246 JOHN ERNST WEAVER 



except on moist north or northeast hillsides or in the narrow 

 intervening valleys. The aerial parts of the lupines begin re- 

 newed growth in April, and come into bloom in June. L. 

 ornatus remains green only until late July or early August, while 

 L. leucophyllus seldom dries out until after the frosts of Sep- 

 tember. The dense coat of appressed hairs on the former, on 

 both leaves and stems, gives the plant a silvery gray appearance, 

 and as the aerial parts reach a height of more than a foot, they 

 add considerably to the leaden aspect caused by Balsamorhiza 

 and Hier actum. As regards abundance, an average of 7 plants 

 per square meter is not unusual, while L. leucophyllus seldom 

 averages more than one per square meter. 



Twenty-four root-systems were examined. Several reached 

 a depth of over 10 feet. The diameter of the tap root is seldom 

 over 0.5 inch. It may have few or no large branches, but is 

 often well supplied with wide-spreading laterals. The whole 

 root is well clothed with fine rootlets to the third order, and the 

 last foot or eighteen inches is often a mat of small branches and 

 root hairs. In fact, the root hairs are far more abundant than 

 on any other plant studied. The roots pursue a very devious 

 course, especially in more compact soils. For example, one 

 plant reached a depth of only 5 feet and 5 inches but the main 

 root ran along under the ground at a depth of only 12 inches and 

 for a distance of 4 feet. It sent up a whole thicket of stems. 

 Another root, with a circumference of 1.5 inches, which it main- 

 tained for 3 feet, was over 10 feet long, but reached a depth 

 of only 5 feet and 5 inches. When the top parts of the main roots 

 die, sprouts, seen as deep as 3 feet, grow up to the surface. The 

 average depth of the roots for all the plants studied was 7 feet 

 and 7.1 inches. Nodules were found to depths of 11 feet. Nine 

 plants on a northeast slope gave an average depth of 6 feet; 

 five on a southwest slope, 5 feet and 11 inches; and ten on a 

 northwest slope 9 feet and 10.4 inches. 



Lupinus leucophyllus {Fig. 8) 



This lupine has a much larger transpiring surface and a much 

 smaller absorbing surface than the preceding. Its tap root, 



