i9i 2] STARR— ANATOMY OF DUNE PLANTS 269 



Lathyrus maritimus. — A smooth 



Leaf 



almost half of the m 



compact; fibers above and below the bundles. Stem 



sharply angled; phloem 



chyma ; a 



ma penetrating a distance 



medullary rays thin; outer wall of epidermis 



6.2 p. Root with large vessels; about one-half the pith made 

 of scattered masses of sclerenchyma. 



Ammophila arenaria. — A stout perennial grass with firm ere 



mor 



ing rootstocks that anchor the dunes, 

 upper surface rolled in; the surface a series of ridges and grooves; 

 bundles under the ridges; edges of the leaf and ridges strengthened 

 with hypodermal sclerenchyma, that in the ridges extending into 

 the bundles ; upper epidermal cells large and globular, or prolonged 

 into conical hairs; stomata on the upper surface sunken to the 

 depth of the epidermal cells; chlorenchyma reduced to strands 

 each side the bundles; air spaces very small; outer wall of the 

 lower epidermis (the exposed side) 6.4 y* thick, the cuticle 3.2/*. 

 Stem with cortical tissue sclerenchyma tous, 

 slightly thickened all around. 



Andropogon sco partus (bunch-grass). — Leaf stiffened with a 

 series of bundles, large ones alternating with three small ones, the 

 space above the small ones filled in with three or four enormous 

 epidermal cells and smaller, hypodermal, colorless cells; epidermal 

 cells occasionally prolonged into sharp hairs, longer than those of 

 Ammophila; the large cells collapse at the bend of the leaf, as it 

 folds with the upper surface in; 



rmis 



masses 



and below 



the mi 



ones; chlorenchyma above the bundles; outer wall 9.3 /*; cuticle, 



thick 



sunken 



Calamovilfa longifolia. — A rigid perennial 



lower surface plane; 



sheaths 



^ 



Leaf with 

 ns on the 



thick 



Ammophila; walls of epidermis 



and below, and sometimes about the phloem; hypodermal scleren- 

 chyma next to the lower surface and at the top of the ridges; short, 



