182 



SCROPHULARIACEAE. 



VOL. III. 



9. PENTSTEMON Mitchell; Solancl. in Ait. Hort. Kew. 3: 511. 1789. 



Perennial herbs, mostly branched from the base only, with opposite or rarely verticillate 

 leaves, or the upper occasionally alternate, and large, usually showy, blue purple red or white 

 flowers, m terminal thyrses, panicles, or racemes. Calyx 5-parted, the segments imbricated. 

 Corolla irregular, the tube elongated, more or less enlarged above, the limb 2-lipped; upper 

 lip 2-lobed; lower lop 3-lobed. Stamens 5, included, 4 of them antheriferous and didy- 

 namous, the fifth sterile, as long as or shorter than the others; anther-sacs divergent or 

 connivent. Style filiform; stigma capitate. Capsule ovoid, o"blong, or globose, septicidally 

 dehiscent. Seeds numerous, angled or even, wingless. [Greek, five stamens.] 



About 100 species, natives of North America and Mexico. Type species: Pentstemon pubcs- 

 cens Soland. 



* More or less pubescent or glandular, at least the calyx and pedicels. 



Corolla r /2 r -i l /4' long; leaves entire, serrate, or denticulate. 

 Stem pubescent or puberulent nearly or quite to the base. 

 Thyrsus open, panicle-like. 



Corolla large, over 10" long; stem hirsute or canescent, often glandular. 



Corolla densely bearded in the throat ; outer calyx-segments ovate or ovate-lanceolate. 



i. P. hirsutus. 



Corolla scarcely bearded in the throat ; outer calyx-segments lanceolate or linear- 

 lanceolate. 2. P. canescens. 

 Corolla small, less than 10" long; stem puberulent. 3. P. pallidus. 

 Thyrsus narrow, raceme-like or spike-like. 



Corolla-tube abruptly enlarged ; sterile filament densely woolly. 4. P. erianthera. 



Corolla-tube gradually enlarged; sterile filament slightly bearded. 5. P. albidus. 



Only the inflorescence, or pedicels, or calyx pubescent. 

 Thyrsus open, panicle-like. 



Stem leaves oblong, ovate, or lanceolate. 



Calyx-lobes lanceolate to ovate, much less than 5" long. 



Corolla purplish ; tube not gibbous above the point of enlargement. 



6. P. Pentstemon. 

 Corolla white or pinkish ; tube gibbous above the point of enlargement. 



7. P. Digitalis. 

 Calyx-lobes linear-subulate from a narrowly lanceolate base, becoming fully 5" long. 



8. P. calycosus. 

 Stem leaves linear-lanceolate. 9- P- gracilis. 



Thyrsus narrow, interrupted; calyx viscid. 10. P. tubiflorus. 



Corolla 2' long, the tube much enlarged above; leaves dentate. n. P. Cobaea. 



** Completely glabrous throughout, mostly glaucous. ' 



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

 Stem leaves rounded, clasping ; flowers 2' long. 

 Stem leaves acute or acuminate; flowers g"-is" long. 

 Corolla 9"-io" long; stem leaves lanceolate. 

 Corolla i'-i l /i' long; stem leaves mostly oblong. 

 Leaves linear or linear-lanceolate ; flowers densely thyrsoid. 

 Bracts lanceolate, small ; flowers 6"-8" long. 

 Bracts ovate, acuminate, large; flowers i' long .or more. 



12. P. grandiftorus. 



13. P. acuniinatus. 



14. P. glaber. 



15. P. angustifolius. 



16. P. Haydeni. 



i. Pentstemon hirsutus (L.) Willd. 

 Hairy Beard-tongue. Fig. 3755. 



Chelone hirsuta L. Sp. PI. 611. I7S3- 



P. pubescens Soland. in Ait. Hort. Kew. 3 : 360. 1789. 



Pentstemon hirsutus Willd. Sp. PI. 3: 227. 1801. 



Stem slender, erect, downy nearly or quite to 

 the base, i-3 high. Leaves puberulent or gla- 

 brous, denticulate or the uppermost entire,^ the 

 basal oblong or ovate, obtusish at the apex, ?.'-$.' 

 long, J'-2' wide, narrowed into petioles, the up- 

 per sessile, lanceolate, mostly acuminate, sessile 

 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 

 i' long, the throat nearly closed by the villous 

 palate at the base of the lower lip; sterile fila- 

 ment densely bearded for about one-half its 

 length. 



In dry woods and thickets, Maine to Ontario, 

 Florida, Minnesota, Alabama and Missouri. Er- 

 roneously recorded from Texas. May-July. 



