56 A Study of the Vegetation of 
is it absent. A medium-sized mature plant occupies an area of 
4-5 square feet ; it may have as many as 50-80 of the large sagittate 
leaves and a total transpiring surface of 30 square feet. From 
the short, thick, multicipital stem (I have counted 39 individual 
leafy shoots on a stem 9 inches in diameter) the new leaves appear 
in April. By the first of May the plant is often in full bloom. 
Then, with its large, yellow flowers, it is the most conspicuous ob- 
ject of the vernal aspect, which lasts until about June 1. After this 
Ft. 
SS 
= 
-——> 4 
SSeS 
——— 
m 
MUNN) 
Ni 
M\ N J 
SS = SS 
Fic. 15%. This and the two following figures (152 and 15°) are bisects 
showing the root and stem relations of important prairie plants. These 
figures were drawn from photographs and from data obtained by the 
excavation and examination of 325 root-systems of these eighteen species. 
H, Hieracium scoulert. K, Koeleria cristata. B, Balsamorhiza sagittata, 
F, Festuca ovina ingrata. G,Geranium viscosissimum. P, Poa sandbergii. 
Ho, Hoorebekia racemosa. Po, Potentilla blaschkeana. 
the whole aérial part dries up, but the dead leaves are conspicuous 
throughout the year. It has a strong, woody tap-root, sometimes 
reaching a diameter of 4 inches, which may penetrate into the soil 
for a distance of 8 feet. Not only is it deep-rooted, but the ex- 
tensive and wide-spreading laterals lay hold upon a very large 
area of soil. 
In another place will be found a detailed report of a study of 
56 
