350 BOTANICAL GAZETTE [NOVEMBER 
in the axils of the two bulb scales as runner rudiments, in preparation 
for the next year. The details are similar to the same steps in the 
primary bulb. 
Immature stages 
Between the development of the secondary bulb and that of 
the bulb which bears a flowering shoot, an indefinite number of 
years may elapse. The least number of intervening seasons has 
been calculated to be three, making, with the first and second 
seasons, a minimum of five years from seed to seed. Many indi- 
viduals at any stage fail to produce runners in any one season, and 
their immature period is correspondingly lengthened. Others 
fail to gain any depth in the development of the new bulbs from 
runners, and these also lengthen the interval between the first and 
final bulbs. With the production of the flower the activity of the 
primary stem apex ceases, the subsequent bulbs being developed 
annually each from a bud at the base of the aerial shoot. In the 
immature individuals more than one bulb is formed in average 
seasons in four species,? more or less specialized structures being 
developed for this purpose. Most of the plants producing runners 
in E. americanum in any one season after the second bulb have 
three at a time. One of these is the apical bud, the other two are 
axillary buds. The relation of these three buds is shown in figs. 
28-33; these buds have been mentioned in a preceding paragraph 
as related to the development of the runners. The runners in the 
four species mentioned are not uniform in character, since in the 
development of the elongated structure of the runner different 
tissues are made use of by the plant in different species. Ery- 
thronium americanum is the most specialized in its development, 
but it is the clearest morpholegically. 
Each of the runners in E. americanum comes from a bud within 
the bulb (text fig. 3), the buds being made up finally of two scale 
leaves and a stem apex inclosed by them. The buds are inserted 
upon the tissues of the bulb in such a manner that the outer surface 
2 These are E. americanum, E. albidum, E. propullans, and E. Hartwegii; ‘others 
rarely multiply. In £. propullans the adult plants have a lateral runner in ition 
to the renewal bulb within the old: Under cultivation cand buds in adult bulbs 
in most species develop into bulbs. 
