The apical membrane of a CC
is recessed from the surface of neighboring PVCs
and may be further deepened through invagination
(Fig. 10c). The smaller accessory cell is
superficially located, semi-lunar or pear shaped,
and generally has a less extensive tubular system
and a poorly developed tubulovesicular system.
Notably, they have low levels of Naþ,Kþ-ATPase
unlike the CCs (Hootman and Philpott, ’80).