362 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



Podocarpaceae, often made to include! two subfamilies, the Podocar- 

 peae and the Phyllocladoideae, while some students consider the lat- 

 ter to represent a third evolutionary line. 



The Podocarpaceae are to-day as distinctively characteristic of 

 the Southern Hemisphere as the Taxaceae are of the Northern. 

 They comprise over 50 of the 72 existing species of the order. 

 Podocarpus is easily the dominant genus with over two score exist- 

 ing species, and is found on all the southern continents, where it 



forms extensive stands com- 

 parable to those of Pinus in 

 the North Temperate Zone. 



The Phyllocladoideae are 

 today confined to the Austra- 

 lian-New Zealand region but 

 both subfamilies have an ex- 

 tended geological history. 

 Probabh* their oldest authen- 

 tic representative is Palissya 

 (Elatocladus) of the Triassic 

 and Jurassic, which had di- 

 morphic foliage and remark- 

 able lax cones made up of flat 

 lanceolate foliar-like sporo- 

 phylls, with two rows of small 

 seeds in cupules on their up- 

 per (ventral) surface. Palis- 

 sya, to which 10 or a dozen 

 species have been referred, is 

 abundantly represented by 

 sterile twigs in the older 

 Mesozoic of Europe, Asia, and 

 America, as well as in both 

 the Arctic and Antarctic re- 

 gions. 



Another equally old genus, 

 of great interest but not com- 

 pletely known, is Stachy- 

 taxus, which has two or three species in the Ehaetic of Sweden 

 and Greenland. It had yew-like leaves and loose cones, each sporo- 

 phyll of which bore a pair of large seeds on their upper (ventral) 

 face, which are compared by their discoverer (Nathorst) with 

 the modern Dacrydium. Podocarpus itself contains about a score 

 of fossil species which appear to have been abundant and rather 

 widespread during the Tertiary, and are doubtfully recognized in 

 the Upper Cretaceous. The allied genus Nageiopsis, represented in 

 the modern flora by the Nageia section of Podocarpus with about a 



Fig. 25. — View of the fructifications of Stachytaxns 

 (after Nathorst). 



