Gramina ceae y 69 
DD. : Lemma without a distinct callus, persisting after the grain has fallen; 
grain free from the palet. 
E. Glumes subulate, | -veined. SECALES(pac fT) 
EE. Glumes lanceolate or ovate, 3- to many-veined. TRITICUM (p. 71) 
AA. Spikelets 2—3 at each joint of the rachis. . 
F. Spikelets 3 at each joint of the rachis, 1-flowered. HORDEUM (p. 71) 
FF. Spikelets 2 at each joint of the rachis, 2- to many-flowered. 
G. Glumes entire; rachis continuous, rarely breaking into pieces. ELYMUS (p. 72) 
GG. Glumes 2- to many-parted or -cleft; rachis jointed, readily falling into 
pieces. SITANION (p. 73) 
LOLIUM RYEH-GRASS 
Annual or perennial, erect. Leaves flat. Spikelets in a simple terminal spike, sev- 
eral-flowered, solitary and sessile at the joints of the rachis, alternate, edge-wise to the 
rachis; rachis somewhat zigzag; rachilla jointed between the flowers. Glume | except 
in the terminal spikelet, opposite the rachis. Lemma rounded on the back, 5—7-veined, 
obtuse or acute or awned. Palet 2-keeled: Stamens 3. Grain smooth, adherent. (Latin 
name. ) 
A. Perennial; glumes shorter than the spikelet (less the awns); leaf-sheaths shorter 
than the internodes. W. LL. perenne L. (Perennial Rye-grass) 
AA. Annual; glumes equaling or exceeding the spikelet (less the awns) ; leaf-sheaths 
longer than the internodes. W. 
L. temulentum Lb. (Darnel) 
SCRIBNERIA 
Annual, slender, 0.5—-3 dm. high. Leaves short, narrow. Spikelets in a spike, 
solitary or in 2’s at the joints of the rachis, |-flowered, perfect; spike slender, simple; 
rachilla extending very slightly beyond the palet. Glumes narrow, rigid, acute, slightly 
unequal, strongly keeled. Lemma shorter than the glumes, membranous, keeled, 2- 
toothed at apex, awned between the teeth; callus hairy. Palet acutely 2-toothed. Stamen 
1. Grain linear, nearly terete. (Honor of F. Lamson-scribner, an American agrostol- 
egit) WiC. S. bolanderi Hack. (Thread-head) 
AGROPYRON BUNCH-GRASS 
Perennial; stem erect, simple. Spikelets in a spike, 3- to many-flowered, closely 
sessile, lat each joint of the rachis; rachilla jointed under each flower. Glumes narrower 
‘and usually shorter than the lemma, acute or awned. Lemma rounded on the back or 
slightly keeled above, 5——7-veined, acute or awned from the apex, rarely obtuse. Palet 
2-keeled, bristly-ciliate on the keels. Grain pubescent at apex, usually adherent. (Gk. 
agros—field, pyros—wheat; they were weeds in wheat.) 
A. Plants densely tufted, not or hardly producing rootstocks; lemma not hairy. 
B. Glume-awns 1—2.5 cm. long; glumes 4—6 mm. long. 
C. Herbage pubescent; spike dense. E. (Elvmus saxicolus.) 
A. saxicola Pip. 
CC. Herbage glabrous; spike loose. E. (Sitanion flexuosum.) 
A. flexuosum Pip. 
BB. Glume-awns either none or more than | cm. long. 
D. Some of the lemma-awns longer than their lemmas. 
