130 BOTANICAL GAZETTE [OCTOBER 
rogenous tissue within the loculi, for example, CN .386.11, 12, it is 
not possible to be sure of the nature of the carbonized contents. 
No recognizable spores occur in any of the specimens included 
in class III, and in several series of sections which exhibit the struc- 
ture of the body from apex to base, such as that in CN .391. 23-27, 
the loculi seem to be filled up by concentric series of blackened 
cells, and in some cases have a well defined nerve ending in the 
center (CN .391.26).? 
The majority of the available specimens belong to class III, 
which may be taken to include also specimens such as that in 
CN .393.6A (fig. 13), in which vegetative development obtains to 
such an extent that the conclusion is obvious that they were abortive 
or almost completely so. These specimens are of value as demon- 
strating the extreme condition of the phenomenon, and render 
probable the suggestion that there was some degree of phyllody 
(approximation to pinna structure) even in those of class II. The 
sections showing vegetative development are sometimes slightly 
larger than those in the normal series CN .307.17-10. 
Significance of specimens in classes II and III 
The explanation of the state of these sporangia, purely on the 
assumption of partial sterilization and maceration before impregna- 
tion with calcite, is not wholly satisfactory. In recent plants, 
when sporangia abort, the process affects the sporogenous tissue 
mainly, as in some specimens of. Angiopteris sporangia, where the 
wall and apical crest (annulus) remain unaffected. A mucilage 
gland results in several familiar instances (7,16). In the specimens 
under consideration, however, the loculi show no sign of a mucilagi- 
nous content, but, together with the septa, are represented by @ 
considerable amount of tissue comparable with that in the vegeta- 
tive pinnae of Heterangium, the parent plant. 
Kipston and LANG (10) point out that the sporange in Rhynia 
and Hornea may be regarded as “corresponding to the tip of a 
branch of a thalloid sporophyte, inclosing sunken tetrasporangia.” 
* Tracheids possibly formed from degenerating sporogenous tissue of the ovule 
have been recorded by Trevs (17) in Casuarina, and by the writer (2) in Castanea, 
but it is an unusual phenomenon. 
