17 



the south of Constantine, the French soldiers made bread of it and 

 cooked it in various ways, actually subsisting on it for several days. In 

 Science Gossip for 1872, at page 6o, was given a description of this 

 curious plant, specimens of which had been presented to the Museum 

 by the gentleman. T. B. W., who furnished the material for that article 

 and articles in subsequent numbers, 1872, p. 186; 1873, p. 118 ; and 

 1875, p. 146. From these it appeared Pallas figured and described 

 this plant in 1776, and said "it occurs in the very driest limestone of 

 the Tartarian desert, scarcely distinguishable from small stones, 

 except by the expert." 



The specimens before them were collected at Reboud Djelfa, in 

 the desert of the Great Atlas Chain, and were about one-fifth the size 

 of those figured by Pallas. Berkeley mentioned that, lying loose on 

 the ground without any attachment, it was easily rolled along by the 

 wind, and sometimes piled together in layers several inches thick, and 

 that at times being carried up by whirlwinds, it was showered down on 

 the ground. One such shower fell at Erzeroun during a time of great 

 scarcity, and afforded very opportune relief to the inhabitants. 

 Lindley, in his Vegetable Botany, speaking of L. Esculentits, says " it 

 sometimes appears in immense quantities in Persia, Armenia, and 

 Tartaiy, where they are devoured by the natives, who fancy that they 

 must fall from heaven, not knowing how to account for the prodigious 

 numbers of the plants, of the origin of which they are ignorant." 

 Parrot says that " in some districts of Persia they cover the ground to 

 the depth of five or six inches," and Eversman, who had an opportunity 

 of studying it, was convinced that even in its earliest stages, the plant 

 had not the slightest attachment to a grain of sand. 



Another fact in connection with L. Esciilenta and L. Affinis v/as, 

 that, instead of being produced at uncertain intervals and only during 

 a few months, it was produced during ihe whole year. It appeared 

 from an article by Dr. Ruke, reprinted in the Pharmaceutical Journal 

 for September, 1 860, that L. Esculenta was presented to the Academy 

 of Sciences in 1828. The lichen was described as being of a fawn 

 colour, granulated, composed of broken crusts, which had fallen in the 

 neighbourhood of Mount Ararat, and which a Russian General of the 

 Persian army had given to M. Th^nard, who presented it to the 

 Academy. It seemed this lichen dried up during the summer in the 

 mountains, and was transported by the winds to great distances ; this 



