OF LOWER GREEXSA.XD PLANTS. 203 



Several Tortiary and Cretaceous representatives of the family 

 are known. For an account of Skuhyotaxut and references to 

 what are probably the earliest reliable records of the family, 

 Nathorst's paper (1908) should be consulted. 



Sub-family TAX ACE At. 



This sub-family contains less than twenty living species, 

 principally grouped in three genera, viz. Taxus, distributed in 

 Europe, North America, and Asia ; Gephalotaxu* in China and 

 Japan ; and Torreya in North America, China, and Japan. 

 The forms resemble each other vegetatively in having spirally 

 attached leaves, which are oriented so as to spread from the 

 branch in two series, simulating a flattened pinnate leaf. The 

 plants are principally bushes, shrubs, and shrubby trees, and 

 the wood is peculiar in having tertiary spirals in the secondary 

 tracheids. The ripe female fructification consists of a single 

 seed or a pair of seeds attached to the ends of foliage twigs. 

 This, however, results from extreme cone-reduction, and the 

 reduced cones are to be seen in young stages of the fructifi- 

 cation. The ripe seed is large, orthotropous, and surrounded by 

 a fleshy envelope, either integument or aril. In some respects 

 the massive seeds are more comparable with the Cycads than 

 with those of the other Gymnosperms. 



Genus TAXOXYLON, Unger (revised by Kraus). 

 [Unger, Chloris protog., 1847, p. 33.] 



Diagnosis. " Lignum stratis concentricis distinctis. Kadi! 

 medullares simplices 1-15 cellulis parenchymatosis superpositis 

 format!. Vasa poroso-spiralia subangusta, versus radios un:i 

 serie pororum disciformiuin " ( Unyer). 



In Kraus' (1870) revision of the genera of fossil woods he 

 diagnoses the genus as follows : " Lignum stratis concentricis 

 distinctis ; cellulis prosenchymatosis poroso-spiralibus ; poris 

 magnis, rotundis ; filis spiralibus sinistrorsis, raro pluribus ; 

 cellulis ductibusque resiniferis nullis ; radii's medullaribus sim- 

 plicibus." He adds : " II est souvent difficile de reconnaitre les 

 bois fossiles appartenant a ce groupe, parce que les fibres 

 spiralaires peuvent facilement etre confondues avec les stries 



