Notes. 
289 
account for all the diversity in their respective reactions. These 
results and considerations support Professor Vines’ criticisms passed 
on Pringsheim’s conclusions as to the seat of origin of the oxygen 
evolved during assimilation. Further discussion of the many points 
here raised would, however, be out of place within the limits of a note, 
but I hope to return to the subject at length on a future occasion. 
J. BRETLAND FARMER. 
Royal College of Science, London. 
A NEW CASE OF POLYSTELY IN DICOTYLEDONS.— The 
stems of Angiosperms and the roots of vascular plants in general may 
be considered as exhibiting almost universally a monostelic structure. 
As regards the former, the only exceptions hitherto described are the 
Gunneras, and the Primulas of the section Auricula , which are poly- 
stelic, and the Nymphaeaceae with a few others, chiefly water-plants, 
which are astelic. In the case of roots, no exception was known 
until polystely was recently discovered in the adventitious roots of 
certain Palms, Areca, Ver s chaff eltia , &c., by Cormack 1 . 
While making a comparative examination of certain Nymphaeaceae, 
the results of which I hope to publish fully at a later time, I have 
found that in addition to astely, this remarkable order also presents 
cases of polystely. 
In certain tropical and sub-tropical species of Nymphaea , the 
plants, at the end of each vegetative period, form numerous tubers 
as a means of surviving through the approaching dry season. Some, 
as Nyviphaea rubra , N. stellata , &c., according to Raciborski 2 , convert 
the whole of the lower part of the rhizome into a tuberous starch- 
laden structure coated with periderm. Others, as N. flava and N. 
tuberosa , examined by me, bear their tubers on lateral stalks of greater 
or less length. In N. flava they form very long stolons or runners 
(30-40 c. m. long), which are but slightly thickened at their termina- 
tions, where they bear below a large number of swollen starch-laden 
sausage-shaped roots, and above a number of buds protected by scale- 
leaves. These runners exhibit a truly polystelic arrangement of their 
vascular tissues, four to five groups of which are found running in the 
lacunar ground-tissue, each consisting of three to four vascular bundles 
grouped around a common centre where their xylems are confluent. 
1 In a paper read before the Linnean Society early this year. 
2 Raciborski, Flora, Band lxxviii, p. 262, 1894. 
