14 CONTEIBTJTIONS FKOM THE NATIONAL HEKBAEIUM. 



placed the species represented by the plate 298 under Panicum, and 

 the other Tournefortian -species of Milium under Holcus. But he 

 has made one important alteration in the description, a comparison 

 of which with the first edition shows the two to be identical except as 

 to the statement concerning the calyx or glumes. In the first edition 

 the diagnosis reads, "Gluma uniflora, trivalvis: Valvulis ovatis, acu- 

 minatis, duabus interioribus oppositis, tertia a tergo alterius posita;" 

 in the fifth, "Gluma uninora, bivalvis: Valvulis ovatis, acuminatis." 

 By the change of trivalvis to bivalvis he has transferred the generic 

 idea of Milium from Panicum miliaceum to Milium effusum. 



It is now necessary to decide upon the type species of Panicum as 

 presented in the Species Plant arum. There is nothing in this work 

 to indicate which species Linnasus considered the type of the genus, 

 but by taking into consideration the description of Panicum as given 

 in the fifth edition of the Genera Plantarum we arrive at a partial 

 interpretation of his ideas. In the latter work he describes the calyx 

 (glumes and sterile lemma) and corolla (fertile lemma and palea) as 

 follows: "Cal. Gluma uniflora, trivalvis: Valvulis ovato-acuminatis : 

 tertia minima a tergo alterius posita. Cor. bivalvis: Valvulae ovato- 

 acuminatae: altera minor planior." The description of the other 

 parts has no significance, but at the end is a note which throws much 

 light on the question under consideration. It reads: "Obs. Aristae 

 terminant in quibusdam corollae valvulam planiorem. Species datur 

 involucro polyp hyllo capillari instructa." It is evident from this 

 note that Linnaeus did not consider as typical those species with awns 

 or with an involucre, though he admitted them as exceptional. As 

 awned species he had in mind particularly Panicum crusgalli, an old 

 and well-known species illustrated by Scheuchzer; and as involucrate 

 species he referred especially to his Panicum glaucum and P. italicum. 



In accordance with the recent American Code of Botanical Nomen- 

 clature a the type is chosen, in the absence of other indications, by an 

 application of Canon 15, section d, which reads: " Where economic or 

 indigenous species are included in the same genus with foreign species, 

 the type is to be selected from (1) the economic species or (2) those 

 indigenous from the standpoint of the author of the genus." The 

 only important economic species described by Linnasus are Panicum 

 americanum, P. italicum, and P. miliaceum, to which might be added, 

 as of much less importance, P. dactylon. It seems evident then, that, 

 since Linnasus did not consider as typical those species having an 

 involucre, the type is the remaining important economic species, 

 namely, Panicum miliaceum. 



It is unfortunate that Linnasus and succeeding botanists did not 

 retain Panicum and Milium for the groups containing the historic 

 types; and especially unfortunate that Beauvois did not retain the 



a Bull. Torrey Club 34: 172. 1907. 



