398 Aristolochiaceae 



lA. Sepals 3, nearly free, strongly reflexed above the middle, valvately contiguous and forming a cup on lower half; filaments much 

 longer than the anthers; styles connate into a column, the stigmas radiate; summer-green perennial; leaves 2, membranous, cor- 

 date 1. A. caulescent 



IB. Sepals 3, united below into a distinct tube; styles free or connate at base. 



2A. Leaves annual, membranous, thin, usually paired, rarely solitary, cordate to reniform-cordate; perianth without a ringlike appendage 

 on the throat; filaments longer than the anthers; styles very short. 

 3A. Calyx-lobes deltoid, or broadly cordate-ovate, acute or subobtuse, often recurved on margin. 



4A. Styles 6; stamens 12; leaves membranous, rather large, 5—10 cm. wide 2. A. sieboldii 



4B. Styles 3; stamens 6; leaves somewhat thicker, 4-6 cm. wide 3. A. dimidiatum 



3B. Calyx-lobes obtuse, recurved on upper half 'i. A. heterotropoides 



2B. Leaves biennial, ovate-orbicular to ovate, rarely cordate, rather thick and firm; perianth with a ringlike appendage on the throat; 

 filaments shorter than the anthers. 

 5A. Styles not bifid. 



6A. Styles slender, entire; stigma discoid; perianth-tube prominently constricted above and urceolate. 

 7A. Perianth-tube with raised longitudinal lines inside. 



8A. Perianth-lobes ovate-oblong, 2—2.5 cm. long, 2-3 times as long as the tube, the tube globose, with prominent raised lon- 

 gitudinal lines inside; petals present 5. A. sakawantim 



8B. Perianth-lobes broadly ovate, 14—16 mm. long, 1-1.5 times as long as the tube, the tube somewhat squarrose, with in- 

 conspicuous or obsolete longitudinal lines inside; petals absent 6. A. costatum 



7B. Perianth-tube with raised longitudinal and transverse lines inside. 



9A. Perianth-tube with prominently raised longitudinal lines and inconspicuous cross-lines inside. 



lOA. Leaves 5-10 cm. long, the nerves not impressed above; flowers glabrous outside 7. A. hexalobum 



lOB. Leaves 11-17 cm. long, lustrous and thick, with impressed veinlets above; flowers densely white-puberulent outside. 



8. A. crassum 

 9B. Perianth-tube uniformly with raised netted lines inside. 



IIA. Bracts longer than the flowers; flowers small, about 10 mm. across; perianth-tube ellipsoidal, the lobes connate below, 



the limb not spreading 9. A. parviflorum 



IIB. Bracts much shorter than the flowers; flowers larger, more than 15 mm. across; perianth-tube depressed-globose, the 

 lobes connate below, the limb spreading. 

 12A. Leaves nearly glabrous, lustrous above; perianth-lobes ovate, slightly narrowed at base, forming an elongate-ovoid 



cone in bud; tube shorter than the limb 10. A. constrictum 



I2B. Leaves short-hairy above, not lustrous; perianth-lobes ovate-deltoid, much-narrowed at base, forming a depressed 



ovoid cone in bud; tube longer than the limb 11.^. asperum 



6B. Styles either longitudinally grooved inside or winged on both sides. 



I3A. Styles longitudinally grooved inside; perianth-tube slightly constricted at apex. 



HA. Styles less than half the length of the perianth-tube, gently recurved above; leaves ovate-orbicular or broadly elliptic, 



pilose on upper side 12. A. tamaense 



14B. Styles more than half as long as the perianth-tube. 



15A. Styles prominently recurved above; leaves nearly glabrous on upper side 13. A. muramatsui 



15B. Styles rectangularly spreading at tip; leaves loosely short-pilose on upper side 11. A. ctirvistigma 



13B. Styles winged on both margins at tip; perianth-tube much constricted above, urceolate. 



16A. Styles recurved and cordate at apex with a broadened wing on each side 15. A. asaroides 



16B. Styles erect, with a narrow auriclelike wing toward top on each side 16. A. satsumense 



5B. Styles bifid. 



17A. Leaves hastate, pubescent beneath; perianth-tube slightly constricted at apex 17. A. blumei 



17b. Leaves elliptic, ovate, or orbicular-reniform. 



18A. Perianth-tube constricted at apex, with a ring on the throat; limb with transverse wrinkles near base. 

 19A. Leaves glabrous beneath; perianth-tube glabrous outside. 

 20A. Styles 6; stamens 12. 



21 A. Perianth short-tubular li. A. k.itisianum 



21B. Perianth-tube globose 19. A. subglobosnm 



20B. Styles 3; stamens 6 20. A. trigynum 



19B. Leaves scattered yellowish pilose on nerves beneath; perianth-tube hairy outside 21. A. ya\usimense 



18B. Perianth-tube not constricted above; limb flat; throat without a prominent ring. 

 22 A. Flowers small; perianth-tube about 10 mm. long. 



23A. Leaves ovate to broadly so, or elliptic-ovate, acute, distinctly longer than broad. 

 24A. Pedicels and perianth-tube glabrous outside. 



25A. Perianth-lobes not contracted at base in bud; leaves with slightly impressed nerves above 22. A. nipponicum 



25B. Perianth-lobes slightly contracted at base in bud; leaves without impressed nerves 23. A. nankaiense 



24B. Pedicels and perianth-tube short-pubescent outside 24. A. li^umageanum 



23B. Leaves reniform-orbicular to broadly ovate, rounded to obtuse, rarely acute, usually not prominently longer than broad. 



26A. Flowering in June and July; fertile shoots without leaves the first season 25. ^. savatieri 



26B. Flowering in winter or spring. 



27A. Styles slighdy longer than the perianth-tube 26. A. jatiriei 



27B. Styles as long as to shorter than the perianth-tube. 



28A. Perianth-lobes broadly ovate-deltoid, rounded to obtuse 27. A. viridiflorum 



28B. Perianth-lobes ovate. 



29A. Leaves usually paired; perianth-lobes smooth, flat, the limb with a narrow ring on the throat 28. A. takfloi 



