74 Linnean Society. [June 16, 



Read, " On the reproductive Organs of Equisetum." By Mr. 

 Joseph Henderson, Gardener to Earl Fitzwilliam, at Milton Park, 

 communicated by the Rev. M. J. Berkeley, F.L.S. 



Mr. Henderson's observations were made on Equisetum hyemale 

 and other species, and embrace the entire period of development of 

 the sporse and of the thecae containing them. Tlie theca is in the first 

 instance filled with cells of extreme tenuity, in the interior of which 

 the sporae afterwards take their origin. After the appearance of the 

 sporse the containing cells gradually become thickened, and sepa- 

 rate from each other; and at a still later period their walls are 

 marked by spiral sutures, by means of which they are subdivided 

 into two narrow bands with broad and rounded ends. As the sporae 

 approach maturity these bands separate at the sutures, and the con- 

 taining cell is thus resolved into its component parts, the supposed 

 filaments and antherse of lledwig. The sporae, when ripe, have a 

 double membrane, which is rendered evident by the addition of 

 tincture of iodine. In the immature state of the thecse, up to the 

 time when the spiral lines become distinctly marked on the integu- 

 ment of the sporse, they form transparent membranous reticulated 

 bags, the meshes of which have diiFerent directions in difierent 

 parts. When the sporae have attained their full size, a new deposit 

 of vegetable matter is added, and spiral vessels are formed within 

 the flattened cells of which the membrane is comi^osed, and the 

 outlines of which are indicated by the meshes on the surface. In 

 some situations these vessels are true spirals, in others they partake 

 more of the character of the annular. 



While making these observations, Mr. Henderson was not aware 

 that he had been in part anticipated by Treviranus, BischofF, Meyen 

 and Mohl. They difi^er, however, in some particulars from the ob- 

 servations of those physiologists, who also differ from each other. 



June 16. 

 The Lord Bishop of Norwich, President, in the Chair. 



Thomas Harris, Esq., of Kingsbury, was elected a Fellow of the 



Society. 



The President nominated the four following Members of the 

 Council to be Vice-Presidents for the year commencing on the 



