228 TREE ANCESTORS 



for the outer coating of candles. It is also used for coating pills, 

 polishing jade, soapstone and delicate furniture, or as a size to give 

 a lustre to cloth. Perhaps its most extensive use is for glossing 

 the higher grade papers of native manufacture. 



A somewhat remotely comparable product is obtained from the 

 Manna-ash {Fraxinus ornus) of Mediterranean Europe. This 

 product is the manna of commerce, and is not a true wax, but a 

 secretion whose chief constituent is mannite or manna sugar. It 

 is obtained in commercial quantities entirely from Sicily, and un- 

 like the Chinese wax it is not due to the activity of scale insects, 

 but is obtained by making incisions in the bark. It is thus not 

 related to the manna of the scriptures, which last was due to the 

 punctures of scale insects working on Tamarix trees. 



There are upwards of 50 existing species of ash and they are 

 widely distributed throughout the temperate regions of Eurasia 

 and North America, extending into the Tropics in both the Eastern 

 (Java) and the Western (Cuba) Hemispheres. Their generalized 

 hmits of distribution together with the knowTi fossil occurrence 

 of the ash are shown on the accompanying sketch-map. The 

 American species number from 18 to 24 according to the varying 

 conceptions of different students as to what constitutes a species. 

 Three of these {Fraxinus breggii, F. cuspidata and F. dipetala) 

 are shrubby forms of the southwest. The three important com- 

 mercial species are the white ash {Fraxinus americana), the green 

 ash {Fraxinus lanceolata) and the black ash {Fraxinus nigra). 

 The lumber trade, however, may only recognize white or dark ash, 

 or more often simply ash, and all or some of the other species 

 that are cut go to swell these categories. 



The white ashes, which include the species F. americana, F. 

 texensis and F. biltvwreana are upland forms. The green ashes, 

 which include a large nimiber of less important species than the 

 important Fraxinus lanceolata (namely F. darlingtonii, F. mi- 

 chauxii, F. profunda, F. berlandieriana, F. pennsylvanica, F. oregona^ 

 F. velutina,F. toumeyi, and F. coriacea),Sire broadly speaking bottom 

 land dwellers. The water ashes, Fraxinus caroliniana and F. 

 pauciflora are swamp trees: while the black ashes, Fraxinus quad- 



