July 1891.] BOTANICAL SOCIETY OF EDINBURGH. 189 



Engler"^ mentions that the natives smear (fix ?) their 

 arrow-heads with the excretion of the leaves. 



Brandegge,t in an enumeration of plants from Baja 

 California, says : — " Larrea and Euplwrhia are held in high 

 repute for their curative properties, and it is difficult to find 

 any common, ill-smelling plant that, for some ailment or 

 other, is not ' buena par medecina.' " 



Opportunity has not been afforded of knowing whether 

 the excretions of Acacia Greggii occur in the same quantity 

 and possess the same qualities as those of Larrea. This 

 seems highly improbable. On the other hand, it is evident 

 that the Larrea by itself can yield the shellac and the dye. 

 The author quoted attributes the secretion to the puncture 

 of insects. "With Larrea such stimulation is not necessary, 

 the exudation being spontaneous and singularly general and 

 copious. No insects were found on the specimens. 



L. cuneifolia, Cav.,| occurs in salt deserts of Cordoba, 

 Argentina. The cuneate leaves consist of a pair of closely- 

 coherent pinnge clothed with hairs. An apical seta is 

 present. As in L. mexicana, only the cells immediately 

 surrounding the stomata have clear contents. Cavanilles 

 describes the stipules as " breves crassse rubentes." They 

 are acute, and bear numerous hairs on the exposed (lower) 

 surface, and stomata are present. The columnar character 

 of the inner (upper) epidermis is very well marked. 



L. divaricata, Cav.,§ covers, almost exclusively, whole 

 tracts of sand steppes in Argentina. The leaves resemble 

 those of L. mexicana in form, but are different in texture. 

 The epidermis of both surfaces is easily separable, a 

 condition not found in any other species. The hairs are 

 fewer, longer, and softer, and the epidermal cells are almost 

 entirely devoid of brown material. The stipules are 

 broader, flatter, and more villous than those of the others, 

 and the stomata are fairly numerous. Their cell-contents 

 are brown, but not so deep a tinge as in the other species. 

 The deep-celled layer of the upper surface is differentiated 

 from the hypodermal cells with extreme distinctness. 



* Pflanzenfamilien, iii. Teil, 4 Abt., p. 86. 



t Proceedings of the California Academy of Sciences, 2ud ser., vol. ii. 

 p. 125. 



J Cavanilles, Icones Plantarum, vol. vi., Tab. 560. 

 § Ibid., Tab. 560. 



