Cunila origanoides (L.) Britton

Dittany

© DETenaglia

Family - Lamiaceae

Habit - Perennial forb with a somewhat woody rootstock and short, slender rhizomes.

Stems - Ascending to erect, to 50 cm, multiple from base, 4-angled, usually well branched, glabrous or sparsely pubescent with short, spreading and/or, crinkly hairs, sometimes mostly along the angles or along 2 opposing, slightly concave sides, brown and appearing woody.

	Stem.
© DETenaglia

Leaves - Opposite, simple, sessile or nearly so. Blades 1.5-4.0 cm long, 0.7-2.0 cm wide, narrowly to broadly ovate, rounded or occasionally shallowly cordate at the base, angled or tapered to a sharply pointed tip, the margins finely toothed or rarely entire, the surfaces glabrous or sparsely to moderately pubescent along the main veins with stiff, spreading, multicellular hairs, also with relatively conspicuous sessile glands. Herbage fragrant with an odor similar to that of oregano.

	Stem and leaves.
© SRTurner

	Leaf abaxial.
© SRTurner

	Pressed leaves.
© DETenaglia

Inflorescences - Dense, terminal and axillary clusters of 6 to numerous flowers, these short-stalked to nearly sessile (0.5-2.0 mm). Bracts inconspicuous (to 1 mm long), linear to narrowly lanceolate, shorter than the flowers. Inflorescence divisions often pubescent with tufts of hispid hairs.

	Inflorescence.
© SRTurner

	Inflorescence.
© SRTurner

Flowers - Calyces 1.5-3.0 mm long at flowering, actinomorphic, funnelform to narrowly bell-shaped, the tube strongly 10-nerved, with a fringe of short, bristly hairs in the mouth, the lobes shorter than the tube, narrowly triangular, glandular on the outer surface. Corollas 6-8 mm long, weakly zygomorphic, pinkish purple to lavender, the surfaces moderately to densely and minutely hairy, also glandular, the tube funnelform, slightly 2-lipped, the lips up to half as long as the tube, the upper lip notched at the broadly rounded tip, straight or slightly arched, the lower lip 3-lobed, arched to spreading. Stamens 2, strongly exserted, the anthers small, the connective short, the pollen sacs 2, parallel or nearly so, yellowish purple to nearly white. Ovary deeply lobed, the style appearing nearly basal from a deep apical notch. Style not or only slightly exserted, with 2 slender branches at the tip.

	Calyces.
© SRTurner

	Flowers, lateral view.
© SRTurner

	Flowers, frontal view of corolla.
© SRTurner

Fruits - Dry schizocarps, separating into usually 2-4 nutlets, these 0.8-1.0 mm long, ellipsoid to ovoid, the surface yellowish brown to brown, glabrous, smooth or very finely pebbled.

	Fruiting calyces. The bristly hairs in the calyx mouth obscure the view into the interior.
© SRTurner

Flowering - July - November.

Habitat - Upland forests, savannas, upland prairies, ledges and tops of bluffs, streambanks, fields, roadsides; often on acidic substrates.

Origin - Native to the U.S.

Lookalikes - None close.

Other info. - This species is found in Missouri within a sharply delineated, southeastern half of the state. Beyond Missouri its range extends southward throughout most of Arkansas, and also eastward to the Atlantic Coast. The plant is quite common within its range, and is easily identified by its axillary clusters of lavender colored flowers, each of these having two strongly exserted stamens. The leaf shape is distinctive, and with a little practice the plant can be identified even when no flowers are present.

This little aromatic plant is sometimes overlooked in the field but is quite nice. The leaves of the plant are strongly aromatic and have been brewed traditionally as a tea for medicinal and culinary uses. The tea was used to treat headaches, fevers, and even snakebites. This species, and a handful of others, are also producers of something called "frost flowers." These are thin, layered eruptions of ice which burst from the xylem of the plant stems after a good freeze in the fall. There are numerous sources of information on frost flowers; see, for example, the October/November 2000 issue of Missouri Conservationist magazine.

Photographs taken at Roaring River State Park, Barry County, MO., 8-25-00, and in the Ozark Scenic Riverways, Shannon County, MO., 8-28-03 (DETenaglia); also at LaBarque Creek Conservation Area, Jefferson County, MO, 8-22-2010, Earthquake Hollow Natural Area, Callaway County, MO, 9-19-2015, Little Lost Creek Conservation Area, Warren County, MO, 10-10-2020, and Don Robinson State Park, Jefferson County, MO, 9-2-2021 (SRTurner).