74 BOTANICAL GAZETTE [JULY 
material, while low temperatures inhibit it. In cold preparations one finds 
collections of chromatin which stain blue and are called pseudonucleoli. 
SCHRAUMEN found the same in the cells of shoots of Vicia Faba kept at both high 
and low temperatures. GErORGEVITCH did not find them in warm preparations. 
In cold preparations the nucleoli show an increase in size, mass, and numbers.— 
R. Catiin Rose. 
Fossil Osmundaceae.—Kipston and GwyYNNE-VAUGHAN'S have continued 
interesting investigations on the fossil Osmundac In the case of the 
ost important of the species which they describe (T aes Schlechtendalit 
‘eichwald) there can apparently be no a that they have really to do with 
the remains of an osmundaceous fern. y find that in this species the center 
of the stele is cake by the presence ae a mass of short tracheids without any 
admixture of parenchyma, which curiously enough they regard as the equivalent 
of a pith. It is surely begging the question as to the origin of medullary struc- 
tures, to regard tissues which admittedly are entirely tracheary and contain not 
the slightest admixture of parenchymatous cells as equivalent to the medulla of 
the higher plants. The difficulty of regarding the central mass of short tracheids 
in Thamnopteris as a pith is rendered insuperable, apparently, by the fact that 
the leaf traces originate from the stele exactly as in those cases where no pith is 
present, that is without giving rise to any foliar gaps. The views entertained by 
the present authors and the majority of English writers on anatomy encounter an 
additional difficulty in that they are quite unable on their hypothesis to explain 
the presence of internal phloem and internal endodermis in closed steles. These 
find apparently a very simple and natural elucidation in connection with the re- 
duction theory now advocated by a considerable number of American anato 
mists.—E. C. JEFFREY. 
Bennettitales.—NatuHorst‘+ has described the more or less complete repro- 
ductive apparatus of a number of bennettitean forms. There are three species 
of Williamsonia from the Jurassic beds of Whitby and Scarborough, England. 
In these were found in different cases both microsporangia with microspores, 
and seeds. The structure of the microspores is illustrated by admirable photo- a 
micrographs. A new genus (Wielandiella) has a very remarkable vegetative 
organization. The stem branches freely in an apparently dichotomous manne. 
and is quite slender. The cones occur in the forkings of the branches. The 
vegetative structure resembles that of the problematic Anomozamites. The 
cones showed remains of both pollen and seeds. The structure of the microspores 
of a third genus (Cycadocephalus Sewardi) is described. These are remarkable 
for their close resemblance to fern spores. For comparison, a figure of Wel- 
13 Kipston, R., and GwyNNE-VAUGHAN, D. T., On the fossil Osmundaceae- 
Ill. Trans. Roy. Soc. Edinburgh 46: 1909 
4 NatHorst, A. G., Tiledhictanlicke: Skis, 8. Handl. Kgl. Svensk. 
Pues -Akad. 45: no. 4. I9t0 : 
