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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