1892] Ou the Stem and Sporangium of Botrychium. 215 
ries, running from Ophioglossum to Botrychium Virginianum; 
the latter being closely related to Osmunda and through it, as 
the connecting link, with the Filices, forming the complete 
phylogeny of the Filicinee. With this in view it was thought 
that if the development and mode of growth of the meristems 
of Botrychium Virginianum were known, it would possibly 
show more closely its relations to Osmunda and help to clearer 
views concerning the position of the eusporangiate ferns. 
Dr. Douglas H. Campbell in a comparative study of the 
roots of Osmunda and Botrychium' shows that the roots grow 
froma clearly defined apical cell in the form of a three-sided 
pyramid. From the general fact that a fern grows from the 
same shaped cell in all parts, roots, stem and leaf, it would be 
expected that a cell of similar form would appear in the stem 
of this same plant (fig. 1). It is slightly longer than that of the 
Toot, but has unmistakably the form of a three-sided pyramid. 
In the stem figured the nucleus also appears ina state of di- 
vision. Unless growing very slowly the segments retain their 
distinctness for a considerable time, often the outline of as 
any as three or four being easily traceable (fig. 2); while the 
Segments follow the general rules of segmentation and divide 
y a transverse wall slightly below the center of the cell. The 
Wer part may then divide into several cells by transverse 
and longitudinal walls; and the upper part first by a longitud- 
inal wall into two, then each of these into two or more, thus 
after a time confusing the limits of each segment 
Turning now to the sporangium, we find that in the Filices 
gel Sporangium always arises from a single epidermal 
a which usually, according to Bower’, projects more or less 
ongly beyond the surrounding tissue before segmentation 
ee a transverse wall cuts off a lower cell from which 
aaa evelops, and from the upper one the sporangium pro- 
Tn ead of the sporangium, arises. 
otrychium this distinction cannot be made. The spor- 
Bs — is first noticed as a cell of large size (fig. 3) on the 
belie cape In section, but not protruding beyond the other 
atively | € nucleus in the specimen figured, from its compar- 
arge size and appearance, seemed ready to divide. 
angiu 
N 
zerre, ova . soe apical growth of Osmunda and Botrychium, BotanicaL Ga- 
2 E . 
netic sti The comparative examination of the meristems of ferns as a phylo- 
Y; Annals of Botany, III. 362. 
