GENERA OF GRASSES OF THE UNITED STATES. 211 



Perennial, creeping, low or delicate grasses, with narrow, flat blades 

 and terminal and axillary panicles. Species about six, in tropical 

 America ; two species in the southern United States. 



Type species: Luziola peruriann Gmel. 



Luzioln Juss. ; Gmel. Syst. Nat. 2: 637. 1791. The genus is first described 

 by Jussieu in his Genera Plantarum (1789), but no specific name *s mentioned. 

 Ginelin assigns a specific name to the species described by Jussieu. 



There are two species in the United States, Luziola peruviana 

 (fig. 126), with fruit 2 mm. long, and L. cdabamemis Chapm., with 

 fruit 4 mm. long, the former from Florida to Louisiana and the latter 

 from Alabama. They have no economic importance. 



107. HYDBOCHLOA Beauv. 



Spikelets unisexual, 1-flowered, awnless, disarticulating from the 

 pedicel, the plants monoecious; staminate spikelets with a thin 

 7-nerved lemma, a 2-nerved palea, and 6 stamens, the glumes want- 

 ing; pistillate spikelets with a thin 3-nerved second glume and 5- 

 nerved lemma, the first glume and the palea wanting, the stigmas 

 long and slender. 



A slender, branching, aquatic grass, probably perennial, the leaves 

 floating; staminate flowers in a small few-flowered terminal spike; 

 pistillate flowers in few-flowered spikes in the axils of the leaves. 

 Species one, in the southeastern United States. 



Type species : Hydrocliloa carolincnsis Beauv. 



Hydrocliloa Beauv., Ess. Agrost. 135, pi. 24, f. 4. 1812. Beauvois figures one 

 species, which he names H. carolinensis. The species was first described as 

 Zizania flnitans Michx., but this name can not be transferred to Hydrochloa 

 because of H. fluitans Host. 



The spikelets of each sex possess but two bracts. From the ap- 

 pearance and nervation it is assumed that the palea is present in the 

 staminate spikelets and wanting in the pistillate. 



Ilydrochloa ccvrolinensis Beauv. (fig. 127) is found in streams and 

 ponds from South Carolina to Florida and Louisiana, sometimes in 

 sufficient abundance to become troublesome. It has no economic im- 

 portance. 



Pharus L., Syst. Nat., ed. 10, 2: 1269. 1759. A tropical American 

 genus, one species of which, P. latifolius L., was included by Chap- 

 man in his Flora of the Southern States. The locality given is 

 "Orange Lake, Florida (Herb. Thurber)." This West Indian spe- 

 cies has not been observed by others in Florida and it should be 

 credited to the United States with doubt. 



Rather tall monoecious perennials, with broad elliptic or oblanceo- 

 late, petiolate blades and terminal panicles, the large terete pistillate 

 spikelets appressed along the rather few stiffly spreading branches, 



