Notes. 
367 
I am of opinion that de Vries' view that the turgidity of the cell is 
mainly dependent on the presence of certain osmotically active sub- 
stances in the sap, of an acid nature, requires some further qualification, 
for my own results agree rather with those of Schwartz, since I find 
that turgid cells may possess either an acid or an alkaline sap. Thus, 
in Drosera itself, the cells of the tentacles have an acid, and those of 
the petals of the flower an alkaline reaction. 
Finally, the property of contractility, which I have established for 
the irritable cells of Drosera and Mimosa , and for the less specialised 
cells of Mesocarpus, is, I believe, a property which is possessed, in a 
greater or less degree, by all the actively living cells which constitute 
the tissues of plants. The important bearing of these results on all 
phenomena of movement and growth is sufficiently obvious. 
WALTER GARDINER, Cambridge. 
THE REPLUM IN CRUCIFERAE.— What is the replum? 
Writers on systematic botany use the term for the framework of the 
fruit, left after the fall of the valves, across which the septum stretches. 
In Continental and American text-books the term is also used in 
this sense. In most British text-books the term is applied to the 
septum itself. The purpose of this note is to point out which of 
those uses is the correct one. 
The word was introduced by Brassai in Flora, Jahrg. XVI, Bd. I, 
p. 313. In a note to a discussion of the morphology of the capsule 
in Papaveraceae, he remarks of the fruit in Cruciferae that it is to 
be regarded as a capsule with two parietal placentas, the walls of 
which are cut out on two opposite sides between the placentas. The 
portions so cut out — his assumenta , our valves — are larger or smaller 
in different cases and may indeed be non-existent, and a series may 
be traced from Thlaspi, in which they are large, to Bunias, where 
they are absent. The whole remaining portion of the capsule after 
removal of the valves is the replum. Although he does not specially 
mention the septum, it is clear from the whole context that Brassai 
introduced the term for the framework across which the septum 
stretches, and not for the septum; and this would correspond with 
the original meaning of the word, viz., ‘ the upright rail fixed in the 
centre of the frame of a door-case in order to guard the crevice 
formed by the junction of two valves’ (White and Riddell). The 
