SYNOPSIS OF THE GENERA. 



147. CALLITRICHE. Perianth none. Bracts 2 or none. Styles 



2, simple. 

 173. ZANNICHELLIA. Barren fl. without a perianth. Fertile 



solitary, of 1 leaf. Stigma peltate. Achenes 4, on short 



stalks. 



170. ARUM. Perianth none. Fertile fl. at the base ; barren ones 



in the centre of a cylindrical spadix; surrounded by a 

 sheathing spatha. 



173. ZOSTERA. Perianth none. Fl. in 2 rows on a flat spadix, 



enveloped by a sheath-like spatha. Style bifid. Marine 

 floating plants with long flat leaves. 



Order 2. DIANDRIA. 



171. LEMNA. Spatha membranous, enclosing 1 barren and 1 



fertile fl. Style 1. Fl. from below the edge of a floating 

 leaf or frond. 



(See Carex. ) 



Order 3. TRIANDRIA. 



174. CYPERACE^E. Fl. in spikes with imbricated scales or glumes. 



Achenes or nuts with 1 style and 2 3 stigmas. Le. grass- 

 like; sheaths not split; stems solid. 



158. TYPHACE^E. Fl. in cylindrical spikes, or globular heads. 

 Perianth 3-leaved or none. Style 1 . Stigmas 2 3. Ovary 

 surrounded by bristles or the 3-leaved perianth. 



Order 4. TETRANDRIA. 



135. LITTORELLA. Barren fl. stalked. Cal. of 4-sepals. Cor. 

 4-cleft. St. very long. Fertile fl. sessile. Cal. none. Cor. 

 3 4-cleft. Style very long. Fruit 1-celled, 1-seeded. 



147. URTICA. Barren fl. with a 4-leaved perianth and 4 st. 



opposite the segments. Perianth of the fertile fl. 2-leaved. 

 Stigma sessile. Fruit an achene. 



148. PARIETARIA. Perianth 4-partite. Style simple. Stigma 



penicillate. Fl. in clusters. Fruit an achene. 



149. ALNFS. Fl. all in catkins. Scale of the catkin 3-lobed, 



with 3 fl. (BETULACE.E. ) 



149. MYRICA. Fl. all in catkins. Scale of the catkin entire, 

 swollen. (MYRICACE^E. ) 



Order 5. POLYANDRIA. 



A. Flowers not in Catkins. 



65. MYRIOPHYLLUM. Fl. axillary or in lax spikes. Pet. of 

 barren fl. 4, deciduous. St. 8. Germen inferior. Stigmas 

 4, sessile. Le. pectinated. 



