251 
MONOCOTYLEDONES. 
HYDROCHARIDACEA E. 
Key to genera. 
1. Freshwater herb ose 2. 
Salt water herb : 6. Halophila. 
2. Stems branch 3. 
Plant stemless ‘ 4 
3. Leaves whorled 1, Hydrilla. 
Leaves scattered 2. Lagarosiphon. 
4. Leaves linear, sessile 5. 
Leaves ovate, petiolate 5. Ottelia, 
5. Leaves serrate at the tip 3. Vallisneria, 
Leaves acute, entire 4, Blyxa, 
1.—HYDRILLA. 
. verticillata, Royle; Hook. f. Fl. Brit. Ind. v. 659. Pools 
along the Lienchow River. Fl. August. 
Le 
el 
9. .—LAGAROSIPHON. 
l. L. Roxburghii, Benth.; Hook. f. l c. 659. Marshy pools 
on hills above Pat-heung, Hongkong New Territory ; 
Lofoushan. Fl. October. 
3.—VALLISNERIA. 
l. V. spiralis, Linn. ; Hook. f. l. c: 660. Lienchow River. Fl. 
ecember. 
4.—BLYXA. 
1. B. Roxburghii, Rich.; Benth. Fl. Hongk. 347. In water- 
courses at the racecourse, Little Hongkong, Shunwan, 
and Chaiwan Gap, Hongkong ; near Kuntong, Hongkong 
New Territory ; Swatow ; Hoifung. Fl, white, Septem- 
ber—January. 
5.—OTTELIA. 
l. O. alismoides, Pers. ; Hook. f. l. ec. 662. Lantao Island, 
Taipo, and Sanwai, dir es New Territory ; Hoifung ; 
ampoa ; Sanning ; West River; Fukwing near Hong- 
kong on the Canton River. Fl. white, August, 
6.—HALOPHILA. 
1. H. ovata, Gaud. ; Hook. f. |. c, 663. Kowloon Bay, Hongkong. 
umen dA 
21515 : B 
