of the Kingdom of Algiers. 435 



plants, and of pointing out the most remarkable species which 

 occur in Algeria, but I find that it would only draw out this 

 paper to an immeasurable length. 



I cannot however pass over a new species of Stapelia, named 

 by Decaisne Boucerosia Munbyana, and discovered by me in the 

 neighbourhood of Oran, interesting in a geographical point of 

 view ; it is well known that the great seat of Stapelias (which is 

 a most distinct and perfectly natural genus) is at the Cape of 

 Good Hope, and until lately only one species occurred in Europe 

 as a representative of this genus ; I speak of Stapelia europcea, 

 which is found in Sicily and the southern coast of Spain. The 

 discovery of an allied species on an intermediate point is I con- 

 ceive very interesting, and will in all probability form the second 

 link in a chain which will connect the humble Stapelia europaa 

 with the remarkable Cape species. 



I shall conclude this paper by noticing a lichen called L. escu- 

 lentus, and which agrees, at least more nearly than any other 

 substance hitherto discovered, with the description of the Manna 

 on which the Israelites fed during their wanderings in the desert. 



This lichen is found on the sand of the desert, which it covers 

 in some parts, and grows during the night, as do many mush- 

 rooms. The French soldiers during an expedition towards the 

 south of Constantine actually subsisted upon it for some days, 

 cooking it in various ways, and even making it into bread. I do 

 not pretend to explain the miraculous portions of the history of 

 the Manna, but it is very probable that if gathered when alive or 

 in a soft state, it would in a very short time ferment if placed in 

 a heap, and from the rapid development of animal life in that 

 warm climate, " breed worms and stink " in a very few hours. 

 Neither would I attempt to explain the double quantity gathered 

 on the sixth day. The description given by Moses is this : "Upon 

 the face of the wilderness there lay a small round thing, as small 

 as hoar-frost on the ground ;" and again, " it was like coriander 

 seed, white ; and the taste of it was like wafers made with honey " 

 There are a few characters in this account of it which disagree 

 with the substance I present to you, yet the discovery of a sub- 

 stance springing up in the short space of a night on the surface 

 of the sandy desert, and that substance capable of sustaining 

 human life, is, to say the least, a remarkable fact, and one well 

 worthy the examination and researches of botanists. 



29* 



