Plains ragwort  (Packera indecora)

The plains ragwort has not yet been assessed by the IUCN.

Found only in North America, the plains ragwort (Packera indecora) has fibrous roots and tall, loosely clustered, hairless stems (2) (3). The oval, oblong, or heart-shaped leaves around the base of the plant are thin and hairless, and usually have toothed margins. On the upper parts of the stem, the leaves become gradually smaller and are usually narrow, with deep lobes and sharply toothed edges (2) (3) (4) (5).

The bright, golden yellow flowers of the plains ragwort grow in a flat-topped cluster, known as an umbel or ‘corymb’. Each inflorescence contains up to 20 flower heads, with the individual flower stalks arising from the same point on the long flowering stem (3) (5) (6). A ring of greenish- or purplish-tipped bracts are gathered around the base of each flower head (3) (4).

Although previously classified in the genus Senecio, recent molecular research and analysis suggests that, along with several other species formerly in the genus Senecio, the plains ragwort should be reclassified into the genus Packera (4) (6).

The plains ragwort occurs in North America, from southeast Alaska to the Northern Territories, Nunavut and Quebec in Canada, and south to the northern United States, including Michigan, Wyoming, Minnesota, Idaho and Wisconsin (2) (3) (4).

Generally occurring in cool, moist habitats, the plains ragwort may be found in damp meadows, along streams, and in wet woodlands and cedar swamps, often in sandy, gravelly or rocky areas with easily drained soils (2) (3) (4) (5) (6). It may also be found along rocky lake shores and on cliffs (4).  

The plains ragwort is found from sea level to elevations of 2,300 metres (2).

A perennial, herbaceous species, the plains ragwort blooms from late June to early September, although the peak flowering period is usually around mid-July to August (4) (6). Flowering typically occurs first in the warmer, inland parts of its range, and slightly later in cooler habitats (6).

The fruit of the plains ragwort ripens soon after flowering. When ripe, the seeds of the fruit usually fall near the parent plant, although many seeds are borne by wind or water and may be carried some distance away before settling (6).

There is very little other information on the biology or ecology of this species, although the plains ragwort has been noted to have a close association with certain other plant species, including balsam fir (Abies balsamea), quaking aspen (Populus tremuloides), wild rose (Rosa acicularis), showy mountain-ash (Sorbus decora), speckled alder (Alnus incana), red-osier dogwood (Cornus sericea), American yew (Taxus canadensis), wild strawberry (Fragaria vesca), common yarrow (Achillea millefolium), and harebell (Campanula rotundifolia) (4).
 

The plains ragwort has specific habitat requirements, so is vulnerable to human activities that may damage or erode its habitat, such as logging, recreational rock climbing and trail creation (6).

Invasive species, for example the orange hawkweed (Hieracium aurantiacum), aggressively compete with the plains ragwort and restrict its access to suitable habitat. Global climate change is also becoming a significant concern for this species, due to the effects it may have on its habitat (6). 

Agricultural runoff, erosion and changes to water quality also pose further threats to the plains ragwort (6).

The plains ragwort is listed as a threatened species by several of the U.S. and Canadian states in which it occurs, meaning that it receives some level of legal protection. Although historic populations of the plains ragwort are declining in many areas, recent surveys have discovered previously unknown populations of this species (6). In Minnesota, one newly discovered population occurs in a state park, which may provide additional protection for this plant (6).

Recommended conservation actions for the plains ragwort include protecting its habitat from both human and natural disturbances, including agricultural runoff and erosion, and changes in water flow and quality (6) (7).

Owing to the paucity of information on the biology of the plains ragwort, further studies into its life history would be beneficial for its management and conservation (6).

Find out more about the plains ragwort:

• Penskar, M.R. (2008) Special Plant Abstract for Senecio indecorus (Rayless Mountain Ragwort). Michigan Natural Features Inventory, Lansing, Michigan. Available at:
  http://web4.msue.msu.edu/mnfi/abstracts/botany/Senecio_indecorus.pdf