PIONEER PLANTS 
139 
the seeds of a few were left close enough to the surface to 
sprout and grow and try their luck against the bourgeoisie of 
weeds. The tomato plant that I found was probably of this 
origin, also the watermelon. The solitary cultivated sunflower 
that stood majestically towering above a jostling crowd of pig- 
weed may have come with the tomato and the watermelon, or 
perhaps from a seed dropped by a bird. The two varieties of 
morning-glory that I found competing with the wild bindweed 
were probably wind-sown. The two specimens of corn were very 
likely remnants of a meal of one of the workhorses ; one of them 
was a half-sized runt with a nubbiny, abortive ear, and the 
other I picked up in mid-October, a mere starveling sprout with 
its half-devoured seed still among its roots. Oddly enough, there 
was little bluegrass on the levee — not enough, I should judge, 
to fill a peck measure ; and when I lost the one specimen of 
white clover I had, I could not, for the life of me, find another. 
So much for the cultivated species and their sources. Now 
how did the new possessors of the land make their appearance ? 
Variously. A few of them were there to begin with. At the 
eastern extremity of the levee the level space between the em- 
bankment and the channel had been covered rather thinly with 
debris, and through this new layer of soil a few perennials, like 
the goldenrod and the aster, managed to fight their way. To 
this class also, I suppose, must be added the cottonwood shoots 
that appeared down on the slopes of the channel itself, on the 
ends of the roots that the steam shovel had severed. 
Again, some of the plants must have come from fragments 
cast up by the steam shovel. To this class must be relegated the 
shoots that I found sprouting from stumps and root fragments 
at various points on the slopes and bottom of the embankment; 
willow, catalpa, cottonwood, maple, and box-elder. Some of 
the perennial herbs, like the burdock and the dandelion, may 
have had this origin. Certainly the Oenothera biennis that I 
found in full bloom must have come from a previous foothold 
somewhere else. And, of course, it is highly probable that a 
good many seeds were sown in this fashion, along with the root 
fragments and the seeds of the cultivated plants. 
Finally, much, if not most, of the vegetation must have orig- 
inated from wind-blojvn seeds. The seedlings of the maple and 
the cottonwood could have come from no other source, for these 
are pre-eminently flying seeds, and moreover must germinate 
