MICHIGAN ACADEMY OF SCIENCE. 
191 
OUTLINE KEY OF THE GROUPS OF THE GENUS HE LI AN Til U S 
IN MICHIGAN. 
S. ALEXANDER. 
In the summer of 1905 I thought to acquaint myself with the sunflow- 
ers which were indigenous in the vicinity of Ann Arbor. On consulting 
the flora of the state, I found that there were but sixteen species listed 
for the whole state and one of these was put down a*s an escape from 
our gardens. There were not more than six or eight species assigned to 
the vicinity of Ann Arbor or southeastern Michigan. 
It looked as if I should have an easy task. I had not more than 
begun my work when, to my perplexity, I found plants in great num- 
bers and forms which could not be diagnosed in any of the manuals at 
my command, including Gray’s “Synoptical Flora.” I had the pleasure 
of accepting one of the two following propositions: either I was inca- 
pable of diagnosing the plants or that there were many species yet un- 
described. After having correctly diagnosed many hundreds of plants 
during a period of forty-five years I was not disposed to accept the first 
proposition. I did accept the second and set about to prove it, in which 
endeavor I traveled over a large stretch of country during a period of 
five years. During this time I collected a large number of sunflower 
plants and placed them in a garden where 1 could study them individu- 
ally and comparatively. I got as many of the old and well known plants 
as I could find for purposes of comparison with the new. After five 
years of study I have concluded that I have found several times as 
many new plants as have hitherto been known. 
The territory of this remarkable development of sunflowers seems to 
have quite definite limits, and within the general limits some of them 
are regional. Each of the following rivers, the Clinton, the Rouge, the 
Huron and the Raisin has a sunflower flora peculiar to itself. The same 
can be said of the intermediate stretches of country. Some of our natu- 
ralists think that these plants are in a plastic, mutating state. I believe 
rather that they are the remains of a once wonderfully copious genus. 
The story of this Botanical TerraTncognita would be very interesting and 
too long to be told here. 
I expect to begin a revision of this paper during the present season in 
which I shall describe and name a large number of plants. The fol- 
lowing key extends only to the great and some of the lesser groups. 
My plants are mostly in the botanical garden of the State University, 
where I hope our botanists will examine and become acquainted with 
them. 
It will be observed that the first division of the perennial sunflowers 
into two heads is based on the underground system of each head. It 
would not be correct to speak of these systems as the root system, since 
the first head is based on the roots entirely and that in the second 
