The morphology of the stomatal complex in Pinus strobus L. and P. banksiana Lamb. is described and it is proposed that the stomatal complex should be considered an eight-celled complex consisting of two guard cells, and two polar, two lateral, and two hypodermal subsidiary cells.
An ontogenetic study found these cells closely related developmentally.
It was also found that the stomatal complex in these two pines could not readily be classified as haplocheilic because a polar subsidiary cell arises from the same protodermal cell as does the guard cell mother cell.
A modification of the classical concept of stomatal development was necessary to describe the stomata as eumesoperigenous.