Penstemon 



SCROPHULARIACEAE 



839 



5o 



Map 1820 



Chelone glabra L, van typica 



50 



Map 1821 



Chelone glabra var. Iinifolia Coleman 



50 



Map 1822 



Penstemon tubaeflorus Nutt. 



7508. PENSTEMON Mitchell Penstemon 



[Key adapted from Pennell's Monograph, loc. cit.] 



Corolla glandular-puberulent within on all sides, the throat slightly inflated, obscurely 

 or not at all ridged within, white throughout, 20-25 mm long, the lobes strongly 



spreading; sepals 3-4 mm long, triangular-ovate, acuminate 1. P. tubaeflorus. 



Corolla pubescent with glandless hairs within over the bases of the anterior lobes, the 

 throat more inflated and plainly ridged within. 

 Throat of corolla much inflated and only slightly ridged within anteriorly, the 

 anterior lobes of the corolla little exceeding the posterior ones; sterile filament 

 slightly to moderately bearded. 

 Corollas purplish (rarely only faintly so), (15) 20-35 mm long, the throat 

 moderately inflated; sepals linear-attenuate, 5-12 mm long, usually con- 

 spicuously widely spreading in flower, generally the margins not plainly 

 scarious; anthers never bearded; cauline leaves widely lanceolate to ovate; 



inflorescence sparingly glandular 2. P. calycosus. 



Corollas white or faintly tinged with purple, 13-30 mm long, the throat amply 

 inflated; sepals ovate or ovate with acuminate tips, 3-9 mm long (con- 

 spicuously scarious and caudate-tipped in Penstemon Digitalis) ; anthers usually 

 bearded with a few, stiff, white hairs on the dorsal part (hairs not to be con- 

 fused with the teeth of the sutures). 

 Corollas 20-30 mm long; inflorescence decidedly glandular; sepals in anthesis 5-8 

 mm long, caudate-acuminate, plainly scarious-margined; stem somewhat 

 shining, glabrous, and slightly glaucous; usually found along roadsides, in 



pastures, and fallow fields, and rarely in woodland 3. P. Digitalis. 



Corollas mostly 13-23 mm long; inflorescence in anthesis glabrous or slightly 

 glandular; stems dull, finely pubescent or glabrous; sepals in anthesis 2-5 

 mm long. 

 Sepals becoming 5-9 mm long at maturity, more than half the length of 

 the capsule, oval with caudate tips, not at all or only scarcely scarious- 

 margined; corollas 17-23 mm long; lower blades lanceolate, acuminate, 



rather sharply serrate, the basal ones usually few at anthesis 



4. P. alluviorum. 



Sepals only 2-4 mm long at maturity, less than half the length of the capsule, 

 ovate or somewhat acuminate, plainly scarious-margined; corollas 15-20 

 (22) mm long; lower blades oblong or oval, rounded, entire or slightly 

 denticulate, the basal ones usually many at anthesis 5. P. Deamii. 



