CLASSIFICATION OF ANGIOSPERMS. 251 



swamps of the United States contains a volatile oil. The fruit 

 of sweet gale (71/. Gale) yields a volatile oil containing a camphor. 

 The sweet fern {Comptonia peregrina) found in the United 

 States, yields a volatile oil resembling that of cinnamon. The 

 rhizome of this plant contains also tannin and possibly gallic and 

 benzoic acids. 



IV. ORDER JUGLANDALES. 



The plants are trees with alternate, pinnately-compound leaves. 

 The staminate flowers are in drooping aments, the pistillate being 

 solitary or several together. The flowers are monoecious and 

 have a more or less distinct perianth consisting of three to six 

 lobes. The fruit is a kind of drupe formed by the union of the 

 torus with the wall of the ovary. There is but one family in tliis 

 order, namely, the Juglandace/E (Walnut family), which in- 

 cludes the hickory (Hicoria) and walnut. The black walnut 

 (Jiiglaiis nigra) of the United States yields a valual)le timber 

 and an edible nut; the white walnut or butternut (/. cincrca) of 

 the United States yields the butternuts which are edible, and a 

 bark which has medicinal properties and w^as formerly official 

 under the name of Juglans. Butternut bark occurs in quills or 

 channelled pieces of variable length, 2 to 10 mm. thick; it is dark 

 brown externally ; has a short, fibrous fracture, characteristic odor 

 and bitter, pungent and acrid taste. It contains about 7 per cent, 

 of a yellow, cr3'stalline acrid principle which is colored purple 

 with alkalies ; 2 to 2.5 per cent, of a crystalline resin ; volatile oil, 

 tannin, sugar and a fixed oil. 



/. regia native of Persia and cultivategl in various parts of 

 Europe and California, yields the edible English walnut. 



The following species of hickory yield edible nuts : The shell- 

 bark hickory {Hicoria ovata) ; the pecan {H. pecan) common 

 from Illinois southward; and western shell-bark hickory {H. 

 sulcata). The wood of these as well as H. glabra and other 

 species of hickory is used where strength and elasticity are 

 required. 



Coloring principles are found in the barks of a number of 

 species and are used for technical purposes. The following con- 



