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33 



Guaiacum Order {Zygophylleae). The abundance, CASE 

 especially of spinous species, of this order is characteristic 18. 

 of desert vegetation in Egypt and Western Asia. Some 

 of them are fine trees. 



Observe mounted specimens of the CREOSOTE PLANT 

 {Larrea niexicana, Moric), a shrubby plant of North 

 America. The twigs are covered with a resinous sub- 

 stance or lac which the Indians mould into balls, and also 

 use in rheumatism. It is sometimes called SONORA GUM. 



No. 92. Lignum Vitae {Guaiacum officinale, L.). 

 A small ornamental tree, native of Tropical America. 

 The wood is remarkable for the singular brownish green 

 of the heart-wood ; its extreme hardness and toughness 

 adapt it for use for the sheaves of pulleys, pestles, 

 mortars, skittle-balls, &c. It contains a green resin, 

 obtained either from incisions in the trunk, or by heating 

 the wood when broken up into fragments. This is 

 greatly used in rheumatism and skin diseases and as a 

 stimulant. 



G, sanctum, L., a tree much resembling the foregoing,, 

 found in Southern Florida, the Bahamas, Cuba, St. 

 Domingo, &c., is the source of Lignum Vitae exported 

 from the Bahamas, as well as of some of that shipped from 

 Hayti. 



Cranesbill Order {Geraniaceae). Herbs or shrubs,, 

 of which the Scarlet Geranium and the common British 

 Cranesbill may be taken as examples. Scattered very 

 unequally over the globe, though particularly numerous 

 at the Cape. Chiefly remarkable for the beauty of their 

 flowers. 



The Rose-leaf Geranium {Pelargonium capitatumy 

 Ait.) is largely cultivated in the South of France, Algeria, 

 and the South of Spain for the oil which is distilled from 

 the leaves, used as a perfume and as a substitute for 

 Otto of Rose. Samples of the oil distilled in France and 

 from English grown plants are exhibited. 



Observe the anomalous structure of the stem in 



No. 93. GiFDOORN or POISONOUS Thorn {Sarcocau- 

 Ion Patersonii, Eckl. and Zey.), from Namaqualand. It 

 secretes such a quantity of w^axy inflammable substance 



25782 C 



