664 GENTIANACEAE 



spreading; corolla blue, about 4 cm. long, open-f unnelf orm ; lobes obovate, obtuse 

 or acute; lobes of the plaits 2-cleft, often laciniate, half as long as the corolla-lobes. 

 G. puberula Michx. Prairies: Ohio Ga. Kans. Sask. Plain. 



7. PLEUROGYNE Eschsch. MARSH FELWORT. 



Low slender annuals. Leaves opposite, entire. Flowers perfect. Calyx 

 deeply 4- or 5-cleft. Corolla rotate, 4- or 5-cleft, its divisions acute, with a pair 

 of scale-like appendages on their base. Stamens inserted on the base of the 

 corolla; anthers introrse, versatile. Style none; stigmas decurrent on the sutures; 

 ovary 1-celled. Capsule lanceolate or oblong, not stipitate. Seeds numerous. 



1. P. fontana A. Nels. Glabrous annual, 1-4 dm. high, with erect branches; 

 leaves linear, thin, with strong midrib and faint lateral ribs, 2-2.5 cm. long; 

 flowers in narrow racemes or panicles, pentamerous; sepals linear, 3-nerved; 

 corolla whitish, about 12 mm. long, often slightly shorter than the sepals; lobes 

 oblong, acute. P. rotata tenuifolia Griseb. Bogs in the mountains: Alta. 

 Colo. Mont. Subalp. Jl-Au. 



8. SWERTIA L. 



Simple-stemmed, caulescent perennials. Leaves opposite or some alternate. 

 Flowers perfect, blue or rarely white, in a thyrsoid inflorescence. Calyx 4- or 

 5-parted. Corolla rotate, usually 5-parted, each division bearing a pair of nectar- 

 iferous pits; lobes convolute in the buds. Stamens inserted on the base of the 

 corolla. Style very short or none; stigma 2-lobed; ovary 1-celled; capsule ovate; 

 placentae not intruded. Seeds large, flat, commonly margined. 



Inflorescence elongate; corolla-lobes linear or oblong. 



Leaves with 3-5 parallel ribs from the base. 1. S. parallela. 



Leaves not parallel-ribbed. 



Petals not spotted; basal leaf-blades much longer than the petioles. 



2. S. scopulina. 



Petals spotted; basal leaf-blades not longer than the petioles. 3. S. Fritillaria. 

 Inflorescence congested; corolla-lobes oval-elliptic. 4. S. congesta. 



1. S. parallela Greene. Stem about 3 dm. high; lower leaves 10-15 cm. 

 long, oblong-oblanceolate or oblong-elliptic; upper stem-leaves oblong, sessile, 

 opposite; inflorescence narrow; corolla lurid-purple; lobes lance-oblong, obtuse, 

 about 1 cm. long; glands with rather long fringe. Mountains: Mont. Ida. 

 Mont. Jl. 



2. S. scopulina Greene. Stem 1-3 dm. high; basal leaves and lower stem- 

 leaves alternate, 10-15 cm. long, thin, oblong or elliptic to oblanceolate, obtuse, 

 pinnately-veined; upper stem-leaves opposite, elliptic or lanceolate, sessile; 

 corolla dark blue or purple; lobes linear to oblong, obtuse, about 1 cm. long; 

 glands orbicular with short, subulate appendages. S. palustris A . Nels. Moun- 

 tains, in wet places: Mont. Colo. Utah. Mont. Subalp. Jl-Au. 



3. S. Fritillaria Rydb. Stem 1.5-3 dm. high; basal leaves and lower stem- 

 leaves alternate, 6-10 cm. long, thin, obovate-spatulate, rounded at the apex; 

 middle and upper stem-leaves all alternate or a single pair of opposite ones, 

 oblanceolate or oblong; corolla-lobes lanceolate, mostly acute, greenish white 

 along the midrib and azure along the margins, all over dotted with dark blue 

 spots; glands inconspicuous, with rather long blue fringes. Wet places in canons: 

 Utah. Mont. Au. 



4. S. congesta A. Nels. Stem about 1 dm. high; basal leaves and lower 

 stem-leaves alternate, 5-10 cm. long, elliptic to oblanceolate, feather-veined, 

 obtuse; upper stem-leaves usually a single pair, opposite, oblong, sessile; corolla 

 dark bluish purple; lobes obtuse or emarginate, 8-10 mm. long; glands cup- 

 shaped, with long appendages; stamens surrounded by a ring of setae. Swales: 

 Wyo. Utah Ida. Mont. Mont. Alp. Au. 



9. FRASERA Walt. AMERICAN COLUMBO. 



Perennial herbs, with hollow stems and taproots. Leaves opposite or more 

 often whorled, entire, thickish. Flowers perfect, in terminal paniculate cymes. 



