rayless mountain ragwort, Page 1 indecorus Rottb. rayless mountain ragwort

State Distribution

Best Survey Period

Photo by Janet Marr Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Status: State threatened Range: This boreal ranges throughout most of the Canadian provinces and territories, from Labrador Global and state rank: G5/S1 through the northern territories and Nunavut to Alaska, ranging southward in the Western cordillera to California Other common names: Rayless mountain butterweed, and Wyoming and in the Midwest to the Great Lakes plains ragwort, elegant groundsel region. It is considered rare in California, Minnesota, possibly Quebec (S2?), Wisconsin, and Wyoming : (aster or daisy family), also known as (NatureServe 2007). the Compositae State distribution: There are nearly 30 localities for Synonyms: This is now widely accepted as this species, the majority of sites occurring in the indecora (Greene) Á. Löve & D. Löve and western Upper Peninsula, with Keweenaw County alone considered synonymous with Senecio burkei Greenman, accounting for 24 records, 18 of which are in Isle Royale S. idahoensis Rydberg, and S. pauciflorus Pursh subsp. National Park. Of the mainland sites, five are known fallax Greenman (Flora of North America 2006). from the Keweenaw Peninsula, with one site each reported for Alger, Delta, Houghton, and Marquette : The treatment Senecio, a large, complex, counties. Eight occurrences, including several localities and wide ranging with numerous North American in Isle Royale, are known only from historical records. species, has changed significantly in recent decades The Delta County record may be questionable, as it is through molecular research and modern phylogenetic not mapped in Voss (1996) and thus should be re- analyses (e.g. Bain and Jansen 1995). Several species examined. Few data are known for most sites, and only formerly included in Senecio are now considered to form one Isle Royale locality—on Passage Island—is known a segregate under the genus Packera, representing the to support a sizeable population. species long referred to in the literature as the “aureoid ” (see D. Trock overview of Packera in Flora of Recognition: S. indecorus is a fibrous-rooted perennial North America 2006). Realignment under Packera and that ranges from 3-8 dm in height. The thin, hairless many other changes indicate a markedly different leaves, which are ca. 6 cm long and 4 cm wide, are systematic arrangement since the well known work of mostly basal and have oval, toothed blades with Barkley (1964, 1963) and others. truncate (abruptly contracted) bases and stalks of

Michigan Natural Features Inventory P.O. Box 30444 - Lansing, MI 48909-7944 Phone: 517-373-1552 rayless mountain ragwort, Page 2 about equal length. The leafy stems, which have FQI Coefficient and Wetland Category: 10, FACW fewer stem leaves on the upper portion than the lower, bear leaves that are narrow, sharply-toothed Habitat: S. indecorus has been collected in Michigan and pinnatifid (comb-like), becoming reduced in size most often on rocky or gravelly and often relatively upwards. Yellow flower heads, numbering as few as 6 calcareous Great Lakes shores. A few specimens, to as many as 40, are borne on long stalks in a flat- however, have come from high, wooded ridges, thicket topped, terminal . A row of purplish margins or swamps where they were associated with tipped (collectively the involucre) occurs at the alder. In Isle Royale National Park, the species grows in base of each head (i.e. subtends). The heads often lack the humus-filled crevices of basaltic outcrops near the ray flowers in this species, as exhibited by many Lake Superior shore, where groundcover associates Michigan specimens. However, specimens from include such species as Poa glauca (bluegrass), P. Wisconsin tend to have some weak rays developed tridentata (three-toothed cinquefoil), Campanula (Barkley 1964) and recently found on Isle Royale rotundifolia (harebell), and Aster macrophyllus (big leaf exhibit this characteristic also. This species is most likely aster). On Passage Island, where it is most abundant, at to be confused with the more common and widespread least locally, it grows in an old disturbance opening or S. aureus (golden ragwort) or S. pauperculus (Northern “meadow” on hummocky ground in fibrous organic soil ragwort). S. aureus can be distinguished by the presence with Anaphalis margaritacea (pearly everlasting), of ray flowers that are at least 6.5 mm long or longer, Clintonia borealis (bluebead lily), Linnaea borealis versus rays that are absent in S. indecorus or when (twinflower), Draba arabisans (rock whitlow-grass), present are shorter, and at least some basal leaves that Cornus canadensis (bunchberry), Oryzopsis pungens are strongly cordate (heart-shaped). S. indecorus is (narrow-leaved rice grass), Castilleja septentrionalis perhaps most likely to be confused with S. pauperculus, (pale Indian paintbrush), and Achillea millefolium which can be distinguished principally by its basal leaves, (yarrow). In the main portion of its range, S. indecorus which have blades that are lance-shaped and taper inhabits moist meadows, open wet woods, and stream toward the base without being abruptly contracted. banks. Fernald (1924) reports its habitat in Quebec as “thickets and woodland-swamps or on talus and cool ledges of limestone.”

