127 
the more primitive type in the Ferns ? 
that fact a measure of farther evidence of the prevalence of 
Ferns with a more bulky sporangium in the earlier rocks 
over those of the true Leptosporangiate type. 
From the above data the conclusion may be drawn that 
though it is not possible absolutely to deny the presence of 
Leptosporangiate Ferns in the primary rocks, still the 
evidences of their occurrence are at least exceedingly rare, 
and the question whether they existed at all in those early 
times is not even yet placed beyond the possibility of doubt 
by observation of microscopic sections r . But, as above 
remarked, it is not the present object to prove their 
absence, but to fully appreciate their rarity in the primary 
rocks, as compared with the Eusporangiate forms. On this 
point Stur 2 has put forward figures relating to the Car- 
boniferous Ferns ; in considering which it is to be 
remembered that many of the Ferns quoted are classified 
by their vegetative organs alone, and not by observation 
of their sporangia : his results may be tabulated as 
follows : — 
Present Flora. 
Carboniferous. 
Ophioglossaceae j 
1 genera 
| species 
3 
2 
l 9 
Marattiaceae j 
1 genera 
[species 
4 
23 
15 
98 
Polypodiaceae (?) | 
j genera 
[ species 
00 0 
0 0 
C* 
4 or 5 
58 
In estimating the value of these figures it must be 
remarked that our knowledge of the present Flora is 
1 Schenk, in his Handbuch (vol. IV, p. 37), writes of the Hymenophyllaceae, 
* one observation due to Zeiller is the only evidence of the existence of this 
family in the older formations;’ and again, speaking of other Leptosporangiate 
Ferns, ‘ they seem to be entirely absent from the older formations, and to appear 
first in the Mesozoic strata.’ 
2 Die Carbonflora, Abh. d. k. k. Geol. Reichsanstalt zu Wien, 1885, p. 41 1. 
K 2 
