The genus Antennaria shares with some of the troublesome genera of Rosaceae the problems of diploid species and apomictic polyploid derivatives. Plants in this genus are dioecious and bloom in early spring (April–May). Involucral characters are based on pistillate plants (which are usually more common). Pappus hairs of staminate flowers are barbellate and/or thicker (± slenderly clavate) than the very fine smooth hairs of pistillate flowers (but the style, if any, is undivided). Staminate flowers are broader than the filiform ones of pistillate flowers. The term “basal leaves” applies both to the rosettes at the base of stems and to those at the ends of stolons. Old basal leaves from the previous year are often best for determining the maximum leaf width and the number of prominent longitudinal veins, whereas young and older leaves of the current year are needed to determine the nature of pubescence.
1. Blades of basal leaves (at least the largest) with 3–5 (–7) longitudinal veins prominent (at least on lower surface) to beyond the broadest part of the leaf; widest leaves (1.2–) 1.7–4 (–4.8) cm wide.
1. Blades of all leaves with only 1 prominent longitudinal vein; widest leaves (0.3–) 0.6–1.7 (–1.9) cm wide.
2. Tips of phyllaries rose-pink; northwestern Lake Superior region.
2. Tips of phyllaries white; widespread.
3. Basal leaves not over 6 mm wide, ± equally and densely pubescent on both surfaces; involucre of pistillate heads ca. 8–10 mm long.
3. Basal leaves at least 6 mm wide, or less pubescent (even glabrous) above, or usually both conditions present; involucre of pistillate heads ca. 5.5–8 (rarely 10) mm long.
4. Middle and upper cauline leaves merely acute or with firm subulate tip (bracts in inflorescence may have an appendage).
A. howellii (in part)
4. Middle and upper cauline leaves with a flat (often ± curled or involute) scarious appendage at the tip.
5. New basal leaves of the season essentially glabrous above or very soon becoming so (may appear hairy along the margin from tomentum of underside).
A. howellii (in part)
5. New basal leaves pubescent above when young (becoming glabrous only in age).
All species found in Antennaria
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. October 23, 2017. http://michiganflora.net/genus.aspx?id=Antennaria.