Ionactis linariifolia (L.) Greene
Family - Asteraceae
Stems - Single or (rarely) multiple from the base, erect, herbaceous, simple, retrorse pubescent, pale green to yellowish, thin, 1-3mm in diameter, terete.
Leaves - Alternate, dense on the stem, linear to somewhat spatulate (slightly broader at the apex), with a minute bristle tip, scabrous, with strigillose margins, shiny deep green above, lighter below, 2-3cm long, 2-3mm broad, slightly shorter and thicker in strong sun, abruptly reduced just below the flower heads.
Inflorescence - Single (typically) flowerhead terminating the stem.
Involucre - To 1cm long, 4-5mm in diameter, cylindrical. Phyllaries glabrous, imbricate, appressed, to 7mm long, +/-1mm broad, linear, scarious, with a white midrib and light green apices, acute. Apices ciliolate.
Ray flowers - +/-14 per flowerhead, fertile, pistillate. Corolla tube green, 3mm long, antrorse pubescent near the apex. Style glabrous, green-translucent, 3mm long, bifurcate in the apical 1mm. Stigmas erect. Pappus white, of capillary bristles. Bristles to 5mm long, antrorse barbellate. Achenes whitish, 3mm long in flower, densely antrorse pubescent.
Disk flowers - Disk 4-5mm in diameter. Corollas glabrous, 6mm long, white basally, yellow apically , 5-lobed. Lobes acute, 1mm long, erect to slightly spreading. Stamens 5, adnate at the base of the corolla tube. Filaments glabrous, 4mm long, pale yellow-translucent. Anthers yellow, 2mm long, included to partially exserted, connate around the style. Style bifurcate, glabrous, yellowish at the apex, whitish basally, +/-4mm long. Stigmas 1.5mm long erect. Pappus as in ray flowers. Achenes as in ray flowers but slightly smaller.
Flowering - August - October.
Habitat - Dry, rocky pine, pine-oak, or oak-hickory woods. Also on glades and upland slopes.
Origin - Native to U.S.
Other info. - This little species can be found in the southern 1/3 of Missouri. The plant is probably the easiest in the genus to identify because of its thin leaves (which appear somewhat whorled), its single terminal flowerhead on each stem, its small size, and its habitat.
Photographs taken in Conecuh National Forest, AL., 10-23-04, and at Fort Benning, GA., 10-12-05 (DETenaglia); also at Taum Sauk State Park, Iron County, MO, 9-19-2012 (SRTurner).