824 FLORA. 



Thyrsus narrow, raceme-like or spike-like. 



Corolla-tube abruptly enlarged ; sterile filament densely woolly. 



3. P. cristatus, - 

 Corolla-tube gradually enlarged ; sterile filament slightly bearded. 



4. P. albidns. 

 Only the inflorescence, or pedicels, or calyx pubescent, or puberulent. 



Thyrsus open, panicle-like. 



Stem leaves oblong, ovate, or lanceolate. 

 Calyx-segments merely acute. 



Corolla white, abruptly enlarged, 2. 5-3 cm. long. 



5. P. Digitalis. 

 Corolla purplish, gradually enlarged, 1.5-2 cm. long. 



6. P. Pentstemon 

 Calyx-segments with long acuminate tips. 7. P. calycosus. 



Stem leaves linear-lanceolate. 8. P, gracilis* 



Thyrsus narrow, interrupted ; calyx viscid. 9. P. tubiflorus, 



Corolla 5 cm. long, the tube much enlarged above; leaves dentate. 10. P. Cobaea. 



** Completely glabrous throughout, mostly glaucous. 

 Leaves lanceolate, oblong, ovate, obovate, or orbicular. 



Stem leaves rounded, clasping ; flowers 5 cm. long. u. P, grandiflorus. 



* Stem leaves acute or acuminate; flowers 1.8-3 cm l n g 



Corolla 1.8-2 cm. long ; stem leaves lanceolate. 12. P. acuminatus. 



Corolla 2.5-3.5 cm - l n ? stem leaves mostly oblong. 13. P. glaber. 



Leaves linear or linear-lanceolate ; flowers densely thyrsoid. 



Bracts lanceolate, small ; flowers 12-20 mm. long. 14. P. angustifolius. 



Bracts ovate, acuminate, large : flowers 25 mm. long or more. 15. P, Haydeni. 



1. Pentstemon hirsutus (L.) Willd. HAIRY BEARD-TONGUE. (I. F. f. 

 3247.) Stem hairy nearly or quite to the base, 3-9 dm. high. Leaves puberu- 

 lent or glabrous, denticulate or the uppermost entire, the basal oblong or ovate, 

 obtutish, 5-12 cm. long, narrowed into petioles, the upper sessile, lanceolate, ses- 

 sile or slightly clasping; inflorescence thyrsoid, rather loose, glandular-pubescent; 

 pedicels mostly short; corolla purplish or violet, the tube gradually dilated above, 

 2-grooved on the lower side, about 2 cm. long, the throat nearly closed by the vil- 

 lous palate at the base of the lower lip; sterile filament densely bearded for about 

 one-half its length. In dry woods and thickets, Me. to Out., Manitoba, Fla., Minn, 

 and Tex. May-July. 



2. Pentstemon canescens Britton. GRAY BEARD-TONGUE. (I. F. f. 3248.) 

 Densely and finely canescent or puberulent, or the leaves sometimes nearly gla- 

 brous, 3-9 dm. high. Leaves denticulate, the lower and basal ones oval, obtuse, 

 narrowed into long margined petioles, the next I or 2 pairs contracted below the 

 middle and somewhat fiddle-shaped, 7-15 cm. long, the upper ovate or ovate, 

 lanceolate, acuminate, clasping; thyrsus elongated, open, glandular pubescent 

 leafy-bracted below; pedicels very short; calyx-segments lanceolate, acuminate; 

 corolla purple or nearly white, about 2.5 cm. long, slightly or not at all bearded ir, 

 the throat; sterile filament slightly hcarded for about one-third its length; capsule 

 ovoid, glabrous, longer than the calyx. In dry soil, western Va., W. Va., N. C. 

 and Tenn. May-June. 



3. Pentstemon cristatus Nutt. CRESTED BEARD-TONGUE. (I. F. f. 3249.) 

 Puberulent below, glandular-villous and viscid above; stem leafy, 1.5-4.5 dm. 

 high. Leaves firm, entire or repand, the lower and basal ones oblong or spatu- 

 late, 5-10 cm. long, narrowed into margined petioles, the upper sessile or some- 

 what clasping, acute or acuminate; thyrsus dense, narrow, leafy-bracted; flowers 

 almost sessile; calyx-segments linear-lanceolate, acuminate; corolla about 2.5 cm. 

 long, red or purple, its lower lip villous within. On plains, Manitoba and the N. 

 W. Terr, to Neb. and Nev. May-July. 



4. Pentstemon albidus Nutt. WHITE-FLOWERED BEARD-TONGUE. (I. F. f. 

 3250.) Stem puberulent below, densely glandular-pubescent above, 1.5-2.5 dm. 

 high. Basal and lower leave? spatulate or oblong, obtusish, mostly entire, the up- 

 per lanceolate or oblong, sessile, denticulate, acute or acuminate, 3-7 cm. long; 

 thyrsus narrow, raceme-like, leafy-bracted, interrupted; calyx-segments lanceo- 

 late, acuminate, viscid, one-half as long as the corolla-tube; corolla white or nearly 

 so, 1.5-2 cm. long, the limb nearly equally 5-lobed, the lobes spreading. On dry 

 plains, S. Dak to Co'o., Neb. and Tex. June- Aug. 



