438 DIOSCOREACEAE, - [Dioscorea. 
e Arrowroot - plant, «Pia», is found wild in the oer woods of the lower Tegions 
e exte from the 
Havaliah Wands through Pcistiei: ae sia ol a the Paiipine ‘eal to Madaanicar 
and eastern Africa. Tahitian name: «Pia»; Vitian: «Yabia 
Orper LXXXIV. DIOSCOREACEAE. 
Flowers Metyae unisexual, usually dioecious. Perianth of 6 lobes or 
divisions in series. Stamens 6 or 3, inserted on the perianth and 
shorter than "a lobes, free, or esaiate in a short column. Anthers 
2-celled. Ovary inferior, 3-celled, with 2 pendulous anatropous ovules 
in each cell, Stigmas 3, entire or 2-cleft, on a single or on distinct 
ge or sessile. Fruit a berry or 3-angled capsule. Seeds albuminous, 
am axile embryo. — Herbs, sometimes woody at the base, 
eal belie iin a tuberous rhizome. Leaves petiolate, with digitate 
or parallel nerves and reticulate veins, sometimes compound. Flowers 
small, in axillary, simple or paniculate spikes or racemes. 
er of few genera, dispersed over the warmer parts of the globe. 
1. DIOSCOREA, L. 
Flowers dioecious. Male fl. Perianth herbaceous, ign campanulate 
or deeply 6-cleft. Fertile stamens 6, free or connate, with as many 
staminodes or without any, Anthers ther ory aa oe contiguous 
or discreet. Fem. fl. Ovary trigonous. Styles 3, very short, with entire 
or , bi bra 
— Twining stems with tuberous rhizomes. Leaves alternate or sometimes 
opposite, generally cordate or hastate, entire or palmati 
A large tropical a cesaabsitaey genus, 150 os common to the ms and New World. 
are entire; mule stam : sativa 
es palmately lobed; fertile stamens 3. Pon >. pentaphytla. 
_ D. sativa, L. Sp. Pl. p. 1463 (not Kunth). — Benth. Fl. sigs p. 368. 
— Stem glabrous, slightly angular, often bearing green globular bulbs or 
tubers in the axils of the leaves. Leaves scattering or subopposite; the 
petioles 2—3'/2', twisted at the thickened base and thereby supporting 
the plant; the blade thin chartaceous, ovate-cordate with broa sinus, 
shortly acuminate, entire, 7—11-nerved, with nerves converging toward 
eo apex, 5—7' long cal 4—6' broad. Male spikes slender, sessile, 
—4'‘ long, either in of eS or arranged in long panicles, the flowers 
sell and distant, each with 2 unequal ovate bractlets. Perianth-seg- 
ments narrow, almost valvate, those of the inner series linear. Anthers 6, 
almost sessile round a rudimentary ovary, oblong, bifid at both ends, 
introrse, affixed above the base. Female spikes pedunculate, simple, often 
