654 



amined plants of the red labunmra in Messrs. Lawson's nursery, three years grafted^ 

 and found several of them producing shoots of the yelloiv, but only one of them hav- 

 ino- C. purpureus ; and in the nursery of Messrs. J. Dickson and Sons, several of the 

 plants, two years grafted, have shoots of the yellow but none of i\ie purple. 



The red laburnum first appeared at Paris in 1828, in the nursery of Mr. Adam, 

 and was a hybrid between the common laburnum and Cytisus purpureus. 



Dr. Graham observed that it was difficult to explain the cause of this phenome- 

 non, namely, of mules reproducing the different forms on one plant. It had occurred 

 also in plants of the Cactus tribe, but had no parallel in the animal kingdom --there 

 the general form and habit merely are affected by crossing. He considered the sub- 

 ject to be one of much interest, as the phenomenon was at variance with the existing 

 theories. 



Mr. M'Nab exhibited recent specimens, in flower, of Orchis ustulata and Ophrys 

 fucifera from Kent, which had been kindly procured by Lady Harvey for the meeting. 

 Dr. Douglas Maclagan presented to the Society, from Mr, John Scott, F.B.S., 

 Greenock, a series of specimens of the more important kinds of timber in use for the 

 purposes of ship-building. The author mentioned, among others, the following kinds 

 of timber. : — Yellow pine {Pinm variabilis) from North America. Pitch pine (P. ri- 

 gida) from Carolina. Red pine (P. resinosa) from Quebec. These kinds are chiefly 

 applicable to making deck-planks, or for light spars. 



The American or rock elm {Ulmus Americana) and the black birch {Betula lento), 

 were likewise noticed along with beechwood, as being the kinds best adapted for keels, 

 bottom planks, and other parts of ships which are submersed in water. 



British and American oak, and East Indian or Malabar teak {Tectona grandis), 

 were mentioned as being of very general applicability to the purposes of the ship- 

 wright, as also the African teak, or, as it is often called, African oak — the tree yielding 

 which is still unknown to botanists. Two varieties of hard and heavy woods were 

 pointed out as being occasionally imported among African teak, and having similar 

 qualities, but which are unknown to botanists or wood-merchants. 



Of timbers imported from the West Indies, two deserve remark. The first is the 

 Mora or Morra timber Mora excelsa, Schomb.), which is a large and valuable timber, 

 now introduced in considerable quantity from British Guiana : it has a foetid odour 

 when scraped. The other is the green-heart timber, produced by an unknown tree of 

 British Guiana, a heavy, hard, and valuable timber, well adapted for ship-building, 

 and now extensively used in the Clyde. Dr. Maclagan had sent specimens of the 

 fruit of this tree to Dr. Lindley and Sir W. Hooker, both of whom considered it as 

 Lauraceous, but had been unable to refer it to any known genus. He stated to the 

 Society that this tree was known in Demerara by the Indian name of Eebeeru, and 

 also by the Dutch name Sipeeri ; and that the bark of it had been found, by Mr. Ro- 

 die, to contain a vegetable alkaline matter, which possessed the power of curing agues. 

 Recent experiments of his own had shown that there were two distinct alkalies present 

 in the bark and seeds of this tree. 



Previous to the reading of these papers. Professor Graham, accompanied by a large 

 party, visited the greenhouses, where he pointed out some of the more rare and inte- 

 resting plants, with which they are now literally crowded. It was pleasing to see so 

 many specimens, brought together from every climate and region, in the most thriving 

 and luxuriant state, with scarcely an exception. 



