Vor. II.] FLAX FAMILY. 351 
8. Linum rigidum Pursh. Large-flowered Yellow Flax. (Fig. 2265.) 
Linum rigidum Pursh, Fl. Am. Sept. 
210. 1814. 
Perennial (?),6’-15’ high, branched, 3 
glaucous, glabrous or puberulent. 
Branches stiff, more or less angular; 
leaves erect, linear or linear-lanceo- 
late, 4/’-12’’ long, 14’/-1’’ wide, acute 
or mucronate, the upper ones glandu- 
lar-serrulate or ciliate; stipular glands 
minute, globose, sometimes wanting; 
flowers yellow, 9/’-15’’ broad; sepals 
lanceolate, acute or awn-pointed, 
glandular-serrulate; petals cuneate- 
obovate, twice the length of the se- 
pals; styles separate only at the sum- 
mit; capsule ovoid, 5-valved, shorter 
than the sepals, 2’’-214’’ long. 
Prairies, Manitoba to Texas, New 
Mexico, Arizona and Mexico. Sum- 
mer, 
g. Linum catharticum J,. Dwarf or 
Cathartic Flax. (Fig. 2266.) 
Linum catharticum J, Sp. Pl. 281. 1753. 
Annual, slender, glabrous, usually branched, 
3/-8’ high. Leaves all opposite, sessile, oval or 
somewhat obovate, entire, 2’’-4’’ long; flowers 
axillary and terminal, white, 2//-3/’ broad, on 
long slender erect or ascending pedicels; sepals 
lanceolate, acute or acuminate; petals obovate; 
pod small, globose. 
Along a low sandy seashore, Pictou, Nova Scotia. 
Apparently naturalized from Europe where it is 
abundant on chalky soils. Called also Fairy, Moun- 
tain or Purging Flax, Fairy Lint. July-Aug. 
Family 53. ZYGOPHYLLACEAE Lindl. Nat. Syst. 1830. 
CaLTRoP FAMILY. 
Herbs, shrubs, or some tropical species trees, the branches often jointed to 
the nodes. Leaves mostly opposite, stipulate, pinnate, or 2~-3-foliolate, the 
leaflets entire. Stipules persistent. Flowers perfect, axillary, peduncled. 
Sepals usually 5, distinct, or united by their bases. Petals the same number as 
the sepals, or none. Stamens as many as the petals, or 2-3 times as many, in- 
serted on the base of the receptacle, the alternate ones sometimes longer; anthers 
versatile, longitudinally dehiscent; filaments usually with a small scale at the 
base or near the middle. Ovary 4-12-celled; style terminal; stigma usually 
simple; ovules 1-numerous in each cavity, pendulous, or ascending. Fruit 
various, dry in our species. Endosperm of the seed copious or none; embryo 
straight or curved; cotyledons linear or oblong. 
About 20 genera and 150 species, widely distributed in warm and tropical regions. 
Fruit spiny, splitting into 5 3-5-seeded segments. 1. Tribulus. 
Fruit not spiny, often tubercled, splitting into 10-12 1-seeded segments. 2. Kallstroemia. 
