10 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



been done and only when the number identifies the sheet. Speci- 

 mens are listed under the names of the States as they are at present 

 recognized and limited. Those labeled as from Indian Territory 

 are listed under Oklahoma. 



The maps illustrating distribution are intended to present graph- 

 ically the general range of each species within the United States. 

 Usually a single dot is placed upon the map in each State in which 

 the species is known to grow, as indicated by herbarium specimens. 

 In the larger States a dot may be placed in each of the general divi- 

 sions in which the species occurs. If the species is found throughout 

 a State the dot representing this may be placed in the center, but if 

 the species is confined to a particular portion of a State, such as the 

 coastal plain of South Carolina, or subtropical Florida, the dot is 

 placed in that portion. 



TEXT FIGURES OF SPIKELETS. 



Each species is illustrated by a text figure showing usually two 

 views of the spikelet and one view of the fruit. The spikelet is 

 usually shown as seen from the front and from the back, but in a few 

 species the side view is shown, when this is more characteristic. The 

 fruit is placed by the side of the spikelet, and on a line with its posi- 

 tion within the spikelet, so that its relation to the other parts is 

 readily apparent. These figures are all magnified ten diameters. 



The spikelets from which the drawings are made were usually 

 from the type specimens of the species. In most cases where the 

 type specimen was not accessible the drawings were made from the 

 type or duplicate type specimens of one of the synonyms. In a 

 very few cases the drawings were made from specimens which were 

 not types or duplicate types. The identity of the specimen from 

 which the drawing was made is indicated in each case. 



TERMINOLOGY. 



No new terms are used in the present paper, but it may be well to 

 call attention to the term "lemma," and to certain other terms used in a 

 somewhat restricted or modified sense. The lemmas, or the flowering 

 glumes of some authors, are the bracts of the spikelet above the empty 

 glumes. A lemma is said to be fertile when it bears a perfect flower 

 in its axil, and sterile when its flower is staminate or suppressed. 

 The term ' 'fruit' ' is used to include the caryopsis and its inclosing lemma 

 and palea. In the subgenus Dichanthelium the terms " vernal form " 

 and " autumnal form " are used for the two successive seasonal condi- 

 tions of the individuals. The vernal form appears early in the sea- 

 son, in spring or early summer, and is followed sooner or later by the 

 branched stage called the " autumnal form." 



