ALISMA 511 



2. Ock. Kennington, Garnsey. Denchworth in flower, 1895, Wait. 



Abingdon. South Hinksey. Radley. With reddish leaves at 

 Uffington. Cholsey. 



3. Pang. Pangbourn Marsh. Purley. Tilehurst, Tufnail. Near 



Moulsford. 



4. Kennet. Near Mortimer, Tufnail. Southcote. Aldermaston. 



5. Loddon, Sonning Meadows. Loddon Bridge, Tufnail. Wargrave. 



Hurst. Coleman's Moor. Waltham. Arborfield. Near Windsor. 

 L. gibba, which is more frequent than the foregoing records show, 

 is recorded for all the bordering counties except E. Gloucestershire. 



Ii. polyrhiza, Linn. Sp. PI. 970 (1753). Greater Duckweed. 



Spirodela polyrrhiza, Schleiden in Linnaea, xiii. (1839)392. 

 Top. Bot. 426. Syme, E. B. ix. 23, t. 1397. Nyman, 756. Fl. Oxf. 315. 

 Native. Lacustral. Ponds and ditches of stagnant water. Not 



uncommon. P. 

 First record. Sonning, Mr. S. Budge, in Herb. Brit. 2Ius. 1800. L. poly- 



rhiza, Mavors Ayr. Berks, 1809, and the author in Bep. of Bot. Bee. 



Club for 1 88 1. 



1. Isis. Wytham. Cumnor. Lechlade. 



2. Ock. Wantage. Radley. Kennington. 



3. Pang. Pangbourn Marsh. Englefield, Tufnail. Moulsford. 



Bucklebury. 



4. Kennet. Mortimer, Tufnail. Southcote. Embrook Mill. Hun- 



gerford. 



5. Loddon. Sonning, Budge. Hurst Green, Melvill. Ditch in Re- 



menham Lane, Stanton. Home Park, Windsor, Bolton King. 

 Bray. Arborfield. Ruscombe. Shottesbrooke. Hurst. Wink- 

 field. Near Wargrave. Wokingham. 

 L, polyrhiza is found in all the bordering counties, and is more plen- 

 tiful in Berkshire than the above records show. • 

 [HoRKELiA (Eeichb. ex Bartl. Ord. Nat. 76, 1830, and Schleiden in Linnaea 



(1839), 389, ARRHIZA (L.). 



Wolffla dlichelii, Schleid. Beit. Bot. i. 238 (1844). Wolffia, Horkel ex Schleiden 

 in Linnaea (1839) 389. W. arrliiza^ Wimm. Fl. Schles. 140 (1857). Lemna 

 arrhiza, Linn. Mant, ii. 294 (1771). Syme, E. B. ix. 24, t. 1398. 

 Has been recorded for Surrey. 



The name Wolffia, for another reason, is scarcely tenable, as there is 

 already a genus Wolfia.} 



ALISMACEAE, DC. Fl. Fr. iii. 181 (1805). 



ALISMA, Linn. Gen. n. 418. 

 A. Flautagfo-aquatica,- Linn. Sp. PI. 342 (1753). Water Plantain. 



Plantago aquaiica, Gerard, 337. 

 Top. Bot. 409. Syme, E. B. ix. 70, t. 1437. Nyman, 679. Fl, Oxf. 280. 



