xxii SYNOPSIS. 
326. Zannichellia. Involucre 0. Male fl. without cal. or cor. 
Fem. fl. with a perianth of 1 leaf. Nuts 4, stalked. 
Stigma peltate. 
326. Zostera. Fl. aggregate in 2 rows on one side of a spadix. 
Spath ending in a leaf. 
Order II. DIANDRIA. 
(Callitriche, N. O. 31. Carex, N. 0. 90.) 
Order III. TRIANDRIA. 
320. Typha. Spikes male and female, cylindrical. Ovary sur- 
rounded with bristles. Perianth 0. 
320. Sparganium. Spikes male and female, globose. Perianth 
single, 3-leaved. 
334. Carex. Fl. in 1 or more imbricated scaly spikes. Pe- 
rianth 0. Perigone urceolate. 
334. Kobresia. Fl. in a compound spike. Perianth and 
perigone 0. 
Order IV. TETRANDRIA. 
247. Littorella. Cor. of male fl. with a cylindrical tube and 
4-parted limb. Stam. very long. 
263. Buxus. Cor. of male fl. of 2 petals, fem. of 3 pet. Caps. 
with 3 beaks. 
267- Urtica. Perianth 4-leaved. Perigone 2-leaved. Stam. 
equalling the perianth. 
283. Alnus. Fl. in imbricated catkins. Scales of male fl. 3- 
lobed, 3-flowered. Perianth 4-fid. Perigone 0. 
Order V. PENT- POLY- ANDRIA. 
* Fl. not in catkins, with cal. and cor. 
108. Myriophyllum. Pet. of male fl. 4, deciduous. Stam. 8. 
Germ, inferior. 
318. Sagittaria. Pet. 3. Stam. about 24. Carp, numerous 
upon a globose receptacle. 
109. Bryonia. Cal. with 5 teeth. Cor. 5-cleft. Filaments 3. 
Anth. 5. Fr. an inferior berry. 
** Fl. not in catkins, imperfect. 
186. Xanthium. Involucre of male many-leaved, with a 5- 
toothed perianth; of female 1-leaved, inclosing 2 flowers. 
104. Ceratophyllum. Perianth many-leaved. Stam. 16 — 20. 
Nut ending in a spine. 
