112 NOSTOCHINEtE. 



within a common pellicle. The same process continues ; these split into other threads, 

 and thus, by gradual bisection of the first formed threads, the frond grows until it 

 become of the form and size proper to its kind. As it grows the filaments twist and 

 curl, and loose their parallelism. All these changes have been figured by M. Thuret 

 with the accuracy and delicacy of execution characteristic of that accomplished naturalist. 

 The Nostochineaj are very rarely marine, and are chiefly found in fresh water streams 

 or ponds and lakes, or in damp places. Nostoc commune is dispersed over most 

 countries of the globe, being found lying on the bare soil after rains, or in very damp 

 weather. It may be observed often on garden walks in the autumn and winter months, 

 and is found throughout both temperate zones, extending almost to the tropics. A 

 similar species has been seen in Australia, after a shower of rain, to cover what had 

 seemed previously to be a bare hill side, Avith such a thick coating of jelly as to render 

 it impossible to walk over it without sliding. Such terrestial species have, in England, 

 the popular name of " fallen stars" ; their sudden appearance and disappearance being 

 accounted for by the supposition that they had fallen from the air. In Dr. Suther- 

 land's account of his Arctic voyage a species bearing a close external resemblance to 

 N. commune was observed in profusion, occurring on the shores of the Arctic Ocean, 

 but in windy weather frequently blown over the ice, and drifted out to sea. This will 

 be found described below as N. arcticum. Dr. Sutherland mentions that he had eaten 

 handfulls of it on several occasions, without any inconvenience ; and although it was 

 generally infested with swarms of the larvte of flies and gnats, he considered it much 

 more nutritious than " tripe de roche," and perhaps not inferior to Iceland moss. A 

 very similar plant was noticed by Dr. Thomson as occurring in Thibet, up to the 

 height of 17,000 feet, floating on the surfxce of pools and lakes, in soils impregnated 

 with carbonate of soda, and drifted in heaps by the winds along their banks. Mr. 

 Berkeley, who examined the specimens of both plants chemically, " thinks we may safely 

 assume the jelly of the Nostoc to be a state of bassorin, passing into cellulose or 

 dextrine." Another species of this genus {Nostoc edule, Mont, and Berk.) is found 

 abundantly in streams in Tartary, whence it is exported to China, where it is sold in the 

 markets as an article of food, and highly esteemed as an ingredient in soups. It is 

 prepared for sale in boxes, one of which is in the ]\Iuseum of the Linna^an Society. 

 These particulars are drawn from the abstract of a paper read by Dr. Hooker before 

 the Liunsean Society of London, January 20, 18.52. (See Taylor's An. Nat. Hist. 

 2nd. Ser. Vol. 10, p. 301-303.J As the edible Nostocs closely resemble N. commune 

 in substance, it may be worth enquiry whether the latter may not also be used as food. 

 Possibly a new source of luxury may lie hid under this humble exterior. Or it may 

 perhaps be a nourishing and delicate food for weak digestions. The dyspeptic had better 

 seek for it betimes. 



