528 FLORA NIGRITIANA. 
Guinea Coast, as in most other parts of the world. It is not in 
the collection before us, but is described by Schumacher and 
Thonning under the name of 7. australis. 
C. NAIADEX. 
l. Potamogeton pusillus, Linn.—Kunth, Enum. 8. p. 186.— 
Cape Coast, Don ; Angola, and in most parts of the globe. 
The only other species of this Order I can find any mention 
of are Ouvirandra Heudelotii, Kunth, from Senegal, and Apo- 
nogeton subconjugatus, Schum. et Thonn., (probably an Ouvi- 
randra), from Guinea. 
CI. ALISMACES. 
Of this Order two species only are given as West Tropical 
African: Alisma sagittifolium, Willd., from Guinea, and A. 
humile, Kunth., from Senegal. 
CH. Hyprocuaripen. 
1. Vallisneria spiralis, Linn. ?—Sierra Leone, deep in the water, 
Don. There is no fructification on the specimens. i 
The extraordinary paucity of aquatic plants in all col- 
lections from West Tropical Africa, as compared with other 
Tropical regions, may be owing rather to the inattention of 
collectors, and the difficulty of gathering them without a longer 
stay in the country than the climate permits, than to any real 
deficiency of vegetation in these waters. 
CIII. Burmanniacez. 
1. Dictyostegia longistyla, Benth. ; caule erecto simplici, flori- 
bus solitariis pluribusve laxe cymosis v. unilateraliter race- 
mosis, stylo perianthium subeequante, ovario ecostato.—On 
the Nun, growing apparently on dead roots, Vogel. 
Herba tenera, alba, 3-6-pollicaris, Dictyostegiis Americanis 
simillima, Folia Squamzformia, pauca, erecto-patentia, semi- - 
