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 xmited. Utricle included. Radicle ascend- 

 ing. 



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



Leaves elUptic. 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. brencuspis. 



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



3. P. sessihflora. 



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 equalhng 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. , , "vf^' *^<^f^^sM. 



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



acuminate. 7- ^- ^^^^d^^- 



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

 stipules ovate, silvery; leaves thick, 3-5 mm. long; flowers sohtary 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 m the upper axils; 

 sepals 2-3 mm. long, bro\\Ti, scarcely scarious-margmed. P. sessthfoha brevx- 

 cuspis A. Nels. Dry hills: Wyo.— Colo.— Nev. SubynonL Jl. 



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

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

 brown with narrow scarious margins, spme-tipped, about 3 mm. long. JJry 

 ridges: Sask.— Tex.— Utah— Alta. Plain— MonL 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 Unear, 2.5-3 mm. long, usually exceeded by the bracts. Ury 

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



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



~ " ' ' lose-tipped, scabrous; 



_ Dry plains, hills, and 



moun'tainsrsTD^.— Kkn's.^^ Plain— Alp, Je-S. 



Perennial, shrubby and branched at the base; stems 



5^15 



linear 



James ii 



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

 caUous-mucronate; sepals about 2.5 mm. long, lanceolate; spme-tips strongly 

 ascending. Dry plains and hills: Neb.— Tex.— N.M.— Wyo. Plain-MouL 

 Je-Au. 



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

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

 earlv deciduous, mucronate, minutely scabrous. Dry stony soil: Jians.— lex 

 N.M.— Colo. Plain— Submont Jl-0. 



