Arales.] PISTIACE.E. 125 



modern systematists regard Pistiacete and Lemnacese as distinct sub-orders of Arads, 

 from which I separate tliem on account of their want of spadix, Ambrosinia connecting 

 them with the curious genus Cr>Tptocoryne. By some oversight, both Adi-ien de Jussieu 

 and Endhcher regard Lemnacese as exalbuminous. 



Lemna inhabits the ditches of the cooler parts of the world ; Pistia the tropics ; 

 Ambrosinia the basin of the Mediterranean. 



Pistia Stratiotes grows in water-tanks in Jamaica, where, according to Browne, it is 

 acrid, and in hot dry weather impregnates the water with its particles to such a degree 

 as to give rise to the bloody flux. A decoction of the same plant is considered by the 

 Hmdoostanees as cooling and demulcent, and they prescribe it in cases of dysuria. 

 The leaves are also made into a poultice for hcemorrhoids. See also Martins Mat. Med. 

 Bras. 97. 



GENERA. 



Lemna,!. I Telmatophace, &^to'd. I Pistia, I. | Ambrosinia, £. 



Wolffia, i/orft. Spirodela, ScA^fid. Za/a, Lour. Tc na, Targ. 



Horkelia, Rchb. \ \ I 



Numbers. Gen. 6. Sp. 20. 



RicciacecE. 



Position. — Pistiace.e. — Araceee. 



NaiadacecB. 



