xii 



"Among the Coniferae proper or Pinaceae a few 

 changes have been made from the grouping of Bentham 

 and Hooker in accordance with the fuller knowledge of 

 certain points of structure that is now available. 

 Tetraclinis is proposed as a distinct genus, represented 

 by the North African Callitris quadrivalvis, on the 

 ground of its structure and geographical distribution. 

 Widdringtonia is separated from Callitris for similar 

 reasons. 



"The sub-divisions of Cupressus and of Thuya have 

 been bandied about between the two genera. The genus 

 Cupressus, as here understood, includes the Cypresses 

 proper and the so-called flat Cypresses (Chamaecyparis), 

 which Bentham and Hooker place under Thuya, and 

 which others prefer to consider as a separate genus. 

 Retinispora, it is now well known, has no claim to a 

 separate generic position, the so-called species of this 

 genus being merely stages of growth of particular species 

 of Thuya, Juniperus, Cupressus, etc* This is proved by 

 the occasional occurrence of many of these forms on the 

 same bush. The North-Western American Thuiopsis, 

 placed under Thuya by Bentham and Hooker, is more 

 like a Cupressus, whilst the Japanese plant known under 

 the same generic name is a true Thuya. Probably the 

 fusion of Cupressus and Thuya into one genus would be 

 the most natural arrangement, but in practice the incon- 

 venience of such a grouping and -the consequent 

 confusion of the nomenclature would be almost 

 intolerable. 



" Pseudolarix of Gordon is shown by the male flowers 

 to constitute a distinct genus, as was indeed suspected 

 by Bentham. 



