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, br 6. Ovary ' 3-winged, 3- 

 celled; ovules 2 in each cell. Capsules 3-vaIved, 3-winged. Seeds winged. 



Genera 9, species about 226, 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 iYi 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 15- 



nerved 3. D. fasciculata 



1. Leaves 3-foliolate; stems spiny 4. D. daemona. 



1. Leaves 5- or 7-foliolate 5. B. pentapAylla 



*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 op- 

 JosT^oblong-ovate, 8 to 16 cm long, 3 to 8 em wide, sharply acuminate, 

 base cordate, 7- to 9-nerved, the basal lobes rounded. Staminate inflores- 

 cence 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 edijble tubers, fl. Oct.-Nov.; widely dis- 

 tributed 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 terkte. Leaves simple, 7 to 14 cm long, ovate, acuminate, 

 ba,se 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 Philippmes. 



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. 



