OSMUNDACEAE ae 
Fructifications with unmistakable Osmundaceous characters have been 
traced back to the Jurassic period. Several species, referred by Raciborski 
even to the genera Osmunda and Todea, have been found, bearing sporangia 
having the characteristic distribution, form, and structure. But, as Raci- 
borski remarks,’ they are there so highly differentiated that their origin 
probably dates back earlier still. I have myself pointed out that certain 
sporangia even from the Coal period show a detailed correspondence 
of section with ‘those of Zodea.2 Without wishing to urge this similarity 
too far, such comparisons of the propagative organs suggest an early 
origin of the Osmundaceous stock, which is fully borne out by the existence 
of stems, with structure, having characters both external and internal 
comparable with those of the Osmundaceae. Such are the stems described 
from external characters as Chelepteris by von Eichwald (Lethaea Rossica), 
from the Permian: while these lead towards Gvrammatopterts, a form 
referred to a Botryopterid affinity. These all share with the modern 
Osmundaceae the general characters of an upright radial stock, with 
closely disposed leaves, the bases of which persist. It will be shown 
below that the anatomical details support the recognition of these stems 
as a probable phyletic sequence. 
SPORE-PRODUCING MEMBERS. 
The development of the sporangium in the Osmundaceae differs from 
that of most Ferns in the variety of its details in different individual 
sporangia, even when they may be in 
close juxtaposition on the pinnule. The 
sporangia fluctuate between two types, as. 
as shown by the details both in (\ 
Osmunda and in Todea: these are = 
illustrated by Figs. 295, which were 
drawn from actual sporangia of Zodea 
barbara, and are not diagrams. They 
represent extreme types, the one with Young sporangia of Tedea barbara in longi- 
segmentation resulting in a square- ween es different’; modes. “of 
based archesporium as seen in the 
Eusporangiates : the other showing the conical type characteristic of Lepto- 
sporangiate Ferns: the latter is the commoner in the Osmundaceae. 
The’ differences of individual detail start from the very first, as is seen 
from Fig. 296 a, in which two sporangia are shown already projecting as 
convex. outgrowths, but the segmentation is not uniform: it is further 
Fic. 295- 
lEnglers Jahro., vol. xiii, p. 7. For further data see also Seward and Ford, Lez. 
Trans., vol. vi., p. 250, etc. 
2 Annals of Botany, vol. v., 1891, p. 109. Renault has also described as Todeopsis 
primaeva a fern sporangium from the Culm of Sanost, having Osmundaceous characters, 
Gites ‘Mineraux, Paris, 1896, p. 21. get ‘ ges 
