( 823 ) 
and ventral placentation. Carpidia dry, a 
hiscent. Lamina of leaves nervose. 
1, Alisma L. Water-PLANTAIN. 
Flowers 8. Calyx herbaceous. Corolla pet- 
aloid. Ovaries , 1-ovulate. Akenes 0, ver- 
ticillate.—2f. Aquatic. Scapigerous. Inflores- 
cence verticillate, paniculate. 
1. A. prantaco L. Flowers pale.—Com- 
mon. Summer. 
Family 2. JUNCAGINEZ. 
Calyx not differing from corolla. Lamina of 
leaves abortive. 
1. Triglochin L. ARRow-Grass. 
Perigonium deciduous, 3 inner sepals some- 
times wanting. Ovary 6-celled; ovules in each 
cell solitary, basal. Styles 3-6; stigmas plum- 
ose, Capsule separating into carpidia; finally 
opening ventrally.—2¢. Scapigerous. Inflores- 
cence spicate. 
1. T. martrmum L. Common. Summer. 
Family 3. POTAMEZ. 
Perigonium if present, 4-cleft. Stamens 1, 
2, or 4. Ovaries 4-0, l-ovulate. Carpidia in- 
dehiscent. Leaves stipulate. 
1. Potamogeton Tourn. PonpWEED. 
Flowers $. Perigonium 4-cleft. Anthers 4, 
sessile, inserted on the base of the sepals. 
