ANATOMY OF SOME PLANTS OF A PROVINCE IN IOWA 
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Summary: The bulliform cells are prominent. The thickened outer walls of the epi- 
dermal cells are indications of water conservation. This plant not only grows in a 
dry habitat but has abbreviated roots. 
Bouteloua curtipendula (Michx.) Torr. 
Habitat: Dry hill crests and slopes. 
Orientation and arrangement: Ascending; alternate. 
Gross structure: Small lanct olate-linear; flat or involute; scabrous above; sometimes 
pubescent beneath. 
Histology (fig. 2, plate IX): 
Outer walls of epidermis about twice as thick as inner walls; upper epidermal cells 
terminating in barb-like points at intervals; lower epidermis with trichomes; 
bulliform cells prominent. 
Mesophyll reduced, represented by a radial row of palisade cells around the bundles. 
Vascular tissue prominent, including a row of large water-storing cells. 
Stomata small. 
Summary: The thickened epidermal cells prominent, bulliform cells well developed; 
the conspicuous vascular tissue and the reduced photosynthetic tissue are marked 
indicators of conservational facilities. Bouteloua lives in drier areas and has a more 
restricted habitat than Andropogon scoparius. 
Muhlenhergia mexicana (L.) Trin. 
Habitat: Damp soil; low land; alluvial basin. 
Orientation and arrangement: Ascending-; alternate; somewhat appressed to stem. 
Gross structure: Lanceolate-linear; small; scabrous. 
Histology: Homogeneous (fig. 3, plate IX). 
Outer walls of epidermis slightly thicker than inner; cells terminating in barb 
occasionally; bulliform cells not prominent. 
Parenchyma: Spongy in appearance; of roundish to oval cells compactly arranged. 
Vascular tissue not prominent. 
Stomata small. 
Summary: This plant shows little tendency to conserve water. Vascular tissue is 
not so prominent as in grasses of drier habitats. Epidermis is not so specialized 
while photosynthetic tissue is fairly prominent. 
Leersia oryzoides (L.) Sw. 
Habitat: Alluvial basin; edge of swamp. 
Orientation and arrangement: Ascending, somewhat appressed to stem; alternate. 
Gross structure: Narrowly lanceolate; scabrous. 
Histology: Homogeneous (fig. 4, plate IX). 
Outer walls of epidermis slightly thickened; bulliform cells not prominent. 
Vascular tissue fairly prominent. 
Stomata small. 
Parenchyma spongy; compact. 
Summary: Water-conserving measures, though somewhat evident in the thickened 
outer wall of the epidermis and the differentiation of bulliform cells — are not so 
prominent as in Andropogon scoparius (fig. 4, plate IX) and Bouteloua curtipendula 
(fig. 2, plate IX), while photosynthetic tissue is better developed than it is in the 
leaves of the two last-named species. 
Polygonaceae 
Polygonum Muhlenhergii (Meisn.) Wats. 
Habitat: Alluvial basin; wet soil and shallow water at edge of ponds. Not submerged. 
Orientation and arrangement: Horizontal to ascending; petiolate. 
