217 



26. vStipules glabrous 

 Stipules hairy ... 



27. Leaves gradually narrowed at the base 

 Leaves shortly narrowed at the base... 



28. Achenes lenticular 

 Achenes trigonous 



29. Leaves round or shortly acuminate at 



the base 

 Leaves gradually attenuate at the base 



30. Achenes 2 lines long ... 

 Achenes 1 line long 



31. Leaves obtuse at the base 

 Leaves attenuate at the base ... 



32. Climbing plant ... 

 Erect plant 



1. P. 



22. jucundum. 



11. 



23. Jiaccidum. 



24. Hydropiper. 



29. 

 31. 



20. virginianum. 

 30. 



25. japonicum. 



26. minus. 



10. serrulatum. 



27. Posumbu. 



28. multiflorum. 



29. sachalinense. 



2. P. 



3. 



4. 



plebeium, R. Br. ; Benth. Fl. Hongk. 287. In cultivated 

 and waste places, Hongkong ; Kwaichong, Hongkong New 

 Territory ; Swatow district ; Pakhoi ; North Eiver. Fl. 

 green, December — March, 

 chinense, Linn. ; Benth. 1. c. 289. Taihang, Taitam Tuk 

 and Victoria Peak, Hongkong ; Taimoshan at 1500 ft., 

 and Castle Peak, Hongkong New Territory ; Swatow 

 district ; Kwaisin, Hoifung ; common in damp waste 

 places, Canton. Fl. white, September. 



P. alatum, Ham. ; Hook. f. Fl. Brit. Ind. v. 41. Lanfa Mt., 

 Hoifung. Fl. white, September. 



P. criopolitanum, Hance in Ann. Sc. Nat. ser. 5, v. 238. Near 

 Chaochaufu ; open waste places around Canton ; along the 

 West River. Fl. pink ? April. 



P. viseosum, Ham. ; Benih. Fl. Hongk. 287. Hongkong 

 without locality ; fields near Chaochaufu ; weed in culti- 

 vated ground, Canton. Fl. pink, April. 



P. lanigerum, R. Br. ; Hook. f. Fl. Brit. Ind. v. 35. River 

 bank near Swatow ; Pakhoi. Fl. white, April. 



P. glabrum, Willd. ; Benth. Fl. Hongk. 288. Hongkong with- 

 out locality ; Swatow district ; garden weed, Canton. 

 Fl. white or rose, November. 



tinctorium, Lour. ; DC. Prodr. xiv. 102. At Chaiwan, 

 Hongkong ; roadsides at Suheang, near Hongkong, on 

 the Canton River. Fl. pink, July. 

 9. P. lapathifolium, Linn. ; Benth. Fl. Hongk. 288. Hongkong 

 without locality ; near Chaochaufu ; weed in cultivated 

 ground. Canton ; Macao and islands near. Fl. white, March. 



10. P. serrulatum, Lagasca ; Hook. f. Fl. Brit. Ind. v. 38. Mt. 



Gough, Hongkong ; near Chaochaufu ; Kwaisia, Hoifung. 

 Fl. white or rosy, September — April. 



11. P. stagninum, Ham. ; Hook. f. 1. c. 37. Quarry Bay, Hong- 



kong ; near Sanwai, Hongkong New Territory ; Hoifung ; 

 edges of pools, Canton. Fl. white, September. 



12. P. barbatum, Linn. ; Benth. Fl. Hongk. 288. Wongneichong, 



and Mt. Gough, Hongkong ; Pakhoi ; Lienchow River. 

 Fl. white, July — October. 



6. 



7. 



8. P. 



