WHITLOW-WORT FAMILY 267 



FAMILY 43. CORRIGIOLACEAE. WHITLOW-WORT FAMILY. 



Herbs, with narrow opposite leaves with scarious stipules. Flowers per- 

 fect, inconspicuous, in dichotomous cymes. Sepals 4-5, distinct or partly 

 united. Corolla wanting. Stamens 4 or 5. Pistil solitary; ovary 1 -celled. 

 Fruit a utricle or an achene. 



1. PARONYCHIA (Tourn.) Adans. WHITLOW-WORT. 



Annual or perennial herbs, with stems often branched at the base. Leaves 

 opposite, narrow. Sepals 5, narrow, concave or hooded at the awn-tipped apex. 

 Stamens 5, included; filaments inserted at the base of the ovary, alternating with 

 5 small staminodia. Styles partially united. Utricle included. Radicle ascend- 

 ing. 



Flowers solitary; leaves scarcely exceeding the bracts; plants densely pulvinate. 



Leaves elliptic, thick, not spinulose-tipped. 1. P. pulvinata. 



Leaves linear, chartaceous, spinulose-tipped. 



Leaves straight, ascending ; spinules of the sepals less than 1 mm. long. 



2. P. brevicuspis. 

 Leaves arcuate-spreading ; spinules of the sepals more than 1 mm. long. 



3. P. sessili flora. 

 Flowers more or less clustered; leaves much longer than the bracts. 



Plants low and diffuse, less than 1 dm. high; calyx fully 3 mm. long. 



Inflorescence much contracted; bracts exceeding the flowers. 4. P. depressa. 

 Inflorescence more open; bracts shorter than or merely equalling the flowers. 



5. P. diffusa. 



Plants taller, 1 dm. or more high; stems erect or ascending; calyx 2-2.5 mm. long. 

 Branches of the cymes ascending; calyx about 2.5 mm. long; sepals lanceolate, 



gradually acuminate. 6. P. Jamesii. 



Branches of the cymes divaricate; calyx about 2 mm. long; sepals oblong, abruptly 



acuminate. 7. P. Wardii. 



1. P. pulvinata A. Gray. Pulvinate-cespitose perennial, 3-5 cm. high; 

 stipules ovate, silvery; leaves thick, 3-5 mm. long; flowers solitary in the upper 

 axils; sepals broadly scarious-margined, ovate, about 3 mm. long. Exposed 

 mountain tops: N.M. Wyo. Utah. Subalp. -Alp. Jl-Au. 



2. P. brevicuspis (A. Nels.) Rydb. Pulvinate-cespitose perennial; leaves 

 3-5 mm. long, linear, with short spine-tips; flowers sessile in the upper axils; 

 sepals 2-3 mm. long, brown, scarcely scarious-margined. P. sessilifolia brevi- 

 cuspis A. Nels. Dry hills: Wyo. Colo. Nev. Submont. Jl. 



3. P. sessiliflora Nutt. Pulvinate-cespitose perennial, 4-10 cm. high; 

 leaves linear or linear-subulate, spinulose-tipped, 4-6 mm. long; sepals lanceolate 

 brown with narrow scarious margins, spine-tipped, about 3 mm. long. Dry 

 ridges: Sask. Tex. Utah Alta. Plain Mont. Je-Au. 



4. P. depressa Nutt. Cespitose perennial, somewhat woody at the base; 

 stems diffuse, much branched; leaves linear, 5-8 mm. long, scabrous, spinulose- 

 tipped; sepals linear, 2.5-3 mm. long, usually exceeded by the bracts. Dry 

 hills or plains: S.D. Neb. Wyo. Plain Submont. Je-Au. 



6. P. diffusa A. Nels. Cespitose perennial, somewhat woody at the base: 

 stems 5-15 cm. long; leaves linear, 7-10 mm. long, spinulose-tipped, scabrous; 

 sepals linear, 2.5-3 mm. long; spine-tips 0.5 mm. long. Dry plains, hills, and 

 mountains: S.D. Kans. Colo. Wyo Alta. Plain Alp. Je-S. 



6. P. Jamesii T. & G. Perennial, shrubby and branched at the base; stems 

 erect, 1-3 dm. high, forking above; leaves strongly ascending, 1-2 cm. long, 

 callous-mucronate; sepals about 2.5 mm. long, lanceolate; spine-tips strongly 

 ascending. Dry plains and hills: Neb. Tex. N.M. Wyo. Plain Mont. 

 Je-Au. 



7. P. Wardii Rydb. Perennial, shrubby and branched at the base; stems 

 erect, 1-2 dm. high; leaves narrowly linear or linear-filiform, 0.7-2 cm. long, 

 early deciduous, mucronate, minutely scabrous. Dry stony soil: Kans. lex. 

 N.M. Colo. Plain Submont. Jl-O. 



