A flora of Manila - Rainforestation

DIOSCOREACEAE 151
26. DIOSCOREACEAE (Yam or Ubi Family)
Usually twining vines, snooth or armed, from fleshy rootstocks. Leaves
simple or digitately 3- to 7-foliolate. Flowers small, in spikes, racemes, or
panicles, unisexual. Male flowers: Perianth 6-lobed. Stamens inserted
at the base of the perianth or on its lobes, 3 or 6, or sometimes 3 perfect
and 3 staminodes. Rudimentary ovary present or wanting. Female
flowers similar to the males. Staminodes 0, 3, or 6. Ovary 3-winged, 3-
celled; ovules 2 in each cell. Capsules 3-valved, 3-winged. Seeds winged.
Genera 9, species about 225, of wide tropical distribution, 2 genera and
18 or more species in the Philippines.
1. DIOSCOREA Linnaeus
Characters of the Family as given above. (In honor of Dioscorides, a
famous Greek physican and botanist.)
Species 150 or more, warmer parts of both hemispheres, about 15 in the
Philippines.
1. Leaves simple.
2. Stems 4-angled or 4-winged 1. D. alata
2. Stems terete, not at all angled or winged.
3. Unarmed, glabrous; leaves 7- or 9-nerved, ovate, slenderly acuminate.
2. D. bulbifera
3. Somewhat spiny, pubescent; leaves orbicular to reniform, 11- to 15nerved
3. D. fasciculata
1. Leaves 3-foliolate; stems spiny 4. D. daemona
1. Leaves 5- or 7-foliolate 5. D. pentaphylla
*1. D. ALATA L. Ubi (Tag., II., Vis.).
A twining glabrous vine from large tuberous roots, the stems acutely
4-angled or narrowly winged, often bearing axillary bulbils. Leaves opposite,
oblong-ovate, 8 to 16 cm long, 3 to 8 cm wide, sharply acuminate,
base cordate, 7- to 9-nerved, the basal lobes rounded. Staminate inflorescence
axillary, narrowly paniculate, up to 30 cm in length, the flowers
alternate, on the short, zigzag, fasciculately and racemosely arranged
spikes, greenish, 1 to 1.5 mm long.
Commonly cultivated for its edible tubers, fl. Oct.-Nov. ; widely distributed
in the Philippines, but certainly not indigenous. India to Malaya.
2. D. bulbifera L.
A glabrous, unarmed, herbaceous vine reaching a length of several
meters, the stems terete. Leaves simple, 7 to 14 cm long, ovate, acuminate,
base broad, prominently cordate, the sinus broad and rounded, the lobes
rounded, 7- or 9-nerved. Spikes slender, panicled, numerous, 8 to 10 cm
long, rather densely many-flowered, the flowers about 3 mm long. Axils
often bulbiferous.
In thickets, occasional, fl. Aug.; of local occurrence in the Philippines.
India to Malaya.
3. D. fasciculata Roxb. Tungo (Tag.); Tugue (II.); Tamis (Vis.).
A slender somewhat pubescent vine reaching a height of several meters,
the stems with scattered sharp spines. Leaves simple, suborbicular to
reniform 6 to 12 cm long, apiculate, base 11- to 15-nerved, prominently
cordate, lobes rounded. Spikes slender, axillary, pubescent, up to 50 cm
long. Flowers green, about 4 mm in diameter.
In dry thickets, occasional, fl. June-Aug. ; widely distributed in the
Philippines. India.