Spores produced in the aecia are referred to as aeciospores and are responsible for infecting the alternate host plant (a grass species: Koeleria, Trisetum, or Stipa).
Koeleria |
Plant species occurring with this cinquefoil in multiple habitat types include prairie junegrass (Koeleria macrantha), elk sedge (Carex geyeri), western yarrow (Achillea millefolium), silvery lupine (Lupinus argenteus), common dandelion (Taraxacum officinale), and beautiful fleabane (Erigeron formosissimus).