33 
THE COMMON TEASEL AS A CARNIVOROUS PLANT. 
Br Miller Christy, E.L.S. 
I have always felt a special interest in the Common Teasel 
(Dipsacus sylvestris), as an exceptionally handsome and (in its cul¬ 
tivated form) an extremely useful plant. Moreover, I have long been 
convinced, as a result of observation, that the Teasel ought to be 
regarded as a carnivorous plant, and have felt surprise that it has 
never been generally recognized as such. Yet, for some reason which 
is not obvious to me, it never has been so recognized, as is shown by 
the fact that it is not mentioned as carnivorous by Sachs, Pfeffer, 
Goodale, Jost, Clements, Reynolds Green, Haberlandt, nor (so far 
as I have been able to discover) by any other writer on plant- 
physiology; nor does Darwin mention it as such in his { Insectivorous 
Plants’ (1875). An accidental occurrence has led me recently to 
examine the point with some care, and the following remarks are the 
outcome. 
Every botanist is aware that the Teasel has, on its main stem, 
certain cup-like receptacles, formed by the bases of its large, obovate- 
lanceolate, connate-perfoliate leaves ; also that, during the time when 
the plant is in perfection and dowering (that is, from the beginning 
of July onwards for about six or seven weeks), these receptacles are 
usually more or less full of water containing dead and putrefying 
insects and other small creatures. 
It must be remembered that the Teasel (a biennial plant) pro¬ 
duces, in its first year, nothing but radical leaves, which, though 
large, scarcely rise above the surface of the ground and form no cups, 
and that it does not produce its familiar tall stem with water-cups 
until its second year. The first-year procumbent leaves differ in 
various ways from the second-year cup-forming leaves described above. 
First, they are remarkably wrinkled, the corrugations in their upper 
surface serving, perhaps, to retain rain-water for the plant’s sustenance ; 
for these leaves possess pores or stomates on both surfaces. Secondly, 
they are provided both above and below with numerous spines 
sufficiently hard and sharp to protect them from being eaten during 
winter by browsing animals ; for these leaves persist until the 
spring, when they die off completely. On their upper surfaces are a 
number of short, stout, straight, white spines, arranged chiefly in 
two well-defined rows, one on each side of and about a quarter of an 
inch from the midrib. Each of these spines is set on the top of 
a curious, raised, pustule-like inflation of the leaf, which readily gives 
when pressed; an arrangement which probably serves to prevent the 
spine being broken when the leaf is trodden upon, as it is very liable 
to be. There are also, nearer the margins of the leaves, other less 
well-defined rows of smaller spines, not set on pustules. Below, a 
number of sharp semi-liooked spines are set close together along the 
entire length of the midrib, and smaller spines along each of the 
branch side-ribs. 
The plant’s habit of catching and retaining water in its cups was 
definitely recorded by a British botanist nearly four centuries ago, 
Journal of Botany.—Vol. 01. [February, 1923. j d 
