ANATOMY OF SPARTINA. 289 



furrows, which are 2-cleft at bottom by the low ridges of the smallei 

 nerves. 



Epidermis: Ventral with cells much smaller ami thinner-walled 

 than on the dorsal surface; stomata on each side of the bottom of 

 the furrows, somewhat prominent; many of the epidermal cells 

 extended into short, rather thin-walled, erect, unicellular papillae 

 with broad, rounded or truncate summits, and, especially at the 

 summit of the ridges, into longer, sharp-pointed, thick-walled, erect, 

 prickle-like hairs; typical bulliform cells none, but at the bottom of 

 each furrow a group of usually 3 large epidermis cells, which are 

 probably functionally homologous. Dorsal with thick, porous wall's, 

 which, in the rows containing stomata, art; unevenly thickened so as 

 to appear wavy, 1 or more often 2 short (tells alternating with the 

 longer ones; cuticle thick; stomata in very shallow furrows; hairs 

 and papillae none. 



Subepidermal stereome not as strongly developed as in most of the 

 strand grasses, in small groups on the dorsal side of each nerve; in 

 flattened supporting strands at the summit of each ventral rib and 

 extending some distance down its sides; and in comparatively small 

 strands in the leaf margins. 



Chlorophyll chiefly in the parenchyma sheath of the mestome bun- 

 dles, with a "bridge" of small-celled chlorenchyma connecting each 

 two neighboring sheaths; palisade none. 



Colorless parenchyma tilling the ventral ribs above the mestome 

 bundles where it interrupts the parenchyma sheath, a few cells also 

 interrupting the parenchyma sheath on the dorsal side. 



Mestome bundles surrounded by a mestome sheath whose walls 

 (especially the inner) an; much thickened only on the leptome side 

 of the larger nerves; parenchyma sheath (enveloping the mestome 

 sheath) containing chlorophyll, continuous about the smaller nerves, 

 interrupted by colorless parenchyma above and below the larger ones; 

 mestome parenchyma (thick-walled) in a single layer between the lep- 

 tome and the hadroine of the larger bundles. 



Spaktina stricta (Ait.) Roth. 1 



Leaf conduplicate when dry, not furrowed on the dorsal surface, 

 deeply furrowed on the ventral side, tin; furrows acute, the inter- 

 vening ridges broad and truncate at summit. 



Epidermis: Ventral with cells narrower and not so high as on 

 the dorsal surface, the walls as in S. patens, except that the outer 

 wall of each cell is covered with silicified papillae; stomata on each 

 side of the bottom of the furrows; hairs none; typical bulliform cells 

 none, but 1 to 3 epidermal cells at bottom of each ventral furrow 

 somewhat larger than the others and probably functioning as bulli- 



1 Although this species belongs to the salt marsh, it is described here for the 

 sake of convenient comparison with the oth r Gram neae. Compare Dnval-Jouve, 

 Histotaxie, pi. IS, Jig. 5. The Or icoke plant is nearly of the typical form. 

 2965 3 



