Chase — Notes on Genera of Panicecg. IV. 



129 



Among North American species of Panicum two approach Brachiaria 

 or Leucophrys, Panicum texanum. Buckl. and P. ciliatissimum Buckl., 

 in which the inflorescence is not strictly racemose, but in the first of 

 which the spikelets toward the ends of the branches are often in the reverse 

 position of those of Brachiaria, while in the second all the spikelets are 

 in the reverse position. The rugose apiculate fruit of both also recall the 

 fruit of Eriochloa and of one species of Brachiaria, B. meziana Hitchc, 

 but the spikelets are not in one-sided racemes. 



14. Genus AXONOPUS Beauv. 



Axonopus Beauv. Ess. Agrost. 12 and 154. 1812. A brief diagnosis is 

 given and the following species cited as belonging to the genus: ' ' Milium 

 compression [Axonopus compressus (Svvartz) Beauv.], digitatum [Syn- 

 therisma digitata (Swartz) Hitchc], cimicinum 

 [Panicum cimicinum (L.) Retz., Coridochtoacimi- 

 cina (L. ) Nees], paniceum [a species of Syn- 

 therisma}." There is little in the diagnosis or 

 observations to favor one species more than 

 another as the type, but such as there is favors 

 M. compression, since Axonopus is differentiated 

 from Ceresia and Paspalum on the digitate inflor- 

 escence and solitary spikelets. All but the first 

 species named have spikelets in pairs. This 

 species, therefore, we take as the type of Axono- 

 pus. Beauvois himself expresses doubts as to 

 the validity of his genus. He says that if 

 Milium can be separated from Paspalum because the axis of the 

 latter is a spike composed of spikelets alternate or geminate, the 

 same character {motif) would serve to distinguish Axonopus in which the 

 axis is digitate ; at least if one does not reunite the three genera, forming 

 of each a division of the same genus ; this, he says, would be perhaps the 

 most natural. But, he adds, " C'est aux Botanists a prononcer: il me 

 snffit de leur presenter mes doutes." Next follows a brief, informal 

 description of a plant received from " M. de Lessert," which, it appears 

 to Beauvois, ought to belong to this genus, with the name of Axonopus 

 aureus. In the index (page 154) all five species mentioned are listed 

 under Axonopus, but all except "aureus" are followed by a question 

 mark. But we find that under Milium in the index these same species 

 are again queried. It would seem that the query refers to the author's 

 doubts as to the advisability of keeping Paspalum and Axonopus distinct 

 from Milium. The omission of the question mark after " aureus" may 

 be a typographical error. However, we hold Axonopus compressus and 

 A. aureus to be congeneric, but to belong to two rather well-marked 

 sections. 



Cabrera Lag. Gen. & Sp. Nov. 5. 1816. A single species is given under 

 this genus, C. chrysoblepharis Lag. " H. in America meridionali, ad Pana- 

 maidem et Aricam portum, ubi legit, eel. D. Lud. .Nee (V. S.)." The 

 type specimen has not been examined but the clear and detailed descrip- 



Fig. 6. 



Axonopus compressus. 



(Two views of spikelet and 



fruit x 10 diam.) 



