7 
. 
: 
Mrs Arber, On Root Development in Stratiotes aloides L. etc. 369 
On Root Development in Stratiotes aloides L. with special reference 
to the occurrence of Amitosis in an embryunic tissue. By 
AGNES ARBER, D.Sc. (Lond.), F.L.S., formerly Fellow of 
Newnham College. (Communicated by Dr Arber.) 
(PLates VIII anp IX.) 
[Read 9 February 1914.] 
I. Introduction. 
On August 11th, 1910, I collected a few plants of the Water 
Soldier, Stratvotes aloides L., at Roslyn Pits, Ely, with the intention 
of examining them in connexion with a general study of water 
plants, on which I have been engaged for some time. On cutting 
sections of the stems, I noticed certain peculiarities in the 
young adventitious roots embedded in the tissues of the axis, 
the chief of which was the occurrence of apparent amitosis. 
These plants had merely been preserved in methylated spirit, with 
no idea of using them for cytological purposes, but in the following 
year (May 30th, 1911) a number of further examples from Roslyn 
Pits were dissected and fixed on the spot in Flemming’s strong 
solution, acetic-alcohol, and methylated spirit. In 1912, for the 
sake of having a control from some other locality, two plants were 
obtained from Perry’s Hardy Plant Farm, Enfield. Hand sections 
were stained with methyl green in 1°/, acetic acid, Ehrlich’s acid 
haematoxylin diluted with an equal volume of potash water, 
borax carmine, etc., while for microtome sections, Flemming’s 
triple stain and Heidenhain’s iron-alum haematoxylin were used. 
The hand sections, especially those stained with methyl green and 
mounted in dilute glycerine, were found on the whole to be the 
most favourable for the particular purpose. 
T have pleasure in expressing my indebtedness to the Committee 
of the Balfour Laboratory, where this work has been carried out, 
and also to my friend, Mr E. Aveling Green, who kept records for 
me of the rate of growth of the roots in the case of some plants of 
the Water Soldier cultivated in a pond in his garden. 
Before describing the observations on the nuclei which form 
the main subject of the present paper, I wish to draw attention to 
a few points concerning the general structure and development of 
the adventitious roots of Stratiotes aloides. 
VOL, XVI. PT, Y, 25 
