15b. Corolla-lobes entire --16. 16a. Flowers sessile; stem softly pubescent =Puccoon, Lithospermum canescens.= 16b. Flowers on pedicels 2-5 mm. long; stem hispid or bristly =Puccoon, Lithospermum gmelini.= 17a. Corolla white; fruit brown and wrinkled (weed 2-4 dm. high; spring and summer) =Corn Gromwell, Lithospermum arvense.= 17b. Corolla yellowish-white; fruit white and smooth (5-10 dm. high) --18. 18a. Corolla distinctly surpassing the calyx in length (spring and summer) =Corn Gromwell, Lithospermum officinale.= 18b. Corolla equaling or shorter than the calyx (spring) =Wild Gromwell, Lithospermum latifolium.= LABIATAE, the Mint Family Herbs with opposite leaves, square stems, and usually aromatic odor; flowers irregular, with united petals, or almost regular; stamens 2 or 4, attached to the tube of the corolla; ovary deeply 4-lobed, with a single style. 1a. Stamens 2 --2. 1b. Stamens 4 --15. 2a. Corolla regular or nearly so; flowers white, in dense axillary clusters; plants usually of wet grounds (2-8 dm. high; summer and autumn) --3. 2b. Corolla distinctly irregular and more or less 2-lipped --7. 3a. Calyx-teeth short, triangular, acute or obtuse (Bugle Weed) --4. 3b. Calyx-teeth narrow, acuminate or cuspidate (Water Hoarhound) --5. 4a. Stems and stolons bearing tubers =Bugle Weed, Lycopus uniflorus.= 4b. Stems and stolons not bearing tubers =Bugle Weed, Lycopus virginicus.= 5a. Leaves serrate; calyx-teeth sharp-pointed --6. 5b. Leaves coarsely incised; calyx-teeth awn-tipped =Water Hoarhound, Lycopus americanus.= 6a. Corolla twice as long as the calyx; leaves narrowed at the base =Water Hoarhound, Lycopus rubellus.= 6b. Corolla barely longer than the calyx; leaves sessile or nearly so =Water Hoarhound, Lycopus lucidus var. americanus.= 7a. Corolla blue, 3-4 mm. long; flowers in loose axillary clusters (1-4 dm. high; summer) (Pennyroyal) --8. 7b. Corolla 8-40 mm. long --9. 8a. Leaves serrate =Pennyroyal, Hedeoma pulegioides.= 8b. Leaves linear, entire =Pennyroyal, Hedeoma hispida.= 9a. Lower lobe of the corolla fringed, very much longer than the upper (5-15 dm. high; corolla pale-yellow; late summer) =Horse Balm, Collinsonia canadensis.= 9b. Lower lobe of the corolla nearly or quite as long as the upper and not fringed --10. 10a. Calyx narrowly tubular; its teeth about equal in size (5-10 dm. high; flowers in dense terminal heads, in summer) --11.