CORRIGIOLACEAE 399 



Family 4. CORRIGIOLACEAE Reichenb. Whitlow-wort Family. 



Herbs, with firm or rigid tissues and erect or creeping commonly tufted stems. 

 Leaves opposite : blades often narrow, entire : stipules scarious, sometimes con- 

 spicuous, or rarely wanting. Flowers incomplete, perfect, in clustered or dichot- 

 omous cymes. Sepals 4-5, nearly distinct or partly united, white or green, 

 persistent. Corolla wanting. Androecium of 4-5 stamens inserted at the base 

 of the ovary. Filaments slender. Anthers short, 2-celled. Gynoecium of a single 

 pistil. Ovary 1-celled, sessile. Styles wholly or partially united, sometimes very 

 short. Ovule solitary. Fruit a utricle or an achene. Seed solitary : endosperm 

 nearly surrounding the embryo. [^Illecebraceae Lindl.] 



Hypanthium wanting or very small : stamens inserted under the ovary at the sepal-bases. 



Calyx sessile in a pair of bracts which simulate the sepals : sepals awned. 1. Paronychia. 



Calyx manifestly pedicelled : bracts simulating the leaves : sepals merely cuspi- 

 date on the back, or the cusps wanting. 

 Styles relatively long : sepals cuspidate : radicle ascending. 2. Anychiastrum. 



Styles wanting or nearly so : sepals barely mucronate : radicle descending. 3. Anychia. 

 Hypanthium present, often about as long as tlie sepals, the stamens inserted near 

 its edge. 

 Flowers subtended by normal bracts. 



Sepals merely concave : flower not urn-shaped : stems or branches simple 



below. 4. Odontonychia. 



Sepals with small cusps back of the hoods : flower urn-shaped : stems or 



branches dichotomous throughout. 5. Siphonychia. 



Flowers subtended by thick clamp-like involucels. 6. Gibbesia. 



1. PARONYCHIA Adans. 



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

 opposite : blades narrow. Flowers in clustered or dichotomous cymes. Calyx persistent. 

 Sepals 5, narrow, concave or hooded at the awn-tipped apex. Stamens 5, included : fila- 

 ments inserted at the base of the ovary, alternating with 5 small staminodia. Styles 

 partially united. Utricle included. Seed resupinate. The plants flower in the sum- 

 mer and fall. Whitlow-wort. 



Annual or biennial : sepals dilated at the apex. 



Leaf-blades fully 2 mm. broad. 1. P.' Drummondii. 



Leaf-blades less than 2 mm. broad. 

 Foliage pubescent. 



Calyx surpassing the bracts : awns spreading at maturity, much shorter 



than the sepals. 2. P. chorizanihoides. 



Calyx shorter than the tracts : awns erect or ascending, about as long 



as the sepals. 3. P. setacea. 



Foliage glabrous, sometimes slightly scabrous. 4. P. Lindlieimeri. 



Perennial : sepals not dilated at the apex. 

 Calyx glabrous or merely puberulent. 



Cymes strict, the branches erect or ascending : leaves scabrous. 5. P. scoparia. 



Cymes open, the branches spreading : leaves smooth. 6. P. dichotoma. 



Calyx manifestly pubescent. 



Calyx exserted beyond the bracts'and stipules ; awns spreading at maturity : 

 species campestrian. 

 Calyx about 2. .5 mm. long : sepals lanceolate, gradually acuminate : 



cymes with ascending branches. 7. P. Jamesii. 



Calyx about 2 mm. long: sepals oblong, abruptly acuminate: cymes 



with divaricate branches. 8. P. Wardi. 



Calyx hidden in the bracts and stipulcfs ; awns erect : species Alleghenian. 9. P. argyrocoma. 



1. Paronychia Drummdndii T. & G. Annual or biennial, stoutish, finely pubescent. 

 Stem simple below, erect, 1-2 dm. tall, corymbosely branched above : leaf-blades tliick, 

 oblong or narrowly oblong-spatulate, 1-2 cm. long, over 2 mm. broad, acute, apiculate, 

 ciliate, sessile ; stipules lanceolate, long-acuminate, silvery : cymes dense : sepals cimeate, 

 1.5 mm. long, with white hoods and short spreading cusps : stamens \ as long as the sepals. 



In dry soil, southern Texas. 



2. Paronychia chorizanthoides Small. Annual, slender, minutely pubescent. Stem 

 erect, 1-2 dm. tall, forking from a point 3-8 cm. above the base : leaf -blades linear-filiform, 

 0.8-2 cm. long, less than 2 mm. broad, acute, with a stout midrib, sessile ; stipules lanceo- 

 late, silvery, acuminate : calyx sessile, 1.5 mm. long, strigose at the base, finally urn- 

 shaped, the base much enlarged : sepals ovate or ovate-lanceolate, with a stout midrib, ab- 

 ruptly contracted into the ascending cusps which are about j as long as the body at maturity. 



In dry soil, Texas. 



3. Paronychia setacea T. & G. Annual, slender, finely pubescent. Stem erect, 

 simple below, forking above, 0.5-1 dm. tall : leaf-blades linear-filiform, 0.5-1.5 cm. long, 



