236 
IOWA ACADEMY OF SCIENCE Vol. XXVIII, 1921 
pubescent beneath ; nearly glabrous, glossy above ^ ; nearly 
glabrous ; glabrous to nearly so ; nearly smooth ® ; lower 
surface glabrous or with few scattered hairs, nearly glabrous ; 
nearly glabrous or somewhat pubescent ; veins pubescent be- 
neath ; smooth and shining ; veins slightly pubescent under- 
neath ; sometimes lower surface covered with glands ; pubescent 
when young ; at length nearly or quite smooth, except the slight 
pubescence on veins underneath ; glabrous, or with few hairs on 
principal veins; nearly glabrous throughout, or AV. races densely 
pubescent The last-mentioned western races are the variety 
puhescens ! 
In the Iowa specimens the upper surface of the leaf is glabrous, 
or very nearly so, occasionally with a few inconspicuous short 
scattered hairs. The lower surface is sometimes slightly pubescent, 
the pubescence being almost wholly on the veins, and quite incon- 
spicuous. Very young leaves are more or less brown-pubescent 
but the upper surface soon becomes green and more or less shiny. 
Size. — The size of the leaf as given in the various descriptions 
varies from 1 to 3 inches (1.5 to 7.5 cm.) in length, and from 
yi to^ of an inch (6 to 18 mm.) in width. 
The Iowa leaves vary from 3.0 to 7.2 cm. in length, and from 
1.2 to 3.4 cm. in width. 
The great variation in characters has resulted in efforts to 
recognize varieties, and several have been named but they are of 
little interest here in Iowa, as they are mostly southern or eastern, 
or of little significance. 
Habitat. — Western references to habitat probably apply in 
large part to the variety. In the references which manifestly 
apply to the typical form the habitat is given as follows: Rocks 
dry rocks ; dry rocks or sandy soil ; barren rocky places ; 
on dry gravelly banks ; sandy shores ; sandy soil ; rocky 
places and on prairies ; knolls in the rolling prairie^®; and 
shade 
The most typical Iowa forms were found in open places on 
rocky slopes — rarely on the prairie. The typical form resembles 
the variety when the leaves and shoots are quite young, but at ma- 
turity the shiny green, glabrous, or nearly glabrous, upper surfaces 
of the leaves, and the scant pubescence elsewhere, give the plant 
a strikingly different aspect. 
This species may be cultivated in much the same manner as the 
preceding form. It is not easily obtained in Iowa, however, and 
the other forms are quite as suitable. 
