Texas or Lady Bird’s centaury

Erythraea texensis Grisebach, Gen. Sp. Gent., 139. 1838; Centaurium texense (Grisebach) Fernald

Herbs annual, 3–30 cm. Stems 1(–5), dividing below middle into ± equal branches, these fur­ther branching throughout or, in the smaller plants, branching only distally. Leaves usually all cauline; blade narrowly elliptic to linear (proximal) to filiform (distal), 7–25 × 0.5–4.5(–8) mm, apex acute. Inflorescences open, much-branched, dichasial, with a central flower in each fork, or distally sometimes mono­chasial cymes; pedicels 4–20 mm. Flowers 5-merous; calyx 6–12 mm; corolla 12–20 mm, lobes narrowly oblong to elliptic-oblong, 3–7 × 0.8–1.5 mm, apex acute; stigmas 2, fan-shaped. Seeds light brown. 2n = 40, 42.

Flowering summer. Prairies, barrens, open woods, other open, usually rocky sites, in calcareous soils; 100–500 m; Ark., Kans., Mo., Okla., Tex.; Mexico (Nuevo León).

Zeltnera texensis has been reported from Nuevo León, Mexico (J. N. Mink et al. 2011b), remote from its range in the United States, but specimens have not been examined in studies for this flora. Reports of Z. texensis (as Centaurium) from Louisiana have been based on misidentified C. pulchellum and C. tenuiflorum (J. S. Pringle 2010b). Reports from New Mexico have been based on Z. arizonica and Z. maryanniana (studies for this flora).

Zeltnera texensis differs from Z. maryanniana most conspicuously in being proximally single-stemmed with­out persistent basal leaves.

The name Lady Bird’s centaury is for Claudia Alta Taylor “Lady Bird” Johnson, former First Lady of the United States, who promoted the conservation of native plant species and their use in beautifying highway verges. She especially liked this species and had seeds of it sown around the airstrip at the Johnson ranch in Texas.