Pycnanthemum. LABIATiE. 355 



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

 nately 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: leaves 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. ii. 99, & Pacif. It. 

 Rep. iv. 122 ; Gray, Bot. Calif, i. 592. 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, Bigelow, 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. — Brachystemum muticum, Miclix. 

 Fl. ii. 6, t. 32. Pyc. Arkansanum, Fresenius in Regensb. Flora, 1842, 325. — Maine to Flor- 

 ida and Arkansas. — Brachystemum verticillatum, Miclix. 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, Fendler) : bracts and especially 

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

 P. pilosum, Xutt. 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- 

 branaceous, 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. ? leptodon, Gray in Am. 

 Jour. Sci. 1. c. — North-western N. Carolina and S. Missouri, Gray & Carey, Geyer. — Per- 

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



•f— -i— +- 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, canescently 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. Yirrjinicum, Nutt. Gen. 1. c. 1 — Dry ground, S. New York to Pennsylvania. 



P. clinopodioid.es, Gray, 1. c. 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 the 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. 1. c. i. 87. Tullia Pycnanthemoides, 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. dubium, Gray, 1. c. — 

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

 or even P. muticum, var. pilosum. 

 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 



