Although the Mallow family boasts 244 genera and 4225 species world-wide (with 27 genera occurring in North America alone), only one native genus, Sidalcea, grows in Willamette Valley Wetland Prairies. Not only does this group include one of Oregon’s federally threatened species, Sidalcea nelsoniana (Nelson’s Checkermallow), but also some of this ecosystem’s top nectar species for the federally endangered Fender’s Blue Butterfly.
Members of the Malvaceae have radially symmetric flowers arranged in a distinct funnel shape with five petals and three to five partially united sepals, often surrounded by several bracts. Stamens are numerous and form a column around the gynoecium. Superiorly positioned ovaries are comprised of five or more united carpels that mature into a round schizocarp. Inflorescences range from solitary flower heads, to racemes, or cymes. Leaves of this family are simple or palmately compound, usually lobed to divided, and can be palmately or pinnately veined. Leaves emerge basally but are arranged alternately along the stem.
Economic importance of the Malvaceae include some of history’s most traded commodities including cotton (Gossypium spp.), jute (Corchorus spp.), chocolate (Theobroma cacao), cola (Cola nitida), okra (Abelmoschus), durian fruit (Durio zibethinus), Hibiscus, and even balsa wood (Ochroma pyramidale).
Sidalcea cusickii – Cusick’s Checkermallow
Growth Habit
Tall, herbaceous perennial, reaching 16 to 70 inches tall. Inflorescence is branched raceme of dense, dark pink flowers.
Leaves
Basal leaves are extremely round with a deeply scalloped (crenate) margin. Cauline leaves are also rounded and very palmately cleft, with veins and dissections starting from the leaf base where the blade connects to the petiole.
Stems
Plants reach heights of 16 to 70 inches tall. Stems are hollow (fistulose), and can be glabrous or have very fine hairs.
Flowers
Inflorescences are spike-like racemes with many, compounded, fuchsia-colored flowers, with 1 to 5 millimeter long pedicels. Five sepals are united at the base, five petals somewhat fringed or heart shaped at their tips, and range from 6 to 10 millimeters long.
Fruits
Round seed clusters form, resembling wheels with wedge-shaped spokes. In the Southern Willamette Valley, seeds are predated on by weevils, negatively impacting fertility.
Ecology
Facultative Wetland Species (FACW), a Hydrophyte that occurs mostly in wet meadows, ditches, or forest edges but can tolerate dryer areas.
Notes
In the Southern Willamette Valley, S. cusickii may be confused with S. campestris, or S. virgata. S. cusickii however, has distinctive, geometrically angular seed pods as well as petals that are dark pink, tightly organized petals. Also, S. cusickii tends to grow in wetter gradients than S. virgata and S. campestris.
Sidalcea malvaeflora spp. virgata – Rose Checkermallow
The currently known, described and accepted number of plant species is estimated at approximately 374,000″ (Christenhusz & Byng, 2016).
Dr. Bitty Roy, University of Oregon Systematic Botany Notes, 2012.
Simpson, M. Plant Systematics 2nd ed. Academic Press, Burlington, MA. 2010. 366.
Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001. 264
USDA Plants Database:
City of Eugene, Seed Collection Manual, Sidalcea cusickii, 2009.
