Spring Flora of Oklahoma 
163 
Stem leaves oblong, ovate, or lanceolate. 
Stem leaves linear-lanceolate. 3. P. gracilis. 
Corolla 2' long, the tube much enlarged above; leaves 
dentate. 4. P. Cobaea. 
Completely glabrous throughout, mostly glaucous. 
Stem leaves rounded, clasping; flowers 2' long. 
5. P. grandifloras. 
Stem leaves acute or acuminate; flowers 9"-15" long. 
6. P. acuminatus. 
1. Pentstemoni hirsutus (L.) Willd. Hairy Beard-tongue. 
Stem somewhat downy, l°-2° high. Leaves varying from oblong to 
lanceolate, 2'-4' long, usually with small teeth. Inflorescence thyr- 
soid, glandular pubescent. Corolla purplish or violet, the tube grad¬ 
ually dilated above, about 1' long, the throat nearly closed by the 
villous palate at the base of the lower lip. Sterile filament densely 
bearded for about one-half its length. 
In dry woods and thickets. May-July. 
2. Pentstemon Digitalis (Sweet) Nutt. Foxglove Beard- 
tongue. Glabrous except the glandular inflorescence. Lower and 
basal leaves oblong or oval, entire or repand, 2'-7' long. Upper 
leaves ovate, lanceolate, sharply denticulate. Thyrsus many-flow¬ 
ered. Corolla white, long, the tube abruptly dilated, the 
limb moderately 2-lipped, the throat open. Sterile filament bearded 
above. 
In fields and thickets. May-July. 
3. Pentstemon gracilis Nutt. Slender Beard-Tongue. Glabrous 
to the glandular-pubescent inflorescence. Stem 6'-18' high. Basal 
and lower leaves linear-oblong or spatulate, denticulate or entire, 
l'-3' long, narrowed into margined petioles. Upper leaves sessile, 
linear-lanceolate, denticulate, acuminate. Thyrsus several many- 
flowered. Corolla purple, 9"-12’" long, its tube gradually enlarged 
above. Sterile filament bearded for about one-half its length. Cap¬ 
sule one-third longer than the calyx. 
On moist prairies. May-July. Frequent. 
4. Pentstemen Cobaea Nutt. Cobaea Beard-tongue. Stem 
densely and finely pubescent below, glandular-pubescent above, l°-2° 
high. Leaves oblong to ovate, 3^-5' long, dentate, the lower glab¬ 
rous and narrowed into margined petioles, upper sessile or cordate- 
clasping, usually pubescent. Thyrsus several-many-flowered. Flow¬ 
ers about 2' long. Corolla purple, its tube narrowed up to the 
top of the calyx, then abruptly dilated and campanulate, the limb 
