94 



ORGANOGRAPHY. 



BOOK I. 



Pinus pinaster, ^1 — sylvestris, H — cembra, /t — larix, ^. 

 — microcarpa f. 



Betula alba and pubescens, ot and ^ — fruticosa gene- 

 rally, -h- 



Corylus avellana, ^t — americana and tubulosa, ^f in their 

 male catkins. 



The whole of this curious question has been greatly simpli- 

 fied by Professor Henslow, in observations printed some 

 months ago for private circulation ; and we are happy to be 

 able, by the permission of their liberal author, to lay them in 

 this place before the public. 



" The scales on a cone of the Spruce Fir [Abies excelsa) are 

 placed spirally round the axis, at equal intervals ; and after 

 eight coils of the spiral, the twenty-second scale ranges verti- 

 cally over the first. If this arrangement be referred to a 

 cylinder, and then projected on a plane cutting its axis at 



