THE ORIGIN OF GYMNOSPERMS 233 



single, pre-existing race, or polyphyletic, from several distinct 

 ancestors. 1 



Those who hold the former view probably constitute a majority 

 at the present time. So far as the fossil evidence is concerned, 

 they are inclined to regard all the modern families of Coniferae 

 as derived from a very ancient, and now long extinct group, 

 the Cordaitales. This race of seed-bearing plants flourished 

 in Palaeozoic times, before the earliest appearance of the 

 Coniferae, and is now well known — thanks to the researches of 

 Grand'Eury and Renault. Cordaites itself is the typical example. 

 This plant was a tall tree, bearing a crown of branches above, 

 which, in turn, bore long, strap-shaped leaves. The veining of 

 the leaf was parallel, thus strongly recalling that of a Mono- 

 cotyledon, a comparison which, however, is quite without any 

 value as a clue to affinity. Among the leaves were borne catkin- 

 like bodies, the inflorescences, consisting of male and female 

 flowers. The seeds were naked, and altogether agree closely 

 with those of the Cycads. 



As regards the vegetative characters, " the Cordaiteas hold 

 the balance very evenly between Cycads and Conifers." 2 The 

 female inflorescence recalls that of a Conifer, but does not 

 resemble a Cycadean cone in the least. The male is quite unlike 

 anything found among modern G3^mnosperms. It is in this 

 group, in many respects a less specialised one than any Gymno- 

 sperm now existing, that those who hold to the Monophyletic 

 theory seek for the origin of the Coniferales. At any rate, 

 the study of fossil botany has produced evidence of an ancient 

 group of Gymnosperms, neither identical with the Conifers nor 

 with the Cycads, but combining certain characters common to 

 both ; and the existence of this group must ever continue as 

 a factor to be taken into account in any discussion of the 

 origin of the Coniferae. 



In this connection it may be pointed out that, fortunately, 

 we have already a clue as to the possible ancestry of the 

 Cordaitales themselves, thanks to the researches of Dr. Scott. 3 

 While, in the internal structure of the stem of many of their 

 later representatives in geological time, we find a condition of 

 affairs almost identical with that of an Araucaria among 

 living Conifers, yet some of the earlier members possessed, 



1 Oliver, Arber, Scott, and Seward, 1906. 



2 Scott, 1900, p. 441. 3 Scott, 1902. 



