Table Of ContentFORM
A PURPLE COLOR OF THISTLE
PITCHER'S
Edward Voss
G.
Herbarium
Michigan
University of
North University Building
Ann
Arbor, Michigan 49109-1057
known
and Superior, has hitherto been to have heads
ron,
•
m
ew form discovered the north end ol Lake Michigan has
at
phenomenon
)f the usual form of C. vulture, 'this is the revers
&
Gray
Cirsium pitched (Eaton) Torr. A. (Compositae),
Pitcher's Thistle
Lake
was found "by Dr. Zina Pitcher, on the great sand banks of Superior"
originally
Amos
(Eaton Eaton admitted, however, that his specimen (and
1829, 180).
p.
hence the type, apparently no longer extant) "was collected by Dr. E. James, at
known
Lake Huron". Besides the Grand Sable dunes, which remain the only site
on the south shore of Lake Superior, the species occurs at one place on the north
As
shore, and on various dunes and beaches along lakes Huron and Michigan. a
species endemic to the Great Lakes shores, has been officially listed as threat-
it
ened under Michigan law since 1980 and federal law since 1988.
am
Eaton said nothing of flower color, although [orrey (1843, p. 456) said
And
subsequent authors have invariably declared
ochroleucous." indeed,
•'flowers
—
the flowers to be white, cream-colored, yellowish white, or similarly pale as in its
&
Hamrick no
Loveless find
nearest canescens Nutt. (see 1988).
relative, C. I
published mention of any other color form [other than a brief last-minute addi-
Michigan Flora Part (Voss Imagine our surprise, therefore,
tion in III 1996)].
when and came upon deep magenta heads growing
Eric Hellquist plants with
C.
I
color—
highway!) with others of normal pale reversal of the
(along federal a
a
usual minor discovery of a white-flowered form in an ordinarily colored species.
The heads population are as deep and rich red-purple as normal in C.
in this is
seem
vulgare (Savi) Ten. and C. muticum Michx. Oth< rwi hi nts identical
p]
•
mm),
lubes shorter than
to tvpical pitclwri: trge ieh< ncs (ca. 7 corolla in
g
( •.
. 1
leaves— one
vulgare, spines absent on margins or surfaces of except a short at
C.
and
the apex of each slender leaf lobe; and leaves (especially beneath), stems,
tomentum normal
peduncles with the typical white of plants.
Mack-
Brevort River
Y\ e disco red this population in 1995 st tithe isl ol the in
end Lake Michigan west end of the
County, Michigan, the north of (or
inac at
of Mackinac, presumably within 15 miles or so from the type locality of the
Straits
species; see Voss 1956, 24). There were three large bushy plants here, at a spot
p.
lb beach. Tabulating the
frequently trampli headi o nsive
uri thi
may
number of individuals for some plants have finished flowering or
difficult,
is
and
be too young at the time of counting (the species is p< r< h ial bul monocarpic), it
numerous
of course impos to deti line the flower color of the seedlings
-ill.-
is
i
and young However, 1996 three purple-headed plants
individ e ieinily. in
ils
i
Always
were and there
were again noted: in 1997 there 7; in 1998. 17; in 1999, 44.
many many young and
cream-headed
were plants plus individuals,
at least as
350 CONTR. UNIVERSITY OF MICHIGAN HERBARIUM VOLUME
23
occasional intermediate pink headed ones. Then 2000 was
there could
in a crash.
I
find only 5 purple-headed ind n (plu some ream and immature ones). The
if
i<
.
was
cause presumably
extensive grading along U.S. lighway scraping the dunes,
2,
1
and decimating
this protected species and as vet tmdcscribcd color form
its at this
With
rebound;
luck, dunes,
site. will after are naturally disturbed (though
it all,
Some
not by heavy equipment).
disturbance required maintenance
in fact for of
is
&
(Hamze
species
this Jolls 2000).
meantime, seems name
In the it well to provide a for this striking form of an
endemic
species:
Cirsium forma magenteuin nov.—
pitcheri E. G. Voss, Type: Michigan. Macki-
f.
nac Co.: disturbed area low sand dimes bake
in alonu Michigan,
sec.
16,
R5W.
T41N, SE
mi
ca. 0.6 of Brevort River, 18 July 1995.^£. G. Voss
16509 MICH!: GH! MSC!
with Eric Hellquist (holotype: UMBS!).
isotypes:
Cirsium forma magenteum
pitcheri forma
diflerl a typica corollis magenteis.
&
Voss 16537
Hellquist, 16 July 1996
y):
named
Cirsium
pitcheri for an eminent 19th century physician Voss
is (see
Evidently Zina Army
1978). Pitcher discovered
this thistle while stationed as an
surgeon at Fort Brady, Saull Ste. Marie, 1826-1828. He later settled in Michigan
when
and Ann
the University was established Arbor governor named him
the
in
among
He
regents. served from 1837 became
its first until the post elective
in
Always
1852. a scholar. Dr. Pitcher offered the motion buy book
to the
first for
the University library— AuduboiTs Birds America
of (at a bargain price of $970).
He
was chairman
of a regents committee brought
that in a favorable report on
establishing a medical department in the University. So he often looked upon
as
is
founder
the of the University of Michigan Medical School, on whose he
faculty
served from 1852 death The
until his in 1872. street approaching the Medical
Center from now named
the south happily Zina and
is Pitcher Place, a large
oil
him
portrait of (on loan from the Medical School) hangs
in the library of the
He
University of Michigan Herbarium. was
an
avid botanist, accumulating
a large
herbarium, and named
other have been
plants for him. have always admired
his
I
thistle, even without knowing ol this exceptional color form (my personal book-
designed
plate, in 1952, features a sketch of
it).
LITERATURE
CITED
Hamze,
S. I., and ('. L. .lolls. 2000. Germination ecology of a federally treaten ed endemic
thistle.
Cits, urn r u<1,rr,. ol the Great .akes. Amer. Midi. Nal. 14 141-153.
I 3:
Loveless, M. D., and J. L. Hamrick. I98N. Genetic oigaui/.atior and evolutionary listory in two North
i 1
American
species of Cirsium. Evolution 254-265.
42:
Torrey, J., and A. Gray. 1843. A Horn of North America, vol. 2 504 New York Wiley & Putnam.
pp.
.
:
A
Voss. E. G. 1956. historv of florist ics in the Douglas Lake region (Emmet an d Cheboygan coun-
ties). Michigan, with an account of rejected records. Jour. Jniv. 44: 16-75.
Beachcombers
Botanical and
197.S. Explorers: Pionc ers of the 19th
cei
.
ireat Eakes. ontr. Univ. Michigan 1-100.
lerb.
( ( 13:
1
1996. Michigan Flora Weals (Pvrohiceav
/'art 111 Co,,
.
Ann
Bull. 61; Arbor: University of Michigan Herbarium.
