230 
& 
Zygophyllum tridentatum DC, Prodr. 1: 706, 1824. 
Larrea Mexicana Moric. Pl. Nouv. Am. 71. £48. 1833-1846. 
Larrea glutinosa Engelm. Wisliz. Rep. 9. 1848. 
Distr. Southern Utah, Nevada, Arizona, Texas, New Mexico, 
Mexico and in the deserts of Chili. 
Careful examination does not reveal any characters that war- 
rant keeping the Mexican species distinct from the South American. 
The principal differences were found in the stamineal scale. The 
latter is a very variable organ, and three.or four variations were 
found, not only on the same plant, but in the same flower.* 
5. JRIBULUS-L, Sp. Pi.:386..°-1753, 
I. TRIBULUS CISTOIDES L. Sp. Pl. 387. 1753. 
Distr. Florida, Texas, Mexico, Lower California, West 
Indies and tropical America. 
2. TRIBULUS TERRESTRIS L. Sp. Pl. 387. 1753. 
Distr. Ballast Grounds, Hunter’s Point, Long Island, N. Y.; 
South Carolina, Mexico and Brazil. A native of Southern 
Europe, East Indies, etc. 
6. KALLSTROEMIA Scop. Introd. 212. 1777. 
I. KALLSTROEMIA CaLirornica (S. Wats.) 
Tribulus Californicus S. Wats. Proc. Amer. Acad. 11: 125. 1876. 
‘Distr. Arizona, North Mexico and Lower California. 
2. KALLSTROEMIA GRANDIFLORA Torrey; A. Gray, Pl. Wright. 1: 28. 
1852. 
Kalistroemia grandiflora var. detonsa A. Gray, PI. Wright. 1: 
28. 1852. 
Tribulus grandifiorus Benth. & Hook. Gen. Pl. 1: 264. 
1862-67. 
Distr. Texas, Arizona, New Mexico, California, North and 
South Mexico, Guatemala. 
3. KALLSTROEMIA Maxima (L.) T. & G. Fl. N. A. x: 213. 1838. 
Tribulus maximus L. Sp. Pl. 386. 1753. 
Tribulus trijugatus Nutt. Gen. 1: 297, 1318, 
* The other species are Covillea nitida (Cav.) and Covillea. cuneifolia (Cav-)» 
both from South America,and described under Larrea in Cav. Icon. 6: 40-41. p% 
559, 500. 1801. 
