GENERA OF GRASSES OF THE UNITED STATES. 197 



97. MUNROA Torr. 



Spikelets in pairs or threes on a short rachis, the lower one or two 

 larger, 3 or 4 flowered, the upper 2 or 3 flowered, the group (reduced 

 spikes) inclosed in the broad sheaths of short leaves, usually about 

 3 in a fascicle, forming a cluster or head at the ends of the 

 branches; rachilla disarticulating above the glumes and between the 

 florets ; glumes of the lower 1 or 2 spikelets equal, 1-nerved, narrow, 

 acute, a little shorter than the lemmas, those of the upper spikelet 

 unequal, the first much shorter or obsolete; lemmas 3-lierved, those 

 of the lower spikelet coriaceous, acuminate, the points spreading, the 

 midnerve extended into a mucro, those of the upper spikelet mem- 

 branaceous ; palea narrow, 2-nerved, inclosing the oval, dorsally com- 

 pressed caryopsis. 



Low spreading, much-branched annuals, the short, flat, pungent 

 leaves in fascicles. Species three, plains of America ; two in Argen- 

 tina, one in the western United States. 



Type species : Crypsis squarrosa Nutt. 



Munroa Torr., U. S. Rep. Expl. Miss. Pac. 4: 158. 1856. One species de- 

 scribed, M. squarrosa (Nutt.) Torr. Torrey spells the genus Monroa, naming it 

 in honor of Munro, whom he refers to erroneously as Major " Monro." 



The prophylla are prominent in the fascicles of leaves, the two 

 nerves extending into long, green tips. The lower spikelet is bulged 

 out on the lower side, throwing the glumes forward; thus they 

 appear somewhat asymmetric. This genus has hitherto been placed 

 in Festuceae, but the structure of the spikelet and spike show closer 

 affinity to genera of Chlorideae. 



Munroa squarrosa (fig. 117) is common on the Great Plains from 

 Montana to northern Mexico, usually in new soil and open ground. 

 It has little or no importance as a forage grass. It is sometimes 

 abundant on recently broken sod. Munroa mendocina Phil., of 

 Argentina, has been referred to M. squarrosa, but it is a distinct 

 species. 



98. BULBILIS Eaf. 

 (BucMoe Engelm.) 



Plants unisexual. Staminate spikelets 2-flowered, sessile and 

 closely imbricate, in two rows on one side of a slender rachis forming 

 a short spike; glumes somewhat unequal, rather broad, 1-nerved, 

 acutish; lemmas longer than the glumes, 3-nerved, rather obtuse, 

 whitish; palea as long as its lemma, 2-nerved. Pistillate spikelets 

 mostly 3 to 5 in a short spike or head, this falling entire, usually 

 2 heads to the inflorescence, the common peduncle short and 

 included in the somewhat inflated sheaths of the upper leaves, the 

 thickened somewhat woody rachis and the 2 or 3 outer (second) 

 glumes appearing like an involucre; glumes very unequal, the first 

 inside relative to the cluster, thin, 1-nerved, keeled, the nerve extend- 



