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This species is accepted, and its native range is Central Madagascar.
A specimen from Kew's Herbarium

[KBu]

Wilkin, P., Andrianantenaina, W.P. et al. (2008). The species of Dioscorea L. (Dioscoreaceae) from Madagascar with campanulate tori, including a new species from Eastern Madagascar. Kew Bulletin 63: 583. https://doi.org/10.1007/s12225-008-9079-x

Distribution
Known from two localities in Central Madagascar, near Antananarivo and in Fianarantsoa Prefecture.
Ecology
Remnants of high altitude forests, presumably in light gaps or forest margins; 1000 – 1500 m a.s.l.
Morphology General Habit
A slender twining vine, probably to no more than a few metres in height, stems annual from a fleshy tuber
Morphology General Indumentum
Indumentum of hairs absent even from very young shoots and axillary buds, colourless modified hairs of crystalline appearance present on the veins of the lower leaf blade surface, to no more than 0.1 mm long, on the leaf blade margins and veins on the lower leaf blade surface, flattened-deltoid, flattened-semicircular or denticular to cylindric or transversely linear, sometimes forming elongate ridges along the veins, dense to sparse but always present
Morphology Leaves
Leaves alternate, blade (2.7 –) 3.5 – 7.6 × (1.6 –) 2.2 – 7.9 cm, ovate to broadly so or elliptic, thinly chartaceous, drying dark olive green above but paler below, adult leaves sometimes with an irregular white variegation along the central vein as in juvenile plants of D. maciba, veins 3 to apex, usually with two more main veins on each side entering the leaf base, base cordate, sinus (2 –) 6 – 29 mm deep, often hippocrepiform, especially in larger leaves, basal margins usually shallowly to quite deeply lobed and auriculate (usually 2 or 3 lobes per side), always so in vegetative shoot leaves, rarely entire in fertile shoot leaves (e.g. type collection), apex 5 – 15 mm long, acuminate with a 1.5 – 4.7 mm long, very narrowly deltoid, concolorous to brown forerunner tip, primary venation prominent on lower leaf blade surface; petiole 1.7 – 6.7 cm long, colour as stem, slender, terete but channelled on upper surface, lateral nodal spines (“stipules” of Burkill 1960) present at point of insertion of petiole base onto node, recurved, with longitudinal ridges when dry, c. 1 mm long
Morphology Reproductive morphology Flowers
Male flowers greenish, scent not recorded, pedicellate, pedicels 0.6 – 1.8 mm long, slender, narrowly obdeltoid in outline, floral bract at pedicel base 1 – 1.9 × 0.4 – 0.9 mm, elliptic to ovate, acuminate, membranous with a thickened midrib, bracteoles similar but smaller, one per bract, inserted at c. 90° to it; tepal whorls differentiated into two whorls of three, outer slightly narrower than inner, free or slightly fused at base, borne on a torus 1 – 1.7 × 0.9 – 1.7 mm in diam., campanulate but not or only slightly apically constricted, torus wall chartaceous (thinner than e.g. D. seriflora or D. madecassa) and partially translucent when dry, with a fleshy, undulate annulus projecting beyond the point of tepal insertion at the torus mouth, to no more than 0.1 mm long, tepals membranous, erect in bud, patent to torus wall at anthesis and never fully reflexed, almost completely translucent when dry, midrib scarcely thickened, apices obtuse to acute, outer tepals 1.2 – 1.7 × 0.7 – 1.4 mm, ovate to broadly oblong-ovate or narrowly ovate, inner tepals 1.1 – 1.6 × 0.8 – 1.5 mm, broadly ovate; stamens erect, exserted, inserted almost at the centre of the torus, filaments 0.7 – 1.0 mm long, filiform, free at base but some or all apically coherent, usually held in a tight contingent bundle and appearing columnar, anthers 0.2 – 0.4 × 0.15 – 0.3 mm, oblongoid, dorsifixed but always held erect to ascending in a ring, pale yellow; pistillode very small or absent, concealed by filament bases Female flowers greenish, scent not recorded, subsessile until they begin to reflex, floral bract 1.3 – 1.9 × 0.5 – 1 mm, elliptic to ovate, membranous with a thicker midrib, bracteole like bract but smaller, one per bract, inserted at c. 90° to it; ovary c. 4.5 – 6.5 mm long, 3-angled, narrowly elliptic in outline, apex narrowing into torus (i.e floral stipe very short or absent); tepals differentiated into 2 whorls of 3, outer slightly narrower than inner, free or slightly fused at base, borne on a 0.9 – 1.1 × 1.1 – 1.4 mm, campanulate torus, apex not or only slightly constricted, annulus absent or very small, tepals membranous, erect in bud, patent to torus wall when receptive and never fully reflexed, almost completely translucent when dry, midrib scarcely thickened, apices obtuse to acute, outer tepals 1.3 – 1.9 × 1.0 – 1.4 mm, ovate to broadly oblong-ovate or narrowly ovate, inner tepals 1.4 – 1.6 × 1.0 – 1.4 mm, broadly ovate; staminodia 0.4 – 0.5 mm long, probably 6 per flower but only 1 seen in each of the flowers dissected (perhaps due to damage during dissection), staminiform and differentiated into filamentode and antherode, styles 3, 1.4 – 1.7 mm long, erect, exserted, free towards base but fused around their mid-point and forming a column, stigmas ascending to reflexed, flat and ovate, deeply bifid
Morphology Reproductive morphology Fruits
Capsules (not fully mature) 18 – 22 × 13 – 16 mm, ascending at c. 45° – 30° to axis at dehiscence on a c. 2 mm long, weakly clavate capsular stipe, not more than c. 10 per infructescence, dense towards its apex, oblong-elliptic to oblong-obovate in outline, base and apex truncate to rounded or apex very shallowly retuse, pale brown with darker brown axis and flecking towards wing margins, torus and tepals sometimes persistent Mature capsules and seeds not seen but probably like those of D. maciba
Morphology Reproductive morphology Inflorescences
Inflorescences 1 per axil, simple, pendent, few-flowered (6 – 15 flowers per axis) and with a long peduncle relative to fertile axis length, axis slender, longitudinally ridged and flattened, pale green to red-hued Male inflorescence axis 1.1 – 8.0 cm long, peduncle 0.8 – 3.8 cm long, lax towards base but often dense towards apex, racemose Female inflorescences 2.1 – 3.7 cm long, peduncle 3.2 – 3.7 cm long, spicate (capsular stipe only developing as ovary grows), axis also becoming longer and wider as capsules develop, flowers pendent when receptive, thereafter reflexing during early capsule development
Morphology Stem
Stems left-twining, to 2.5 mm in diam., terete with shallow longitudinal ridges, unarmed, pale green to reddish, a few small cataphylls present towards stem base, c. 5 mm long, differentiated into a forerunner tip, unexpanded ovate blade and short petiolar regions; bulbils not present
Note
D. acuminata is most easily recognised by its male and female inflorescences possessing no more than 15 flowers per axis and a long basal sterile region relative to the fertile axis length. Its leaves have lobed basal margins and are auriculate at the base, but are sometimes entire on fertile shoots.
Vegetative Multiplication Tubers
Tubers (Perrier 12495 only) subtended by a small woody crown bearing papery scales (cataphylls?) buried c. 12 cm deep, two at the time of flowering, divergent, with one growing and the other becoming flaccid as it is absorbed, narrowly cylindrical and 60 – 100 cm long (according to Burkill & Perrier 1950), apical parts 2 – 3 mm in diam. when dry
Vernacular
Ovy (presumably Merina, according to Burkill & Perrier 1950).

