﻿26 SCOTT, Early History of Seed-bearing Plants. 



different main groups sprang from the common, fern-like 

 stock, at different times, and at different points. 



It is an interesting fact that in a wholly distinct 

 group from any we have been considering, that of the 

 Lycopods or Club-mosses, seed-like organs were developed 

 in some of the Palaeozoic representatives. The two genera 

 in which this has been established — Lepidocarpon and 

 Miadesmia (Scott, 'oi ; Benson, '02) — agree in having 

 possessed a single functional megaspore or embryo-sac 

 within the sporangium, and in the enclosure of the sporan- 

 gium or nucellus by an integument, leaving an opening 

 comparable to a micropyle. The whole organ, like a true 

 seed, was indehiscent, and was shed entire. The analogies 

 with true seeds are undoubtedly striking, but there is a 

 total absence of detailed agreement with the seeds of the 

 typical Spermophyta. The Lycopods, as shown not only 

 by these characters, but by their complex anatomical 

 structure, attained an extraordinarily high development in 

 Palaeozoic times. We cannot wonder that it was among 

 them that the great French school of palaeobotanists long 

 sought the nearest affinities with the Gymnosperms. But 

 striking as the analogies are, there is, I think, no proof 

 that they are more than analogies. It appears that Lyco- 

 pods, as well as members of the Fern series, acquired the 

 seed-bearing habit in Palaeozoic times, while approaching 

 the higher plants in other features also. We have, however, 

 no clear indication that they left any descendants among 

 the Spermophyta that have come down to our own times. 



One point that comes out clearly from the facts that 

 we have been considering this afternoon, is that the balance 

 of power among the plants of carboniferous times must 

 have been very different from what we have been accus- 

 tomed to believe. From the days of Brongniart onwards, 

 the Palaeozoic age, represented for our purposes by the 



