800 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



A large and diverse family, comprising many plants that are culti- 

 vated as ornamentals. The plants are mostly innocuous, but the Old 

 World foxglove (Digitalis purpurea L.), often grown in the United 

 States as an ornamental, is the source of the drug digitalis, a powerful 

 cardiac stimulant. 



Key to the genera 



1. Anther-bearing stamens 5; corolla nearly regular, rotate, yellow. 



1. Verbascum. 



1. Anther-bearing stamens 4 or 2 (rarely 5 in genus Penstemon) ; corolla usually 



distinctly irregular and bilabiate (2). 



2. Corolla spurred, saccate, or gibbous on the lower side at base, mostly with 



a prominent palate in the throat; capsules not valvate, opening by 



pores near the apex, or bursting irregularly; leaves mostly alternate (3). 



3. Perfect stamens 2 3. Mohave a. 



3. Perfect stamens 4 (4) . 



4. Leaf blades broad, triangular-hastate, or reniform and deeply lobed. 



5. Maurandya. 

 4. Leaf blades ovate to linear, entire (5). 



5. Corolla tube with a narrow spur at base 2. Linaria. 



5. Corolla tube merely gibbous or saccate at base__ 4. Antirrhinum. 

 2. Corolla not spurred or saccate at base, without a prominent palate, some- 

 times with ridges on the lower side of the throat; capsules opening by 

 valves (6). 

 6. Upper lip of the strongly bilabiate corolla helmet-shaped, keeled, or deeply 

 concave, erect; stamens 4 or 2 (7). 

 7. Anther cells equal, parallel, approximate; stamens 4 (8). 



8. Leaves opposite; calyx 4-toothed, becoming bladderlike and veiny, 

 completely enclosing the fruit and not filled by it. 



23. Rhinanthus. 



8. Leaves mostly alternate or basal; calyx cleft on one or both sides, 



becoming distended, but not bladderlike or completely enclosing 



the fruit 24. Pedicularis. 



7. Anther cells unequal, separated, the outer one versatile, the inner one 

 pendulous by its apex and mostly smaller, sometimes sterile or 

 rudimentary; leaves alternate, commonly (at least the upper ones) 

 more or less dissected (9). 



9. Calyx mostly spathelike, 1 -lobed (sometimes appearing 2-lobed when 



the opposite bract is similar) ; floral bracts and calyx not highly 

 colored, sometimes dull purple; stamens 4 or 2. 



21. CORDYLANTHUS. 



9. Calyx gamosepalous, tubular or tubular-campanulate; floral bracts 



and calvx (at least their tips) often brightly colored; stamens 4 



(10). 



10. Upper corolla lip (galea) very much longer than the small, 3- 



toothed or 3-keeled lower lip; calyx tubular, cleft above and 



below, the lips usually toothed or cleft; plants mostly perennial. 



20. Castilleja. 

 10. Upper corolla lip not, or not greatly, surpassing the inflated, sac- 

 cate lower lip; calyx tubular-campanulate, equally 4-cleft, or 

 cleft on one or both sides and the lips cleft or parted; plants 



annual 22. Orthocarptjs. 



6. Upper lip of the corolla not helmet-shaped, keeled, or deeply concave (11). 

 11. Stamens 5, of these 4 anther-bearing and the fifth sterile; leaves oppo- 

 site; corolla moderately to stronglv bilabiate (12). 

 12. Plant a small annual; corolla with the midlobe of the lower lip deeply 

 concave and enclosing the stamens; sterile stamen represented 

 by a minute glandlike body near the base of the corolla tube. 



6. Collinsia. 



12. Plants perennial; lower lip of the corolla not with a concave lobe 



enclosing the stamens (13). 



13. Sterile stamen represented by a scale, this partly adnate to the 



upper side of the corolla throat; corolla somewhat urceolate, 



broad and open, with little distinction of tube and throat. 



7. SCROPHULARIA. 



