1. Ajuga reptans L. (carpet bugle)

Map 1936

Plants perennial herbs, with fibrous roots, usually strongly colonial and sometimes matforming. Main stems stoloniferous, to 60 cm long or longer, spreading, forming rosettes where rooting, bluntly to sharply 4-angled, the angles sometimes narrowly winged, leafy, glabrous or sparsely to densely pubescent with fine, straight to crinkly, multicellular hairs, sometimes mostly at the nodes. Flowering stems 1 to few per rosette, 7–30 cm long, erect or strongly ascending, bluntly to sharply 4-angled, usually unbranched, sparsely to moderately pubescent with fine, straight to crinkly, multicellular hairs, sometimes mostly at the nodes. Leaves in rosettes basal to the flowering stems and long-petiolate, also opposite on the stems and mostly short-petiolate to less commonly nearly sessile, the petiole winged, especially above the midpoint, often strongly purplish-tinged, less commonly copper-colored in the overwintering state. Leaf blades 0.8–6.0(–10.0) cm long, 0.4–4.0 cm wide (those of rosette leaves usually larger than those of flowering stems), variously narrowly to broadly elliptic, ovate, obovate, or nearly circular, sometimes appearing oblanceolate or spatulate, rounded or angled to tapered at the base, rounded or broadly angled to a bluntly pointed tip, the margins with fine to moderately coarse, rounded teeth or scallops, sometimes appearing wavy, the surfaces glabrous or sparsely to moderately pubescent with soft, more or less appressed, multicellular hairs, also with inconspicuous, sessile glands. Inflorescences appearing as terminal spikelike racemes, these appearing relatively dense but interrupted between some or most of the nodes, more or less cylindric, the flowers 6(–10) at each node and not or somewhat overlapping those of adjacent nodes, the stalks 0.5–1.0 mm long. Bracts leaflike, all but the uppermost noticeably longer than the flowers. Calyces actinomorphic or nearly so, 2.5–5.0 mm long, lacking a lateral projection, more or less symmetric at the base, bell-shaped, the tube inconspicuously 10-nerved, 5-lobed, the lobes as long as or somewhat longer than the tube, similar in size and shape, triangular to lanceolate-triangular, not spinescent, not becoming enlarged at fruiting. Corollas 12–20 mm long, zygomorphic, blue (rarely pink or white), the surfaces sparsely to moderately hairy, the tube funnelform, 2-lipped to about the midpoint, the upper lip reduced and inconspicuous, a small, relatively flat, unlobed flap of tissue, the lower lip prominent, spreading to somewhat recurved, mostly 4-lobed with 2 small lateral lobes and a large central lobe that in turn is notched (less commonly unlobed or shallowly 3-lobed apically). Stamens 4, slightly exserted (shorter than the lower lip), the lower 2 stamens with slightly shorter filaments, the anthers small, the connective very short, the pollen sacs 2, appearing angled to more or less spreading from their tips, dark blue. Ovary relatively shallowly lobed, the style appearing more or less lateral from a shallow apical notch. Style exserted, more or less equally 2-branched at the tip. Fruits dry schizocarps, often not separating into nutlets (or only tardily so) and often with only 1 or 2 of the ovules developing into fruits, these 1.5–2.0 mm long, oblong-obovoid, the surface brown, glabrous or sparsely short-hairy near the tip, with a prominent, honeycomblike network of ridges. 2n=32. April–June.

Introduced, uncommon, widely scattered (native of Europe, Asia; introduced sporadically in the eastern and less abundantly western U.S., Canada). Bottomland forests, gardens, and old homesites.

Carpet bugle is commonly cultivated as a hardy ground cover, but can spread aggressively in some garden situations. The basal rosette leaves usually are singificantly larger than those of the flowering stems and often overwinter, turning dark purple or coppery-tinged.