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FORM 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.