HITCHCOCK: MEXICAN GRASS 549 



uses the name P. schiedeanum because it appears on the printed 

 labels of the plants distributed by Pringle (No. 2423). The 

 citation given by Beal, however, is a nomen nudum (a name 

 without description or citation of a synonym). A specimen in 

 the Trinius Herbarium labeled Panicum schiedeanum is a species 

 of Paspalum. Beal gives Panicum palmeri Vasey on a succeeding 

 page as a distinct species. 



In 1897 Scribner revised the genus Ixophorus, describing 

 I. unisetus, I. pringlei Scribn. ''{Panicum schiedeanum Beal, 

 not Trin.)," and I. pringlei var. minor Scribn. 



The descriptions of the forms do not differ except in the size 

 of the vegetative parts, the specimens assigned to I. pringlei 

 being smaller, the blades shorter and narrower, and the spikes 

 fewer and shorter. The variety is a still more depauperate form, 

 with blades only i to 3 inches long {Palmer 1256 in 1891 from 

 CoHma, Mexico). 



Finally, in 1900, Scribner and Merrill, in their revision of the 

 genus Chaetochloa (Setaria), listed among the excluded species 

 Setaria cirrhosa Fourn. (see above), which they refer to Panicum 

 as P. cirrhosum. In this they depended upon Fournier's de- 

 scription as they had not seen the single collection cited by him. 



The above account of the nomenclatorial history of a little- 

 known species is instructive as showing how variable are the 

 judgments of different botanists, or of the same botanist at 

 different times, when working with inadequate material. The 

 single species has been described under five different specific 

 names and has been referred to four genera. Fournier had not 

 seen Presl's specimen and American authors had not seen Four- 

 nier's nor Presl's specimens. Only recently has there been 

 sufficient material to confirm the judgment that all the forms 

 belong to one species. 



A peculiarity of the sterile palea is worthy of note. At first 

 the margins, wide and thin, overlap and inclose the three large 

 anthers of the sterile or lower floret. At maturity the margins 

 expand and spread around the sterile lemma, appearing wingHke 

 and papery. This expansion appears to be rather sudden as it is 

 observed only in specimens with fruiting spikelets. 



