GENERA OF GRASSES OF THE UNITED STATES. 101 
so that only the row of central spikelets on each side of the spike is 
prominent. Naked barley is a kind of 2-rowed barley in which the 
grain is free from the lemma and palea. Rice barley (4. zeocriton 
L.), with spreading spikelets and divergent awns, is not grown in this 
country and but sparingly in Europe. Beardless barley (H. vulgare 
trifurcatum Wenderoth) (fig. 50, A) is a variety of 6-rowed barley 
in which the awns are suppressed or converted into irregular short 
lobes or teeth. Schulz+ divides the cultivated barleys into two 
groups.. The first group, derived from H. spontaneum Koch, in- 
cludes the 2-rowed varieties. The second group, derived from Z. 
ischnatherwm (Coss.) Schulz, includes the 4 and 6 rowed varieties. 
The glumes of Hordeum are thought by Schenck to be sterile spike- 
lets or branchlets. (See footnote under Elymus, p. 93.) 
Three common species of Hordeum are annuals. One of these, 
H. pusillum Nutt., with glumes broadened above the base, is a native 
species. The other two, introduced from Europe, are common weeds on 
the Pacific coast. In 7. murinwm L. a part of the glumes are ciliate; 
in H. gussoneanum Parl. the glumes are setaceous, smooth below. 
Hordewm nodosum L. (fig. 51) is similar to H. pusillum but differs 
in being perennial and in having uniformly subulate glumes. This 
species is abundant throughout the western half of the United States. 
Another perennial species, H. jubatum L., called squirreltail grass 
because of its soft brushlike spikes, is common in the Western States, 
where it is not infrequently a troublesome weed in alfalfa fields. 
This species is called foxtail in Wyoming, barley grass in Utah, and 
tickle grass in Nevada. Hordewm murinuwm, mentioned above, is 
called barley grass, foxtail, and wild barley in different localities. 
The species of Hordeum furnish forage during the early stages of 
growth before the awns are produced. The mature spikes break up 
into sharp-pointed joints that become a serious pest to stock. These 
joints with the forwardly roughened awns work into the eyes and 
nostrils of animals, causing inflammation. 
For a revision of the species of Hordeum found in the United 
States, see Scribner and Smith, U. S. Dept. Agr., Div. Agrost. Bull. 
4:23-25. 1897. 
41. Lotium L. 
Spikelets several-flowered, solitary and sessile, placed edgewise to 
the continuous rachis, one edge fitting to the alternate concavities, the 
rachilla disarticulating above the glumes and between the florets; first 
glume wanting (except on the terminal spikelet), the second outward, 
strongly 3 to 5 nerved, equaling or exceeding the second floret ; lemmas 
rounded on the back, 5 to 7 nerved, obtuse, acute, or awned. 
1Mitt. Natf. Ges, Halle 1:18. 1911. 
