Calycadenia fremontii A. Gray

Calycadenia fremontii is variable and not easily divisible. It ranges from Siskiyou County through Mendocino, Lake, and Butte counties in California with one outlying population near Grants Pass in southern Oregon. Genetic change and chromosome repatterning have produced an extremely complex taxon that (as here circumscribed) includes populations with individuals to 20 cm and extensively branched with white corollas as well as populations with individuals to 100 cm and unbranched or with relatively few branches with yellow corollas. Some relatively small forms with white corollas are more closely related to tall forms with yellow corollas than they are to each other. At present, there is no known combination of characters that allows reasonably con-sistent delimitation of these or other elements within this assemblage of populations. The present circumscription combines three previously described species, including one traditionally considered an element of C. pauciflora. Additionally, C. fremontii intergrades with C. pauciflora (see discussion under 10. C. pauciflora).

Plants 10–100 cm; self-incom-patible. Stems simple or branched (main axes usually obvious, branches relatively few, ± rigid), hispidulous to strigose (especially proximally, usually strigose with scattered, stouter hairs distally). Leaves mostly alternate, 2–8 cm (proximal), hispid to hispidulous and ± long-hairy (especially on margins and adaxial faces). Heads borne singly or in open, spiciform arrays (1–2+ per node). Peduncular bracts narrowly elliptic to oblanceolate, 2–10 mm (hispidulous, ± bristly and/or strongly pectinate-fimbriate) apices rounded or truncate, tack-glands 1–5+. Phyllaries 3–7 mm, abaxial faces ± hispidulous, ± bristly, shaggy long-hairy on distal margins, tack-glands (0–)1–5+. Paleae 3–7 mm (receptacular cups ± campanulate, lengths often ± equaling diams.). Ray florets (1–)2–6; corollas white or cream to pinkish, or yellow (sometimes basally reddish), tubes 1–2 mm (± papillate, throats sometimes with dark red "eyes"), laminae 4.5–7 mm (central lobes ± equaling or narrower than laterals, mostly obovate, widest beyond middles, sinuses nearly equaling laminae). Disc florets (4–)6–21; corollas white to pinkish, or yellow, 4–5 mm. Ray cypselae 2.5–4 mm, smooth, glabrous or glabrate. Disc cypselae 2–4 mm (often ± angular), appressed-hairy; pappi of 8–14 long-aristate and short-blunt, fimbriate scales 1–3 mm (alternating). 2n = 12.

Calycadenia ciliosa Greene; C. elegans Greene; C. pauciflora A. Gray var. elegans Jepson

Calycadenia fremontii is a species of flowering plant in the daisy family known by the common name Frémont's western rosinweed (after John C. Frémont). It is native to southwestern Oregon (Josephine + Jackson Counties) and northern California (mostly north of Napa and Placer Counties but with a few isolated populations in Santa Clara and Tuolumne Counties). It is a common member of the flora in several types of habitat in the mountains, foothills, and valleys. This annual plant is variable in appearance.

Calycadenia fremontii produces a rigid, erect, hairy stem reaching a top height anywhere between 10 centimeters (2 inches) and one meter (40 inches). The leaves are linear in shape and arranged alternately along the stem, especially on the lower part. The largest is up to 8 centimeters long. The inflorescence bears one or more glandular flower heads, each with 2 to 6 three-lobed ray florets in shades of white to red to yellow, and up to 20 disc florets at the center. The fruit is an achene; achenes from the disc florets may have a pappus of scales.