Native to:

Madagascar

Dioscorea acuminata Baker appears in other Kew resources:

Date Reference Identified As Barcode Type Status
Perrier de la Bâthie, J.M.H.A. [12495], Madagascar K000098652 Unknown type material
Perrier de la Bâthie, J.M.H.A. [12495], Madagascar K000098653 Unknown type material
Baron, R. [2654], Madagascar K000098654 Unknown type material
Perrier de la Bâthie, J.M.H.A. [12495], Madagascar K000099035 Unknown type material
Baron, R. [2654], Madagascar K000432436

First published in J. Linn. Soc., Bot. 21: 449 (1885)

Accepted by

  • Govaerts, R. (2000). World Checklist of Seed Plants Database in ACCESS D: 1-30141.
  • Govaerts, R., Wilkin, P. & Saunders, R.M.K. (2007). World Checklist of Dioscoreales. Yams and their allies: 1-65. The Board of Trustees of the Royal Botanic Gardens, Kew.
  • Wilkin, P., Andrianantenaina, W.P., Jeannoda, V. & Hladik, A. (2008 publ. 2009). The species of Dioscorea L. (Dioscoreaceae) from Madagascar with campanulate tori, including a new species from Eastern Madagascar Kew Bulletin 63: 583-600.

Herbarium Catalogue Specimens
Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Kew Bulletin
Kew Bulletin
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0