Packera malmstenii

A smooth perennial herb that is soboliferous (with slender rhizomes to 20 cm or longer connecting the buried upslope caudex to the year's stems); each year, the stems arise from the ends of the sobols. Plants are typically 4.5-7 cm tall above ground, with above-ground stems more or less upright. Leaves (essentially all basal) are thick, stalked, and round to egg-shaped with the widest part at the top; they are 1-3 cm long and are either unlobed or have a few, regular lobes. There are 1-2 flower heads per plant. The involucre is 7-10 mm high with 12-16 suffused purple, narrowly lance-subulate flower bracts. All flowers in the head are discoid (no ray flowers) and are yellow to orangish. The pappus is white with smooth bristles and the achene is smooth (Rodriguez 2004, Utah Native Plant Society 2008, Fertig and Reynolds 2009).

Distinguished from S. werneriifolius primarily by its lack of ray flowers, and also by its thinner sobols (1mm thick vs. 2-3 mm thick in S. werneriifolius) and glabrous foliage (the pubescence of S. werneriifolius varies from copious to almost none, but there is usually a hint of pubescence) (Welsh et al. 2008). Distinguished from Senecio musiniensis and S. castoreus by its glabrous foliage; these other species are grayish to white woolly pubescent (Fertig and Reynolds 2009). Other co-occurring Senecio species differ in having yellow ray flowers, taller and leafier stems, tomentose herbage, or leaf blades that are either narrower or pinnately lobed (Fertig and Reynolds 2009). Distinguished from Senecio soldanella and Senecio (Packera) porteri of adjacent Colorado by its smaller flower heads.

Podunk Groundsel is associated with spruce-fir and mixed conifer forests on talus slopes of Tertiary Claron Limestone Formation (Welsh et al 2015). It occurs at high elevations primarily on steep creeping talus slopes (also eroding outcrops and cliff edges) of the Tertiary Claron (also known as Wasatch) Limestone Formation, an Eocene-age sandy limestone derived from an ancient deep lake. Few other plants typically establish in these habitats, due to the high pH and erodibility of the rock, the fact that slopes are underlain by thick clay that is very hard when dry, and the exposure of sites to the elements (strong winds, intense sunlight, blowing snow, freeze-thaw cycles, intense thunderstorms). The special soil conditions (particularly the high pH) have resulted in several endemic plants (W. Fertig pers. comm. 2009). This species' soboliferous habit appears to be an adaptation to mantle-creep of the limestone slopes (Welsh et al. 2008). In the Cedar Breaks area, populations are often found associated with shallow erosional channels or rills that run parallel to the slope axis and expose bare, clayey soil (Fertig and Reynolds 2009). The immediate community typically has very low vegetation cover (averaging less than 10%, often 1-2%), and has been described as "barrens" and as a "cushion-plant community." The surrounding community is conifer woodland (western bristlecone pine, western bristlecone pine-limber pine, spruce-fir, western bristlecone pine-douglas fir, mixed conifer); sometimes some of these trees manage to establish on the slopes. Associated species include Cymopterus minimus, Silene petersonii, Senecio atratus, Astragalus miser var. oblongifolius, Eriogonum panguicense var. alpestre, Haplopappus zionis, Calamagrostis scopulorum, and Monardella odoratissima. 2250-3200 m (Fertig and Reynolds 2009, W. Fertig pers. comm. 2009).