Pittonia3: 245. 1897
e, w North America.
Species 5 (5 in the flora).
Ionactis has often been included within Aster; its morphologic distinction has recently been reemphasized (G. L. Nesom and T. J. Leary 1992; Nesom 1992, 1994b). Plants of Ionactis are distinctive in their woody caudices, narrow, stiff, evenly distributed leaves, heads borne singly or in loose, corymbiform arrays, keeled phyllaries, flattened and slightly dimorphic cypselae, pappi of apically attenuate bristles with a shorter outer series, and base chromosome number of x = 9.
|1||Plants strongly woody at bases; stems and leaves glandular; disc florets functionally staminate (with sterile ovaries)||Ionactis caelestis|
|1||Plants basally herbaceous to becoming woody, not strongly woody; stems and leaves eglandular; disc florets bisexual, fertile||> 2|
|2||Heads usually in loose, corymbiform arrays, sometimes borne singly; e North America||Ionactis linariifolia|
|2||Heads borne singly, rarely 2–3; w North America||> 3|
|3||Proximal cauline leaves densely clustered, internodes not visible; leaf faces glabrous or sparsely puberulent; cypselae 2–2.5 mm; pappus bristles terete; New Mexico||Ionactis elegans|
|3||Proximal cauline leaves separated, internodes evident; leaf faces hispidulous; cypselae 5–6 mm; pappus bristles flattened; nw North America||> 4|
|4||Plants 5–12(–20) cm; mid cauline leaf blades ovate to oblong or linear, 4–15 mm, with whitish hyaline margins; cypsela faces eglandular||Ionactis alpina|
|4||Plants 12–30 cm; mid cauline leaves linear-lanceolate, 15–25(–30) mm, with green margins; cypsela faces glandular||Ionactis stenomeres|
|Author||Guy L. Nesom +|
|Common name||Ankle-aster +|
|Etymology||Greek ion, violet, and aktis, ray, alluding to colored ray florets +|
|Illustrator||Barbara Alongi +|
|Synonym||Aster Ianthe +|
|Taxon name||Ionactis +|
|Taxon parent||Asteraceae tribe Astereae +|
|Taxon rank||genus +|
|Volume||Volume 20 +|