Biology: S. indecorus is a perennial which grows from a caudex, an enlarged, stout stem base characteristic of many composites. There is virtually no published literature on the biology and ecology of this species, with the exception of noting it as an associate allied with certain vegetation associations (e.g. Patten 1963).

Conservation/management: This species is probably relatively secure — although rare — in Isle Royale National Park, which contains the majority of extant populations. Its existence and status at mainland localities in the state is still unknown, however, since Photo by Janet Marr efforts to relocate it there have failed. A putative collection of this species in the Huron Mountain Club in Close-up of rayless heads in Senecio indecorus the early 1990s needs verification. Observations of the habitat in Isle Royale National Park suggest that this ragwort is restricted to open, sunny sites maintained by Best survey time/phenology: This species must be either natural disturbances (e.g., along the Lake Superior observed in flower for positive identification, thus based shore) or slow succession following human disturbance, on occurrence records, a somewhat conservative such as in a meadow on Passage Island. Periodic fire estimate of blooming period would be from early July may also have been a factor in regenerating habitat for through approximately mid-August.

Michigan Natural Features Inventory P.O. Box 30444 - Lansing, MI 48909-7944 Phone: 517-373-1552 rayless mountain ragwort, Page 3 this plant. Populations are so few that care should be Abstract citation: taken to avoid human disturbances to surviving colonies. It should continue to be sought on the mainland, Penskar, M.R.. 2008. Special Plant Abstract for especially in Keweenaw County, and in other central Senecio indecorus (rayless mountain ragwort). and western Upper Peninsula counties with potential Michigan Natural Features Inventory. Lansing, MI. 3 bedrock habitat. pp.

Research needs: Owing to the paucity of literature on this species, virtually any kind of life history study would provide information relevant for conservation and management. Copyright 2008 Michigan State University Board of Trustees. Related abstracts: Volcanic bedrock lakeshore, alpine bluegrass, alpine bistort, squashberry Michigan State University Extension is an affirmative- action, equal-opportunity organization. Selected references:

Bain, J.F. and R.K. Jansen. 1995. A phylogenetic This project was funded, in part, by:

analysis of the aureoid Senecio (Asteraceae) The Michigan Coastal Management Program, complex based on ITS sequence data. Pl. Syst. Michigan Department of Environmental Quality Evol. 195: 209-219. and the

Barkley, T. M. 1964. Preliminary reports on the flora National Oceanic and Atmospheric Administration U.S. Department of Commerce of Wisconsin No. 49. Compositae II - Composite Family II. The genus Senecio – The Ragworts – in Wisconsin. Trans. Wisconsin Acad. 52: 343-352.

Barkley, T. M. 1963. A revision of Senecio aureus L. and allied species. Trans. Kans. Acad. Sci. 65: 318-408.

Fernald, M. L. 1924. Some Senecios of eastern Quebec. Rhodora 26: 1-122.

Flora of North America Editorial Committee. 2006. Flora of North America, North of Mexico. Volume 20: Magnoliophyta: Asteridae, part 7, Asteraceae, part 2. Oxford Univ. Press. New York, NY. 666 pp.

NatureServe. 2007. NatureServe Explorer: an online encyclopedia of life [web application]. Version 6.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: October 15, 2007).

Patten, D.T. 1963. Vegetational pattern in relation to environments in the Madison Range, Montana. Ecol. Mon. 33: 375-406.

Michigan Natural Features Inventory P.O. Box 30444 - Lansing, MI 48909-7944 Phone: 517-373-1552