Hedeoma reverchonii (A. Gray) A. Gray var. reverchonii, rock hedeoma, mock pennyroyal. Annual or perennial herb, taprooted, not rosetted, 1—several–stemmed at base, branching opposite–decussate along principal shoot spreading to ascending, to 35 cm tall; shoots with cauline leaves, foliage conspicuously gland–dotted with sessile glandular hairs having colorless heads sunken in pits, strongly lemon–scented when crushed.
Stems 4–sided, to 2 mm diameter, tough, green or lower stem aging reddish, rounded on edges, with a pair of ledges across each node, the edges initially whitish with downward–arching nonglandular hairs, faces with nonglandular and sessile glandular hairs.
Leaves opposite decussate, simple, short–petiolate, without stipules; petiole hemicylindric, < 1.5 mm long, whitish, with upward–arching short hairs; blade obovate or elliptic to oblong or oblanceolate, < 6—19 × 1.5—5 mm, tapered at base, entire or with an inconspicuous pair of teeth approaching tip, obtuse at tip, pinnately veined with principal veins sunken on upper surface and raised on lower surface, surfaces short–hairy with upward–arching hairs and sunken sessile glandular hairs; at base of plant young leaves with denser, longer hairs (pilose–hirsute).
Inflorescence cyme, axillary paired at successive nodes (verticils), cyme 1—3(—8)–flowered, among leaves, flower ascending, bracteate, with arching short hairs and sessile glandular hairs having colorless heads on axes; peduncle spreading at 45°, cylindric, 0.5—1 ×0.4 mm, green, with downward–arching puberulent hairs and glandular hairs with tiny heads; bractlets subtending each pedicel 2 and opposite, linear, at anthesis 1 × 0.3 mm increasing 2× in fruit and persistent on old axes, with spreading nonglandular short hairs and glandular hairs; pedicel widely spreading, cylindric, 1.5—2.8 mm long, with upward–arching short hairs and glandular hairs.
Flower bisexual, bilateral, 2.5—4 mm across; calyx 2–lipped, 5–lobed, 6—7 mm long, green or lobes purplish, with stiff, bristly hairs and glandular hairs with heads reddish to colorless; tube expanding from above base then constricted above midpoint before expanding to orifice, 4—5 × 1—1.3 mm, conspicuously 13–ribbed with 5 ribs ending in lobes, bristly hairs to 1.5 mm long and underneath having a layer of short hairs to 0.2 mm long along ribs, glandular hairs along furrows, inner surface with puffy, colorless surface, at orifice and lower lips fringed with thick layers of straight white hairs 0.7—0.8 mm long concealing access to nectar; upper lip 3–lobed, lobes linear and bend upward, 0.8—1.4 mm long, purplish at tip; lower lip 2–lobed, lobes linear and straight appressed to corolla tube, 1.7—2.3 mm long; corolla 2–lipped, 4–lobed, exserted, pink to light pink–purple; tube somewhat 4–sided, 1.5—2.5 mm long, white aging reddish, glabrous; throat narrowly funnel–shaped, 5—7 mm long, ca. 2 mm diameter at orifice,10–veined, on outside straight–puberulent with scattered glandular hairs above midpoint, inner surface with some short hairs at level of filament; upper lip somewhat roundish shallowly notched at top, 1—1.5 × 1.5—1.8 mm, with hairs on back; lower lip 3–lobed resembling dogbone notched at top, ca. 2 × 2.5—4 mm, lateral lobes semicircular, 0.8—0.9 × 1.8—2 mm, before central lobe lower lip white having nectar guide with several purple spots; stamens 2, attached to corolla ca. 5.5 mm from base near base of lower lip, anthers slightly exserted beyond upper corolla lip; filaments straight, 2.5—3 mm long, pink to light pink–purple, glabrous; anther ⊥ filament with 1 sac on each end of a split connective, ca. 1 mm across, sacs 0.4 mm long, dark pink, longitudinally dehiscent; pollen pink; nectary disc beneath ovary, 0.5 mm long, greenish; pistil 1; ovary superior, strongly 4–lobed, lobes equal, rounded, 0.25 mm long, whitish, glabrous, 2–chambered, each lobe with 1 ovule; style attached to ovary base at center of ovary lobes (gynobasic), to level of corolla upper lip, to 11.5 mm long, white at base and pink to light pink–purple from midpoint, glabrous, unequally 2–branched, the upper branch appressed, triangular, ca. 0.25 mm long, the lower stigmatic branch narrowly lanceolate, 1.5 × 0.3 mm, exserted next to upper corolla lip and curved downward across corolla orifice and beneath anthers.
Fruits nutlets, (1—)3—4, oblong, ca. 1.5 × 0.5 mm, smooth, brown with darker cell outlines, initially glossy drying duller, outer side rounded, lateral sides ± flat with attachment scars at base.
A. C. Gibson