722 SCROPHULARIACEAE (FIGWORT FAMILY) 



1. P. hirsutus (L.) Willd. Stem 2-9 dm. high, covered with fine and often 

 crowded spreading whitish mostly gland-tipped hairs ; leaves oblong to lanceo- 

 late, 5-10 cm. long, the lowest and radical ovate or oblong, usually denticulate ; 

 thyrse rather slender ; corolla dull violet or purple (or partly whitish), scarcely 

 enlarged upward, the throat nearly closed by a villous palate ; sterile filament 

 densely bearded. (P. pubescens Ait.) Dry or rocky grounds, centr. Me. to 

 Ga., westw. to Wise, and Mo. May-July. 



2. P. gracilis Nutt. Stem 2-4 dm. high, minutely granular-pubescent; 

 stem-leaves mostly linear-lanceolate, the radical spatulate or oblong ; inflores- 

 cence glandular-puberulent ; corolla tubular-funnel-form or nearly cylindrical 

 with open throat, lilac-purple or whitish. Man. and Minn, to Mo., Okla., and 

 westw. MayJuly. 



3. P. Cobaea Nutt. Soft-puberulent, 3-6 dm. high ; leaves ovate or oblong, 

 or the lower broadly lanceolate and the upper cordate-clasping, mostly sharp- 

 toothed ; thyrse short; corolla large (3.5-5 cm. long), strongly ventricose, dull 

 purple or whitish. Prairies, Mo. and Kan. to Tex.; reported from n. O. 

 (Hacker). May, June. 



4. P. canSscens Britton. Stem erect or somewhat decumbent, 3-7 dm. high, 

 mostly simple to the inflorescence, minutely granular-puberulent ; leaves oblong 

 to lance-linear, the upper cordate-clasping, sometimes a little panduriform ; 

 inflorescence loosely paniculate, glandular-puberulent ; corolla about 2.5 cm. 

 long, pale purplish or nearly white, with distinct proper tube, dilated somewhat 

 ventricose throat, and ringent limb. (Including P. pallidus Small, at least in 

 part.) Rocky banks, w. Va. to Mo. and Ga. May, June. 



5. P. albidus Nutt. Stems several from a branched caudex, erect or nearly 

 so, 2-4 dm. high, closely puberulent ; leaves lance-oblong to linear ; thyrse strict, 

 raceme-like; calyx densely viscid-pubescent; corolla 2-2.5 cm. long, white or 

 purplish-tinged, perceptibly dilated in the throat, the limb of ample roundish 

 widely spreading lobes. Prairies, etc., w. Minn, to Assina., south w. to Col. 

 and Tex. 



6. P. tubiflbrus Nutt. Wholly glabrous up to the glawhilar-puberulent inflo- 

 rescence ; stem 5-10 dm. high ; leaves oblong or ovate-lanceolate, entire or 

 sparingly toothed, the floral shorter than the remote dense clusters of the 

 virgate thyrse ; corolla 1.5-2 cm. long, trumpet-shaped, with gradually dilated 

 throat and widely spreading limb, white or whitish. Low prairies, barrens, etc., 

 Mo., Kan., and Ark.; also locally established in the Eastern States. May-July. 



7. P. laevigatus Ait. Stem 5-15 dm. high, glabrous to the inflorescence; 

 leaves rather firm, somewhat glossy, the cauiine ovate-oblong or lanceolate, 

 5-15 cm. long, with subcordate clasping base; thyrse rather open ; calyx-lobes 

 3-7 mm. long ; corolla 1.5-2.5 cm. long, white or tinged with purple, gradually 

 enlarged upward, the throat somewhat widely open but the limb scarcely 

 spreading; sterile filament thinly bearded above. (P. Pentstemon Britton.) 

 Moist or rich soil, Pa. to Fla., and westw.; also established in fields northw. 

 June, July. 



Var. Digitalis (Sweet) Gray. Calyx-lobes 6-10 mm. long ; corolla larger, 

 23 cm. long, more abruptly inflated. (P. Digitalis Nutt.; P. calycosus 

 Small.) Pa. to la., Mo., Ark., etc.; locally established northeastw. 



8. P. grandiflorus Nutt. Glabrous and someichat glaucous; stem 5-10 dm. 

 high ; leaves thickish, the upper and floral roundish, all but the obovate radical 

 ones clasping or perfoliate; pedicels short; corolla large (4-5 cm. long). 

 ventricose-campanulate, lilac or lavender-blue ; sterile filament hooked and 

 minutely bearded at the apex. Prairies, 111. and Wise, to Wyo. and Kan.; 

 established locally in the Eastern States. May, June. 



9. P. glaber Pursh. Glabrous; stems 3-8 dm. high; leaves mostly oblong- 

 lanceolate or the upper ovate-lanceolate ; thyrse elongated, the peduncles and 

 pedicels very short; corolla 2.4-3.7 cm. long, bright blue to violet-purple, 

 dilated above; anthers and apex of the sterile filament glabrous or sparsely 

 hirsute. Plains of e. Neb. and s. Dak. to Wash, and N. Mex. June-Aug. 



10. P. acuminatus Dougl. Glabrous, erect or ascending, 3 dm. high ; leave* 

 thickish, firm, very smooth and somewhat glaucous, ovate-lanceolate to narrowly 



