Notes on Recent Literature. 359 
author’s conception of the plant as a physiological organisation and 
though the reviewer cannot agree with several views that are 
warmly expounded by the author, yet it is pleasant to meet in print 
this vigorous personality and one regrets very much that it is for 
the last time. F.F.B. 
NOTES ON RECENT LITERATURE. 
Recent Researches on Williamsonia. 
[With Two Figures in the Text] . 
S INCE the publication in 1870 of Williamson’s classic paper on 
Zamia ( Williamsonia) gigas, our knowledge of the Bennettitales 
has received few additions from the study of the Jurassic Flora of 
Yorkshire. The materials collected by the earlier workers, 
Williamson, Bean, and Leckenby had been re-examined and 
considerable difference of opinion had been expressed with regard 
to them, but no very definite conclusions had been reached. In 
view of the rather unsatisfactory state of preservation of the York¬ 
shire remains this is not surprising, but it has remained for Professor 
Nathorst of Stockholm not only to contribute very materially to our 
knowledge of these forms, but also to introduce methods of studying 
them which are of the greatest value. It had long been recognised 
that many of the Jurassic fossils were not entirely structureless and 
that by treating them with nitric acid and potassium chlorate, the 
form of the cuticular cells, of the stomata and of spores could be 
made out, but this method had not yielded many important results. 
Professor Nathorst has improved the process and used it with great 
success especially in the investigation of microsporangia. 
The results of the investigations on the “ flowers ” of William¬ 
sonia have been published in two papers, the second of which 
recently appeared. In the first paper 1 he describes his re-investi¬ 
gation of the species previously known ( Williamsonia pecten, W. 
gigas and Williamson’s carpellary disc) together with some 
important new forms (W. spectabilis, W. Lignieri). He further 
describes the flowers of the interesting Swedish Rheetic form 
Williamsonia ( Anomozamites) augustifolia, which he now places in 
a new genus Wielandiella. In the second paper- the Yorkshire 
Williamsonia “flowers” are treated more critically and several 
interesting new species found by Dr. T. G. Halle are described. 
The “ flowers ” of Williamsonia were probably mostly unisexual: 
as yet, no certain case of an hermaphrodite structure has been found. 
In this respect therefore, they probably differ from the American 
Bennettites (Cycadeoidea ). The male flower consisted of a number 
of microsporophylls, more or less united into a cup-shaped structure 
at the base, and either sessile, or as in W. spectabilis, borne on a stout 
stalk. On the free upper parts of the sporophylls sessile reniform 
synangia are seen, in which the microspores were produced. In 
1 PaliLobotanische Mitteilungen, 8, K. Svenska Vet. Akad. Hand., 
Bd. 45, Nr. 4, 1909. 
3 Palaobotanische Mitteilungen, 9, K. Svenska Vet. Akad. Hand., 
Bd. 46, Nr. 4, 1911. 
