14. Linum macrocarpum C. M. Rogers, Brittonia. 15: 109, fig. 3(1–4). 1963.
Spring Hill flax Spring Hill flax
Herbs, perennial, 60–150 cm, glabrous. Stems erect, unbranched below inflorescence. Leaves: proximal opposite, distal alternate, ascending; stipular glands absent; blade of cauline leaves narrowly elliptic or linear-oblanceolate, 23 × 4 mm, margins entire, not ciliate, apex acute or apiculate. Inflorescences panicles. Pedicels 0–2.5 mm. Flowers: sepals persistent, lanceolate or oblanceolate to obovate, 2.8–3.8 mm, inner broader, somewhat shorter than outer, margins not scarious, entire, apex apiculate; petals yellow, obovate, 8–11 mm; stamens 6 mm; anthers 0.8 mm; staminodia absent; styles distinct, length unknown; stigmas capitate. Capsules ovoid, 3.4–3.9 × 3.2–3.5 mm, apex obtuse, dehiscing freely into 10, 1-seeded segments, segments persistent on plant, falling tardily, false septa nearly complete, proximal margins very sparsely and inconspicuously ciliate. Seeds 2.8–3 × 1.2 mm.
Flowering May–Jul. Pitcher-plant seepage bogs, wet longleaf and/or slash pine flatwoods and savannas; of conservation concern; 0–30 m; Ala., Fla., La., Miss.
Linum macrocarpum is known only from about 20 populations in Bay, Franklin, and Okaloosa counties in Florida; St. Tammany Parish in Louisiana; Hancock, Harrison, Jackson, and Stone counties in Mississippi; and Baldwin, Escambia, Mobile, and Washington counties in Alabama. Its range overlaps both varieties of L. floridanum, but L. macrocarpum may be distinguished by its larger capsules, larger seeds, and usually taller stems (B. A. Sorrie, pers. comm.).