THE AMERICAN BOTANIST. 
121 
with peculiar names. — [Without going into the gardener's hst, 
we could add from the botanical manuals, butter-and-eggs, 
brown-eyed Susan, Dutchman's breeches and bloody noses. 
—Ed]. 
Plant Distribution — Whai one sees the water cress 
(Nasturtium officinale) so common along our streams he is 
led to wonder from whence it came, also how and when. I 
have heard a number of persons say that it was introduced 
into Colorado, by the soldiers at the many Forts found within 
the State in early days. This plant has a reputed medical 
quality, that of relieving, and, in some cases of curing, the 
scurvy and hence was planted for this purpose. As to the 
correctness of this I do not know. If one tastes this plant he 
finds it not unwholesome with its very marked Brassica acrid- 
ness. If any other reader of the Botanist has heard anything 
relating to this plant could we not have it made public through 
this great clearing house of botanical knowledge ? — Earl Lynd 
Johnston, Evans, Colo. 
The Cause of Annuals. — Undoubtedly annual plants 
have arisen in response to more than one set of conditions, 
but it is an interesting fact that dry regions greatly favor the 
production of such plants. This is of course due to the fact 
that annuals can spring up after the rains, and mature their 
seeds before overtaken by drouth. The more deliberate per- 
ennial plants find this impossible. Alpine and Arctic con- 
ditions, on the contrary, favor the existence of perennial 
plants. Moist tropical regions also produce a large number 
of perennials, but the tropical perennials differ from the Arctic 
perennials in one important particular. In the tropics the 
perennials of dry regions are, nearly all of them, like those of 
Arctic regions in having the perennial parts underground, 
though the conditions, that necessitate this are so widely dif- 
ferent. Bulbous plants usually form the great majority of 
dry ground perennials. 
