GRAMINEAE (GRASS FAMILY) 



167 



1S7. A. bifiorum. 

 Spikelet x 3. 



high; leaves often lax, 2-5 mm. wide; spike dense^ 5-10 cm. 

 long, usually tinged icith purple ; glumes conspicuously 5-7- 

 nerved, the inaryins thin and widened above the middle, rather 

 abruptly narrowed into a short awn ; lemma 8-10 mm. long, 

 glabrous or nearly so, terminating in an awn shorter than itself. 

 (^4. violaceum Lange.) — Alpine regions of the 

 Wliite Mts., L. Superior, northw. and westw. 

 June-Sept. (Eu.) Fig. 187. 



6. A. tenerum Vasey. Culms erect, 5-10 dm. 

 high, rigid ; leaves subrigid, narrow, fiat or invo- 

 lute in drying; spike usually almost cylindrical, 

 green or straw-color, 1-1.5 dm. long; ghimes 

 firm, nearly as long as the spikelet, the scarious 

 margin narrow, tapering more gradually into the 

 awned point ; lemma short-awned. — Nfd. to Pa. 

 and Minn. , and common in the far West. July, Aug. — The 

 typical form has slender spikes with rather distant spikelets, 

 which are nearly inclosed in the glumes ; this is common westw. 

 and extends into Minn. ; also introduced on the 

 coast of Mass. {Eaton.) Fig. 188. Passing into 

 a form with stouter and denser spikes and broader 

 less rigid leaves which extends eastw. to Nfd. and 

 N. E. ; this is A. novae-angliae Scribn. and essen- 

 tially A. pseudorepens Scribn. & J. G. Sm. 



7. A. caninum (L.) Beauv. (Awned Wheat Grass.) Culms 

 erect, 3-10 dm. high ; leaves flat, rather lax. 8-20 cm. long, 2-6 

 mm. wide, scabrous ; spike more or less nodding, at least in fruit, 

 rather dense, 7-15 cm. long ; spikelets 1.2-1.5 cm. long exclud- 

 ing the awns ; glumes pointed or awned ; lemmas 3-5-nerved ; 

 axons straight or somewhat spreading, fully twice the length of 

 the lemma. — Sparingly naturalized in cultivated grounds and 

 meadows ; indigenous along our northern borders, and westw. 

 July-Sept. (Eu.) Fig. 189. 



8. A. Richards5nii Schrad. Similar to the preceding ; culms 

 usually taller and stouter ; spike larger, as much as 2 dm. long, 

 erects l-sided ; spikelets 2 cm. long., excluding the awns., which 

 are often as much as 3-4 cm. long. — Prairies and shores, e. Que. ; IMlnn., la., 

 and northwestw. June-Sept. 



188. A. tenerum 

 Spikelet x 3. 



189. A. caninum. 

 Spikelet x iVa. 



80. HORDEUM [Toum.] L. Barley 



Spikelets 1 (rarely 2)-flowered, 3 together in our species at each joint of the 

 flattened articulate rhachis, the middle one sessile, perfect, the 

 lateral pair usuall}^ pediceled, often reduced to awns and 

 together with the glumes of the perfect spikelet simulating 

 a bristly involucre at each joint of the rhachis ; rhachilla 

 prolonged behind the palea as an awn, sometimes with a 

 rudimentary floret ; glumes equal, rigid, narrow-lanceolate, 

 subulate or setaceous, placed at the sides of the dorsally com- 

 pressed floret which is turned with the back of the palea 

 against the rhachis of the spike ; lemma obscurely o-nerved, 

 tapering into an awn ; palea slightly shorter, the 2 strong 

 nerves near the margin ; grain haiiy at the summit, usually 

 adherent to the palea at maturity. — Caespitose annuals or 

 perennials with terminal spikes which disarticulate at matu- 

 rity, the joints falling with the spikelets attached. (The 

 190. H. jubatum. ancient Latin name.) 



Three spikelets xl. 1- H. jubatum L. (Squirrel-t.\il Gkass). Biennials. 



Middle, fertile sjiike- 3-7 dm. high, evect or geniculate at base ; leaves 5 imii. wide 

 let X 114. or less, scabrous; spike nodding, 5-12 rm. long, about as 



