Fig.
10.2-9.
Transverse section of elephant’s ear leaf (Colocasia; a relative of Philodendron).
These are papillose
epidermis cells. The outer wall was softened and then turgor pressure
pushed the wall outward into the shape of a papilla. This can occur to various
degrees in different species, such that the outer wall merely bulges slightly,
or to the extreme of bulging out so much that it is considered to be a trichome
rather than a papilla (there is no fundamental difference between a unicellular
trichome and a papillose epidermis cell). Four dark red nuclei are visible, all
located against the inner wall.