Life-history of Tetraclinis articulata. 601 
Three, four, and five cotyledons were found respectively in the three 
mature embryos examined. 
The #and z x numbers of chromosomes are 12 and 24 respectively. 
Arguments are brought forward to show that the CallitroTdeae were 
derived from the Cupressoideae through some plant closely resembling 
Tetraclinis. The general trend of evolution is considered to have followed 
a line from Northern to Southern Africa, and thence, by means of a former 
antarctic land connexion, to Australia. Thus Widdringtonia is the most 
primitive of the Callitroi'deae, and differs least from the Cupressoideae, while 
Callitris and Actinostrobus are more specialized. 
This investigation was begun in the Botanical Laboratory of the South 
African College, Cape Town, and completed at the Botany School, Cam- 
bridge. My thanks are due to Professor Seward for placing a room and 
research facilities at my disposal, as well as for the interest he has taken in 
the progress of the work, and for advice and criticism on certain points. 
I am also glad to acknowledge criticism on some cytological points from 
Mr. R. P. Gregory. 
May, 1913. 
Note. — The nomenclature adopted for the families and sub-families 
has been altered somewhat from that used in the writer’s previous papers 
on Conifer morphology. The classification adopted is discussed in a recent 
paper on Conifer classification (Saxton ( 48 )). The alterations in nomen- 
clature have been made in order to conform to the international rules. My 
thanks are due to Dr. C. E. Moss for assistance in the interpretation of 
these rules. 
Literature cited. 
1 . Arnoldi, W. : Beitrage zur Morphologie einiger Gymnospermen. I: Die Entwicklung des 
Endosperms bei Sequoia sempervirens. Bull. Soc. Imp. Moscou, vol. xiii (N. S.), 1899 
(1900), pp. 329-41, Taf. VII, VIII. 
2. : Beitrage zur Morphologie einiger Gymnospermen. V : Weitere Untersuchungen 
der Embryogenie in der Familie der Sequoiaceen. Bull. Soc. Imp. Moscou, vol. xiv (N. S.), 
1900, pp. 449-76, Taf. VII, VIII. 
3. Baker, R. T., and Smith, H. G. : A Research on the Pines of Australia. Sydney, 1910. 
Ball, J. (with Hooker, J. D.). See Hooker and Ball. 
4. Blackman, V. H. : On the Cytological Features of Fertilization and related Phenomena in 
Pinus silvestris , L. Phil. Trans. Roy. Soc., London, B., vol. cxc, 1898, pp. 395-426, 
Plates XII-XIV. 
5. Burlingame, L. L. : The Morphology 01 Araucaria brasiliensis. I : The Staminate Cone 
and Male Gametophyte. Bot. Gazette, vol. lv, 1913, pp. 97-114, Plates IV, V. 
6. Chamberlain, C. J. : Oogenesis in Pinus Laricio. Bot. Gazette, vol. xxvii, 1899, pp. 268-80, 
Plates IV-VI. 
