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180 BOTANICAL GAZETTE | SEPTEMEER 
I do not know what rule may exist in this alternation or by 
what factors the formation of a runner may be determined 
Nevertheless, from my notes it seems that a shallow position a 
the plant favors the development of a runner. Probably all the 
shallow, small individuals are derived from seedlings, germinated 
near the surface of the soil. Their mode of growth must bring 
them gradually into the depth of the full-grown individuals. By 
the yearly duplication of their bulbs a rapid vegetative multipl 
cation takes place. | 
Erythronium mesachoreum Knerr.—This plant, which reset 
bies £. albidum very much, inhabits the open prairie. I found 
the growing point of the bulb in about twenty-five full-gow 
individuals which I examined between g and 13™ distant from 
the surface of the earth, the average depth being about ae 
In this species the small, sterile individuals occupy # ™%* 
superficial position, being found at a depth of from 308 
They apparently have originated from seeds. In the 
part of April the formation of the new bulb begins. In the 
young shallow individuals I always found the new bulb remo 
from the old one by a runner, but the latter is short, _— 
est I saw being about 20™™ in length, and it grows _ 
beginning vertically downwards, thus placing the pa 
year from 3 to 20™™ deeper (fig. 8). In this species ‘ 1 
noticed the formation of more than one runner by one b a “a 
result of this manner of growth is that the on 
subsequent years are arranged ina vertical row, and I 
fact, the remainders of the products of five years located 
way above the living bulb; the leaf of the present ee . 
its way through the long channel formed by all the dea? ® 
ments ( fig. 9). By such a movement of growth the plat : 
reaches a depth beyond which it does not ae oe 
indeed, that in the old full-grown individuals, S08" 
depth of about 11°, the bulb grows no longer pe 
horizontally or nearly so, the new bulb rooting about 
ally from the old one. . 
