XLHI] CLASSIFICATION 123 



this protrudes through the micropyle : in Fitzroya patagonica the 

 prolongation of the integument as a micropylar tube with a stigma- 

 like terminal expansion is particularly striking. There is no 

 regular pollen-chamber as in Cycads and Ginkgo, but in Pseudo- 

 tsuga^ a two-storied chamber, analogous to the pollen-chamber, is 

 formed by a knee-like bend in the integument. A pecuhar type 

 of pollination characterises Araucaria : the microspores germinate 

 on the ligule or on the megasporophyll and their tubes grow over 

 or into the scale-tissues on their way to the ovule^. The archegonia 

 of Conifers usually occur at the apex of the proth alius and are few 

 in number, they are separated by a few layers of cells (Abietineae) 

 or form a compact group (Cupressineae). In some Podocarps 

 there may be as many as 14, in Taxodium 34, in Agathis 60, 

 irregularly distributed on the sides of the prothallus. In Widdring- 

 tonia^ 100 archegonia are recorded occupying a lateral position ; in 

 Actinostrobus* Saxton has discovered groups of laterally placed 

 archegonia. In Sequoia^ the archegonia are also numerous and 

 not confined to the apex. It is an open question whether or not 

 the greater number and irregular disposition of the archegonia 

 are primitive features. The occasional occurrence of lateral 

 archegonia in Pimcs may be a revival of an older habit. 



Classification. 



The result of recent research into the morphology and life- 

 histories of genera demand certain changes in the generally 

 adopted grouping. The following classification is an attempt to 

 give clearer expression to the inter-relationships of existing 

 gen era ^. Arnoldi ' proposed to withdraw Sciadopitys from Sequoia, 

 Taxodium, and other members of the Taxodineae as the type of a 

 separate family ; he also suggested the isolation of Sequoia. The 

 more recent work of Coker^ and Lawson^ favours the removal of 

 Taxodium and Cryptomeria . to the Cupressineae. Miyake's re- 

 searches-'^'' point to a similar affinity in the case of Cunninghamia. 

 The genera Athrotaxis, Fokienia, and Taiivania are placed tenta- 

 tively in the Cupressineae. The family-name Callitrineae, first 



1 Lawson (09). " Thomson (07); Eaiiiea(13); Burlingame (13); (15). 



3 Saxton (10). * Ibid. (13). = Shaw, W. R. (96); Arnoldi (01). 



« See also Saxton (132). 7 Arnoldi (01); Lawson (10); Radais (94). 



8 Coker (03). » Lawson (04), " Miyake (10). 



