THE ORIGIN OF GYMNOSPERMS 



By E. A. NEWELL ARBER, M.A., F.L.S., F.G.S. 



Probably no aspect of botanical research is held to be of 

 greater interest than that which tends to throw light on the 

 ancestry of some race or group of living plants. The study 

 of fossil plant-remains possesses a peculiar fascination in this 

 respect. Although attempts have been made, from a detailed 

 comparison of the organs and the structure of recent plants, to 

 obtain clues as to their lines of descent, it is but rarely, and 

 to a limited extent, that success has been achieved. The 

 tendency to segregate living plants into self-contained groups, 

 by the erection of isolated phyla for their reception — e.g. 

 Coniferales, Cycadales, and the like — as well as the lack of 

 definite evidence as to their probable ancestry, are proofs that 

 for help in these matters we must seek elsewhere. Happily, 

 within the last few decades, Palaeobotany has come to the 

 rescue. The study of Palaeozoic fossil plants, the possibilities 

 of which in this direction were foreseen by Brongniart, and 

 Williamson, among others who bore the brunt of the early 

 reconnaissance or pioneer work in this domain during the past 

 century, has proved especially fruitful in this respect. But 

 the greatest achievement to be recorded, so far, is the clear 

 light which such researches have thrown on the origin of the 

 plants known to botanists as the Gymnosperms. This race 

 includes the four phyla — Coniferales, Cycadales, Ginkgoales, 

 and Gnetales — all of which are still represented, in greater or 

 less degree, in the vegetation of the world at the present day. 

 As opposed to the Angiosperms, the outstanding feature of 

 this group is found in the fact that the seed is naked ; carpels, 

 which in the Angiosperms envelop the seed, being absent. 

 While the solution of the problem of the ancestry of the 

 Angiosperms themselves remains for the future, that relating 

 to the Gymnosperms has now been solved. It is proposed 

 to consider briefly here the bearing of a series of remarkable, 



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