Vol. XXI, pp. 175-188 July 27, 1908 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



NOTES ON GENERA OF PANICEAE. III.* 

 BY AGNES CHASE. 



The grasses in Paniceae having two forms of spikelett form one 

 well-defined group, the Olyrae, an outstanding genus, Amphi- 

 carpon, and a small group of polygamous grasses, Phyllorachis, 

 Thuarea and Spinifex, not closely related to each other nor to any 

 other genera in this tribe. The latter group will be taken up in 

 a later paper. In natural systems these forms have been dis- 

 posed of in various ways, only the more important of which are 

 here considered, as the history of the classification of this tribe 

 will be taken up later. 



Beauvois'i disposition of these forms is interesting since his 

 is the first attempt at a systematic arrangement of all the known 

 genera of Gramineae into divisions and subdivisions. His con- 

 fidence in the enduring excellence of his Methode, however much 

 the rest of the Essai might fall short of perfection, is also inter- 

 esting. § He places these forms in " Familia II. Polythalama. 

 Locustae dissimiles;" " Tribus quarta, axis integer. Glumae 

 alternatim insertae," [as distinguished from tribe III Tripsacum, 

 -etc.]. Olyra comes under " Cohors Octava. Axes androgyni " 

 with Zizania and Pharus, while Lithachne comes under " Cohors 

 Nona. Axes monoici aut dioici. Sectio Prima. Axes monoici " 



* Notes on Paniceae I appeared in Proe. Biol. Soc. Wash. 19 : 183-192. Dec. 1906 ; Notes 

 on Paniceae II op. cit. 21: 1-10. Jan. 1908. 



t The text figures in the present paper are all magnified 5 diameters only, as most 

 of the fruits in this group are unusually large. 



t Agros. tab. meth. and pp. 124, 135, 137 ; 1812. 



§Les changements qu'on pourra y faire par la suite, pourront porter sur quelques 

 details, sur des reunions ou des separations de genres; mais je ne pense pas qu'ils puis- 

 sent attaquer en rien les bases et les principes de la Methode. Les genres y sont tous 

 distingues par des caracteres certains, constants et facile a saisir." Op. cit. Avertisse» 

 ment. 



28— Peoc. Biol. Soc. Wash., Vol. XXI, 1908. (175) 



