MARATTIACEAE 513 
view of its origin, since its sporangial structure is closely similar to that 
of dugiopterts, while such elongated sori are absent from the corresponding 
fossil types. A similar elongation of a synangial sorus of the JZaratztra- 
type, 50 as to extend the full length of the vein, would give the condition 
seen in Danaea (Fig. 283 J, K, or better in Fig. 286 A); here also the 
sporangia are disposed as in Jarattia, but differing in the minor fact 
FIG. 283. 
Sori and sporangia. A, B=Angiopteris crassipes, Wall, A=sorus. B=two 
sporangia, one in surface view from without, the other cut longitudinally. C, D=Arch- 
angiopterts Henryt, Christ et Giesen. C=sorus. D=two sporangia in section. #4, F#= 
Marattia fraxinea, Sm. #=synangium; /=the same in section. G, H= Kaulfussia 
aesculifolia, Bl. G=part of the lamina seen from below, with three synangia; the 
numerous small circles on the leaf-surface are stomata. H/=section through a synangium. 
» K=Danaea elliptica, Sm. /=two synangia; A’=section through a synangium. 
4, B, £, G, J after Bitter. C, D after Christ and Giesenhagen. /, A, XK after 
Hooker-Baker. From Engler and Prantl, Nat. Planzenfam.). 
that the valley between the rows of them is almost levelled up, and the 
sorus thus forms a solid cake. It will be shown shortly that developmental 
details support the view that such elongation has actually taken place, 
while the fact is worthy of note that the length of the sorus varies greatly 
in different species of Danaea. And lastly, in Kazlfussia the synangial 
association of the sporangia together in the circular sorus is on the plan of 
Marattia and Danaea (Fig. 283 G, H). The origin of the numerous sori 
by fission from the Dawaea-type as the lamina expanded has already been 
2K 
