5. Boykinia rotundifolia Parry ex A. Gray, Proc. Amer. Acad. Arts. 13: 371. 1878.
Therofon rotundifolium (Parry ex A. Gray) Wheelock
Plants: rhizomes proliferating underground. Flowering stems (30-)50-80(-130) cm. Basal leaves: petiole 5-22 cm; blade usually orbiculate-cordate, sometimes reniform, shallowly and indistinctly lobed, (3.5-) 7-16 × (4-)9-18 cm, margins 2-3-times serrate. Cauline leaves: stipules 1-2 mm expansions of petiole base, fringed with brown hairs. Inflorescences ± pyramidal, (10-)15-25-flowered per primary branch. Pedicels densely stipitate-glandular. Flowers: hypanthium campanulate, free portion 1-2 mm, densely stipitate-glandular; sepals erect, triangular to lanceolate, 1.5-2 mm, apex acute; petals narrowly spatulate, 2-3 × 1 mm, shorter than or to 1.5 times as long as sepals, base tapered to claw, margins plane; nectary green; stamens 1.2-1.6 mm; ovary 2/3 inferior. Capsules ovoid, turbinate, or urceolate. Seeds usually black, tuberculate. 2n = 14.
Flowering early-mid summer. Damp woodlands, margins of lakes, ponds, and watercourses, often on disturbed soil, trailsides, mudslides; 800-2000 m; Calif.; Mexico (Baja California).
The record of Boykinia rotundifolia from "Lower California" (Williamson, 20 July 1901, PH) is the only collection seen from Mexico. The species is occasionally grown in gardens.