34 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
For a revision of the species of Festuca found in North America, 
see Piper, Contr. U. S. Nat. Herb. 10 : 1-48, pi. 1-15. 1906. 
. Scleropoa Griseb., Spicil. Fl. Kumel. 2 : 431. 1844. 
The one species. Scleropoa rigida (L.) Griseb., a native of southern 
Europe, is sparingly introduced in the United States, mostly as a 
ballast plant. It is a low annual with racemes of spikelets resembling 
those of Puccinellia. The glumes are 1-nerved, the lemmas convex 
on the back and obscurely nerved. The type is Poa rigida L. 
Brachypodium Beauv., Ess. Agrost. 100, 155. 1812. 
One species, Brachypodium distachyon (L.) Beauv., of Europe, 
has been found on ballast at Portland, Oreg., and Camden, N. J. It 
is a low tufted annual, with stiff culms ending in a raceme of 1 to 
few short-pediceled, many-flowered cylindric spikelets, the awned 
lemmas rounded on the back, the paleas stiffly ciliate on the keels. 
4. Panicularia Heister. 
(Glyceria B. Br.) 
Spikelets few to many flowered, subterete or slightly compressed \ 
the rachilla disarticulating above the glumes and between the florets ; 
glumes unequal, short, obtuse or acute, usually scarious, mostly 1- 
nerved ; lemmas broad, convex on the back, firm, usually obtuse, awn- 
less, scarious at the apex, 5 to 9 nerved, the nerves parallel, usually 
prominent. 
Usually tall aquatic or marsh grasses, with flat blades, closed or 
partly closed sheaths, and open or contracted panicles. Species about 
35, in the temperate regions of both hemispheres; 16 species in the 
United States. 
Type species: Poa aquatica L. 
Panicularia Heister ; Fabr., Enum. PI. Hort. Heinist., ed. 2, 373. 1763. The 
genus is based on the species that Linnaeus named Poa aquatica. 
Festucaria Heister; Fabr.. Enum. PI. Hort. Helinst. ed. 2, 374. The 
genus is based on the species that Linnaeus named Festuca fluitans. 
Glyceria B. Br., Prodr. Fl. Nov. Holl. 179. 1810. Based on Festuca fluitans L. 
Nevroloma Baf ., Journ. de Phys. 89 : 106. 1819. " Type, le Briza canadensis 
de Michaux." This is Panicularia canadensis. 
Our species are divided into two rather well marked groups. One 
group, consisting of five species, has linear spikelets usually as much 
as 1 cm. long. These species are represented by Panicularia fluitans, 
the type of Festucaria and Glyceria. The group to which P. aquatica 
belongs has ovate or oblong spikelets usually not over 5 mm. long. 
The commonest species is Panicularia nervata (Willd.) Kuntze 
(fig. 8), with small prominently 7-nerved spikelets in open panicles. 
Panicularia canadensis (Michx.) Kuntze has larger less prominently 
