120 ZYGOI'HYLLACEiE. 



Fruit villous or tomentose, globular, deeply five-lobed, 

 separating (from a filiform axis in L. Mexicana) into five 

 indehiscent cocci. Seed solitary by abortion, oblong, some- 

 what incurved, marked with a narrow acute raphe ; the 

 micropyle produced beyond the hilum, superior ; the testa 

 very thin and smooth. Embryo slightly incurved in nearly 

 corneous albumen and almost of its length : cotyledons 

 narrowly oblong, flattish, parallel with the raphe and with 

 the axis of the fruit : radicle rather slender, superior. 



Shrubs evergreen, strong-scented, exuding a balsam, usu- 

 ally with low, much-branched stems, and nodose-articulated 

 distichous and mostly alternate branchlets. Leaves oppo- 

 site, equal, consisting of a single pair, rarely of several pairs, 

 of inequilateral leaflets which are more or less united at the 

 base ; the common petiole short or none. Stipules persistent. 

 Peduncles short, terminal, one-flowered. Flowers yellow. 



Etymology. Dedicated to J. A. H. de Lcirrea, a Spanish ecclesiastic. 



Geographical Distribution. The three species described by Cavanilles 

 are found on the Cordilleras of Chili and Paraguay ; the fourth (which 

 Moricand has identified with the Zygophyllum tridentatum, DC) is com- 

 mon through the interior of Northern Mexico and New Mexico, extending 

 to the Upper Arkansas {Major Emory) and to Southern Texas, Mr. Wright. 



Properties. They exude a heavy-scented, balsamic resin, esteemed in 

 the Cordilleras for bruises, &c. The northern species, called Gohernadora 

 or Guamis by the Mexicans, and Creosote-plant by the Anglo-Americans, 

 from its scent, is used for dysuria and for rheumatism. 



PLATE 147. Larrea Mexicana, iVfonc. (L. glutinosa, Engelm.) ; — a 

 branchlet, of the natural size. (Chiefly from Gregg's specimens.) 



1. Diagram of the flower. 



2. A magnified stamen and scale, seen from within ; and 3. from without. 



4. Pistil and receptacle, magnified. 



5. IMagnified vertical section through the ovary and base of the flower. 



6. An ovule more magnified, showing its tubular apex. 



7. A fruit of the natural size. 



8. The same, magnified, with two of the cocci removed. 



9. One of the cocci of the same detached. 



10. Vertical section of the same, and of the seed and contained embryo. 



11. The seed entire, more magnified. 



12. The embryo entire, with the cotyledons opened, magnified. 



