Dioscorea 



DIOSCOREACEAE-IRIDACEAE 



Iris 



oblong (sometimes ovate), acuminate 2. D. hypoglauca 



Frs. and lvs. green, not glaucescent: lvs. mostly 7-lobed, more 



or less cordate, acute or acuminate 3. D. nipponica 



var. rosthornii 



aa. Lvs. (or most of them) opposite. 



Lvs. not lobed, ovate-lanceolate, acuminate, sometimes hastate; 



length mostly more than 2 x the width 4 . D. belophylloides 



Lvs. 3-lobed, ovate-deltoid, acute or cuspidate; length mostly less 



than 2 x the width 5. D. opposita 



1. Dioscorea bulbifera Linn. Am Potato ^^ffii&IM (Chin Mien Tiao Hsia Mo; 

 Toads-caught-with-golden-floss) (B.M. 262). Twining vine; fls. greenish white, 

 VII. Tropical and subtropical Asia; locally in An., Che., Hun., Hup. Ki. Thickets. 



2. Dioscorea hypoglauca Palibin (E.P. 87: 252). Twining vine; fr. VII. Eastern 

 China; locally in Che., Ki., Ku. Forest shade. 



3. Dioscorea nipponica Mak. var. rosthornii (Diels) Prain & Burk. (D. giraldii R. 

 Kunth) (E.P. 87: 315). Twining vine; fls. greenish white, VII. China; locally in 

 An., Hup., Woodland shade. 



4. Dioscorea belophylloides Prain & Burk. (E.P. 87: 268). Twining vine; fls. 

 whitish, VII; fr. VIII-IX. Southeastern Asia; locally in An., Che., Hun., Ki. 

 Thickets. 



5. Dioscorea opposita Thunb. (D. batatas Decne.*) Chinese Yam ^[MM (Chia Shan 

 Yao; Domesticated-mountain-medicine) (B.M. 262). Twining vine; fls. greenish, 

 VI-VII; fr. VII-VIII. China; locally in An., Che., Ku., Hun., Hup. Thickets 

 and cultivated, food, medicine. Fig. 491. 



* According to Burkill in a letter to Merrill, dated 111/22/1926. 



191. IRIDACEAE Iris Family MBPc (Yuan Wei K'o) 

 Perennial herbs (ours), often from thickened rootstocks or corms, rarely shrubs, 

 with mostly basal, equitant, linear lvs.: fls. usually showy, perfect, each with 2 spathe- 

 like bracts, usually opening one or two at a time; perianth of 6 petaloid segments in 

 2 series, joined in a tube and adnate to the ovary below; stamens 3; anthers 

 extrorse; ovary inferior, 3-celled: fr. a capsule. About 60 genera with 1,000 species, 

 widely distributed; 5 genera and 20 species in China. 



Key to the Genera 



A. Style branches petal like 1 • Irw 



AA. Style branches not petal-like. 



B. Fls. more than one from each spathe on the main axis of the inn". 2. Belamcanda 

 BB. Fls. only one from each spathe. 



Perianth very irregular 3. Gladiolus 



Perianth nearly regular. 



Style branches simple 4. Tritonia 



Style branches bifid 5. Freesia 



1. Iris Linn. Fleur-de-lis MMM (Yuan Wei Shu) 



Herbs with sword-shaped or grass-like equitant lvs. and large showy fls.: outer 

 perianth segments reflexed, the inner smaller and erect; stamens distinct, inserted at 

 the base of the outer perianth segments; anthers linear or oblong, covered by the 

 over-arching petal-like style-brs. ; most of the style connate with the perianth segments 



525 



