I lO 
BEAUTIFUL FERNS. 
the frond. Many sporangia are imperfectly formed, and the 
spores are very rare : — both Mr. Faxon and I have searched 
many fronds, and found very few spores, which however 
were ovoid-reniform and minutely roughened. Milde’s ex- 
perience is similar, and he thereupon argues the possibility 
of this fern being a hybrid, though in his latest writings 
he considers it a variety of A. cristatum. * 
Soon after the early fertile fronds, or at the same time, 
but from small side-branches of the root-stock, are produced 
much smaller sterile fronds, the segments of which are less 
distinct, more confluent, and less deeply toothed. Later in 
the season,* another set of fronds is produced, intermediate 
in size and outline, but with pinnatifid pinnae and oblong 
obtuse confluent segments more like the fertile fronds of A. 
cristatum. These fronds may be either fertile or sterile. The 
spring fronds decay in the late autumn, but those of the 
late growth remain green till late in the winter. All this is 
clearly pointed out by Mr. Moore, and my own observations 
confirm his remarks. 
* “ It is remarkable that the spores of the numerous specimens I have examined 
were either colorless and without contents, or black, as if carbonized, and that the sporan- 
gium itself was often filled with only a shapeless dusty mass.” (Nov. Acta. Acad. Nat. 
Cur. xxvi., ii., p. 536) — “Of this plant I have seen so many specimens, that I may justly 
contend that it is in very truth intermediate between A. cristatum and A. spinulosum, so 
that the first passes gradually into the second, and no absolute distinctions may be found 
between A. cristatum and A. spinulosum.” (Fil. Eur. et Atl., p. 131.) 
