SCIENCE-GOSSIP. 



22g 



THE MANNA OF THE ISRAELITES. 

 Bv M. J. Teesdale. 



r N a recent botanical work of authority (i) occurs 

 -'■ the following passage : " It should be mentioned 

 that the manna sent to the Israelites on their 

 journey out of Egypt to the Holy Land is identical 

 with the lichen described here and figured on page 

 695, and the older view that the manna of the 

 desert was the sap of a tamarisk (Tamarix gallica- 

 mannifera) exuded under the influence of a parasite 

 is without any foundation." 



The lichen thus positively asserted to be iden- 

 tical with the manna of Scripture (see Exodus 



stones, preferably on small fragments of limestone .' 

 the outer colour of the crust is a greyish yellow, 

 while on breaking it appears as white as a crushed 

 grain of corn." The Algerian specimens in the 

 Cryptogamic Department of the Natural History 

 Museum are smaller than the Asiatic, and are 

 of a reddish colour, probably borrowed from the 

 soil on which they are rolled about, as here- 

 after described. " As they get older the crusts 

 become rent, and separate either partially or 

 wholly from their substratum, to which they were 







'■^ 





Fig. I. — The Edible Lichen, the Alleged Manna of the Israelites, and Allied Species. 



a, Lecanora esculenta,'Pa\\; b, Lecanora affinis,'EhT.; c, Lecanora affinis,'E'hx. (section showing dichotomous growth); 

 d, Lecanora tartarea (brought in shiploads from Sweden under the name of Swedish moss, and used in the making of the 

 blue dye "Litmus" or " Lacnius " ; grows also in the Canary and Cape Verde Islands); e, Lecanora fruticulosa, Ehr. ; 

 /, Lecanora /ruticulosa, Ehr. (section showing concentric growth). 



xvi. and Numbers xi.) is described in the same 

 work as consisting of three species, spread over an 

 enormous region in South- West Asia and extending 

 as far as the south-east of Europe and the north 

 of Africa. It was first observed by the celebrated 

 naturalist and traveller, P. S. Pallas, in 1769, in 

 the deserts of Tartary, and was named Lecanora 

 esculenta, Pallas (fig. la) ; it is also known a.sSph(£ro- 

 thallia esculenta, Nees. "It forms," says Professor 

 Kerner, "thick, wrinkled and warted crusts on the 



(1) "The Natural History of Plants," from the German of 

 Anton Kerner von Marilaun, Professor of Botany in the 

 University of Vienna. Translated and edited by F. \V. 

 Oliver, M.A., D.Sc, Quain Professor of Botany in the 

 University of London. Vol. ii, p. 812. 



February, 1897.— No. 33, Vol. 3. 



only lightly attached by root-like fringes. When 

 they first become loosened the edges of the de- 

 tached portion become somewhat rolled back. The 

 rolling then continues, and ultimately the loosened 

 piece forms an elliptical or spherical warted body, 



with a very much contracted central cavity 



As a rule the hole is filled with air, and when 

 dried the pieces weigh very little. It is easy to 

 see that the loose portions will be rolled about by 

 the wind, and that a storm will sometimes sweep 

 them up from the ground and carry them hither 

 and thither through the air. In rainy seasons the 

 manna-lichen is also washed by rivulets into the 

 depressions in the Steppes, and in some years in 



