SECTION K.—BOTANY. 
THE TYPES OF ENTRANCE MECHAN- 
ISMS OF THE TRAPS OF UTRICULARIA 
(INCLUDING POLYPOMPHOLYX) 
ADDRESS BY 
PROF. FRANCIS ERNEST LLOYD, M.A., D.Sc., 
PRESIDENT OF THE SECTION, 
Ir is an honour greatly appreciated atid wholly unexpected to have been 
selected to preside over your Section of Botany on this occasion, the 
Leicester Meeting of the British Association for the Advancement of 
Science. To express my feelings in any plenary sense would take too 
much of your time, better spent on the subject before us. I therefore 
offer you my best thanks for your confidence. If the subject which I have 
chosen is one as full of interest as it is devoid of practical importance (so 
far as we can at present see), I may plead that I am following the example 
of your illustrious Hooker, whose address at the Belfast Meeting in 1874 
was in the same field and equally open to the criticism. 
This subject * has the purpose of setting before you the variety and, so 
far as I have compassed them, the minutiz of structure and behaviour of 
the door, or valve (as Darwin called it), and its contactual parts, par- 
ticularly the threshold, of some 75 species of the genus Utricularia. Such 
a number out of the whole of some 250 known species may be taken as 
sufficiently representative to allow us to obtain a fair picture of the lot. 
That I have been able to examine this fairly adequate series has been due 
to the helpfulness of correspondents in various parts of the world, 
acknowledgments of which I have already made elsewhere. It must, 
however, be added that the study of preserved material to any good purpose 
would not have been possible without the foundation work of studying 
such living material as has been available, including the following species : 
U. vulgaris, U. intermedia, U. gibba, U. emarginata, U. capensis, U. reni- 
formis, U. cornuta, U. longifolia, U. coerulea, etc. In this connection 
I should not fail to add that I have had the able co-operation of Mrs. E. R. 
Johnson, née Reed, of Perth, Western Australia, and of Mr. Allan 
McIntyre and Mr. A. V. Giblin, of Hobart, Tasmania, in carrying out 
1 The present paper may be considered a continuation of my presidential 
address, entitled ‘The Carnivorous Plants—A Review with Contributions,’ 
delivered at the recent meeting of the Royal Society of Canada, May 18~20, 
1933. A motion picture showing the action of Drosera and of Dion@a, exhibited 
te eae occasion, is shown as part of the motion pictures as completed especially 
or this. 
