Vol. XXI, pp. 1-10 January 23, 1908 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



NOTES ON GENERA OF PANICEAE. II.* 

 BY AGNES CHASE. 



The two genera, Hymenachne and Sacciolepis, discussed in the 

 present paper, while not very closely related, have been con- 

 fused because of the similarity in the form of the inflorescence of 

 most of the species in each, a spike-like panicle. 



Genus HYMENACHNE Beany. 1812, Agros. 48. t. 10. f. 8. 



"Axis paniculatus: Panicula simplex, spicseformis: Rami confetti. — 

 Glumse insequales, herbacese, acutse : infer, mnlto brevior. Flosc. infer 

 neut.: Palea infer, acuta: super, brevissima, membranacea, hyalina. — 

 Flosc. super, hermaphroditus : Palest herbacese membranacese acutse. * * * 

 Spec. Agrostis myuros Lam. monostachya Poir." 



The illustration represents the second species mentioned by Beauvois, 

 Agrostis. monostachya Poir. , which according to the American Code, t should 

 therefore be taken as the type of the genus, although Beauvois gives the 

 name Hymenachne myuros in the explanation of 

 plate 10, showing that he misunderstood Lamarck's 

 species. 



Agrostis monostachya Poir. 1810, Encyc. Suppl. 

 1 : 256. ' ' Cette plante a ete recueillie a Porto-Bicco, 

 par M. Riedle. (V. s. in herb. Desfont.)" 



The type labeled in Poiret's hand, "Agrostis mo- 

 nostachya Poir. enc. sup. Reidel Porto-Ricco," was 

 examined by Professor A. S. Hitchcock* in the Des- 

 fontaine herbarium at Florence. The accompany- 

 ing figure is drawn from this specimen. 



Panicum myuros Lam. ( incorrectly given as Agros- 

 tis myuros Lam.) cited by Beauvois under Hy- 

 menachne is not the same species as Agrostis mono- 

 stachya Poir., as most subsequent authors seemed 

 to think. The type of this was seen in Lamarck's herbarium in Paris, 



* Notes on Paniceae I, with general discussion of the importance of the fruit as a 

 generic character in this tribe appeared in Proc. Biol. Soc. Wash., 19: 183-192. Dec. 1906. 



+ Canon 15, b. 



t All the type specimens definitely mentioned as found in the different European 

 herbaria were examined by Professor A. S. Hitchcock in the spring of 1907. 



Fig. 1. 



Hymenachne amplexi- 

 eaulis. 



1— Proc. Biol. Soc. Wash., Vol. XXI, 1908. 



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