ME. a. BENTHAM ON GEAMINE^. 55 



plant, and possibly also South- American, if Sello's single specimen 

 described by Trinius and figured by Doell as Z. microstacyJis, 

 Nees, was really from Soutb Brazil. I see nothing in the figure 

 or description to distinguish it from Z. miliacea. 



3. LuzioiiA, Juss., has, like Zizania, unisexual spikelets with 

 only two glumes ; but the spikelets are smaller, not awned, the 

 styles short and quite distinct, and there are usually more than 

 six stamens in the males. Six species are known from tropical 

 America or the southern States of North America. The relative 

 arrangement of the males and females varies as in Zizania. In 

 the typical L. peruviana, Juss. (i. hrasiliensis, Moric), in L. ala- 

 hamensis, Ohapm., and ia an apparently unpublished G-uiana 

 species, both sexes are in terminal panicles, but on distinct stems. 

 In L. Spruceana, Benth., described by Doell (figured by G-. P. W. 

 Meyer as L. peruviana, but not Jussieu's plant), the males are in 

 ^terminal panicle, whilst the females are in the lower axils of 

 the same stem, as they are also said to be in L. longivalviSjUoeW, 

 a Brazilian plant which I have not seen. In the proposed genus 

 Caryochloa, Trin. {Arrozia, Schrad.), also Brazilian, the males and 

 females are in the same panicle, the former in the upper, the latter 

 in the lower part. The stamens in this species appear also to be 

 always six only, which only occasionally occurs in the others ; but 

 the other characters are entirely those of Luziola, to which I 

 should unite the Caryochloa as L. mierantha (Arrozia micraniha, 

 Schrad.). 



4. PoTAMOPHiLA, Br., if we include in it Maltelrunia, Kunth, 

 is a natural genus of three species, connecting in some measure 

 Zizania, of which it has the habit, with Oryza, of which it has the 

 small setaceous or acuminate outer glumes. In the typical 

 P. parmfiora, Br., from Australia, the spikelets are more or less 

 polygamous, though the greater number appear to be her- 

 maphrodite ; in P. leersioides {Maltelrunia leersioides, Kunth) 

 from Madagascar, and in P. preJiensilis (Maltehrunia prehensilis, 

 Nees) from South Africa, they are usually all, or nearly all, her- 

 maphrodite. Kunth also distinguishes Potamophila from Malte- 

 hrunia as having two flowers to the spikelet, a character not 

 mentioned by Brown and which I liave been unable to verify. 

 The spikelets figured by Kunth, Eev. Gram. t. 5. figs. 1, 2, & 5, 

 must be very rare and probably abnormal ; I have searched in 

 vain for them both in Brown's and in Beckler's specimens. 



5. Htgeoehiza, Ifees {Fotamochloa, G-rifi'.), is a single East- 



