92 SYNOPSIS OF THE FLORA OF COLORADO. 



cles, 6"-12" long ; flowers purple or occasionally nearly white ; anthers 

 glabrous except along the dehiscence. Colorado, Parry. 



PENTSTEMON C^ERULEUS, Nutt. Gr. Rev. 1. c., p. 61. (P. angustifolim, 

 Nutt.) A span high ; glabrous or the upper stem and leaves usually min- 

 utely pubescent ; leaves linear-lanceolate, thick, entire, sessile, erect, 

 crowded; sepals lanceolate, gradually acuminate, often ciliolate on the 

 margins, white-membranaceous; corolla 6" long, somewhat dilated, 

 scarcely 2-lipped, bright azure or purplish-blue ; anthers glabrous, often 

 with short- ciliate margins; sterile filament, usually dilated and yellow- 

 bearded at the apex. Foot-hills near Denver, Coulter. 



PENTSTEMON ACUMINATUS, Dougl. Gr. Rev. 1. c., p. 61. Glabrous and 

 glaucous, 6'-18' high ; radical leaves spatulate, cauline lanceolate, oblong 

 or ovate-lanceolate, or the upper ones subcordate, rigid, glaucous ; thyr- 

 sus elongated, many-flowered, often secund ; sepals either ovate or lan- 

 ceolate, acute or acuminate; corolla Q"-W long, blue or purple, tube 

 gradually dilated upward, lobes rounded, flat, spreading; capsule very 

 sharply acuminate. Hall & Harbour, 386; Parry. Near Denver, Dr. 

 Smith. Colorado Springs, Porter. B. H. Smith. Monument Park and 

 Clear Creek Canon, Coulter. 



PENTSTEMON SECUNDIFLORUS, Benth. DC. Prod, 10, p. 325. Glabrous, 

 pale, and somewhat glaucous, 12'-30' high; radical leaves petioled, ellip- 

 tic-spatulate or narrowly -lanceolate, obtuse or acute, upper ones lanceo- 

 late or linear-lanceolate, sessile, middle ones 3'-4' long, erect ; thyrsus 

 elongated, narrow, 6'-9' long, interrupted; cymes secund, few-many- 

 flowered; segments of the calyx oval-oblong, acute oracutish, with mem- 

 branous margins ; tube of the corolla more or less abruptly ampliated 

 below the middle; anthers glabrous or very minutely puberulent; 

 sterile filament dilated at the apex, not bearded, (bearded, Benth.) This 

 species is merged by Dr. Gray into the preceding one, Rev. Pentst.,p. 62, 

 but it seems to maintain its distinctive characters well. It is extremely 

 abundant on the plains and at lower elevations in the mountains. Canon 

 City, Brandegee. Denver, Dr. Smith. Georgetown, B. H. Smith. Colo- 

 rado Springs, Porter. Monument Park, Canby. 



PENTSTEMON AMBIGUUS, Torr. Gr. Rev. 1. c., p. 64. Glabrous, l-2 

 high, paniculately branching from a ligneous base ; lower leaves linear, 

 attenuated at base ; upper ones subulate-filiform or acerose-subulate ; 

 racemes loosely-flowered ; corolla 5"-8" long, tube 6", often incurved, 

 scarcely dilated above, with the spreading limb, 6" in diameter ; sterile 

 filament glabrous. Southeastern Colorado, F. R. Diffenderffer. 



PENTSTEMON C^ESPITOSUS, Nutt. Gr. Rev. 1. c., p. 66. Grayish puberu- 

 lent, depressed, branching from the base ; branches crowded, short, 2 / -6 / 

 long, decumbent or ascending, very leafy to the apex ; leaves 3"-12" 

 long, lanceolate or linear-spatulate, acute or submucronate, veiiiless, en- 

 tire ; peduncles axillary, short, secund, at length de-curved, spread- 

 ing, with 2 leafy bracts at the apex and 1-3 flowers ascending on short 

 pedicels ; sepals linear-lanceolate, rather broader and scarious-marglned 

 at the base ; corolla 6 /x -9 7/ long, bluish-purple, tubular, somewhat dilated 

 above and biplicate; limb shortly bilabiate, with nearly equal lobes; 

 sterile filament long-bearded. Middle elevations. Hall d; Harbour, 393; 

 Middle Park, Parry. South Park, Porter. Taylor River, Coulter. Canon 

 City, Brandegee. Canby. 



PENTSTEMON ALBIDTJS, Nutt. Gen. 2, p. 53. Stem puberulent, 6'-9' 

 high; lower leaves petioled, oblong, obtuse, subentire, upper serrate, 

 lanceolate, glabrous or puberuleut; thyrsus oblong, subverticillately- 



