74. BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
Type species: Triodia pungens R. Br. s 
Triodia R. Br., Prodr. Fl, Nov. Holl. 1: 182. 1810. Six species are described, 
the first of which is selected as the type. In this the lemma is firm, rather ob- 
securely 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, pl. 15, f. 10, 1812, not Tricuspis Pers.. 1807. 
The figured species is 7. caroliniana, discussed in the following paragraph. 
Tridens Roem. and Schult., Syst. Veg. 2: 84. 1817. Under the description of 
the genus is a reference to a figure of Beauvois.t’ 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- 
cens 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 7. quinquejida, based upon 
Poa quinquejfida Pursh, which is Triodia flava. 
Windsoria Nutt., Gen. Pl. 1: 70. 1818. Two species are described, W. poae- 
formis Nutt., which is Triodia flava, and W. ambigua (Hll.) 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’ state that two North Ameri- 
can species, Triodia albescens and T. trinerviglumis, are allied to this. Nash? 
recognizes the genus Rhombolytrum and transfers to it Sieglingia albescens 
(Vasey) Kuntze. 
Hrioneuron Nash, in Small, Fl. Southeast. U. 8S. 148. 1903. The type, Uralepis 
pilosa, is indicated on page 1327 of the Same work. Only one species included. 
Dasyochloa Willd.; Rydb., Colo. Agr. Hxp. 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.® 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 (.) 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. Z'riodia flava (the type of Tridens) and 7. 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, 7. 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 7’. avenacea, with the midnerve of 
the lemma excurrent between the teeth, the lateral nerves not ex- 
current but extending into the teeth. TZviodia pulchella 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 
1Beauv. Hss. Agrost. pl. 15, f. 10. 1812. 4Nom. Bot., ed. 2, 1: 484. 1840. 
2Gen. Pl. 3: 1176. 1883. 5 Syst. Verz. Pflanz. Erfurt. 40. 1800. 
8In Britton, Man. 129. 1901. 
