6 MONANDRIA. TETRAGYNIA. " 



notched at the end. Fertile flowers in the bosom of the lower 

 leaves ; barren ones amongst the upper leaves, which are crowded 

 together. Petals thick, flar, bowed inwards, at the edge like a 

 crescent. When magnified they appear to be a collection of air- 

 vessels, and are undoubtedly intended to float the flower. < 

 In ditches and still waters, frequent. A. Apr. — Aug. 



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Var. 3. All the leaves roundish, on leaf-stalks, very entire ; 

 in pairs, except the lower ones. Hall. 553. 



FL dan. I?S-/. B. iii. 7«6« :-Park. 1263- 2-Fructlfica. 



tion. Va'ill. 32. ie; 

 Var. 4. Leaves egg-shaped. Stamens and pistils in various 



dispositions. Scop. 



Col. ecphr. 31 6. 



In places where wat^r, that stood during the winter, has 

 been dried up f 



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autumna / lis.CAL. All the leaves strap-shaped, cloven at the end. 



Flowers hermaphrodite. 



Pet. 6. \-Gmel. iii. 1. 2-bad. 



Leaves oblong. Stamens and Pistils in different plants. Scop. 

 Bloss. yellowish white. 



Autumnal Stargrass. Ditches and still waters, frequent. 



A. Sept.* 



TETRAGYNIA. 



ZANNICHEI/LIA. Flowers male and female on 



the same plant ; without petals. 

 M. Cal. none. 



F. CaL 1 leaf, bell- shaped : Seeds about 4. 



palus'tris. Zannichellia. 



Var. 1. Anther 2-celled : summits scolloped. Mich. 



Mill. ill-FL dan. 97-Pluk. 102, J. Pet. (>. 2-Mich. 34. 2. 



Seeds either entire or toothed on the back. Huds, Relhan. 



The uncommon breadth of the summits is the most remarkable 



< peculiarity in this plant ; and whether they float upon the surface 



of the water, or are sunk beneath it, they are equally calculated 

 to receive the pollen, from the anthers which stand above them. 

 St. — The habit of a Potamogeton ; slender and much branched. 

 Leaves thread-shaped, grass-like, 2j 3, or 4 out of the same 

 sheathing stipule. Seed-coats sitting," 3 or 1, placed crosswise 

 in the bosom of the leaves j somewhat compressed, with a toothed 



* It sometimes grows so thickly matted together as to allow one to 

 walk upon it without sinking. Dr. Sibthorpe assures us, that the C, 



verna, cultivated in the Oxford garden, changed into C, autumnal is. 



***! 



