290 



LEMNACEAE. 



1— LEMNA. 



Key to species. 



Fronds ^ inch long ... ... ... 1. minor. 



Fronds J inch long 2. polyrrhiza. 



1. L. minor, Linn. ; Hook. f. Fl. Brit. Ind. vi. 556. Common in 



pools, Hongkong ; Hongkong New Territory without 

 locality ; Ngchungshan, near Hongkong. Fl. . 



2. L. polyrrhiza, Linn. ; Hook. f. 1. c. 557. In swamps at East 



Point, Hongkong; Ngchungshan, near Hongkong. Fl. . 



ALISMACEAE. 



Key to genera. 



1. Leaves cordate .. . ... ... ... 2. Lophotocarpus. 



Leaves not cordate ... ... ... 2. 



2. Leaves lanceolate ... ... ... 1. Alisma. 



Leaves linear, hastate or sagittate ... 3. Sagittaria. 



1.— ALISMA. 



1. A. Plantag:o, Linn. ; Hook. f. Fl. Brit. Ind. vi. 559. Lienchow 

 River. Fl. pink, August. 



2.— LOPHOTOOARPTJS. 



1. L. guyanensis, Durand et Schinz ; Sagittaria cordifolia, Roxb. ; 

 Benth. Fl. Hongk. 346. Belcher's Bay and Shako, 

 Hongkong ; Hoifung ; Shiukwan (Shaochaiifu) N. River. 

 Fl. white, September. 



3.-SAGITTARIA. 



1. S. sagittifolia, Linn.; Hook. f. Fl. Brit. Ind. vi. 561. 

 Pokfulam, Hongkong ; Chaochaufu ; Hoifung ; Canton ; 

 Macao; Sanning; North River. Fl. white, April— August. 



NAIADACEAE. 



Key to genera. 



1. Flowers hermaphrodite 2, 



Flowers bisexual 



2. Stamens 6 or more 

 Stamens (anthers) 4 



3. Stamens (antlicrs) 2 

 Stamen 1 



4. Filament slender 

 Anthers sessile ... 



3. 



1. Aponor/eton. 



2. Potamof/ctoii. 



3. Ruppid. 

 4. 



4. Zannichrliid. 



5. Najas. 



