THE ANNALS 



AND 



MAGAZINE OF NATURAL HLSTOUY. 



No. 46. AUGUST 1841. 



XLIV. — On Gloionema paradoxum. By the Rev. M. J. 

 Berkeley, M.A., F.L.S. 



[With a Plate.] 



The genus Gloionema has been long considered as consisting 

 of productions of a very doubtful nature. Some of its species 

 indeed have been rejected as the ova of insects; but notwith- 

 standing the communication of Roberge* to the Linna^an 

 Society of Paris, mIio is stated to have proved by repeated 

 experiments that Gloionema paradoxum is not a vegetable, the 

 species is still retained by Agardhf. KlitzingJ also, who re- 

 jects the other species as ova, though he refers to Agardh's 

 treatise, and therefore must have known of Roberge^s expe- 

 riments, still retains this, and has published it as an alga in 

 his * Decades.' Kiitzing, indeed, informs us that he kept his 

 specimens in Avater for many weeks or even months without 

 obtaining any positive result ; and Prof. Nitzsch, to whom he 

 communicated the production, was not more successful. 



No detail of M. Roberge's experiments, as far as I am 

 aware, has as yet been published ; I have therefore no hesita- 

 tion in offering to public notice my oa\ n observations, made 

 at the end of last May, which completely confirm the report 

 of Roberge, and which must be considered as quite decisive. 



I have not indeed had an opportunity of comparing my in- 

 dividuals with authentic foreign specimens, but they agree so 

 completely with Kiitzing's description, that I have not the 

 least doubt of their identity. 



So early as 1825 I found a small patch at Cherry Hinton, 

 near Cambridge, and communicated a sketch to Dr. Greville. 

 The production was however considered of so doubtful a na- 

 ture that it was not published in my ' Gleanings of British 

 Algae,' nor is it included in the English Flora. I did not meet 

 with it again till May 25, 1841, when I found a large mass 

 at King's ClifFe, forming a loosely reticulated mass of tortuous, 

 very elastic, yellows-green threads, several inches in extent, 



* Linn. Soc. Par. 1827, p. 47. 

 f Conspectus Criticus Diatomacearum, p. 30. 

 + Bot. Zeit. 1833, vol. ii. p. 513. 

 Ann. ^ Mag. N. Hist. Vol. vii. 2 G 



