74 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



Type species: Triodia pungcns R. Br. 



Trioclia R. Br., Prodr. Fl. Nov. Holl. 1 : 182. 1810. Six species are described, 

 tlie first of which is selected as the type. In this the lemma is firm, rather ob- 

 scurely 3-nerved, villous along the lower half of the back and margins, 2-toothed 

 at the summit, the midnerve excurrent between the acute teeth as a short awn 

 as long as the teeth, the lateral nerves extending into the teeth. 



Tricuspis Beauv., Ess. Agrost. 77, pi. 15, f. 10, 1812, not Tricuspis Pers., 1807. 

 The figured species is T. caroliniana, discussed in the following paragraph. 



Tridens Roern. and Schult., Syst. Yeg. 2 : 34. 1817. Under the description of 

 the genus is a reference to a figure of Beauvois. 1 Beauvois describes the figure 

 (which represents Triodia flava) under the name Tricuspis caroliniana. Under 

 the description of the genus (p. 77) Beauvois mentions two species, Poa caerules- 

 fcns Michx. and Tricuspis novaeboracensis Beauv. Both are nomina nuda, the 

 first never having been published by Michaux, and Beauvois giving no descrip- 

 tion of the second. Roemer and Schultes on a later page (p. 599) describe the 

 single species referred to Tridens, under the name T. quinquefida, based upon 

 Poa quinquefida Pursh, which is Triodia flava. 



Windsoria Nutt, Gen. PI. 1 : 70. 1818. Two species are described, W. poae- 

 formis Nutt., which is Triodia flava, and TV 7 . ambigita (Ell.) Nutt. The first is 

 selected as the type. 



Rhombolytrum Link, Hort. Berol. 2 : 296. 1833. The single species described 

 is R. rhomboidea from Chile. Bentham and Hooker 2 state that two North Ameri- 

 can species, Triodia, albcscens and T. trin-errif/1 urn-is, are allied to this. Nash 3 

 recognizes the genus Rhombolytrnni and transfers to it Sieglingia albescens 

 (Vasey) Kuntze. 



Erioneuron Nash, in Small, Fl. Southeast. U. S. 143. 1903. The type, Uralepis 

 pilosa, is indicated on page 1327 of the same work. Only one species included. 



Dasyochloa Willd. ; Rydb., Colo. Agr. Exp. Sta. Bull. 100: 37. 1906. (Flora 

 of Colorado.) The name first appeared in Steudel's Nomenclator * as a synonym 

 of Uralepis (Uralepsis), where two species are listed, D. avenacea Willd. and D. 

 pulchella Willd., both being herbarium names. The type and only species men- 

 tioned is D. pulchella (H. B. K.) Willd. 



Some authors have referred our species to Sieglingia Bernh. 5 The type of 

 Sieglingia is Festuca decumbens L. This species seems to represent a distinct 

 genus, differing in having 5 to several nerved lemmas. The single species, /S. 

 decumbens (L.) Bernh., a native of Europe, is found in Newfoundland, but does 

 not occur in the United States. 



The species of Triodia are diverse in habit and in floral characters, 

 but it does not seem practicable to segregate any of them as distinct 

 genera. Triodia flava (the type of Tridens) and T. pulchella (the 

 type of Dasyochloa) represent the two extremes, but they are con- 

 nected by a series of intergrading species. The type species of 

 Triodia, T. pungens, of Australia, in the form of its spikelets, stands 

 about midway between our two extremes. Its spikelets, though less 

 pubescent, are much like those of T. avenacea, with the midnerve of 

 the lemma excurrent between the teeth, the lateral nerves not ex- 

 current but extending into the teeth. Triodia putchella H. B. K. 

 (fig. 34) differs in habit from all the other species. It sends 

 up from the basal cluster of leaves slender branches with 

 elongate internodes, which produce at the extremity a cluster 

 of short leaves and short, few-flowered spikes. Later from these 

 clusters are produced slender branches, which in their turn form 

 clusters of leaves and spikelets. The clusters bend to the ground and 

 take root, so that ultimately there is formed a colony of these clusters 



1 Beauv. Ess. Agrost. pi. 15, f. 10. 1812. * Norn. Bot, ed. 2, 1: 484. 1840. 



2 Gen. PI. 3: 1176. 1883. - 6 Syst. Verz. Pflanz. Erfurt. 40. 1800. 



3 In Britton, Man. 129. 1901. 



