MONANDRIA— MONOGYNIA. Zostera. 5 



thread-shaped, acute, curved. Drupa cylindrical, pointed, 



somewhat juicy. Nut 1, oval, striated. Kernel of the 

 same shape, with 2 flattish, partially combined, cotyledons. 

 Embryo central, cylindrical, curved. Radicle inferior, 

 (that is, opposite to the scar of the seed). See Prof. 

 Hooker's dissections in Fl. Lo?id. new series t. 35. 



The two cotyledons seem to me to confirm the propriety of 

 removing this genus from the Aroidece ; for this plant is 

 surely as truly dicotyledonous as Cyamus. See Gaertner 

 t. 19, Nclumbo. 



Root creeping. Herb smooth, long and slender, floating 

 under water. Stem roundish, branched, leafy; decumbent 

 at the base, with tufts of fibrous radicles from each knot 

 or joint. Leaves alternate, linear, flat, very long; their 

 sheaths containing the spadix, and at length torn longi- 

 tudinally, to let out the seeds. 



Professor Hooker, following Schreber and Willdenow, re- 

 moves this genus to Mo?ioecia, because he observes the 

 number of anthers and pistils not always to correspond ; the 

 former being sometimes about twice the most numerous. 

 This may arise from occasional suppression of some pistils, 

 often incident to plants of a simple structure, and indeed 

 . to all plants when the source of nourishment is weakened. 

 I have found these two organs regularly corresponding 

 in number, and placed respectively right and left alter- 

 nately, as in Engl. Bot., which is a strong indication of 

 each anther and pistil making naturally one Jlower, and 

 for this reason I persist in my original opinion, which 

 has been adopted by Vahl. 



1. Z. marina. Common Grass-wrack. 



Leaves entire, obscurely three-ribbed. Stem slightly com- 

 pressed. 



Z. marina. Linn. Sp. PL 1374. It. W. Goth. 166. tA. Willd. 

 v.4. 179. Vahl Enum. v. 1. 14. Fl. Br. 7. Engl. Bot.v.7. 

 t. 467. Hook. Lond. t. 35. Scot. 259. Fl. Dan. t. 15. Toz- 

 zetti. Cat. Mus. 87. t. 3. 



Alga. Rail Syn. 52,53 ; the whole genus. 



In creeks and ditches of salt water, or about the mouths of rivers. 



Perennial. August, September. 



Variable in size. Leaves long, flaccid, obtuse, of a light green, 

 bleaching very white on the shore. Spadix green, about 2 inches 

 long, with 8 or 10 anthers, and as many pistils, closely applied 

 to its flat surface. The plant is used for package; in poor 

 countries for thatching, or bedding. 



