332 
The British Association at Sheffield. 
particularly with the structure of the ovary wall. Mrs. Thoday 
discussed “ The Morphology of the Ovule of Gnetum africanum ,” and 
concluded that it is more primitive than that of Welwitscliia. 
Professor F. W. Oliver next gave a paper “ On the Diversity of 
Structures termed Pollen-Chambers,” in which he showed that 
several of the lesser known fossil seeds possessed a nucellar apex 
of a much more complex character than that found in Lagenostoma 
or Physostoma. The author suggested some interesting comparisons 
between these seeds and those of some of the Medullosae and also 
Ginkgo and Cycads. A lengthy but very interesting afternoon 
session concluded with a paper “On the Stock of Isoetes” by 
Professor W. H. Lang. Dr. Lang’s explanation of the downwardly 
growing root-bearing region, with its depressed and hidden apex, 
was thoroughly convincing. It throws welcome light on an obscure 
morphological problem. 
On Tuesday morning a number of physiological papers were 
read. Mr. S. Mangham gave an account of some experiments he 
made in order to determine “The Paths of Translocation of Sugars 
from Green Leaves.” His results furnish positive experimental 
proof of Czapek’s belief that the sieve-tubes alone are responsible 
for rapid translocation over long distances. Mr. D. Thoday next 
discussed “ Assimilation and Translocation Under Natural Condi¬ 
tions,” dealing particularly with increases in dry weight of both 
attached and detached leaves under varying experimental conditions. 
Mr. A. S. Horne read a paper on “ The Absorption of Water by 
Certain Leguminous Seeds.” The author dealt with the swelling 
of these seeds under different conditions, in the light of a knowledge 
of their anatomy. 
On Wednesday morning Professor Bottomley gave an account 
of some observations on “ The Association of certain Endophytic 
Cyanophyceae and Nitrogen-fixing Bacteria.” The Cyanophyceae 
in the leaves of Azolla and the thallus of Anthoceros appear to be 
always associated with Azotobacter and Pseudomonas. The author 
suggested that the association of the Algae and Bacteria may be a 
symbiotic one. Mr. J. H. Priestley gave some “ Notes on the 
Distribution of Halophytes on the Severn Shore,” and discussed 
the general adaptation of the plants of the pelophilous zones to 
their habitat. The last paper was by Mr. M. Wilson, on “Plant 
Distribution in the Woods of North east Kent. Mr. Wilson 
concluded that the most important factor in this distribution is the 
character of the soil. 
