5SO FLORA, 



Family 4. ZYGOPHYLLACEAE Lindl. 



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, axil- 

 lary, 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, inserted on the base of the receptacle, the 

 alternate ones sometimes longer ; anthers versatile, longitudinally dehis- 

 cent ; filaments usually with a small scale at the base or near the middle. 

 Ovary 4-1 2-celled ; style terminal; stigma usually simple; ovules i-nu- 

 merous in each cavity, pendulous or ascending. Fruit various, dry in our 

 species. 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 i-seeded segments. 2. Kallstroemia. 



1. TRIBULUS L. 



Herbs, with evenly pinnate leaves and peduncled axillary yellow flowers. 

 Sepals 5, persistent. Petals 5, deciduous. Stamens 10, the alternate ones some- 

 what longer. Ovary sessile, 5-lobed, 5-celled, hairy, the hairs erect; style short; 

 stigma 5-ridged; ovules 3-5 in each cavity, pendulous. Fruit 5 -angled, spiny, 

 splitting into 5 3-5-seeded segments. [Greek, three-pronged, Caltrop, from the 

 resemblance of the fruit to that implement.] About 12 species. • of warm and 

 tropical regions. Besides the following, another occurs in the Southwestern States. 



1. Tribulus terrestris L. Ground Bur-nut. Land Caltrop. (I. F. f. 

 2267.) Pubescent, the stem prostrate or ascending, sometimes 3 dm. long or more. 

 Leaves petioled; stipules small; leaflets 4-8 pairs, oblong, inequilateral, opposite, 

 short-stalked, 6-16 mm. long; flowers solitary, about 1.2 cm. broad, peduncled; 

 petals oblong, about as long as the sepals; segments of the fruit usually with 2 long 

 spines, 2 shorter ones, and a row of very short ones forming a crest on the back, 

 also commonly with some bristle-like hairs. In ballast and waste places about the 

 Eastern seaports, and 111., Ark., Neb. Fugitive from Europe. June-Sept. 



2. KALLSTROEMIA Scop. (See Appendix.) 



Mostly annual pubescent herbs, with opposite stipules, evenly pinnate leaves, 

 and solitary axillary peduncled yellow flowers. Sepals usually 5. Petals the 

 same number, obovate or oblanceolate, deciduous. Stamens twice as many as the 

 petals. Ovary sessile, 10-12 celled; ovule 1 in each cavity, pendulous; style long, 

 or short, 10-12 grooved, persistent; stigma mostly it) 1 2 -ridged. Fruit 10-12- 

 lobed, not spiny, often tuberculed, splitting into IO-I2 I-seeded segments. [In 

 honor of Kallstroem.] About 10 species, widely distributed in warm and tropical 

 regions. Besides the following, 3 others occur in the Southern and Western States. 



1. Kallstroemia maxima (L.) T. & G. Greater Caltrop. (I. F. f. 



2268.) Branches slender, prostrate, 1 .5-4.5 dm. long. Leaves short-petioled ; 

 Stipules subulate; leaflets 3 5 pairs, oval oroblong. inequilateral, rounded or sub- 

 cordate at the base, 8-20 mm. long; peduncles slender, 1.2-5 cm. long in fruit; 

 flowers 2.5 cm. broad, or less; sepals linear-lanceolate, very pubescent, persistent, 

 shorter than the petals; fruit ovoid-conic, about 6 mm. in diameter, about as long 

 as the stout persistent style, the segments tubercled. In dry soil, Kans. to Ga., 

 Fla. and Tex. Also in tropical Am. April-Sept. 



