io6 
K. Miyake. 
Thus, as already mentioned, there is considerable variation in the 
precise point at which the different phases of change in the orienta¬ 
tion of the xylem and phloem of the cotyledonary bundles takes 
place, and a further complication is introduced by differences in the 
level of insertion of the plumular traces. But the essential uni¬ 
formity of the series of individual cases making up the general type 
cannot be mistaken. 
The extreme case described by Mr. Hill in Piper, in which the 
whole change of orientation occurs in the cotyledons themselves, 
seems to have been previously described and figured only in Raphanus 
niger (Gdrard, loc. cit. PI. 15, Fig. 15). We have, however, found 
precisely the same case in numerous other Rhoeadales; indeed it 
seems characteristic of that group. 
The importance of this simple and striking type of hypocoty¬ 
ledonary structure is sufficiently apparent from its uniformity in the 
orders named. The temptation to regard it as of phylogenetic 
importance in relation to the Dicotyledons as a whole, already 
strong in view of its occurrence in the almost certainly primitive 
Ranunculacem and their allies, is distinctly increased by its dis¬ 
covery in the Piperaceae. But it is as yet too early to say more. 
The striking diversity in the vascular structure of the seedlings 
existing between many of the Liliaceous genera described by Miss 
Sargant (loc. cit.) and the similar diversity found by Mr. Wright in 
different species of Diospyros, 1 afford some parallel to the difference 
described by Mr. Hill between Piper and Peperomia, a difference 
which is in striking contrast with the uniformity exhibited by the 
Ranunculaceae, Papaveraceae and Cruciferae. 
The publication of Mr. Hill’s full results will be expected with 
much interest. 
1 Herbert Wright, Ann. Roy. Bot. Garden, Feradeniya, 1903. 
University College, 
April, 1904/ 
A. G. TANSLEY. 
E. N. THOMAS. 
REVIEW. 
ON THE STRUCTURE AND PHYSIOLOGY OF THE 
CYANOPHYCEAE-CELL. 
By F. G. Kohl. 1 
I N spite of the efforts of numerous investigators the problem 
of the structure of the Cyanophyceae-cell remains still 
unsolved. According to some the Cyanophyceae-cell represents a 
mass of protoplasm without a nucleus, while others maintain that 
1 F. G. Kohl; Ueber die Organisation und Pliysiologie der 
Cyanophyceenzelle und die Mitotische Teilung ilires 
Kernes. Svo. pp. 240., pis. 10. Gustav Fischer, Jena, 1904. 
Price 20 in. 
