Dunedelion

Malacothrix incana, a dune endemic, grows currently on the coastal mainland in Santa Barbara and San Luis Obispo counties, and on San Miguel, San Nicolas, Santa Cruz, and Santa Rosa islands. Its nomenclatural type specimen was collected at San Diego, probably from the Silver Strand dune areas on Coronado Island.

Populations of a glabrous form, var. succulenta, occur in Santa Barbara County (e.g., Casmalia Beach) and San Luis Obispo County (e.g., west of Oso Flaco Lake). Glabrous forms and tomentose forms grow together on San Miguel and San Nicolas islands.

Extensive hybridization between Malacothrix incana and M. foliosa subsp. polycephala occurs on San Nicolas Island where dunes have extended into areas of normal soil, particularly along the western and southwestern portions of the island.

Hybridization between Malacothrix incana and M. saxatilis var. implicata occurs on San Miguel Island on east-facing slopes above Cuyler Harbor.

Perennials, 12–70 cm (often mounded). Stems 1, branched proximally and distally, usually tomentose, sometimes glabrous. Cauline leaves: proximal obovate to narrowly spatulate, sometimes pinnately lobed (lobes 1–2+ pairs, subequal, apices obtuse), sometimes ± fleshy, margins usually obtuse-lobed, sometimes entire; distal not notably reduced (similar to others). Calyculi of 5–16+, ovate to lanceolate bractlets, hyaline margins 0.05–0.2 mm. Involucres 10–14 × 4–8+ mm. Phyllaries 16–30 in 2–3 series, (red-tinged) lanceolate or oblong to linear, hyaline margins 0.05–0.1 mm wide, faces glabrous. Receptacles not bristly. Florets 47–99; corollas medium yellow, 11–20 mm; outer ligules exserted 5–10 mm. Cypselae usually cylindro-fusiform, sometimes weakly prismatic, 1.5–2.2 mm, ribs extending to apices, ± equal; persistent pappi 0. Pollen 70–100% 3-porate. 2n = 14.

Malacomeris incanus Nuttall, Trans. Amer. Philos. Soc., n. s. 7: 435. 1841; Malacothrix incana var. succulenta (Elmer) E. W. Williams; M. succulenta Elmer

Malacothrix incana is an uncommon species of flowering plant in the aster family known by the common name dunedelion. It is endemic to California, where it grows only in sand dunes on the beaches of the Channel Islands and isolated spots along the mainland coastline in San Luis Obispo and Santa Barbara Counties. The type specimen was collected in San Diego, but the plant no longer occurs there. This is a perennial herb forming a leafy mound up to about 70 centimeters in maximum height. It may be hairless to densely hairy. The leaves are smooth-edged or have dull lobes. Leaves at the base of the stem are similar to those distal. The inflorescence is an array of flower heads lined with hairless phyllaries. The ray florets are one or two centimeters long and yellow in color.