THE DUNES AND THEIR PLANTS 



119 



a weed everywhere that its burrs and coarse leaves are famihar. 

 The sand thistle (Fig. 82) is a pale, hairy thistle with very weak 

 prickers and heads of cream-colored blossoms. 



Then comes the fore-dune association (Fig. 83) including, in 

 addition to the foregoing, the sand reed grass, marram grass, 

 rye grass (Elymus) winged pigweed, green milkweed, seaside 

 spurge, mullein, sand cherry, and the furry willow. The sand 

 reed grass (Fig. 84) grows in clumps from underground running 

 root stalks. It bears its seeds in a spreading cluster. Where 

 its leaves sheath the stalk they bear a ring of short hairs. 



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Fig. St,. — The beach, the storm beach, fore-dune, pine and oak associations. 



The Cottonwood zone is missing here. 



Marram grass (Fig. 85) also grows in clumps, springing from 

 underground running root stalks, and bears its seeds on a dense 

 spike. Its leaves are tipped with a long slender point. There 

 is no ring of hairs on the leaves where they clasp the stem. Rye 

 grass (Fig. 77) or wild rye looks like growing grain. The leaves 

 are broad. The seedlike fruits grow in a spike, each one bearing a 

 long bristle or awl. The winged pigweed (Fig. 78) is a much- 

 branched, coarse annual. Very small scattered flowers give it a 

 characteristic appearance shown in the illustration. Green milk- 

 weed (Fig. 79) has milky juice and broad, glossy, almost sessile 

 leaves. Its flowers are green, and their hoods have no crests 



