102 Report of Botanical Section. 



20th December, 1843, — The President in the Chair. 



The following members were elected: — Messrs. Robert Stewart, 

 John Geddes, James Connell, and Alex. Grant. 



Mr. Keddie reported that the Botanical Section had met for tho 

 first time on the 18th, when the office-bearers were chosen. Ho also 

 read tho following : — 



Report of Botanical Section, 18th Dec. — Dr. Balfour in the Chair. 



The Botanical Section met for the first time on Monday evening. 

 Office-bearers were appointed — a list of whom has been given in to 

 the General Secretary. 



Mr. Gourlie presented to the herbarium specimens of Cryptogamic 

 plants, from British Guiana, gathered by Dr. W. H. Campbell. 



Dr. Balfour presented specimens of Juncus suhverticillatus, Sagina 

 apetala, /3 glabra, and Impatiens fulva, from Sussex. 



Dr. Balfour read a letter from Professor Connell of St. Andrews, 

 giving an analysis of the substance called vegetable ivory, the product 

 of a palm named Phytelephas macrocarpa. Mr. Connell has determined 

 the presence of an azotised substance, which seems to have all the 

 properties of vegetable casein. He has also detected vegetable 

 albumen and oily matter. Specimens of the fruit of the ivory palm, 

 and of the horny seed of the Doom palm, were exhibited. 



Dr. Balfour also read extracts from a communication by Mr. J. 

 Ralfs, of Penzance, on the natural order Desmidiacece. This order 

 includes plants which are closely allied to the lowest classes of 

 animals, and have been looked upon by Ehrenberg and others as of 

 an animal nature. Mr. Ralfs considers them as distinct from the 

 Diatomacece, under which tribe they have been usually included. Tho 

 latter have a siliceous covering, and, after being gathered, quickly 

 acquire an offensive odour ; while the desmidiacea3 have no siliceous 

 covering, and are remarkable for the length of time during which 

 they may be preserved in a moist state without material change. 



The desmidiacea) are minute plants, formed in fresh water, and 

 often forming finger-like tufts at the bottom of pools. They consist 

 entirely of cells, which divide in a remarkable manner, and thus give 

 rise to peculiar motions, which have led some authors to consider them 

 of an animal nature. Mr. Ralfs, however, shows that these motions 

 by division take place in many true algre. He also shows that tho 

 desmidiacea) exhibit distinct evidences of the presence of starch on 

 addition of tincture of iodine ; and on tliis account, too, ho considers 

 them as of a vegetable nature. 



The views of Meyen, Dalrymple, and Bailey were brought forward 

 and discussed. Mr. Ralfs reconciled conflicting opinions, by showing 

 that starch granules aro only to be detected at certain periods of 



