GRAMINEJE. (GRASS FAMILY.) 583 



64. AreRROPOCJON, L. BEARD-GRASS. 



Spikelets in pairs upon each joint of the slender rhachis, spiked or racemed; 

 one of them pedicelled and sterile, often a mere vestige : the other sessile, with 

 the lower flower neutral and of a single palea ; the upper perfect and fertile, of 

 2 thin and hyaline paleie shorter than the herbaceous or chartaceous glumes, the 

 lower awned from the tip. Stamens 1-3. Grain free. Coarse and mostly 

 rigid perennial Grasses, with lateral or terminal spikes commonly clustered or 

 digitate ; the rhachis huiry or plumose-bearded, and often the sterile or stami- 

 nate flowers also (whence the name, composed of avTjp, aVSpoj, man, and Trcbycoi/, 

 beard). 



# Sterile spikelet staminate (stamens 3), awnless: spikes digitate. 



1. A. furcfttus, Muhl. Culms (4 high) and leaves nearly smooth, 

 bearing 3-5 straight and rather rigid hairy spikes together at the naked summit 

 (or fewer on lateral branches) ; spikelets approximated, roughish-downy ; awn 

 bent. Sterile soil ; common. Sept. 



# * Sterile spikelet neutral, reduced to a small pointed glume raised on a long bearded 

 pedicel ; the fertile 2 - 3-androus, bearing a slender mostly bent or twisted aim : culms 

 paniculate-branched. 



2. A. SCOpfsrins, Michx. Culms slender (2 -4 high), with many pa- 

 niculate branches ; the lower sheaths and the narrow leaves hairy ; spikes mostly 

 single, terminating the short branches, peduncled, very loose, slender (2' long, often 

 purple), sparsely silky with dull white hairs; the zigzag rhachis hairy along the 

 edges ; pairs of spikelets rather distant. Sterile or open sandy soil ; common. 

 July -Sept. 



3. A. argenteilS, Ell. Culms rather slender (about 3 high) ; spikes in 

 pairs, on a peduncle exceeding the sheaths, dense, very silky with long white hairs 

 (l'-2' long) ; rudimentary flower much shorter than the hairs -of its pedicel. 

 Sten'le soil, Virginia, Illinois ? and southward. Sept., Oct. Spikes much 

 denser, and the flowers larger and more silky, than in the next ; which it con- 

 siderably resembles. 



# =* * Sterile pikelet abortive, reduced to a mere awn-like plumose pedicel, or bearing 

 distinct rudiment of a flower : the fertile l-androus, and bearing a straight slender 

 awn : spikes clustered, lateral and terminal, partly enclosed in the flattened bract- 

 like sheaths; the slender rhachis, $'c, clothed with copioui very long and silky 

 (white) hairs. 



4. A. VirginicilS, L. Culm flattish below, slender, sparingly short- 

 branched above (3 high) ; sheaths smooth ; spikes 2 or 3 together in distant appressed 

 clusters, weak and soft (I 1 long). Sandy soil ; Massachusetts to Illinois, and 

 southward. Sept. 



5. A. macroftrus, Michx. Culm stout (2 -3 high), bushy-branched at 

 the summit, loaded with numerous spikes forming dense leafy dusters; sheaths 

 rough, the upper hairy. Low grounds, New York to Virginia, near the coast 

 and southward. Sept., Oct. 



