7. Monarda punctata L. (dotted beebalm, horsemint)
Pl. 438 c, d;
Map 1973
Plants annual or
perennial. Stems 15–50 cm long, unbranched or branched, moderately to densely
pubescent with minute, downward-curved hairs, rarely with sparse to dense,
longer, bristly spreading hairs (sometimes only at the nodes). Leaves sessile
or the petioles to 15 mm long, the median leaves the largest. Leaf blades 2–9
cm long, lanceolate to oblong-lanceolate or narrowly elliptic, rounded to more
commonly angled or tapered at the base, angled or tapered to a sharply pointed
tip, the margins with moderately to widely spaced, fine teeth, usually also
hairy, the upper surface sparsely to moderately pubescent with minute, curved
hairs, the undersurface sparsely to densely pubescent with minute, curled
hairs, occasionally also with longer, somewhat woolly hairs along the main
veins. Inflorescences consisting of (1)2–7 flower clusters forming an
interrupted terminal spike (some of the lower clusters sometimes associated
with relatively large bracteal leaves and thus appearing axillary), the bracts
15–40 mm long, oblong, elliptic, ovate, or obovate, the margins entire but
hairy (at least near the base), the surfaces usually minutely hairy, whitish to
pinkish- or purplish-tinged. Innermost bracts 3–8 mm long, linear, the margins
hairy. Calyces 5–8 mm long, the outer surface sparsely to densely pubescent
with minute, curled hairs, sometimes with sparse, longer hairs toward the tip,
densely bristly-hairy in the throat, the lobes 1.0–1.5 mm long, triangular to
narrowly triangular, sharply pointed but lacking a bristlelike extension.
Corollas 15–28 mm long, cream-colored to pale yellow, sometimes pinkish-tinged,
the lips with prominent purplish brown to maroon or brownish purple spots or
mottling, moderately to densely pubescent with fine nonglandular hairs
externally, also dotted with sessile glands, the lips with longer, denser hairs
toward the tips, hairy in the throat, slightly shorter than the tube, the upper
lip strongly arched downward, the lower lip 3-lobed with a pair of short
lateral lobes and a flangelike, oblong (sometimes shallowly notched) extension
at the tip of the central lobe. Stamens not exserted from the corolla, hidden
under the upper corolla lip. Nutlets 1.2–1.5 mm long, usually brown. 2n=22,
24. June–October.
Uncommon, mostly
in counties along the Mississippi and Missouri Rivers (eastern U.S. west to
Minnesota and New Mexico; Canada, Mexico). Sand prairies; also margins of crop
fields, railroads, roadsides, and open disturbed areas; usually in sandy soil.
Monarda
punctata consists of a
messy and complicated series of morphologically overlapping infraspecific taxa.
McClintock and Epling (1942) accepted eight subspecies, but reported only ssp. villicaulis
Pennell from Missouri. Steyermark (1963) treated two varieties, var. villicaulis
and var. occidentalis. Scora (1967) accepted eleven varieties and
reported the same two taxa for Missouri as had Steyermark. In his study of the
genus in Texas and Mexico, B. L. Turner (1994) raised four of the taxa treated
earlier as subspecies or varieties to species level and also named a twelth
variety endemic to southern Texas and adjacent Mexico. Thus, there is reason to
believe that the dozen total taxa accepted in the M. punctata complex
over the last few decades include at least six well defined entities (the five
species accepted by B. L. Turner and his new variety), but the other six taxa
include some varieties that exhibit a great deal of morphological overlap.
Future taxonomic studies may show that most of these are better treated as a
single polymorphic species, including the taxa reported from Missouri and
accepted tentatively in the present work.