

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



21. Staminode bearded only at and near the apex with relatively short 

 coarse deep-yellow hairs, dilated apically (22). 

 22. Corolla pinkish lavender, glabrous throughout; calyx lobes 

 acuminate, scarious-margined only at base; cauline leaves 



acuminate 21. P. angustifolius. 



22. Corolla bright blue, slightly pilose at the orifice; calyx lobes 

 acute to short-acuminate, scarious-margined nearly to the 

 apex; cauline leaves obtuse or rounded, mucronate. 



22. P. LENTUS. 

 18. Herbage green or, if pubescent, then often grayish (more or less glauces- 

 cent in P. comarrhenus) ; leaves mostly thin, relatively narrow (23). 

 23. Throat of the corolla 2-ridged within ventrally, the ridges densely 

 hairy about the orifice; corolla relatively narrow (24). 

 24. Plants strongly cespitose, not more than 10 cm. high, cinereous- 

 puberulent; leaves up to 2 cm. long, mucronate; corolla narrowly 

 funnelform, lavender purple (25). 

 25. Stems scarcely creeping; leaves cinereous-whitened with closely 

 appressed hairs, oblanceolate, spatulate-oblong, or obovate; 

 herbage of the inflorescence very obscurely viscid. 



23. P. THOMPSONIAE. 



25. Stems widely creeping; leaves greenish with spreading hairs, in 



Arizona linear-oblanceolate to lance-obovate, smaller; herbage 

 of the inflorescence more obviously viscid. 



24. P. CAESPITOSUS. 



24. Plants not cespitose, more than 10 cm. high, not cinereous; leaves 

 (at least the basal ones) more than 2 cm. long, not mucronate (26) . 



26. Calyx and corolla glandular-puberulent, the latter pale blue, 



much paler on the strongly 2-ridged ventral portion, the lower 



lip exceeding the upper lip 25. P. oliganthus. 



26. Calyx and corolla essentially glabrous, the latter moderately 2- 

 ridged ventrally, the upper and lower lips subequal (27). 

 27. Leaves and calyx lobes prominently white-margined, thick; 

 inflorescence conspicuously leafy; corolla pinkish, moderately 



ampliate; staminode glabrous 26. P. albomarginatus. 



27. Leaves not prominently white-margined, thin; calyx lobes more 



or less hyaline-margined; inflorescence scarcely leafy; corolla 



blue purple, tubular; staminode densely bearded (28). 



28. Stems terminating rootstocks, arising from a basal rosette of 



leaves; verticillasters dense, the peduncles and pedicels 



obscure; calyx lobes oblong, caudate-tipped, rather 



prominently erose, 3.5 to 5.5 mm. long; corolla densely 



golden-bearded at the palate 27. P. rydbergii. 



28. Stems densely tufted from a subligneous caudex, leafy 

 throughout but with no definite rosette at base; verticil- 

 lasters looser, the peduncles and pedicels more obvious; 

 calyx lobes ovate or obovate to rotund, very short-tipped, 

 slightly erose, 2 to 3.5 mm. long; corolla lightly white- 

 bearded at the palate 28. P. watsoni. 



23. Throat of the corolla rounded ventrally, lightly if at all hairy at the 

 orifice (29). 

 29. Plants shrubby or decidedly suffrutescent (sometimes nearly herbace- 

 ous in P. linarioides) ; leaves crowded, narrowly linear, mucronate 

 (30). 

 30. Staminode bearded; corolla viscid-puberulent externally, the 

 limb moderately expanded (31). 

 31. Corolla 14 to 24 mm. long, blue purple; leaves 8 to 20 (or 30) mm. 

 long, not fleshy, grayish or greenish on both faces. 



29. P. LINARIOIDES. 



31. Corolla 10 mm. long, white tinged with lavender; leaves 5 to 8 



(or 10) mm. long, fleshy, white-puberulent on the flat upper 

 face, deep green and glabrous on the rounded lower face. 



30. P. DISCOLOR. 

 30. Staminode glabrous; corolla glabrous externally, the limb much 

 expanded (32). 



32. Corolla blue purple (rarely pinkish) throughout, funnelform, 10 



to 12 mm. long, the limb pubescent only at base of the lower 

 lip, scarcely oblique, the throat not curved but ventricose; 

 stamens exserted 31. P. thurberi. 



