1870.] Botany. *99 



arc of the coil last formed will exhibit a gradual fading-off of light 

 towards its extremity. Mr. Proctor has calculated that a star ten 

 times as far off as a Centauri, and having a real diameter as large 

 as our sun's, would give an arc of fading light about 56 degrees 

 in length. 



4. BOTANY. 



Edible Fungi. — During the last few years great attention has been 

 paid by botanists on the one hand, and epicures on the other, to the 

 edible qualities of certain fungi. Notwithstanding the prejudice 

 generally entertained against this class of vegetable productions, 

 extending in Scotland, Wales, and some parts of England even to 

 the common mushroom, there is no question that a considerable 

 number of species, very abundant in this country, are not only 

 wholesome, but delicious articles of diet, and are at least as easily 

 distinguished, with a little practice, from the poisonous or suspicious 

 species, as berries or other wild fruits. Containing a larger propor- 

 tion of nitrogen than any other family of the vegetable kingdom, 

 they furnish an abundant supply of nourishment at a period of the 

 year when very little else is to be obtained. It is calculated that 

 there is scarcely a parish in England where tons of wholesome food 

 are not allowed to waste every year, to say nothing of the facilities 

 for their artificial culture. Mr. Berkeley reckons that there are at 

 least 30 distinct English edible fungi ; Dr. Curtis has partaken of 

 40 in North Carolina, and enumerates 111 species in that state 

 alone reputed to be edible. Fries, the greatest living cryptogamist, 

 is publishing a large work on the edible and poisonous fungi of 

 Sweden ; several works of a similar character have recently been 

 brought out in Italy ; in our own country the Kev. M. J. Berkeley, 

 Mr. Worthington Gr. Smith, and Dr. Bull of Hereford, may be 

 mentioned as having paid special attention to the subject. In addi- 

 tion to the mushroom Agaricus campestris and the truffle Tuber 

 testivum, the following species are wholesome, pleasant to the taste 

 when cooked, easily distinguished from all other species, and more 

 or less abundant in different parts of the country: — Agaricus 

 arvensis, or the horse-mushroom ; A. procerus, the parasol-mush- 

 room; A. ostreatus, the vegetable oyster, growing on the trunks of 

 trees; A. melleus, abundant on dead stumps; A. orcella, the vege- 

 table sweet-bread ; A. prunulus, the plum-mushroom ; Morchella 

 esculenta, the morel ; Hydnum repandum, the hedge-hog ; Fistulina 

 hepatica, the vegetable beef-steak, on the stumps of hollow trees ; 

 Coprinus comatus, very common in gardens ; Marasmius oreades, 

 the fairy-ring champignon; Boletus edulis, in woods; and Lyco- 

 perdon giganteum, the giant puff-ball, when in the young state. 



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