272 Botanical Society of London. 



Dr. Wilde is of opinion that the reservoirs he discovered were the 

 vat> or mortars in which the shells wire broken up, in order to ob- 

 tain the dye (which lies in a sac in the neck of the mollusc inhabit- 

 ing them,) and showed that it accurately accords with the descrip- 

 tion of Pliny, who states, that the smaller shells (of which those in 

 the specimen are examples) were broken in certain mills. 



BOTANICAL SOCIETY OF LONDON'. 



October 5th. — J. E. Gray, Esq., F.R.S., President, in the Chair. 



Mr. Daniel Cooper, the Curator, exhibited a specimen of the natural 

 living fence mentioned at a former meeting, vol. ii. p. 234. Mr. James 

 Rich communicated a translation from the French " On the Forma- 

 tion of Crystals in the Cellules of Plants." 



November 2nd. — The President in the Chair. 



Dr. F. Bossey read a paper, being the results of an excursion from 

 Woolwich to Cobham, Kent, made in company with several members 

 of the Society. At the commencement of the paper Dr. B. alluded 

 to the general imperfect manner in which the habitats of uncommon 

 species were in general described, and proposed the use of the com- 

 pass in defining particular habitats. Particular attention was directed 

 to the habitat of Polypogon monspeliensis and P. liltoralis, which 

 were discovered in the marshes east of Woolwich, particularly in 

 front of the south of the butt or mound in the Plumstead practice 

 ground. 



On ditch banks, forming the east border of the practice ground, Poa 

 distans, P. procumbens, and P. maritima, were observed, and in the 

 water Zannichellia palustris, Potamogeton pectinatum and Scirpus la- 

 custris with the Polygonum maritimum of Ray, see vol. ii. p. 234. In the 

 hedge banks towards Plumstead a small patch of Erysimum cheiran- 

 thoides was noticed. Passing over Plumstead Common to a road 

 called the King's Highway, Dr. B. found in a little wood on the 

 right the Orobus tenuifolius of Roth. This plant, which Willdenow, 

 Smith, and Hooker agree in regarding as a narrow-leaved variety of 

 0. tuberosus, is considered by Don and others as a distinct species. 

 The characters which are permanent in cultivated plants are given 

 by Mr. D. Don in the 3rd volume of the Memoirs of the Wernerian 

 Society, and sufficiently distinguish it from the common species. 

 In fields, near Darne Wood, the following plants were met with — 

 Linaria minor, El dine and spuria, Adonis autumnalis, Ajuga Chamce- 

 pitys, AnngaUis ccerulea, Galium tricorne, Papavcr hybridum and som- 



