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AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
verified by the more recent work of West,^ that the stelar theory, as usually 
understood, cannot be reconciled with the facts as revealed by a study of 
the Eusporangiatae. The writer has therefore thought it worth while to 
summarize this evidence, and also to add further facts derived from a 
recent study of Botrychium. 
From an extensive series of investigations on nearly all the genera of 
eusporangiate ferns, the writer was forced to the conclusion that a cauline 
stele is either completely wanting in these ferns, or that, where cauline 
stelar tissues are present, they constitute an insignificant part of the fibro- 
vascular skeleton. West's studies on the Marattiaceae confirm these 
conclusions, which, however, as already indicated, seem to have been quite 
overlooked by some of the recent investigators. 
According to Van Tieghem's view, most of the ferns are "polystelic," 
the individual strands of the net-like woody cylinder of the stem being 
considered to be of independent origin, the reticulate structure resulting 
from the coalescence of these independent "steles." Most of the later 
students of the ferns consider the "dictyostele," or reticulate woody cylinder, 
to be a single structure, i.e., the stem is regarded as "monostelic," the 
openings being designated "leaf-gaps" where the leaf-traces join the 
cylindrical cauline stele. In nearly all the recent studies on the stelar 
structures of the ferns, the strictly cauline nature of the axial fibro- vascular 
tissues is apparently taken for granted. 
Brebner^ first pointed out that in the very young sporophyte of Danaea 
simplicifolia the primary fibro-vascular bundle is common to the cotyledon 
and root, and that for a considerable time there is no evidence of any cauline 
stele. Little attention has been paid to these facts by most recent students 
of the ferns, but in a recent paper by West^ the accuracy of Brebner s 
conclusions has been fully recognized. 
The writer's attention was first called to the real state of afifairs in the 
Eusporangiatae as the result of a study of the embryology of Ophioglossum 
Moluccanum.^ 
Many years ago, Mettenius^^ described the young sporophyte of Ophio- 
glossum pedunculosum as consisting at first simply of a leaf and root, the 
definitive sporophyte arising secondarily as a bud upon the primary root. 
Very little attention was given by later students of the Ophioglossaceae to 
this really remarkable discovery, and it has been either forgotten or ignored. 
The writer collected in Java a considerable number of young sporophytes 
^ West, C. A contribution to the study of the Marattiaceae. Annals of Bot. 31: 
361-414. 1917. 
^ Brebner, G. On the prothallus and embryo of Danaea simplicifolia, Rudge. Annals 
of Bot. 10: 109-122. 1896. On the anatomy of Danaea and other Marattiaceae. Annals 
of Bot. 16: 517-552. 1902. 
8 Loc. cit. 
3 Studies on the Ophioglossaceae. Ann. Jard. Bot. Buitenzorg II, 6: 138-194. 1907. 
^° Mettenius, G. FiHces Horti Botanici Lipsiensis. Leipzig, 1856. 
