2. Pycnanthemum muticum (Michx.) Pers. (clustered mountain mint)
Pl. 440 a, b;
Map 1983
Stems 40–110 cm
long, moderately to densely pubescent on the angles and sides with mostly
short, curled hairs, occasionally with a few longer, spreading hairs. Leaves
sessile or nearly so. Leaf blades 3–8 cm long, 15–40 mm wide, ovate to broadly
lanceolate or oblong-ovate, mostly rounded to cordate at the base, the margins
usually finely toothed, the upper surface glabrous or sparsely short-hairy,
mostly along the veins (rarely the uppermost pair whitened with dense, short,
curled hairs), usually green, the undersurface usually green, glabrous or
sparsely to moderately short-hairy, mostly along the veins. Inflorescences
relatively dense, often appearing broadly rounded, often appearing sessile or
nearly so, only the lowermost branches observable. Bracts leaflike, whitened
with dense, short, curled hairs on the upper surface, glabrous or nearly so on
the undersurface. Bractlets 1–3 mm long, linear to narrowly lanceolate. Calyces
3–5 mm long, actinomorphic, densely pubescent with minute, appressed hairs,
mostly above the midpoint, lacking longer bristly hairs on the margins or tip,
the lobes all similar in size and shape 0.5–1.5 mm long, narrowly triangular,
sharply pointed. Corollas 4–7 mm long, white to pale pinkish-tinged or pale
lavender. Nutlets 1.0–1.4 mm long, glabrous. 2n=ca. 108. July–September.
Uncommon in the
Mississippi Lowlands Division (eastern U.S. west to Missouri and Texas).
Bottomland forests; also ditches, roadsides, and grassy disturbed areas.
Where this
species grows in proximity to P. albescens, rare putative hybrids have
been collected.