ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 767 



yellow-green colour, insoluble in alcohol, in 1 per cent, acetic acid, 

 and in 1 per cent, hydrochloric acid, soluble with difficulty in 5 per 

 cent, solution of potash. After forty-eight hours the cell-contents 

 are of a different nature. The cells now contain numerous bodies 

 which present the appearance of flat sphaerocrystals. They are 

 usually perfectly circular in outline, and are clear and colourless, 

 insoluble in alcohol, but extremely soluble in water. 



In Drosera similar changes take place, but much more rapidly. 



Septal Glands of Monocotyledons.* — P. Grassmann describes the 

 nectar-glands found in the septa of the ovary, which are peculiar to 

 Monocotyledons, and in them occur only in the series of LiliifloraB 

 and ScitaminesB. They occur one in each septum, and therefore 

 almost invariably three in each ovary. The gland forms in the 

 sejitum a fissure of varying size and form, visible even to the naked 

 eye. It usually occupies the greater part of the septum, and is bounded 

 on each side by a secreting layer, consisting of from two to three rows 

 of cells. In the same family they are very constant in form and 

 size. The glands are filled with nectar, which escapes by means of a 

 narrow canal to the receptacle, the mode of escape varying according 

 as the ovary is superior, half-inferior, or inferior. 



The glands are formed by the incomplete cohesion of the carpels 

 in the septa ; they are recognizable at a very early stage of develop- 

 ment, and are then quite destitute of nectar, and the stages of cohesion 

 can be very readily followed. Their object is unquestionably the 

 attraction of insects to assist in fertilization. They are found only in 

 species with conspicuous flowers ; the nectar always contains grape 

 sugar, and, when it flows out of the glands, either collects on the 

 receptacle or unites with the juice flowing from nectaries in other 

 parts of the flower. It begins with the opening of the flower, and 

 usually lasts several days. The canal is also surrounded by secreting 

 cells which pour out nectar. 



Secretory System of Compositae.t — According to P. Van Tieghem, 

 the secretory system of Compositae presents itself in three different 

 forms — as oleiferous canals, as anastomosing laticiferous cells, and as 

 long, isolated resiniferous cells. Disregarding some transitional 

 forms, the first of these types is characteristic of the Eadiiflorse, the 

 second of the Ligulifloraj, and the first and third of the Tubuliflorae. 

 The present paper is devoted especially to the situation and structure 

 of the laticiferous network of the Liguliflorse, which he finds to be 

 situated in the layer of cells previously denominated by him the 

 jiericyde, situated between the cndoderm and the first sieve-tubes of 

 the fibrovascular bundles of the central cylinder. This network does 

 not belong to the liber, being separated from the sieve-tubes whicli 

 constitute the outermost portion of it by the entire thickness of tho 

 Bclerenchymatous bundle. From here it may extend right and left, 

 and may even penetrate between the liber and the sclereuchynia, tho 



* Flora, Ixvii. (1881) pp. 113-28, I29-3G (2 ijIs.). 

 t bull. Soc. Bot. France, xxx. (1884) pp. 310-3. 



