ffrns and ffrn arrifs. 133 
3000 or more species, it can show only three genera and a 
few over 20 species. 
There is abundant evidence that the Ophioglossaceae 
now in existence are but the scanty remnants of a group 
which formerly was widely distributed and which success¬ 
fully competed with co-existing plants long before the spe¬ 
cialized forms now common were evolved. While Ophio- 
a glossum, as we find it today, may be very 
unlike the first fern-plant (pteridophyte) 
which branched off from the pre-existing 
moss-plants (bryophytes) it is more like 
what that plant must have been than any 
other plant at present known. Kven could 
the theory of some students that our plant is 
an instance of reversion be proved it would 
not alter the case. This little plant, then, 
(Fig. i)isa representative, probably a di¬ 
rect descendant, of the earliest fern-plants, 
which appeared away back in the first part 
of the paleozoic era. Up to that time the 
structure of all plants, algae, fungi, liver¬ 
worts, mosses, had been cellular, though 
prophesies of a more advanced structure 
might have been observed in certain liver¬ 
worts, ancestors of the curious ‘ ‘hornworts’ ’ 
(Anthoceros) now in existence. This ad- 
Fig. 2. vance in structure was accomplished by 
means of the arrangement of certain cells longitudinally in 
such a way as to form what are called vessels. A more rapid 
and efficient circulation was thus established and the evolu¬ 
tion of the higher, more complex plants rendered possible. 
In this way from cellular cryptogams (liverworts and mos¬ 
ses) arose vascular cryptogams (fern-allies and ferns). 
Forms allied to horn wort (Anthoceros) had the most com¬ 
plex structure of any liverwort, and forms allied to adder- 
