58 TETRAND. TBTRAG. 



floating subcoriaceous ovato-lanceolate tapering into a rather 

 sliort footstalk, lower ones long lanceolate sessile. E. B. t. 

 1286. 



Hab. In the Clyde at Dalbeth, Hopk. Ditches and lakes near For- 

 far, G. Don. Fl. Aug. Sept. l(. . 



Two feet or more long. Upper leaves far less coriaceous and more 

 obtuse than in the two former species. Whole plant olivaceous or 

 even reddish,, beautifully veined. 



**■ Leaves all submersed. 



4. P. perfoUatum (petfoliale Po?id-weed) , leaves cordate embra- 

 cing the stem. Light/, p. 121. E. B. t. 168. 



Hab. Rivers and lakes, very common. Fl. July. % . 

 Very distinct in the shape and insertion of the leaves. Spike on a 

 rather short peduncle, oblongo-ovate. 



5. P. deiisum {close -leaved Pond-weed), leaves (all) opposite 

 crowded ovato-acuminate sessile, stem forked, spike of about 

 4 flowers. Lightf. p. 122. E. B. t. 397. 



Hab. Ditches on the right hand of the walk going down the meadows, 

 near Edinb., and Corstorphine hills, I)r. Parsons. About Glasg., 

 but not common 5 in Bardovvie Loch, Hopk. Fl. June, July. 1/. 



Plant rather small. Leaves much crowded upward. Spike of fructi- 

 fication very small. Peduncle very short. 



6. P. lucens {shining Pond-iveed), leaves ovato-lanceolate 

 petiolate. Lighlf. p. 122. E. B. t. 376. 



Hab. Rivers and lakes, frequent. Fl. July. % . 



Stems long. Leaves large, very pellucid and beautifully veined. 



Spike or spadix the longest and most crowded with flowers of any 



in the genus. 



7. P. crispum {curled Pond-iveed), leaves lanceolate tapering 

 sessile remarkably waved serrate. Lightf. p. 122. E. B. 

 t. 1012. 



Hab. Ditches and ponds, frequent. Fl. June, July. 1/ . 

 Sterns long. Floivers rather distant on the spike. 



8. P. lanceolalum {lanceolate Pond weed), leaves linear-lan- 

 ceolate tapering at the base sessile. E. B. t. 19§5. 



Hab. Loch of Linthothen, Augus-shire, G. Don. In a mill-head 

 close by the bridge at Bervie, Kincardineshire, Maugh. 



9. P. compressitm {fiai-sfalked Po7id-weed), leavef^Wnear very 

 obtuse sessile, stem compressed, spikes about 4-flowered. 

 Lightf. p. 123. E. B. t.4\S. 



Hab. Ditches and stagnant waters, but not common, Lightf. Frank- 

 field Loch, and loch near New Kilpatrick, lilentifully, Hopk. Fl. 

 July. 1/. 



Plant small. Leaves the same width throughout. Stipules large, very 

 conspicuous, whitish. )* 



10. P. graynineum {grasn/ Pond-iveed), *' leaves linear-lanceo- 

 late alternate .sessile broader than the stipules, stem rounded^^ 

 subdichotomous" {Sm.). Lightf. p. 123. E. B. I. 2253, 



