar
4
75
1
paratype
1958-11-26
TEF
Madagascar
-12.366667
Tendrombohitr'Antsingy
1293
49.35
5
76
1
paratype
1963-12-17
TEF
de Sakoramy
Madagascar
Sakaramy
-12.433333
Diego-Suarez
1293
49.266666
d'Analandriana
5
76
1
paratype
1966-01-26
TEF
Madagascar
-12.25
l'Ouest de Diego-Suarez
1293
49.166668
Ambongoabo
5
76
1
paratype
1966-10-14
TEF
Madagascar
-13.366667
Vohemar
1291
50.0
5
76
1
paratype