32 24. Zannichel. 6. FLUVI ATILES. Pl.end.ph. 
1. Flowers unisexual ; stamens 1 or 2. 
FI. on a one-sided spadix ; ovary 1 Zostera. 27. 
FI. solitary ; ovaries 2 to 6, sessile, gibbous 
Zannichellia. 24. 
2. FI. hermaphrodite ; stamens 4 ; perigonium k-cut. 
FI. two-rowed on a solitary spadix ; 
cariopsides 4, on footstalks Ruppia. 25. 
FI. spiked ; cariopsides 4, sessile .... Fotamogiton. 26. 
I. 24. ZANNICHELLIA. Miclieli. Pondweed. 
Flowers solitary, monoicous. — Male. Perigonium, none ; 
stamen 1 ; filament long ; anther 2 or 4-celled. — F em. Pe- 
rigonium campanulate; ovaries 2 to 6; stigmata flat, pel- 
tate; capside one-seeded, sessile, compressed. — Flowers 
axillary ; the male at the exterior base of the perigonium 
of the female flower ; leaves linear, grasslike, 2 or 3 from 
the same membranaceous sheathing stipula. 
1. Zannichellia palustr is. Marsh pondweed. 
Anthers 4-celled ; stigmata undivided ; capsule keeled, 
toothed at the back. 
Aponogeton aquaticum graminifolium, staminibus singularibns, Raii 
Syn. 135. 
Zannichellia palustris, Lin. S. P. 1375. 
Horned pondweed. 
Ponds and ditches; annual; July. 
2. Zannichellia dentata . Toothed pondweed . 
Anthers 2-celled ; stigmata scolloped; capsule warty. 
Z. palustris minor, Mich. N.G. P.71. 
Z. palustris /3, Lin. S. P. 1375. 
Z. dentata, Willd. S. P. 
Ponds and ditches ; annual ; July. 
II. 25. RUPPIA. Lin. Gen. PL Tasselgrass . 
Flowers hermaphrodite, two-rowed on a solitary spadix; 
perigonium caducous, 2 valved ; stamens four; anthers 
sessile, 2-celled; ovaries four, oval, conic; stigmata obtuse; 
nuts four, oneseeded, oval, on a long threadlike peduncle. 
Plant herbaceous, capillary, branchy; leaves cauline, al- 
ternate ; floral leaves mostly opposite; spadix terminal. 
Ruppia maritima . Sea tasselgrass. 
Leaves linear, not nicked at the tip. 
