382 BOTANICAL GAZETTE [DECEMBER 
Plainly enough, therefore, these eminent botanists, starting 
from very different conceptions, have arrived at the same con- 
clusion, namely, that the central cylinder of the Osmundaceae 
resembles that of the phanerogams. 
_ Itis important to note, however, that heretofore all anatomical 
researches in this family have been confined to the tropical genus 
Todea and the cosmopolitan Osmunda regalis; and that hence 
the conclusion just stated has been based on the phenomena 
presented by these alone. When Van Tiegham proposed his 
‘“stelar hypothesis” several cryptogams besides the Osmunda- 
ceae were cited as exceptionally possessing medullated mono- 
stelic central cylinders. Since then more extended researches 
have been made which have yielded important results. Thus it 
has been shown that the central cylinder of Ophioglossum and 
of Botrychium instead of being medullated monostelic is in 
reality “‘gamodesmic;”* that the central cylinder in the entire 
family Equisetaceae, some of whose species were included in 
the exceptions, is of the same kind;5 and that the central 
cylinder of the genus Helminthostachys is also of the ‘* gamo- 
desmic”’ type.© It is true that Strasburger holds’ that the 
internal endodermis and endodermal sheaths about individual 
bundles are of intrastelar origin, and not of cortical as is the 
external endodermis, and that therefore these exceptions still 
stand; but this objection may be advantageously left for sub- 
sequent consideration. Of the apparent exceptions, the family 
Osmundaceae has remained untouched, and I have undertaken 
the present research on this anomalous case, with the primary 
object of furnishing data that will help determine the proper 
morphological interpretation of its vascular system. 
The family Osmundaceae is a very limited one in point of 
numbers, consisting of but two genera, Osmunda with eight 
species, and Todea with six, and therefore constitutes a very 
*PoIRAULT: Ann. Sci. Nat. Bot. VII. 18: 113. 1893. 
SJEFFREY: Mem. Boston Soc. Nat. Hist. 5:155. 1899. 
*FARMER: Ann, Bot. 13: 421. 1899. 
7 STRASBURGER: Histologische Beitrage. 3:—. 1891. 
