2 Linnean Society. [Nov. 21, 



tive power, Mr. Graham considers that it arises from the natural de- 

 cay of their mycelium or internal filaments, which he has found tra- 

 versing the tissues of plants, beneath the external tufts of mildew. 

 That the tissues of plants are extensively permeated by this myce- 

 lium, has been frequently shown by the Rev. M. J. Berkeley and other 

 mycologists ; but the important fact that these roots (as they may 

 be termed) die within the tissues of plants, along with their super- 

 structure, assuming a dark colour in decay and ultimately dissolving 

 into a viscous mass, has hitherto, Mr. Graham states, escaped the 

 notice of authors. Decaying matter being thus secretly introduced, 

 corrupts the adjacent tissues, and in many cases spreads over the 

 entire plant and kills it. Mr. Graham states that he has arrived at 

 this conclusion after repeated examinations under powerful micro- 

 scopes, but that the effects are visible in some cases to the naked 

 eye. Experiments made by enclosing tufts of mildew in the sap of 

 those plants on which it grew, also exhibited the results above stated. 



November 21.' 

 Edward Forster, Esq., V.P,, in the Chair. 



Mr. A. Adams, F.L.S., presented specimens of the habitations of 

 a species of Spider, collected by Captain Sir E. Belcher on the north- 

 west side of Majambo Bay, in the Island of Madagascar, and com- 

 municated by him to Mr. Adams, with the particulars of their history. 

 It appears that on this coast the north-east wind blows so constantly 

 and to such a degree, that it would effectually destroy the more usual 

 forms of web ; to remedy which, the spiders of the locality collect 

 together a number of small even-sized grains of quartz-sand, of which 

 they fabricate a tolerably firm horn-shaped habitaculum, uniting them 

 together by means of a fine loose web, which they hang from the low 

 shrubs that grow upon the sand, and thus suspended defy the breeze 

 and ride out the gale in safety. 



Mr. J. Clarke exhibited specimens of Filago Jussicei and Melilotus 

 arvensis, found near SaflFron Walden, Essex. 



Mr. J. Hogg, F.R.S., F.L.S., exhibited dried specimens of a plant 

 ■which he regarded as a double variety of Matricaria Chamomilla, L., 

 found by himself on the saridy road- side near Whitburn, Durham, to- 

 gether with a coloured drawing of the natural size. He stated, in a 



