PROF. F. O. BOWER ON APOSPORY AND ALLIED PHENOMENA. 318 
made at Kew from material supplied by him, and thus to suggest a comparison of these 
peculiar modes of development with those above detailed. 
Taking first the subvariety elegans, the specimen showed that the sorus is, as in var. 
plumosum generally, without a normal indusium; before culture on damp soil, it 
already showed signs of abnormal development. The swollen base of the sorus was of 
considerable size and bore sporangia in various stages of development: some of these 
had a mature annulus and contained spores. That these spores, in some cases at least, 
attain maturity is indicated by the fact that prothallia not of vegetative origin were 
occasionally found about the sori, after cultivation on damp soil. Thus this subvariety 
cannot be regarded as an example of complete sporal arrest, but that it is a case of 
partial arrest is shown by the fact that the large majority of sporangia do not attain the 
condition of producing mature spores. Over and above this, the chief peculiarity con- 
sists in the outgrowth of irregular processes from the base of the sorus (Plate LIX. figs. 37, 
38). These were present in small size in the specimens before cultivation, but increased 
in number and size after germination on damp soil: the frond was placed with its lower 
surface uppermost on soil in a pot; presently young frond-like organs became clearly 
visible to the naked eye, growing vertically upwards, without any circinate curvature: 
their form was very variable, being sometimes simply conical and tapering to a fine 
point; sometimes they were variously branched (fig. 39) in a manner similar to that 
seen in the fronds of young Ferns, which they also resembled in their general structure. 
At first no clearly marked axis or apex of a stem was to be seen; this appears to 
originate later. There is no question of intervention of a prothallus in this case, as is 
clearly shown by sections (fig. 40), whieh demonstrate that the tissues of the young 
frond are severally continuous with those of the base of the sorus, and through it with 
those of the original frond. 
The other subvariety, named divaricatum, shows in the main similar characters 
to those of elegans; there is no indusium, the sporangia are in most cases arrested, 
but are not unfrequently developed so as to form an annulus and sometimes spores. 
Irregular outgrowths appear as before, usually in a lateral position below the insertion 
of the sporangia (fig. 41). Sooner or later the apex of the axis is formed, with young 
leaves, covered with brown scales and glandular hairs; sections show, as before, a 
continuity of the vascular and other tissues of the outgrowths with those of the 
parent frond. We have thus, in these two Ferns, examples of partial sporal arrest 
followed by sporophoric budding. 
No doubt a search through the more aberrant forms of the more variable Ferns would 
bring to light other examples of the formation of abnormal growths in connection with 
the sorus, and often associated with a partial or complete arrest of spore-formation ; only 
one further case will be mentioned here, viz. that of a monstrous variety of the Japanese 
Fern Aspidium (5 Lastrea) erythrosorum, Eat., var. monstrosum vel prolificum. Here a 
vegetative bud arises in connection with the basal sorus of the larger pinne or pinnules. 
The sporangia of that sorus develop normally and form mature кро; whether they | 
will germinate ог not I am not able to state. The sori in question lie on Ше асговсоріс 
