8 CIRCULAR NO. 115, BUREAU OF PLANT INDUSTRY. 
strated in experiments conducted at the Arlington Experimental 
Farm during the past season. 
In a great many cases where stem proliferation is developed to 
2 considerable degree the center of the plant dies out, leaving that 
portion of the crown quite devoid of shoots. A similar condition 
is found in the true grasses, especially in forms of Festuca rubra and 
other fine-leaved fescues. Many explanations of this condition have 
been based on erroneous conclusions; in other words, it has been 
argued that underground stems and rhizomes by virtue of their 
ability to produce new growth keep these old plants alive, even after 
the original crown has died. As a matter of fact, the barrenness 
of the old crown is probably due in most cases to unfavorable con- 
ditions for the development of buds or new growth in the center of 
the clump. Where the original plant is grown in a crowded condi- 
tion or in a condition not conductive to spreading, the center remains 
productive for an indefinite period. The fescues already referred 
to behave almost exactly in this manner. Barren centers are found 
very frequently in procumbent types, while in the semierect or up- 
right plants the tendency is not so common. 
ROOT PROLIFERATION. 
The brief studies at Brookings and Highmore developed nothing 
particularly new regarding the type of proliferation heretofore 
described, but tended only to confirm the conclusions of other investi- 
gators. The studies disclosed, however, what is thought to be a type 
of proliferation heretofore undescribed as occurring in alfalfa—a 
type wherein new plants are produced from true lateral roots 4 to 
12 inches, rarely more, beneath the surface and running almost 
directly parallel with it.1 These proliferous roots apparently are 
given off from any portion of the branching taproot within the limi- 
tation of the depths above indicated. At irregular intervals along 
the lateral roots, swellings occur, usually about twice the diameter 
of the roots and three-fourths of an inch to 14 inches in length. 
(See figs. 2and3.) Upon these swellings buds appear, some of which 
give rise to new plants, while many remain undeveloped.? Fibrous 
roots are rather sparingly produced from the lateral proliferous 
roots, and in many instances the swellings are devoid of them; in 
1 Hitchcock, A. S., and Clothier, G. L. Fifth report on Kansas weeds—Vegetative prop- 
agation of perennial weeds. Kansas Agricultural Experiment Station, Bulletin 76, 23 p., 
12 pl., 1898. Clothier, G.L. Root propagation of Ipomoea leptophylla. Botanical Gazette, 
vy. 25, p. 52-53, illus.,. 1898. These articles discuss vegetative reproduction by true roots 
in Rhus glabra, Ambrosia psilostachya, Cnicus undulatus, Convolvulus arvensis, and 
Tpomoea leptophylla. 
2In this type of proliferation it will be noted that definite provision is apparently 
made by the lateral proliferous roots for the production of new plants. There is a mate- 
rial difference in this respect from the case in stem proliferation noted by Oliver, where 
new shoots arise from the taproot appreciably below the crown. 
Riri] 
