334 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Corolla 15 to 18 mm. long, violet-blue or blue, the throat more inflated; 
sepals 3 to 4 mm. long, with narrow, nearly entire, scarious margin; 
stem leaves frequently dentate; thyrsus lax; plants deeper green. 
. 63. P. virens. 
Corolla 8 to 12 mm. long; stem uniformly puberulent. 
Plants greenish, minutely puberulent, 10 to 30 cm. tall; basal leaves ovate 
to broadly oval; stem leaves mostly oblong-lanceolate to oval-ovate; 
sepals lanceolate, two-thirds to three-fourths the length of the capsule. 
Trailing subaerial rhizome-like stems much developed; blades of basal 
leaves ovate to broadly ovate, acute, 1.5 to 2.5 cm. long, 1 to 2 cm. 
wide; stem leaves mostly oval-ovate............ 64. P. brevifolius. 
Trailing subaerial rhizome-like stems little developed; blades of basal 
leaves broadly ovate, obtuse (to acutish), 2 to 3 cm. long, 1.5 to 2.2 
cm. wide; stem leaves mostly oblong-lanceolate..65. P. obtusifolius. 
Plants grayish, evidently puberulent throughout, 20 to 40 cm. tall; basal 
leaves lanceolate to narrowly ovate; stem leaves lanceolate; sepals 
triangular to ovate-acuminate, about one-half the length of the cap- 
BUle... 2... eee ce eee eee eee cece 66. P. humilis. 
Corolla pale blue, decidedly paler anteriorly, the throat strongly ridged within 
anteriorly and abruptly and slightly inflated posteriorly, the posterior lobes 
projecting, spreading only at the apex, somewhat exceeded by the anterior 
ones; plants strictly erect. 
Plant grayish-puberulent throughout. Rootstock slender, much branched 
and densely matted. Leaves entire.................. 67. P. radicosus. 
Plants green, minutely puberulent or glabrous; rootstock stout, less branched 
and not matted. 
Leaves entire; blades of basal leaves mostly 2 to 3 cm. long, those of the 
cauline ones lanceolate-linear and mostly shorter than the internodes; 
thyrsus lax, the lower peduncles ascending, mostly 2 to 4 cm. long, 
the pedicels over 5 mm. long.................... 68. P. oliganthus. 
Leaves denticulate; blades of basal leaves mostly 3 to 5 cm. long, those of 
the cauline ones narrowly lanceolate and mostly longer than the inter- 
nodes; thyrsus more strict, the lower peduncles erect, rarely 2 cm. 
long, the pedicels shorter.......-..........222-200-. 69. P. gracilis. 
Corolla violet, the throat 5 to 6 mm. wide; capsule ovate, 8 to 9 mm. long; plants 
spreading in tufts, 10 cm. tall; thyrsus of few usually 1-flowered fascicles. 
70. P. harbourii. 
XV. CAESPITOSI.! 
Leaves linear-lanceolate to obovate. 
Leaves cinereous-whitened; plants little spreading. 
Stems 15 to 20 cm. tall; calyx lobes not scarious, acutish, 3 to 5 mm. long; corolla 
16 to 20 mm. long, the anterior lobes decidedly exceeding the posterior ones. 
71. P. retrorsus, 
Stems rarely 10 cm. tall; calyx lobes scarious-margined below, acuminate, den- 
tate, 5 to 8 mm. long; corolla 15 to 17 mm. long, the anterior lobes scarcely 
exceeding the posterior ones.................2....-- 72. P. thompsoniae, 
Leaves light green; plants widely spreading, forming mats. 
Corolla 20 to 25 mm. long, with broad tube, more deeply 2-lipped. Anterior 
corolla lip 5 to 7 mm. long.... .........2.22......20200- 73. P. crandallii. 
1 Limitation of species of this group difficult and unsatisfactory. They need much 
more field study. 
