182 CERATOPHYLLEZ. 
1. CERATOPHYLLUM. 
Ceratophyllum, Linn. Gen. Plant. n. 1065; Benth. et Hook. Gen, Plant. iii. p. 415. 
_ Two species or distinct varieties, divided into eight or ten by some authors, united into 
one by others. . peer hk a 
1. Ceratophyllum demersum, Linn. Sp. PI. 1409; DC. Prodr. iii. p. 73 ; 
Cham. in Linnea, iv. p. 504; Schnizl. Iconogr. ii. t. 83. 
In fresh water nearly all over the world, including Mexico and CENTRAL Awnrtoa. 
Hb. Kew. 
GYMNOSPERMEZ. 
Order CXXXV. GNETACEZ. 
Gnetacee, Benth. et Hook. Gen. Plant. in. p. 417. 
This Order comprises the singular Welwitschia mirabilis, Hook. f., and the genera 
Gnetum and Ephedra. Of these there are about forty shrubby and arboreous species, 
widely spread in the tropics, rarer in temperate regions. Gnetum itself is represented 
by several species in tropical South America. 
1. EPHEDRA. 
Ephedra, Linn. Mant. p. 18. n. 1278; Benth. et Hook. Gen. Plant. iii. p. 419. 
About thirty species have been déscribed; but some of them were founded on very 
slight characters. They inhabit the south of Europe, temperate and subtropical 
Asia, and extratropical and Andine America, extending southward to Chili and Buenos 
Ayres. 
1, Ephedra antisyphilitica, Berland., ex C. A. Mey. Monogr. Ephedr. p. 101; 
DC. Prodr. xvi. 2, p. 354; Torr. Bot. U.S _& Mex. Bound. Surv. p. 207. 
Texas to CaLirornia.—Norta Mexico, Sierra Madre (Palmer, 1289), Rinconado 
Pass, Coahuila (Thurber), between Mapimi and Guajaquilla, Durango (Gregg). Hb. Kew. 
2. Ephedra, sp. 
Norra Mexico, region of San Luis Potosi, 6000 to 8000 feet (Parry & Palmer, 855). 
Hb. Kew. © 
8. Ephedra, sp., Torr. in Bot. U.S. & Mex. Bound. Surv. p. 208. 
Norra Mexico, Oja de Vaca (Thurber). 
4, Ephedra, sp. 
Nortu Mexico, Sierra Madre (Palmer, 1288). Hb. Kew. 
