Benham, the tube, though smaller, and with a but little pronounced funnel, has still an intercellular duct.
It is by no means certain that a hard and fast line can be drawn between intraand intercellular lumina.
The upper epidermis alone possesses only small intercellular spaces, except where stomata happen to be present (fig.
Cellular activity and oxygen appear to be essential for its development; it is found usually in the cells of certain organs, or it may be deposited in the intercellular tissues.
In the cortical tissue beneatJI each furrow a wide intercellular space is present running the length of the internode, and called the (C, D, E from Strasburger's Lehrbuch der Bolanik, by permission of Gustav Fischer.) FIG.
This is a large group of about 2000 forms. They are all intercellular parasites living mostly on the leaves of higher plants.
The epithem is penetrated by a network of fine intercellular spaces, which are normally filled with water and debouch on one or more intercellular cavities below the epidermis.
They are accompanied by intercellular channels serving for the conduction of oxygen to, and carbon dioxide from, the living cells in the interior of the wood, which would otherwise be cut off from the means of respiration.
The usually fistular pith is surrounded by a ring of collateral vascular bundle, (see Anatomy Of Plants, and Pteridophyta), each of which, with rare exceptions, has an intercellular canal at its inner edge, containing the disorganized spiral tracheae, just as in the recent genus.
This system of intercellular spaces, extending throughout the plant, constitutes a reservoir, charged with an atmosphere which differs somewhat in its composition from the external air, its gaseous constituents varying from time to time and from place to place, in consequence of the interchanges between itself and the protoplaste.