Vol. XXIV, pp. 103-160. June 16, 1911 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



bo 





NOTES ON GENERA OF PANICEAE. IV.* 

 BY AGNES CHASE. 



The work upon the genera of Paniceae as originally outlined 

 contemplated a consideration bj r groups. It was the intention 

 of the writer to prepare as a final paper a synopsis of the entire 

 work, in a sequence representing, so far as possible in a lineal 

 series, the natural relationship of the genera investigated. This 

 synopsis with special reference to American genera together 

 with notes on the North American genera are offered in a pre- 

 liminary way at this time at the request of Mr. G. V. Nash, of 

 the New York Botanical Garden, who wishes to cite the refer- 

 ences in his forthcoming treatment of the tribe Paniceae in the 

 North American Flora. 



PANICEjE. 



Spikelets ideally 2-flowered, the terminal floret perfect, the lower stami- 

 nate or neuter (perfect in Isachne and Dissochondrus), its glume (the 

 sterile lemma) unlike the flowering glume (the fertile lemma) in form 

 and texture and simulating a third empty glume, a membranaceous or 

 hyaline sterile palea (indurated at maturity in Ixophorus and in a few 

 species of Panicum) present or wanting, the spikelet or at least the fruit 

 (the fertile floret) dorsally compressed (laterally in Lithachne); fertile 

 lemma and palea alike in texture, indurated, or at least tinner than the 

 glumes and sterile lemma, firmly clasped together (open at the summit 

 in Leptocoryphium and Hymenaehne) inclosing the free grain (in the 

 cultivated Pennisetum americanum the enlarged grain forcing open the 

 lemma and palea), awnless (sometimes mucronate, acuminate-pointed or, 

 in Coridochloa, AUoterupsis, and species of Eriochloa, evenshort-awned), 

 the nerves obsolete (present in Reimarochloa and Acritochaete) . 



* Notes on Genera of Paniceae I appeared in Proc. Biol. Soc. Wash. 19 :183-192. 

 1906; same II, op. cit. 21 : 1-10. 1908: same III, op. cit. 21 : 175-188. 1908. 



25— Proc. Biol. Soc. Wash., Vol. XXIV, 1911. (103) 



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