Pycnanthemum. LABIAT/E. 355 



-) -! Leaves from lanceolate to ovate sessile, or almost so, denticulate or sometimes entire, pin- 

 iiately veined: flowers in larger and fewer less dense heads: verticillastrate glomerules subtended 

 by fewer and looser bracts. 



P. Calif ornicum, Torr. Usually tomentose-canescent, rather stout: loaves ovate- 

 lanceolate or almost ovate, with rounded or subcordate sessile base ; glomerules terminal 

 and in the axils of 2 or 3 uppermost pairs of leaves, at first very dense (0 to 12 lines in 

 diameter): bracts setaceous, lax : teeth of the calyx lanceolate-triangular, villous, 3 or 4 

 times shorter than the cylindraceous tube. Jour. Acad. Philad. n. ser. if. ()!), & Pacif. 11. 

 Hep. ir. 122; Gray, Bot. Calif, i. 5!J2. California and borders of Nevada. Passes into 



Var. glabellum, not canescent : leaves and stems from pubescent to almost glabrous : 

 inflorescence less dense. Torr. 1. c. Upper Sacramento, Biyclow, Brewer, &c. 



P. muticum, Pers. 1. c. Puberulent, cinereous-pubescent, or glabrate but pale, much 

 branched: leaves from lanceolate to ovate, subsessile, rather rigid, commonly obtuse at 

 base; those subtending the (sometimes proliferous) dense capitate glomerules canescent: 

 calyx-teeth ovate-deltoid or triangular-lanceolate, acute. Brachysttmum muticum, Michx. 

 Fl. ii. 6, t. 32. Pyc. Arkansanum, Fresenius in Hegensb. Flora, 1842, ;]25. Maine to Flor- 

 ida and Arkansas. Brachystemum verticillatum, Michx. 1. c. t. 31 (coll. at Pittsburgh, Penn.), 

 is intermediate between the typical (eastern) plant, with short bracts, shorter and broader 

 calyx-teeth, and leaves glabrate or minutely cinereous, and 



Var. pilosum. Cinereous with looser pubescence: leaves thinner, oblong-lanceolate, 

 mostly acute or acutish at base, sometimes ovate (Memphis, I-\ndl<r) : bracts and especially 

 the rather narrower calyx-teeth canescent with more copious often villous pubescence. 

 P. pilosum, Nutt. Gen. ii. 33; Gray, 1. c. Ohio to Illinois and Arkansas. Calyx often 

 (but inconstantly) somewhat unequal, two or three of the teeth more united. 

 P. leptodon. Soft-pubescent, or glabrate below, loosely branched, tall: leaves mem- 

 branaccous, green (1^ or 2 inches long), lanceolate or oblong-lanceolate, subsessile : glom- 

 erules larger and looser than in the preceding, canescent-hirsute : long-acuminate bracts 

 and calyx-teeth slender-subulate, villous-hirsute. P. pilosum, var. 1 leptodon, Gray in Arn. 

 Jour. Sci. I.e. North-western N. Carolina and S. Missouri, Gray & Carry, Geycr. Per- 

 haps a hybrid between P. muticum, var. pilosum, and P. Tullia, var. dubium. 



- -t -1 Leaves linear- or oblong-lanceolate, short -petioled, not even the uppermost canescent: 

 flowers in mostly terminal capitate glomerules, which are dense even in fruit : calyx almost or quite 

 equally 5-toothed, eaiiescently pubescent, the teeth subulate. (Ambiguous species.) 



P. Torreyi, Benth. Puberulent : stem strict, corymbose at summit ; leaves narrowly 

 lanceolate, green, glabrate, entire or slightly and sparingly denticulate : heads cymose- 

 corymbed, small; the bracts subulate, mostly appressed : corolla rather large. Prodr. 

 1. c. 188. P. Vinjinicum, Nutt, Gen. 1. c. ? Dry ground, S. New York to Pennsylvania. 



P. clinopodioides, Gray, I.e. Pubescent: leaves broadly or oblong-lanceolate, sharply 

 denticulate or sometimes entire: heads fewer and larger: bracts loose. Dry soil, S. New 

 York to E. Pennsylvania. 



* * * Calyx distinctly bilabiate through the union of three teeth to form (he upper lip: the teeth 

 and the tips of the loose bracts if slender not rigid: flowers in dense flattened glomerate cymes, 

 which are usually expanded with age: leaves membranaceous, mostly serrate, distinctly petioled, 

 the uppermost more or less canescent: stems loosely branching. 



P. Tullia, Benth. Rather stout, loosely more or less pubescent : leaves ovate- or lanceo- 

 late-oblong, acuminate, obtuse or acutish at base, somewhat serrate, thin (2 to 4 inches 

 long), pale green both sides, only the uppermost tomentulose-whitened : calyx-teeth aristi- 

 form-subulate, equalling the tube in length, above and the long-attenuate tips of the bracts 

 setose-barbate. Lab. 328, & in DC. I.e. i. 87. Tullia Pycnanthemoldes, Leavenworth in 

 Am. Jour. Sci. xx. 243, t. 5. S. Virginia and N. Carolina to Tennessee and Georgia, 

 chiefly in and near the mountains. 



Var. dubium. Greener, not canescent, except the setose-villous bracts and calyx ; 

 the teeth of the latter shorter than the tube: leaves lanceolate. P. dnlilum. Gray, 1. c. 

 Ashe Co., N. Carolina, Gray & Carey. Perhaps a hybrid between P. Tullia and P. leptodon, 

 or even P. muticum, var. pi/osunt. 



P. incanum, Michx. 1. c. Cinereous-pubescent : leaves ovate-oblong, with obtuse or 

 rounded base, serrate (2 to 4 inches long), the lower surface or both surfaces of the upper- 

 most canescent, at least when young, and with more or less loose or villous pubescence : 

 calyx-teeth subulate or triangular-lanceolate and cuspidate or pointed, not exceeding half 



