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MICROSCOPICAL SOCIETY OF LONDON. 



March 19, 1845. — Prof. Bell, F.R.S., &c.. President, in the chair. 



Read, a paper by Edwin Lankester, M.D., F.L.S., B.S.E., &c., "On 

 some abnormal forms of Fungi, with Remarks on their Morphology." 

 The Fungus which led to these remarks, was found by Dr. Lankester 

 in the neighbourhood of Cheshunt, in December, 1844. It was a spe- 

 cimen of Agaricus personatus, which was in a decaying state, from 

 the effects of a previous frost. It exhibited in all its parts a normal 

 structure, with the exception of the pileus, in the centre of which, im- 

 mediately over the insertion of the stipes into the hymenium, a second 

 and smaller hymenium was developed. The gills of this were appa- 

 rent, and presented towards the light, and its edges were covered with 

 a pileus, which gradually united itself with that of the lower hyme- 

 nium. There was, however, no appearance of any development of a 

 stipes. On making a section of the whole plant, no connexion be- 

 tween the lower and upper hymenium was discoverable, so that the 

 latter was evidently an independent development. Although too dry 

 to exhibit under the microscope much of the pecuHarity of structure of 

 this class of bodies, sufficient was seen to prove that, whatever might 

 have been the character of the lower or normal hymenium, the upper 

 one was of precisely the same nature. In accounting for this appear- 

 ance, Dr. Lankester considered that in the Fungi, the pileus and sti- 

 pes were to be regarded as the representatives of the leaves, or nutri- 

 tive organs in the higher plants, and the hymenium as the analogue 

 of the flower, or reproductive organs, and consequently, that the influ- 

 ence of cold, or of some o*ther external agent, causing an arrest of the 

 development in the vegetable tissue of the Fungus, would be attended 

 with the development of reproductive tissue, such as we know occurs 

 under similar circumstances in the higher forms of plants. That this 

 view of the office of the parts is correct, he considered might be made 

 out by passing from the Fungi to the lichens, from these to the Hepa- 

 ticae, mosses and ferns, in which the green parts are undoubtedly the 

 nutritive tissue of the plant, and the analogues of the leaves. In the 

 Fungi, however, it should appear that the whole body must be looked 

 upon as the analogue of the flower in the higher plants, the thallus 

 being, in this family, at its minimum of development. Hence, then, 

 just as the calyx and corolla stand in the relation of nutritive organs 

 to the more especially reproductive stamens and pistils, so the pileus 

 and stipes stand in a similar relation to the hymenium. An abnormal 

 form, figured by SchaefFer, presenting two smaller Fungi growing up- 

 on the pileus of a larger one. Dr. L. considered as produced in the 

 same manner as double seeds, or proliferous flowers. — ./. TV. 



