The occurrence of heartwood crystals in certain timbers

Abstract

Crystals of a very characteristic shape and colour have been observed in the heartwood of 52 species form 19 different families. They are quite distinct in composition and appearance from the crystals of calcium oxalate that occur in the wood of many timbers, and they have never been seen in sapwood.

The crystals appear first in the ray cells, where these are in contact with a vessel element. The area in which the crystals occur extends through all the tissues of the heartwood. The shape they take is partially dependent on the tissue in which they occur. They have frequently been found in close association with fungal hyphae.

Their distribution has been studied intensively in Eucalyptus hemiphloia F. Muell. and E. sideroxylon A. Cunn., in which species they occur from the pith to a short distance from the outer edge of the heartwood and from the base of the tree to the upper limit of the heartwood. In a random selection of discs from other species of the genus Eucalyptus the crystals have a similar distribution within the heartwood.

The crystals in E. hemiphloia have given identical chromatograms with crystals of ellagic acid, and it is probable that crystals in other Myrtaceae are of a similar nature.

Further research is needed for identification of the fungi with which these crystals are associated, and to determine the chemical composition of the crystals and of the heartwood extractives of the woods in which they occur.