Unpublished paper, 'On the protrusion of protoplasmic filaments from the glandular hairs on the leaves of the common teasel (Dipsacus sylvestris)' by Francis Darwin

Description

The protoplasmic structures described in Darwin's paper are connected with the glandular hairs or trichomes found on both surfaces of the leaf of the common teasel (Dipsacus sylvestris). The trichomes are of two kinds, differing in a marked manner in shape. The gland from which alone the protoplasmic filaments issue consists of a multicellular pear-shaped head, supported on a cylindrical unicellular stalk which rests on a projecting epidermic cell. The whole structure projects about 1/10 of a millimetre (1/250 inch) above the surface of the leaf. The filaments issue from inside the gland cells, reaching the surrounding medium by passing through the external cell wall of the gland. The point where protrusion takes place is on the summit of the gland, and usually at the point of junction of several radiating cells at the centre of its dome-like surface. The act of protrusion happens rapidly; a previously naked gland may be seen to send forth a minute thread of trembling protoplasm, projecting from its summit freely into the surrounding water. The filament grows by clearly visible increments, and may ultimately attain the length of nearly one millimetre. The filaments appear to pass through the substance of the external cell wall of the glands, as no apertures to allow of their passage have been observed.

Annotations in ink throughout. Marked on front as 'Archives May 17/77'.

Subject: Botany

Received 30 January 1877. Read 1 March 1877. Communicated by Charles Darwin.

Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 26 of the Proceedings of the Royal Society as 'On the protrusion of protoplasmic filaments from the glandular hairs of the common teasel (Dipsacus sylvestris)'.

A version of this paper was published by Darwin in the Quarterly Journal of Microscopical Science [later Journal of Cell Science]: Darwin, Francis. 'JOURNAL ARTICLE| 01 JULY 1877
Memoirs: On the Protrusion of Protoplasmic Filaments from the Glandular Hairs on the Leaves of the Common Teasel (Dipsacus sylvestris).' The Quarterly Journal of Microscopical Science, volume s2-17, number 67 (1877), pp. 245-272.

Reference number

AP/59/1

Earliest possible date

1877

Physical description

Ink on paper

Page extent

62 pages

Format

Manuscript