254 de Fr aine. — The Morphology and Anatomy of the 
1856 as consisting of a group of four cells, a mistake in which he was 
followed by the subsequent workers, Licopoli 1 and Maury. 2 
The glands were described by de Bary 3 as arising from epidermal cells 
which were rounded quadrate in surface view. Two intersecting walls 
at right angles to one another, and perpendicular to the surface, divided 
each of the gland-mother-cells into four ; each of the cells thus formed 
is then divided by a vertical wall into a narrow' inner, and a peripheral cell. 
The eight cells thus produced constitute the gland proper, the walls between 
the cells are extremely thin, and the contents are composed of very finely 
granular protoplasm. Volkens 4 states that the walls which limit the gland 
towards the inner tissue of the leaf are somewhat thickened, and are distin- 
guished by the fact that they do not swell up or dissolve under the action of 
concentrated sulphuric acid. He further describes the occurrence of special 
‘ nebenzellcn 5 outside the gland cells ; these ‘ nebenzellen which are not 
mentioned in de Bary’s description, may be level with the epidermis, 
or maybe deeper and appear as half-moon shaped appendages of the gland 
elements ; he regards them as epidermal cells which were displaced from their 
original level on the formation of the gland. 
Vuillemin 5 also describes the glands as composed of eight thin walled 
secreting cells, surrounded by four subsidiary cells whose walls are not dis- 
solved by treatment with boiling potash ; the margins of these cells are 
marked by cutinized attachments which join them to the base of the gland. 
He further states that ‘ ces aretes sont legerement carenees et pourvues de 
deux expansions laterales, exactement appliquees sur la commissure qui 
separe les cellules annexes ’, so that the latter form an uninterrupted 
barrier between the parenchyma on the one hand and the epidermis on the 
other, nothing passing from one to the other except through these sub- 
sidiary cells. He further states only four of the eight glandular cells are 
secretory, though exchanges can readily take place between all of them on 
account of their thin walls. 
The description of the glands given by Solereder 6 differs from Vuille- 
min’s account in that the walls of the glandular cells separating the internal 
surface of the gland from the neighbouring tissues are described as being 
suberized, and the subsidiary cells are stated to have a double cap instead 
of a single one. 
1 Licopoli : Gli stomi e le glandole. Atti R. Accad. d. Sc. Fis. e Mat., vol. viii, 1879. 
2 Maury, P. : Etudes sur l’organisation et la distribution geographique des Plombaginacees. 
Ann. Sci. Nat., Pot., ser. 7, t. 4, 1886, p. 1. * 
3 de Pary : Vergl. Anat., 1877, p. 113. 
4 Volkens, G. : Die Kalkdriisen der Plumbagineen. Per. deutsch. bot. Gesell., 1884, Pd. 2, 
P. 334 - 
5 Vuillemin, P. : Reeherches sur quelcjues glandes epidermiques. Ann. Sci. Nat., Pot., 1887, 
ser. 7, t. 5, p. 152. 
6 Solereder, PI. : Systematic Anatomy of the Dicotyledons. Oxford, Clarendon Press, 1898, 
p. 496. 
