54 
as constitutional peculiarities. Where cattle are Continually grazing, 
those tall growing plants which produce flowers only towards the 
ends of the branches extend amazingly if they happen to be distasteful 
to the animals. Plants of similar habit, if agreeable to cattle, cannot 
spread, because they are eaten off before they flower. Accidental 
introductions may thus be totally eradicated the first season, if 
annual — or confined to the original spot if a perennial plant. Thus, 
in Pennsylvania we have Ramcnculus bulbosiis and Leucanihctniim 
vulgare common in our pastures because the cattle suffer them to go 
to seed. In vacant lots about our cities we have Stramonium^ may- 
weed and many other plants progressing with amazing rapidity sim- 
ply because not even the half-starved cattle of the " poor man" will 
pasture on them. But if an introduced plant can flower and 
fruit close to the earth, where some seed may mature though cattle 
eat the tops, it may survive and spread in spite of its being a good 
morsel for a hungry beast. Hence the Lespedeza striata, or Japan 
clover, has taken possession of immense territory in the South, be- 
cause numerous seed-vessels mature close to the ground, between the 
crevices. of rocks, or underneath loose stones, where cattle cannot get 
at them. If this were an erect instead of a prostrate plant, and did 
not flower till several inches high, it could not survive in a grazing 
country. There is no adaptation of the plant to the circumstances 
the fitness is in the accident which came at the proper time to de- 
stroy or to save it. 
In so^-ne gardens-weeds the accident is the early flowering. Chick- 
weed, Draba verna, Arabis Thaliana, the shepherd's purse, and many 
other things are common in Penn'sylvania gardens solely because 
they mature so very early in spring that seed is perfected before the 
gardener commences to use the hoe. When Tie begins this branch 
of cultivation the earth is full of seed for the next year's crop. If 
they flowered a month later than they do, they would soon be among 
rare plants, instead of being the common weeds they are. In a part of 
my grounds I have what I term mv '^botanical patch." There I sow 
every "weed '* I can get from any part of the earth. Some escape, 
and I often enjoy noting how their peculiar characters fit them to 
spread without any modification of character to enable them to advance. 
Some four years ago, I had in this botanical border the pretty Siber- 
ian Nonea rosea. It matures its seeds sometimes in the early part of 
April with me. I am so situated that our serious attack on weeds 
seldom commences before the end of May. The Nonea has now 
spread and is not uncommon in many parts, and it is quite pleasant 
to note it struggling with, and successfully holding its own against, the 
Thlaspi, Arabis and other immigrants that have before ventured to 
regard the soil as their own. Having the broadest leaves and the rankest 
growth, it is of course more " fitted to survive " in its battle with the 
two named and similar others. But we may now bring in specula- 
tion and say "if" the Arabis should grow stronger— " if " the leaves 
should get broader— " if *'. the plant should flower earlier— n 
many other points Avhich would be an advantage to the Arabis m the 
struggle should occur, these superior plants would produce ^ J?f^,, 
which might in time crowd down the Nonea. Of course; but ii 
