734 SCROPHULARIACEAE 



sule septicidal, cartilaginous. Seeds numerous, with irregularly angled cellular coat. 

 [Greek, meaning five and stamen, the fifth and sterile filament being strongly developed.] 



A genus of some 230 species, most plentiful in the western United States, but extending from, Alaska to 

 Guatemala, with one species in Kamtchatka and northern Japan. Type species Penstemon laevigatus Sol. 

 Chromosome numbers, determined or verified by the contributor, are given when known. 



Filaments glabrous at base or, at most, two of them puberulent. 



Anthers glabrous or sparingly hairy, not comose; corolla rounded dorsally. 



Orifice of corolla more or less open, revealing the stamens, bearded only ventrally within or glabrous; 

 staminode at least half the length of the corolla. 

 Anther-sacs opening from the free tips throughout or partially, after dehiscence almost always 

 becoming divaricate. Subgenus I. Eupenstemon. 



Seeds 0.5-1. 5 mm. long (sometimes longer in subsections Gairdnerani, Deusti, and Arenarii); 

 corolla somewhat compressed dorso-ventrally, 2-ridged on floor of throat, tubular or 

 only moderately ampliate, never red; anther-sacs widely divaricate and glabrous (occa- 

 sionally denticulate along the suture). 

 Stems erect or slightly decumbent at base; leaves ample^ not densely crowded; inflores- 

 cence an interrupted strict dense thyrsus, or sometimes more openly paniculate. 



Section 1. Spehmunculus. 



Stems low, generally tufted at base, often repent; leaves filiform to broadly linear, when 

 wider less than 3 cm. long, densely crowded; inflorescence a narrow leafy racemi- 

 form thyrsus. Section 2. Ericopsis. 



Seeds l.S-S mm. long; corolla-throat rounded, scarcely if at all 2-ridged ventrally, tubular 

 to strongly dilated. 

 Staminode densely bearded with prominent golden hairs; herbage in ours densely cinereous- 

 puberuient or canescent, the inflorescence glandular-pubescent; short-lived few- 

 stemmed perennials from a taproot. Section 3. Aurator. 



Staminode glabrous or, if bearded, the beard not prominently golden; herbage in ours 

 essentially glabrous below, the inflorescence glabrous or glandular-pubescent. 



Corolla blue or purple to carmine, rose, or white, if scarlet, the anthers peltately 



explanate. 



Leaves not glaucous or thick, always entire, reduced above to lanceolate bracts; 



corolla obviously bilabiate, the limb not rotately spreading, the throat 



ample, blue-purple, glabrous; inflorescence secund; anther-sacs in ours not 



dehiscent throughout nor explanate, hairy or glabrous. 



Section 4. Habroanthus. 



Leaves more or less glaucous and fleshy; inflorescence not secund; anther-sacs 

 never hairy. 



Inflorescence congested, leafy, the bracts in ours cordate; corolla subregular, 

 the short limb rotately spreading, light blue-purple, glabrous; anther- 

 sacs boat-shaped. Section 5. Anularius. 



Inflorescence more open, the bracts various; corolla commonly glandular- 

 pubescent externally, shape and color various; anther-sacs mostly 

 peltately explanate. Section 6. Peltanthera. 



Corolla scarlet; anther-sacs opening by a slit, never peltately explanate. 



Section 7. Elmigera. 



Anther-sacs opening across their contiguous apices, the free tips remaining saccate, parallel even 

 after dehiscence, glabrous or somewhat hairy. Subgenus II. Saccanthera. 



Corolla bluish or purplish, usually ampliate; limb relatively short, with both lips more or less 

 spreading. Section 8. Eusaccanthera. 



Corolla scarlet-red, tubular; limb relatively long, the upper lip erect, the lower lip sharply 

 reflexed. Section 9. Emersus. 



Orifice of corolla closed, concealing the stamens, bearded on all sides within; staminode barely one- 

 fifth the length of the corolla. Subgenus III. Cryptostemon. 



Anthers densely comose, the cells peltately explanate; corolla strongly 2-ridged on floor of throat and 

 prominently keeled dorsally. 

 Low, often decumbent plants, considerably woody; leaves coriaceous; inflorescence subracemose; corolla 

 externally glabrous. Subgenus IV. Dasanthera. 



Tall, erect plants, herbaceous quite to the base; leaves thin; inflorescence openly paniculate; corolla 

 externally glandular. Subgenus V. Nothochelone, 



Filaments all strongly pubescent at base; corolla strongly bilabiate, the upper lip subgaleate, lower lip reflexed; 

 shrubs. Subgenus VI. Hesperothamnus. 



Subgenus I. Eupenstemon. 

 Section 1. Spermunculus. 



Plants with aerial more or less suffrutescent or woody caudex. 

 Suflrutescent or herbaceous at base; staminode bearded. 



Leaves all opposite, linear-lanceolate to broadly ovate, flat or folded but never revolute. 



Leaves very entire (sometimes toothed in P. attenuatus and P. Vaseyarnii) ; inflorescence of com- 

 pact many- flowered verticillasters, glabrous or glandular; corolla not paler within, usually 

 obscurely bilabiate. Subsection o. Proceri. 



Leaves more or less serrate or toothed at least some of the time; inflorescence of rather loose 

 verticillasters, or the cymules few-flowered, always glandular-pubescent; corolla paler within 

 throat, usually obviously bilabiate. Subsection b. Humiles. 



Leaves alternate or .opposite, linear, entire, revolute; suffrutescent; inflorescence glandular; corolla not 

 villous nor ridged but glabrous or glandular within; anther-sacs not explanate. 



Subsection c. Gairdnerani. 



Shrubby, caudex obviously woody at base; leaves serrate, coriaceous; inflorescence glandular; corolla often 

 glandular within, narrowly tubular, whitish or yellowish; anther-sacs broadly ovate, explanate; 

 staminode glabrous or sparsely bearded. Subsection d. Deusti. 



Plants with buried caudex, fibrous rootstocks, and no rosette; inflorescence leafy; anther-sacs broadly ovate, 

 explanate; plants of desert sand dunes. Subsection e. Arenarii. 



