1847.] Linnean Society. 345 



podiaceee, which from other points of structure may be supposed to 

 be most nearly related to the fossil, Mr. Brown has named it 

 Triplosporite . 



The structure of the axis, which is well-preserved, distinctly 

 shows, in the arrangement of its vascular bundles, a preparation for 

 the supply of an equal number of bractese. These vascular fasciculi 

 are nearly equidistant in a tissue of moderately elongated cells. 

 The vessels are exclusively scalariform, very closely resembling those 

 of the recent Ferns and Lycopodiacece, and among fossils, those of 

 Psarolites, Lepidodendron and its supposed fruit Lepidostrobus, as 

 well as several other fossil genera, namely Sigillaria, Ulodendron and 

 Diploxylon. 



Mr, Brown does not propose to enter fully into the question of 

 the affinities of Triplosporite ; but contents himself with remark- 

 ing that in its scalariform vessels it agrees with all the fossil genera 

 supposed to be Acotyledonous ; and that in the structure of its spo- 

 rangia and sporules it approaches most nearly, among recent tribes, 

 to Ophioglossece and Lycopodiacece, and among fossils to Lepidostro- 

 bus, and consequently to Lepidodendron. The stem-structure oi Le- 

 pidodendron, known only in Lepidodendron Harcourtii, offers no ob- 

 jection to this view, the vascular arrangement of the axis of its stem 

 bearing a considerable resemblance to that of Triplosporite. To this 

 argument, derived from the agreement between axis of stem and 

 axis of strobilus, Mr. Brown attaches considerable importance, as 

 an equal agreement exists both in recent and fossil Coniferee. 



Mr. Brown adds, that Dr. J. D. Hooker has very recently de- 

 tected, in the sporangia of a species referred to Lepidostrobus, spo- 

 rules united in threes ; there still however remain, in the form and 

 arrangement of the sporangia of that species, characters sufficient to 

 distinguish it generically from the fossil here described. 



The paper was illustrated by drawings, both of the natural size 

 and microscopic. 



Read also a note " On the occurrence of the Potatoe Disease 

 independent of the Attacks of Insects." By J. O. Westwood, Esq., 

 F.L.S., Secretary of the Entomological Society, &c. &c. 



This note, in which the author maintained that the disease which 

 has of late years been so destructive to the potatoe is wholly inde- 

 pendent of the agency of insects, was illustrated by numerous recent 

 specimens of the potatoe-plant, in which the disease had made con- 

 siderable progress in the tuber, while the haulm appeared perfectly 

 healthy ; and on which the ravages of insects, and in particular of 



