162 Botanical Society of Edinburgh : — 



under a bright clear sky during the dry season, though there also its 

 growth is checked in the cloudy and rainy months ; and yet the 

 sunny season of the mountains is subject to night chills, or even 

 frost at certain elevations, whereas tlie wet mouths are not so. Light, 

 therefore, seems the essential condition to the recurrence of the more 

 luxuriant vegetation, as observed in the successive climates of the 

 Andes. 



4. "On some of the leading Plants of the lowest zone in TeneriflFe," 

 by Professor J. Piazzi Smyth. 



The author described the manner and characteristics of growth of 

 the chief plants as met with advancing from the sea-coast inland, 

 and Ibund both the indigenous and cultivated plants to exhibit a 

 poverty of growth as compared with many other lands in the same 

 latitude (28°). The cause of this, he thought, was owing to the 

 special predominance of the trade-wind throughout the archipelago 

 of the Canaries during the whole of the summer season, and to the 

 want of rain, and the low temperature which that wind produces, 

 both primarily and secondarily. The author treated at length on the 

 Draccena Draco as being, ^9«/* excellence, the characteristic plant of 

 the lowest zone of Teneriffe. 



June II, 1857. — Professor Fleming, President, in the Chair. 

 The following papers were read : — 



1 . " On the Identity of Achorion Sckonleini, and other vegetable 

 parasites, with Asperyillus ylaucns,'" by Mr. John Lowe. 



The object of this communication was to show the relation which 

 exists between the parasitic growth in Porriyo favosa and other skin- 

 diseases, and a common species of fungus, Asperylllus ylaiicus, and 

 to establish the identity of a number of these forms which have 

 hitherto been regarded as specifically distinct. A quantity of favus 

 crust having been procured from a case of Porriyo Ivpinosa, a por- 

 tion Avas immersed in pure glycerine, another was placed on cheese, 

 and a third in a solution of raw sugar. The first did not germinate, 

 but became disintegrated after about ten days. This Mas ])robably 

 owing to the temperature of the fluid not being sufficiently high, as 

 it is well known that the yeast-plant grows with facility in the same 

 medium, at an elevated temperature, during the manufacture of 

 butyric acid. The cells placed on cheese also failed to germinate, 

 and died in about the same time as those put into glycerine. Those 

 immersed in the saccharine solution gave a different result. At the 

 end of forty-eight hours the cells had become swollen and more oval 

 than at first ; on the day following, they began to unite into monili- 

 form chains forming a mycelium, the filaments of which after a time 

 were observed to contain graiudes and nucules. At the end of a])out 

 a month, the perfect fructification of Asperf/illus glavcus appeared. 

 During the growth of the plant, the different stages of development 

 were observed daily, under the microscope, and the whole of the fol- 

 lowing species (so-called) were found accurately represented, so far 

 as appearance goes, by one or other of the forms produced : Micro- 



