710 RHIZOCARPEZ. 
both endemic, one of which has been found in Arkansas and Chili, and the other 
only in Bolivia; but being very obscure plants, they are doubtless often overlooked or 
neglected by collectors. The Order consists entirely of aquatic and subaquatic plants. 
1, SALVINIA. 
Salvinia, Micheli, Nov. Pl. Gen. (1729) p. 107, t. 58, ex Pfeiff. Nomencl. Bot. ii. p. 1030. 
A genus of about half a dozen species very widely spread in both hemispheres, 
though not known in America north of Mexico. 
1. Salvinia auriculata, Aubl. Pl. Guian. ii. t. 367; Mart. Fl. Bras. i. p. 655, 
t. 81. figg. 9,10; Fourn. Mex. Pl. Enum. i. p. 143. 
Salvinia rotundifolia, Willd. Sp. Pl. v. p. 587; Ch. et Schl. in Linnea, v. p. 622. 
Salvinia hispida, H. B. K. Nov. Gen. et Sp. i. p. 44. 
Sovra Mexico, Tampico (ex Fournier) ; Nicaragua, in many localities near Granada 
(Lévy, 230).—Southward to Peru and Brazit, and in the West Inpizs. 
2. AZOLLA. 
Azolla, Lam.; Strasburger, Ueber Azolla, p. 76. 
Four species spread over America, Asia, Africa, and Australia. Besides the following 
there is one other species (A. filiculoides, Lam.) in America; and it is widely spread 
in South America, ranging from Colombia to Patagonia; it is also recorded by Stras- 
burger from California, though it is not included in Watson’s ‘ Botany of California.’ 
1. Azolla caroliniana, Willd. Sp. Pl. v. p. 541; Mett. in Linnea, xx. p. 278, 
t. 3. fig. 9; Mart. Fl. Bras. i. p. 659, t. 82. figs. 1-6; Strasb. Azolla, p. 78, t. 7. 
figg, 112@ et 6; S. Wats. Bot. Calif. ii. p. 352; A. Gr. Man. Bot. Northern U.S. 
ed. 5, p. 678; Fourn. Mex. Pl. Enum. i. p. 148. 
Azolla mexicana, Ch. et Schl. in Linnea, v. p. 625. 
New York and Inunois to Texas and Catirornia.—Souta Mexico, Ingenio, Sierra 
de la Cruz (Miller, 136), between Serpillo and Estero (Schiede & Deppe), near Mexico 
(Bourgeau, 65).—CoLomBia to Guiana and Brazit, and in the West INDIES. 
3. MARSILIA. 
Marsilia, Linn.; A. Braun in Monatsb. Konigl. Akad. Wiss. Berlin, Aug. 1870, p. 713. 
This genus is even more generally diffused than the foregoing, covering the same 
range and the southern half of Europe in addition, and it is much more numerous in 
species: Braun enumerates upwards of fifty. 
1. Marsilia mexicana, A. Braun in Monatsb. 1870, p. 747; Fourn. Mex. Pl. 
Enum. i. p. 148. 
Souru Muxico, Jalisco (Beechey), Chapultepec (Schajfner). Hb. Kew. 
