On the Development of the Sporangia and Spores 
of Aneimia phyllitidis. 
BY 
WILLIAM CHASE STEVENS, 
Professor of Botany in the University of Kansas, US. A. 
With Plates LXXXIV and LXXXV, 
I N a contribution to the Botanical Gazette, Binford (’07) has advanced 
our knowledge of the Schizaeaceae by a careful study of the sporangia 
of Lygodimn. He confirms the work of Prantl (’81) in all essential respects, 
and carries his research on into the development of the tapetum and 
sporogenous tissue. 
Material which I put through Flemming’s fixative some years ago in 
Strasburger’s laboratory affords me opportunity to give an account of 
Aneimia phyllitidis also in more detail than Prantl has related it. Prantl 
begins with the earliest stage of development of the sporangium, and shows 
that it arises from a single protodermal cell not far from the growing apex 
of the sorophore. A series of sporangia is thus formed in acropetalar order 
along the margins of the sorophore ; and while this is going on the sorophore 
grows faster on its upper than on its lower surface, and so shifts the sporangia 
from their marginal to a dorsal position. This unequal growth at the two 
surfaces is shown in PI. LXXXIV, Fig. 6 . As the sorophore elongates, 
new sporangia continue to be started ; but not all of these come to maturity, 
evidently because, in part at least, those first formed divert nutriment to 
themselves to such an extent that those coming later are starved. 
Prantl reports that the protodermal cell that is to produce a sporangium 
grows out beyond the general level before dividing. My sections do not 
show this. Rather I would conclude from them that a sporangium arises 
from several protodermal cells ; but I do not have all stages complete 
enough for a critical discussion of this point. At the early stages shown 
in Fig. i, a and c , we find a few initials of the sporangium wall, and 
a central cell or initial of the archesporium and tapetum. Anticlinal 
divisions in the wall initials multiply them many times (Figs. 3 , 4 , &c.). At 
the same time the central cell by periclinal divisions cuts off an outer layer 
[Annals of Botany, Vol. XXV. No. C. October, 1911.] 
