Review. 
209 
elsewhere. The endodermis in this species may also extend inwards 
through the foliar gaps, while the pith resembles the cortex in 
containing brown sclerotic strands ; this last character re-appears 
in O. regalis and Todea superb a , but neither internal phloem nor 
endodermis occur in any species but O. cinnamomea , nor have they 
in any case been found in the young plant. The author regards the 
various species as forming a “ series of degeneracy,” 0. cinnamomea 
being the least reduced. In support of his theory of reduced 
“ polystely,” Professor Jeffrey brings forward the concentric nature 
of the foliar bundles and the mesarch structure of those in the 
stem, but as both these characters appear in protostelic stems 
( e.g . Gleichenia , Heterangium ) it is difficult to see how they affect 
the question. The author’s theory of reduction is no doubt a 
tenable one, but as it receives no support from the development of 
the young plant, its basis is weak, and many botanists will probably 
prefer to read the series the opposite way. 
The vascular system of the Ophioglossaceas receives the same 
interpretation; “ evidences of its derivation from an originally 
concentric stelar tube are, however, not so abundant” (p. 128). 
In the case of the Schizaeaceae, Professor Jeffrey agrees with 
Mr. Boodle as to the facts; he thinks it probable, however, that the 
medullate type of Schizaea has been derived by reduction from the 
“ polystelic ” structure of Mohria and Anemia. This is a difficult 
question, on which we may hope for new light from further investi¬ 
gations now in progress. 
The chief point in the author’s remarks on the Gleicheniaceae 
is his ingenious comparison between the petiolar bundle of certain 
Gleichenias and the stele of the Osmundaceae. In both cases he 
finds that the enclosure of ground-tissue within the vascular system 
is correlated with the disappearance of internal phloem. 
The Cyatheaceae show a general agreement with the 
Marattiaceae; the author’s account of the Polypodiaceae, however, 
contains some new points of great interest. He finds that in a 
considerable number of these Ferns, e.g. various species of A atro¬ 
phy um and Vittaria , Davallia stricta and Adiantum pedatum, the 
internal phloem and endodermis are wholly or partially lost. In the 
case of Antrophyum reticulatum, the pith at the same time assumes 
a structure different from that of the cortex, and the type of stele 
comes to resemble that of a Botrychium. These interesting results 
appear to constitute the strongest part of the author’s case; he has 
here established a strong presumption that the medullated-mono- 
