joTETRANDRIA TETRAGYNIA. 
Natans. Broad leaved Pondweed with oblongo-oval 
petiolated fwimming leaves. In rivers. Per. Ang. 
Perfoliatum. Per foliated Pondweed with cordate leaves 
furrounding the ftalks. In rivers. Per. June and July. 
Lucens. Loyig-leaved Pondweed with plain lanceolated 
leaves ending in petioles. In rivers and lakes. Per. June. 
Crifpum. Phe great Water -Caltrops with lanceolated 
leaves alternately undulated and ferrated. In rivers, dit- 
ches, and ftanding waters. May and June. 
Seraturn. P l\e lejj'er Water-caltrcps or Frog's-lettuce with 
oppofite, lanceolated leaves, partly undulated. In fmooth 
running rivers. Per. June. 
CompreJJum. Pondweed with linear, ohtufe leaves and 
a flat llaik. Per. June and July. 
Pegiinatum. Fennel-leaved Pondweed w’ith fetaceous, 
parrallel leaves growing in diflichs. In the Serpentine 
river in Hide-Park. Per. June. 
Gramineum. Grafs-leaved Pondweed with linearly, lanr 
ceolated leaves, alternately fefiile and broader than the 
ftipula. In the ditches about Deptford. Per. 
Marinum. ^ea Pondweed wdth linear leaves alternate- 
ly diftindt, and at the bottom forming a kind of a fheath. 
In ditches near the fea. Per. Aug. 
Piifillum. Small grafs-leaved Pondweed with oppofite, 
alternately diflant leaves, patent at the bafe, on a long 
round ftaik. In ditches and ftanding Waters. Per. 
June — Aug. 
S AGINA. Pea^ilwort oi'Chickweed break-stone, 
The cup confifts of four oval, concave, patent leaves 
that remain till the fruit be ripe; and the flower com 
flits of four oval, obtiife, patent petals that are fhorter 
than the cup. The four filaments are capillary with 
roundifli anthercC: The germen is partly globofe, with 
four .fubulatcd ftyles, bending back and downy. The 
ftigmata are Ample. The fruit is an oval quadrilocular 
capfule confifting of four valves, containing many fmaU 
feeds fixed to the receptacle. 
Procumhcns. 
