218 



THE AMERICAN NATURALIST 



[Vol. XL VI 



tative connection, and the very normal Lycopodium has 

 none. 



Once we talked of the evolution of the strobilus as 

 shown by Lycopodium, Selaginella, and Equisetum, and 

 fancied that we saw in these modern forms the highest 

 expression of the pteridophyte strobilus. Now we know 

 that these strobili of to-day are excessively simple as 

 compared with those of the Lycopodiales and Equisetales 

 of the Paleozoic. The evolution of the pteridophyte 

 strobilus that is in sight, therefore, is an evolution from 

 a complex strobilus to a simple one. 



According to the old morphology of external form, the 

 club mosses were entirely capable of having given rise to 

 the conifers. With some knowledge of structure this 

 idea faded away, except in certain quarters, and the bril- 

 liant discovery of the so-called " seed-ferns " seemed to 

 dispose of it entirely. Now we find among the paleozoic 

 lycopods, notably some of the herbaceous ones, that a 

 seed-like structure has been attained, and we have ' 1 seed- 

 club mosses" as well as "seed-ferns." This does not 

 mean that the club mosses gave rise to conifers or to any 

 other existing group of seed plants, for more important 

 structures forbid it; but it does mean that the paleozoic 

 groups had advanced very far; that the seed-condition 

 may have been attained by several groups of paleozoic 

 pteridophytes ; and that it takes more than a seed to dis- 

 tinguish a "seed-plant." 



These are a few illustrations of the upsetting facts that 

 modern paleobotany has been introducing into the old- 

 time phylogenies of Lycopodiales and Equisetales. 



It is among the phylogenies of Filicales, however, that 

 modern paleobotany has wrought the greatest change, so 

 far as pteridophytes are concerned. The old picture in- 

 cluded a luxuriant fern vegetation during the Paleozoic, 

 which culminated in the Coal-measures, whose so-called 

 "fronds" made up at least one half the vascular flora. 

 The occasional attached synangium or sorus was plainly 

 like those of the Marattiacea?, and since the Marattias 



