MATONINEAE 567 
Sporangia in which the annulus is not tilted are shown in Figs. 317 A, C; 
from these it will be seen that the annulus starts close to the stalk ; it 
first curves downwards towards the basiscopic side of the sporangium, 
then circling round it, curves upwards, the highest point being reached 
at the distal end of the sporangium ; passing this it again curves down- 
wards towards the basiscopic side, and stops short at some distance from 
the stalk; it is at this point that the dehiscence takes place, but though 
the cells immediately beyond the end of the annulus may show some 
regularity of division, there is in Matonia no highly specialised stomium 
as is the case in most Leptosporangiate Ferns. Fig. 317 (the central 
Fié. 317. 
Matonia pectinata, A,B, C and the central figure represent the mature sporangia in 
various aspects. /=young sorus; 2, 7=indusium; s=sporangium. £=sporangium 
with cap-cell; @=acroscopic, J=basiscopic side. D=sporangium with tapetum 
doubled. A-Cx50. D-FX 200. 
figure) shows the rupture; it also shows a case of the annulus stopping 
short of the stalk on either side, and that there is not here any 
continuous series of non-indurated cells, such as that seen in Loxsoma. 
Thus MMZatonia has a sporangium with a short and massive stalk and 
a large head, in which the annulus is not of a highly specialised, nor 
even of a constant type, though in its main features it corresponds to 
that of the Gleicheniaceae. It differs here, however, in its variability, 
its lateral dehiscence, and in the comparatively small output of spores. 
Of the fossil Matonineae the sori are’ best known in Laccopteris, which 
is practically identical with da¢onza in the size, disposition, and structure 
of the sporangia and spores, but differs in having apparently no indusium 
(Fig. 318). Probably, however, the sori of Matonidium and of Microdictyon 
