HOW TO KNOW THE GRASSES 



13a. Leaf margins rough to the touch; plants widespread. Fig. 258. 



SLOUGH GRASS Spartina pectinata Link 



Perennial; spreading by tough, scaly 

 rhizomes which are up to 1 cm. thick; 

 culms tall, 1 — 2 m. in height. The whole 

 plant is coarse and tough, with saw- 

 edged leaves. Slough grass was former- 

 ly one of the dominant grasses of the 

 tall grass prairie region of the north cen- 

 tral United States. Now it survives 

 largely along roadsides, in ditches, and 

 on wet ground. July — September. 



/^ 



Spartina cy^°^^^^^^^^ ^^-^ Roth is 

 taller, has numerous spikes; second 

 glume without an awn. Salt marshes, 

 Atlantic and Gulf coasts. 



Figure 258 



13b. Leaf margins smooth; plants of Atlantic coastal salt-marshes. Fig. 

 259. 



Spartina alterniflora Loisel 



Perennial; spreading by rhizomes; culms 

 .5 — 2.5 m. tall, thick and spongy; leaf blades 

 flat, 5 — 15 mm. wide, tapering to a fine 

 point; panicles narrow, the spikes slender and 

 erect, 5 — 15 cm. long; spikelets about 1 cm. 

 long, the floret smooth or sHghtly hairy. 

 Coastal salt marshes, often growing in shal- 

 low water. Introduced along the coast of 

 southwestern Washington. July — October. 



Nearly a century ago, this species was in- 

 troduced into southern England. There it 

 formed a highly successful natural hybrid 

 with a European species. This hybrid, Spar- 

 tina townsendii, is now building extensive 

 areas of dry land from former tidal mud 

 flats there. 



/o 



Figure 259 



14a. Second glume without a protruding bristle on the back; inflores- 

 cence of 1 — many spikes 15 



137 



