142 



GRAMINEAE (GRASS FAMILY) 



Teeth of the lemma triangular, not aristate 1. D. spicata. 



Teeth of the lemma aristate. 



Florets not over 5 mm. long 2. D. comprestsa. 



Florets 7-8 mm. long. 



Spikelets nearly sessile, in small crowded panicle, purple . . . . 3. D. intermedia. 

 Spikelets in loose panicle, pale green. 



Sheaths and blades villous ; lemma silky -hairy 4. D. sericea. 



Sheaths and blades glabrous ; lemma pubescent on margins and base 



only 5. D. epilis. 



I. D. spicata (L.) Beauv. Culms 2-7 dm. high terete ; sheaths and involute 

 blades glabrous or sparsely pilose, the numerous basal leaves often curled, those 

 of the culm erect ; panicle few-flowered, the few short branches 

 erect or ascending, often reduced to a raceme ; spikelets 

 10-12 mm. long, on short stiff pedicels ; glumes acuminate : 

 lemmas 4-5 mm. long, sparsely clothed with stiff hairs, teeth 

 triangular, the awn longer than the lemma. Dry and sterile 

 or rocky soil. June- Aug. FIG. 126. 



2. D. compre'ssa Aust. Usually taller than the preceding : 

 culms flattened, often decumbent at base ; leaves elongated, 

 2-3 mm. wide, flat or involute on the margins only ; panicle 

 more open ; teeth of the lemma aristate, at least 



2 mm. long. Dry woods, Me. to N. Y., and \ 

 southw. 



3. D. intermddia Vasey. Culms 1-4 dm. high, 

 with numerous mostly involute basal leaves; 

 culm-leaves 5-15 cm. long, involute ; spikelets 

 15 mm. long, rather crowded in a raceme or 

 simple few-flowered panicle ; glumes broad, acu- 

 minate, purplish, with pale scorious margins; 

 lemma 7-8 mm. long, glabrous except at the base 

 and margins below the middle, the teeth aristate ; 

 awn 7-8 mm. long. Mt. Albert, Gaspe" Co. , 

 Que. ; n. Mich. (Farwell), and westw. July, 

 Aug. 



4. D. sericea Nutt. Culms 5-9 dm. high ; sheaths and blades 

 villous, at least the lower ones ; basal blades elongated, mostly 

 involute, those of culms flat or involute ; panicle 6-10 cm. long, 

 rarely longer, rather loose, the branches ascending or spreading ; 

 spikelets about 1.5 mm. long; glumes narrow, acuminate, pale; 

 lemma densely clothed with long silky hairs, the aristate teeth more 

 than % the entire length of the lemma, awn 12-15 mm. long. 

 Sandy soil, Mass, to Pa., and southw. FIG. 127. 



5. D. 6pilis Scribn. Very similar to the preceding, not so tall ; sheaths and 

 blades glabrous ; panicle smaller ; lemma glabrous, except at the base and on the 

 margins below the middle. (D. glabra Nash, not Philippi.) Sandy soil, N. J., 

 and southw., rare. May. Possibly only a variety of the preceding. 



48. SPARTlNA Schreb. CORD or MARSH GRASS 



Spikelets 1-flowered, flattened laterally, sessile and closely imbricated in 2 

 rows along one side of a continuous rhachis, forming unilateral spikes which are 

 scattered along a common axis ; glumes unequal, keeled, acute or bristle- 

 pointed, the second usually exceeding the obtuse thinner 1-nerved lemma ; 

 palea equaling or exceeding the lemma. Coarse perennials with strong creeping 

 rootstocks, rigid simple culms, and long tough leaves. (Whence the name, from 

 ffiraprLvrj, a cord, such as was made from the bark of the Spartium or broom.) 



* Culms stout, usually over 1 m. high; leaves 1 cm. or more wide, flat or 



nearly so when fresh. 



1. S. Michauxiana Hitchc. (SLOUGH GRASS.) Culms 1-2 m. high ; 

 leaves 6-12 dm. long, 15 mm. wide or less, tapering to a very slender point. 



126. D. spicata. 

 Panicle x %. 

 Spikelet and floret 



x 1%. 

 Lemma x 2. 



