806 MISC. PUBLICATION 4 2 3, U. S. DEPT. OF AGRICULTURE 



8. PENSTEMON. Beardtongue 

 Contributed by Davjd D. Keck 



Perennial herbs or shrubs; leaves opposite, the upper ones sessile; 

 flowers showy, paniculate; calyx 5-parted; corolla tubular, usually 

 somewhat ventricose, 2-lipped, the upper lip 2-lobed, the lower lip 3- 

 cleft; fertile stamens 4, paired, with arching filaments; sterile filament 

 (staminode) attached to the upper side of the corolla at the junction 

 of the tube and the throat, extending downward and forward ; anthers 

 2-celled, the cells often confluent; capsule septicidal; seeds numerous, 

 angled. 



These plants mostly flower in spring or early summer and are often 

 very showy. One may expect them in light, dry, neutral soils in 

 eroded or mountainous regions throughout the State and at all 

 elevations, although few species are found on the deserts. Some use 

 has been made of them for ornamental plantings, which, on account 

 of the wide range of growth habits and colors available, offer greater 

 opportunities than have been realized thus far. Otherwise, the species 

 are of insignificant economic importance, although many of them are 

 browsed, especially the shrubby, evergreen P. microphyllus . The 

 name of the genus is usually spelled Pentstemon. 



Key to the species 



1. Corolla scarlet, carmine, yellow, or (in P. parryi) rose magenta (2). 



2. Corolla sulphur yellow, strongly bilabiate, 10 mm. wide; fertile filaments 

 strongly pubescent at base; shrub up to 2 m. high; leaf blades less than 

 2 cm. long, usually elliptic; staminode densely long-bearded. 



1. P. MICROPHYLLUS. 



2. Corolla scarlet to carmine, rarely orange or rose; fertile filaments glabrous (3) . 



3. Calyces and pedicels obviously glandular-pubescent; corolla strongly 



'bilabiate (4). 



4. Leaves filiform, 1 mm. wide, crowded; anthers dehiscent throughout, 



explanate; plant woody below; corolla scarlet. _ 2. P. pinifolius. 



4. Leaves much wider, not crowded; anthers not explanate (5). 



5. Anther sacs broad, dehiscent from apex to base; leaves linear-attenu- 

 ate; stems more or less densely puberulent below the inflorescence, 

 entirely herbaceous; corolla orange to dull red. 



3. P. LANCEOLATUS. 



5. Anther sacs narrow, dehiscent across their contiguous apices for less 



than half their length, the lower portion saccate; leaves linear- 

 oblanceolate; stems glabrous below the inflorescence, often 

 slightly woody near the base; corolla bright red. 



4. P. BRIDGESII. 

 3. Calyces and pedicels glabrous or puberulent, at most very obscurely 

 glandular; plants strictly herbaceous (6). 



6. Corolla strongly bilabiate, the prominent lower lip reflexed, the upper 



lip projecting, scarlet; stems tall, virgate 5. P. barbatus. 



6. Corolla obscurely bilabiate, the lips about equally erect or spreading 

 (7). 

 7. Anther sacs dehiscent only part way from the free tips, not ex- 

 planate; corolla glabrous, scarlet; herbage not at all glaucous. 



6. P. EATONI. 

 7. Anther sacs dehiscent throughout and explanate (8). 



8. Corolla glabrous throughout, narrowly tubular, the limb very 

 narrow, scarlet; herbage green or glaucescent; cauline leaves 



linear-lanceolate 7. P. subulatus. 



8. Corolla glandular externally and internally, the limb broad and 

 flaring; herbage glaucous (9). 

 9. Glands on the corolla sessile; throat tubular; staminode 

 glabrous (rarely obsoletely bearded); corolla carmine; 

 cauline leaves lance-oblong; northern Arizona. 



8. P. UTAHENSIS, 



