LAMIACEAE 1045 



34. THYMUS L. 



Perennial herbs, with low or creeping stems. Leaves opposite : blades small, flat, 

 mostly entire. Flowers perfect, in axillary or terminal clusters. Calyx narrow : tube 

 relatively short, 10-13-ribbed, 2-lipped : upper lip ascending : lower lip of 2 narrow, 

 longer lobes. Corolla purple or pale, surpassing the calyx, 2-lipped : upper lip erect, 

 emarginate : lower lip 3-lobed, spreading. Stamens 4 : filaments mostly surpassing the 

 corolla : anthers 2-celled ; sacs diverging. Nutlets smooth. THYME. 



1. Thymus Serpyllum L. Diffusely spreading or forming wide mats. Stems and 

 branches wiry, tough, pubescent in lines : leaf -blades oblong to oval 6r ovate, 3-10 mm. 

 long, obtuse, entire, short-petioled : bracts like the leaves but smaller : panicles spike-like, 

 dense : calyx becoming 3-4 mm. long ; lobes of the lower lip slender, about as long as the 

 tube : corolla purplish ; tube about as long as the calyx : nutlets about 0.5 mm. long. 



On roadsides and in woods, and in waste places, Nova Scotia to Pennsylvania and North Carolina. 

 Naturalized from Europe and Asia. Summer. 



35. KOELLIA Moench. 



Perennial* caulescent herbs, with glabrous or pubescent foliage. Leaves opposite, often 

 numerous on short branches : blades narrow or broad, flat, entire or toothed. Flowers in 

 dense axillary and terminal clusters. Calyx ovoid to tubular : tube 10-13-ribbed, not con- 

 spicuously pubescent in the throat : lobes 5, equal or unequal. Corolla white or purplish, 

 surpassing the calyx, 2-lipped : upper lip erect, entire or notched : lower lip 3-lobed. 

 Stamens 4, often nearly equal : filaments often surpassing the corolla : anthers 2-celled ; 

 sacs parallel. Nutlets smooth, variously roughened or pubescent. [ Pycnanthemum Michx.] 

 MOUNTAIN MINT. HORSE MINT. 



Calyx not 2-lipped ; lobes equal or nearly so. 

 Calyx-lobes much surpassed by the corolla. 



Flower-clusters relatively loose, in terminal apparently naked corymbs : bracts shorter than the 



clusters. 1. K. nuda. 



Flower-clusters very dense, in terminal conspicuously bracted corymbs. 

 Calyx-lobes not awn-tipped. 

 Bractlets ciliolate. 



Calyx-lobes triangular or ovate-triangular. 2. K. Virginiana. 



Calyx-lobes subulate to lanceolate. 



Leaf-blades or most of them over 3 times as long as broad. 



Leaves with strictly entire blades. 3. K. flexuoaa. 



Leaves, or the larger ones, with toothed blades. 



Flower-clusters 1-2 cm. broad at maturity, compact. 

 Flower-clusters conspicuously woolly at maturity : 



stems copiously pubescent. 

 Calyx-lobes acute : leaf-blades firm ; species cam- 



pestrian. 4. K. pilosa. 



Calyx-lobes acuminate : leaf-blades thin : species 



Alleghenjan. 5. K. leptodon. 



Flower-clusters not woolly at maturity : stems pilose 



or slightly pubescent. 6. K. verticillata. 



Flower-clusters 2-3 cm. broad at maturity, not crowded. 7. K. clinopodioidrs. 

 Leaf-blades or most of them less than 3 times as long as broad. 8. K. mutica. 

 Bractlets copiously villous-ciliate. 9. K. montana. 



Calyx-lobes awn-tipped. 10. K. arietata. 



Calyx-lobes equalling the corolla. 



Calyx-lobes, at least the lower ones, shorter than the tube : bracts with 



tips mostly shorter than the body : coastal species. 11. K. hyssoptfolia. 



Calyx-lobes, at least the lower ones, longer than the tube : bracts with 



tips mostly longer than the body : Alleghenian species. 12. K. Hugeri. 



Calyx manifestly 2-lipped by the partial union of the 3 upper lobes. 

 Calyx-lobes destitute of long hairs, or only a few at the tip of a lobe. 



Calyx-lobes ovate or triangular-ovate, obtuse, incurved at maturity. 13. K. albescem. 



Calyx-lobes lanceolate or triangular-lanceolate, subulate-tipped, erect. 14. K. incana. 

 Calyx-lobes furnished with long hairs. 



Upper leaf-blades whitened. 15. K. pycnanthemoides. 



Upper leaf-blades green. 



Stems pilose : calyx-lobes plumose. 16. K. dubia. 



Stems puberulent : calyx-lobes sparingly hairy. 17. K, Beadld. 



1. Koellia nuda (Nutt. ) Kuntze. Stems glabrous or nearly so, 3-7 dm. tall, corym- 

 bosely branched above : leaf-blades rather thick, oblong, elliptic or oval, 1-2 cm. long, 

 acute or obtuse, entire or nearly so, sessile : calyx 3-4 mm. long, slightly enlarged upward ; 

 lobes triangular, acute, ciliated corolla 6 mm.* long, pubescent, the lips oblong, as long 

 as the tube, obtuse, or the lower lip 3-lobed : filaments and style glabrous. 



In pine lands, North Carolina to Florida and Alabama. Summer and fall. 



