4. Hesperolinon bicarpellatum (H. Sharsmith) H. Sharsmith, Univ. Calif. Publ. Bot. 32: 297. 1961.
Two-carpellate western or dwarf flax Two-carpellate western or dwarf flax
Linum bicarpellatum H. Sharsmith, Madroño 8: 143. 1945
Herbs, 10–30(–70) cm, puberulent on stems immediately distal to nodes, otherwise glabrous; branches usually alternate from distal nodes on short main axis, sometimes whorled from basal nodes, widely spreading. Leaves alternate; stipular glands present at proximal nodes, usually absent distally; blade threadlike to linear, 15–20(–30) × 1–1.5 mm, base flat, not clasping, margins without stalked glands. Inflorescences: cymes dichasial, open, internodes long, flowers widely scattered; bract margins without prominent glands. Pedicels (2–)10–12 mm, to 40 mm in fruit, spreading at 45–90° angle, not or only slightly bent at apex. Flowers: sepals all or outer 2 spreading, not reflexed at tip, lanceolate, 1.5–2(–3) mm, ± equal, marginal glands minute or absent, surfaces glabrous; petals horizontally widely spreading, bright yellow fading white, tinged with orange or red along veins, oblanceolate to obovate, (2–)3–4 mm, apex acute or apiculate; cup yellow, rim lobed between filaments and petal attachments; stamens exserted; filaments 2–3(–3.5) mm; anthers yellow, dehisced anthers 1.2–1.5 mm; ovary chambers 4; styles 2(–3), yellow, 2–3.5 mm, exserted. 2n = 34.
Flowering May–Jul. Rocky slopes, chaparral in Pinus sabiniana belt, serpentine soils; of conservation concern; 60–1000 m; Calif.
Hesperolinon bicarpellatum grows in the southern part of the Inner North Coast Ranges of Lake and Napa counties. Plants in the northern part of its range consistently have two carpels; those in the southern part occasionally may also have three carpels, and sometimes both conditions occur on one plant.