results from the metamorphosis of chlorophyll. Mr. Sorby examined the
colouring matter with the spectroscope, and informs me that it consists
of the commonest species of erythrophyll, "which is often met with in
leaves with low vitality, and in parts, like the petioles, which carry
on leaf-functions in a very imperfect manner. All that can be said,
therefore, is that the hairs (or tentacles) are coloured like parts of
a leaf which do not fulfil their proper office."

Dr. Nitschke has discussed this subject in 'Bot. Zeitung,' 1861, p.
241 &c. See also Dr. Warming ('Sur la Diffrence entre les Trichomes'
&c., 1873), who gives references to various publications. See also
Groenland and Trcul 'Annal. des Sc. nat. bot.' (4th series), tom. iii.
1855, pp. 297 and 303. [page 6]

part, which alone is capable of movement, consists of a prolongation of
the leaf; the spiral vessels being extended from this to the uppermost
part. We shall hereafter see that the terminal tentacles of the divided
leaves of Roridula are still in an intermediate condition.

The glands, with the exception of those borne by the extreme

FIG. 3. (Drosera rotundifolia.) Longitudinal section of a gland;
greatly magnified. From Dr. Warming.

marginal tentacles, are oval, and of nearly uniform size, viz. about
4/500 of an inch in length. Their structure is remarkable, and their
functions complex, for they secrete, absorb, and are acted on by
various stimulants. They consist of an outer layer of small polygonal
cells, containing purple granular matter or fluid, and with the walls
thicker than those of the pedicels. [page 7] Within this layer of