A delicate annual in the meadowfoam family (Limnanthaceae), large-flowered woolly meadowfoam grows 2 to 6 inches tall; with 2 inches leaves divided into 5 to 9 segments. The stems and leaves are sparsely covered with short, fuzzy hairs. The flowers, and especially the sepals, are densely covered with woolly hairs. Each of the five yellowish to white petals has two rows of hairs near their base. In the Agate Desert, large-flowered woolly meadowfoam flowers in the early spring, from March to mid-April and fruits from mid-May or when the soil becomes dry (USFWS 2012).
A genetic study conducted at Oregon State University focused on inbreeding systematics and gene flow within previously named Limnanthes floccosa subspecies (Meyers 2010; Chambers and Meyers 2011). This research used hybridization trials and molecular data to evaluate genetic relationships of the various Limnanthes subspecies in the Rogue Valley. Researchers determined that ssp. grandiflora is reproductively isolated from L. floccosa ssp. floccosa and is more closely aligned with ssp. pumila, and therefore proposed transferring ssp. grandiflora from L. floccosa to L. pumila under the more accurate scientific name Limnanthes pumila ssp. grandiflora (Meyers 2010; Chambers and Meyers 2011).