GRIFFITHS THE GBAMA GRASSES. 349 



This is not the method followed in some of the recent literature of 

 the grasses, and it is in no closer accord with recent practice than is 

 the comprehension in one genus of all the species here included. 

 Kunth a was the first excessively to divide the group, and to some 

 extent his work has been adopted by some recent authors. Others 

 have contented themselves with adopting Kunth' s genera as sub- 

 genera or sections. Were I to divide the genus, however, the lines 

 laid down by Kunth would have to be somewhat modified as has 

 been done by Nash. 6 Kunth includes in Dinebra Bouteloua curti- 

 pendula and B. aristidoides as well as B. radicosa, B. repens, and B. 

 chondrosioides , while for Aristida americana of Linnaeus, the West 

 Indian representative of our B. filiformis, which is a variant very 

 close indeed to that species, the monotypic genus Heterostega of 

 Desvaux was adopted. The other monotypic genus, Polyodon H. B. 

 K., should also, without doubt, be included with the radicosa-repens 

 section of the genus to which Kunth applied the name Dinebra Jacq. 

 Chondrosium on the contrary is better delimited and could stand on 

 its merits without change better than the others. 



Although Kunth formally recognized all these genera it was against 

 his best judgment that this was done. He specifically states that 

 in his opinion these genera should be united. The disposition made 

 here was decided upon before the opinion of Kunth was discovered. 

 His opinion corresponds very closely indeed with my own preference. 



There has been much difference of opinion as to the relationship of 

 Cathestecum ever since it was established by Presl.^ By Bentham 

 and Hooker it was placed in the Zoysieae along with Aegopogon, 

 which closely resembles some species of Bouteloua and probably 

 should stand closer to that genus than it is now placed. By Hackel 

 Cathestecum is included in the Festuceae. But the species of this 

 genus in general aspect as well as in minuter details very closely 

 resemble some species of Bouteloua. The resemblance in the field 

 is so great that botanists usually refer their collections of Cathes- 

 tecum to Bouteloua. 



The group differs from the remainder of the grama grasses in hav- 

 ing 3 spikelets in the spike, in the reduction of the first glume in one 

 or all of the spikelets, and in a tendency to multiplication of awns 

 by division of the nerves of the lemma of the upper florets. 



«H. B. K. Nov. Gen. & Sp. 1: 171-176. 1816. 



& Small, Fl. Southeast. U. S. 137. 1903. 



cli. B. K. Nov. Gen. & Sp. 1: 173. 1816. The last paragraph on the page reads 

 as follows: "Heterostega vix genus distinctum, habitus Dinebrae, characteres Chon- 

 drosii; genera Heterostegae, Chondrosii et Polyodontis, ut mea fert opinio, valde 

 artificialia, et aptius generi Dinebrae conjungenda sunt." 



dRel. Haenk. 1: 295. pi. 42. 1830. 



