186 



DE CANDOLLE'S SYSTEM. 



USES. Unknown. 



TYPICAL GENERA. Potamogeton, Zanuichellia. 



Zannichellia palustris. 1. A flower. 2. A cluster of ripe ovaries. 3. An 

 ovary opened to exhibit the ovule. 4. A vertical section of a seed, showing the 

 folded up embryo. 



179. Araceee. ' Herbaceous or shrubby, stemless or arbo- 

 rescent plants. Leaves with parallel or branching veins ; 

 sometimes compound. Spadix generally enclosed in a spathe. 

 Flowers unisexual. Perianth wanting. Stamens definite or 

 indefinite, very short. Ovary 1-celled, very seldom 3-celled ; 

 ovules erect, or pendulous, or parietal. Fruit succulent. Em- 

 bryo in the axis of albumen, with a cleft in one side. 



USES. Acrid plants which are sometimes dangerous, as 

 the Dumb cane, Dieffenbachia Seguina, which paralyses the 

 muscles of the mouth if bitten. Nevertheless, by cooking, this 

 acridity is so much diminished, that the leaves of Colocasia 

 esculenta and others are used in tropical countries instead of 



