On the Cuticles of some Recent and Fossil Myrtaceæ

Abstract

Summary There is a strong family resemblance between the cuticles of Rhodomyrtus and Tristania, but the latter more frequently has isodiametric stomata and a larger number of narrow and very distinctive girdling cells encircling the guard-cells. There is, moreover, relatively less parenchyma and there are more stomata per unit of area in Tristania than in Rhodomyrtus. The presence of two genera belonging to such a typical Southern Hemisphere family as the Myrtaceae in the Eocene of Bournemouth is a point of some interest. This investigation is not, however, the first to demonstrate their presence in Europe, for Mrs. Reid (1930) has described fruits and seeds of Rhodomyrtus from Tertiary beds of St. Tudy, Finistère, and the latter flora is also regarded as of Eocene age. A cluster of fruits referred to Tristanites by Saporta has been found in the Oligocene of France. He also figures a leaf, and points out that, though its connection with the fruiting branch is doubtful, it agrees in form and venation with the recent genus Tristania. Schenk referring to the fossil fruits described by Saporta says that as far as one can judge from their external characters they show decided relationship to the Myrtaceæ. I know of no other fossil records of these genera except of two species of Tristanites recorded by Deane from the Miocene flora of Berwick, Australia.