Thurovia

Rose

Contr. U.S. Natl. Herb. 3: 321. 1895

Etymology: For naturalist and plant collector Frederick William Thurow, 1852–1952, originally from Germany, of Hockley, Texas, near Houston
Treatment appears in FNA Volume 20. Treatment on page 86. Mentioned on page 8, 12, 87, 88, 89, 95.
Annuals or perennials, 6–45 cm (eglandular; taprooted or roots spreading laterally in perennials). Stems erect, branched mostly in distal 1/2, glabrous. Leaves cauline; alternate; sessile; blades (1-nerved) linear-filiform, margins entire, faces glabrous. Heads discoid, usually in (secund) spiciform arrays. Involucres narrowly cylindro-obconic, (3–4 ×) 1.5–2 mm. Phyllaries 5–9 in 2 series, 1-nerved (usually convex and without prominent midnerves) outermost linear-oblong and mostly green, oblong-lanceolate, subequal to unequal, white-indurate proximally, proximal margins scarious, (apices acute), faces glabrous. Receptacles flat, shallowly pitted (glabrous), epaleate. Disc florets 3, bisexual, fertile; corollas white or pale yellow, tubes shorter than funnelform throats, lobes 5, spreading-recurved, narrowly lanceolate (lengths 1/2 corollas); style-branch appendages linear-lanceolate. Cypselae obconic, subterete, 4-nerved (subdermal, hardly evident), densely and evenly white-sericeous; pappi persistent, of 10 silvery white, ovate-lanceolate, erose or apiculate scales in 2 series. x = 5.

Discussion

Species 1.

Thurovia was treated by M. A. Lane (1985) within Gutierrezia; data of Y. Suh and B. B. Simpson (1990) indicated it to be the sister group of Amphiachyris. The species is distinctive in its spiciform arrays of tiny, axillary, few-flowered, discoid heads with white corollas, densely sericeous cypselae, and pappi of scales.

Lower Taxa