ANATOMY OF SOME PLANTS OF A PROVINCE IN IOWA 
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Histology: Bifacial (fig. i8, plate XII). 
Upper epidermis with outer wall twice as thick as lower; wall of lower epidermis 
uniformly thin, but with numerous trichomes. 
Palisade parenchyma of 3 layers, occupying 1/2 the parenchyma space. 
Spongy parenchyma loose.. 
Summary: Photosynthetic tissue prominent; prominent air space; moderate conser- 
vational tendencies. 
Helianthus grosseserratus Martens. 
Habitat: Dry prairie; roadsides. 
Orientation and arrangement: Horizontal to ascending; petioled; alternate. 
Gross structure: Elongated lanceolate to ovate-lanceolate; glabrous above; finely 
pubescent beneath. 
Histology: Bifacial (fig. 19, plate XII), 
Outer wall of upper epidermis about 3 times as thick as inner; outer wall of lower 
epidermis about twice as thick as inner; cells small. 
Palisade, 5 layers; medium-sized, occupying 2/3 of parenchyma space. 
Spongy parenchyma loose. 
Summary: Epidermal tissue better developed in H. grosseserratus than in H. tuberosus. 
Photosynthetic tissue is more compact. 
Silphium laciniatum L. 
Habitat: Rather dry priarie; sometimes moist slopes. 
Orientation and arrangement: Stem leaves ascending; lower and root leaves vertical; 
alternate; petioled. 
Gross structure: Pinnately parted, lobes lanceolate or linear, cut-lobed or pinnatifid; 
rough-bristly. 
Histology: Subcentric (young leaf) (fig, 22, plate XII). 
Epidermal cells square; with outer wall of epidermis 4 to 5 times as thick as inner 
wall. 
Palisade in 5 layers, the longest at the top; fairly compact. 
Summary: The well cuticularized epidermis indicates the ability to modify transpira- 
tion, while the prominent palisade implies pronounced photosynthetic activity. 
Solidago rigida L. 
Habitat: Dry soil; ridges and hillsides. 
Orientation and arrangement: Ascending, somewhat appressed; petioled; upper leaves 
sessile. 
Gross structure: Oval or oblong; rough-hoary with minute pubescence. 
Histology: Concentric (fig. 26, plate XIV), 
Epidermal cells small with outer walls 3 times as thick as inner; trichomes on both 
sides, 
Stomata on both sides. 
Palisade parenchyma, 3 layers on upper and 2 on lower side; loose; occupies 2/3 
the parenchyma space. 
Spongy parenchyma, small-celled; loose. 
Stomata small, level with lower edge of epidermis. 
Summary: Epidermis well equipped for conservation of water with the exception of 
stomata. Solereder states that stomata are often found on the upper sides of ap- 
pressed leaves from dry habitats. Photosynthetic tissue well developed with promi- 
nent air space. 
Solidago serotina Ait. 
Habitat: Moist soil; slopes. 
Orientation and arrangement: Horizontal to ascending, somewhat appressed; sessile. 
Gross structure: Lanceolate to oblanceolate; glaucous. 
