118. Labiatae 221 



5. Calyx-lobes subulate-aristate; corolla pink or white, not spotted; 

 dry ground, occasionally adv. from the west; Cook Co. 



Lemon Mint [M. pcclinata sensu auth., non Nutt.] 



M. citriodora Cerv. 



22. Hedeoma Pers. 



1. Leaves elliptical, sparingly serrate, petioled; caK^ with the upper 

 teeth triangular-lanceolate, the lower subulate; dry soil in 

 fields, along roads, and in open woods, common. July-Oct. 

 American Pennyroyal H. pulcgioidcs (L.) Pers. 



1. Leaves linear, entire, sessile, ciliate; calyx-teeth all subulate; sandy 

 soil in open woods, chiefly in the n. half of the state, but extend- 

 ing southw. along the Mississippi R. June-July. Rough Penny- 

 royal H . hispida Pursh 



23. Melissa L. — Balm 



M. officinalis L. Waste places, occasional; introd. from Eur. 

 June-Aug. 



24. Clinopodium L. — Basil 



C. arkansanum (Nutt.) House. Rocky woods or sandy ground, 

 local; chiefly in n.e. 111. June-Aug. [C. glabrum (Nutt.) Kuntze; 

 Satureja arkansana (Nutt.) Briq.; S. glabella var. angustifolia (Torr.) 

 Svens.] 



25. Thymus L. — Thyme 



T. serpyllum L. Roadsides and old fields and gardens, rarely col- 

 lected; introd. from Em\ July-Aug. 



26. Pycnanthemum Michx. — Mountain Mint 



1 . Leaves ovate to ovate-lanceolate. 



2. Upper leaves whitish ; calyx-teeth and bracts pubescent and 

 usually with long bristles; roadsides, fields, and open woods, 

 s. 111. July-Sept P. pycnanthemoides (Leavenw.) Fern. 



2. Upper leaves not whitish; calyces and bracts canescent; woods, 



s. 111. Aug.-Sept. .-- P. incanum (L.) Michx. 



1. Leaves lanceolate to linear-lanceolate or linear. 



3. Stem glabrous throughout (or rarely with a few minute curved 



hairs) ; leaves linear; calyx-lobes subulate-lanceolate; dry 

 soil in open woods, along roads, and in fields, common. 



June-Sept P. flexiwsum (Walt.) BSP. 



3. Stem pubescent. 



4. Stem short-pubescent on the angles; leaves linear-lanceolate, 

 glabrous or nearly so; moist ground in woods and along 



roads. July-Sept P. virginianum (L.) Dur. & Jacks. 



4. Stem copiously short-pilose throughout, or at least above the 

 middle; leaves elliptic-lanceolate, finely pubescent on veins 

 beneath; sandy soil along roads and in open woods; chiefly 

 n. and central 111. July-Sept P. pilosum Nutt. 



