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The Stomata of Gnetum
by Maheshwary P., Vasil V. (1961)
in Ann. Bot 25: 313-319.
In both Gnetum gnemon and G. ula the stomatal development in the collars and axes of the male and female cones and the outer two envelopes of the ovule is of the haplocheilic type.
In the leaf some stomata do show parallel subsidiary cells, but they arise from the surrounding epidermal cells and do not seem to have a common origin with the guard cells. This conflicts with earlier accounts and is of interest in relation to the types of stomata met with in other gymnosperms, living and fossil.
See the text: Ann. Bot.