PHYLOGENY 439 



In general, the evidence indicates that the Taxodiaceae and Cu- 

 pressaceae came from the Abietaceae, perhaps originating as a com- 

 mon line which later differentiated into the two families. Jeffrey, 

 who strongly supports the theory that the Abietaceae are the an- 

 cestral stock, believes that the two families were differentiated from 

 that stock earlier than the Araucariaceae. The other two families, 

 Podocarpaceae and Taxaceae, constituting the Taxares, certainly 

 belong together. 



In the Podocarpaceae the scales of the ovulate cone, and the spo- 

 rophylls and spores of the staminate cone, indicate relationship with 

 the Abietaceae. The wood is similar to that of the Cupressaceae and 

 Taxodiaceae. It seems possible that a thorough study of very 

 young ovulate cones might limit somewhat the application of the 

 old phrase "conifers without cones." 



In the Taxaceae, Cephalotaxus seems to be the most primitive 

 genus. The ovulate strobilus looks like a cone, and has several ovulif- 

 erous scales with young ovules, but usually only one ovule, the 

 terminal one, develops. In Taxus usually one ovule develops. Oc- 

 casionally two ovules develop and three have been known to start. 

 A study of the development of the young ovulate strobilus in ma- 

 terial which is fruiting superabundantly might be suggestive. Such 

 material was noted on the" estate of Reginald Cory Esq., at Duf- 

 fryn, near Cardiff, Wales. This Taxus baccata was pruned to form 

 an out-of-door room — without a roof — and the pruning may have 

 caused the extreme production of seed, which gave a reddish tinge 

 to the walls. Possibly such material might show ovules in the axils 

 of the numerous bracts, and indicate the ancestral condition of 

 Taxus. 



The Taxaceae are not known with certainty below the Cretaceous, 

 although their morphological structure would indicate a greater age. 



It seems safe to say that from the Carboniferous onward the two 

 great lines, Cycadophytes and Coniferophytes, have been distinct. 

 They have some common characters, but the general outline of the 

 life-history is the same in all seed plants, and the pteridophyte 

 structures from which the seed evolved are similar, even in lycopods 

 and ferns. If the two great lines of gymnosperms had a common 

 origin, it is still to be demonstrated. 



