74 
ADA HAYDEN 
Gross structure: Lanceolate to ovate; water form smooth; land form scabrous. 
Histology: Bifacial (figs. 5a and 5&, plate IX). 
Epidermis: Moderately thin-walled; slightly thicker on outer surface of water 
form; trichomes present on land form, also mucilagin us epidermal cells. 
Stomata smaller on land than on water form. 
Palisade parenchyma in two layers in both forms; the upper of irregular long cells, 
the lower of shorter and irregular cells; the land leaf is thicker than the water 
leaf, because the palisade parenchyma occupies 3/8 of the parenchyma space 
in the water form and 5/9 of the parenchyma space in the air form. 
Spongy parenchyma about equally developed in both forms; loose. 
Summary: These leaves indicate abundant water for needs with little provision for its 
conservation. The air leaf is a little thicker because of its increased thickness of 
the palisade, and its lower epidermis is equipped with trichomes and smaller stomata. 
Ranunculaceae 
Anemone cylindrica Gray. 
Habitat: Dry, gravelly hill crests; dry, wind-swept. 
Orientation and arrangement: Blade horizontal; radical leaves petiolate, involucrate 
leaves sessile. 
Gross structure: Digitately cleft to parted; pubescent. 
Histology: Bifacial (fig. 6, plate IX). 
Epidermis with curved walls; outer walls about three times as thick as inner; 
large-celled compared with the parenchyma. 
Stomata small; level with lower edge of epidermis. 
Palisade parenchyma in 2 layers; slender; irregular; occupies 2/5 parenchyma space. 
Spongy parenchyma small-celled ; close ; compact ; about 3/5 the parenchyma space. 
Summary: This leaf is equipped with trichomes, thick outer epidermal walls, and com- 
pact photosynthetic tissue. 
Leguminosae 
Amorpha canescens Pursh. 
Habitat: Hill crests and dry hillsides. 
Orientation and arrangement: Horizontal; petiolate; alternate. 
Gross structure: Pinnately compound; hoary pubescent. 
Histology: Subcentric (fig. 7, plate X). 
Epidermis with approximately straight-sided cells; cells small; outer walls hardly 
thicker than the inner; trichomes present. 
Palisade parenchyma in four layers graduated in size, longest on upper side; 
compact. 
Spongy parenchyma absent. 
Summary: The compact structure and the prominent trichomes show marked conser- 
vational features in accord with its specialized photosynthetic tissue. This plant, 
though living in dry situations, has a deep root which may reach a lower water table 
than "the roots of some of its associates. 
Baptisia leucantha T. & G. 
Habitat: Alluvial basin; moist soil. 
Orientation and arrangement : Horizontal or somewhat inclined ; almost sessile. 
► Gross structure: Palmately 3-foliolate; leaflets wedge-shaped. 
Histology: Subcentric (fig. 6a, plate X). 
Walls of outer epidermis about three times as thick as inner; fairly large oblong 
cells with long axis horizontal. 
Palisade parenchyma rather loose; cells medium-sized. Stomata slightly de- 
pressed. 
