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Comparative studies of the nodal and vascular anatomy in the Cyatheaceae are discussed as they relate to the taxonomy and phylogeny of the family. There is in the Cyatheaceae (excluding Metaxya and Lophosoria) a basic nodal pattern consisting of four major phases of leaf trace separations. Abaxial traces arise from the leaf gap margins, and the last abaxial traces from each side of the gap are larger and undergo numerous divisions. Distally adaxial traces separate from the gap margins, and the last adaxial traces are usually larger and undergo multiple divisions. In addition, medullary bundles frequently become petiole strands of the adaxial arc in the petiole. Rarely, cortical bundles form petiole strands in the abaxial arc in the petiole. Leaf gaps of the squamate genera of the Cyatheaceae are fusiform and possess prominent lateral constrictions which result from medullary bundle fusions and the separation of leaf traces. A characteristic petiole pattern is found in all members of the Cyatheaceae. There is an increase in the complexity of the petiole vascular tissue which results in a gradation from the undivided strand in Metaxya, to the three‐parted petiole pattern in Lophosoria, and finally to the much‐dissected petiole vascular tissue in the advanced genera. Nodal and vascular anatomy data basically support Tryon's phyletic scheme for the family. The Sphaeropteris‐Alsophila‐Nephelea line shows certain tendencies toward increased complexity of nodal and vascular anatomy, whereas the Trichipteris‐Cyathea‐Cnemidaria line shows the same anatomical and morphological characters in a direction of increased simplification or reduction.

Comparative studies of the nodal and vascular anatomy in the monotypic genera Metaxya and Lophosoria are discussed as they relate to the taxonomy and phylogeny of the Cyatheaceae. Both genera are distinctive and primitive with respect to habit, stem and petiole indument, stelar pattern, and nodal anatomy. Metaxya possesses a prostrate, dorsiventral rhizome, whereas a short, upright radial stem occurs in Lophosoria. Trichomes occur on the stems and leaf petioles of these genera. Both Metaxya and Lophosoria have a spiral phyllotaxy, and adventitious buds occur on the petiole bases. The stelar pattern is basically a siphonostele, although frequently a dictyostele is found in Lophosoria. Accessory bundles are lacking in both genera. A characteristic petiole pattern is found in these genera, with an increase in complexity from an undivided strand in Metaxya to the three-parted petiole pattern in Lophosoria. Data from nodal and vascular anatomy indicate that these taxa are distinct from the other genera in the Cyatheaceae and belong in an independent position at the base of the Cyatheoid line, although in some respects an affinity to members of the Dicksoniaceae is indicated.

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Summary• The chemistry, crystallography and ultrastructure of intracellular calcium oxalate deposits in the angiosperm, Dracaena sanderiana are reported here.• Crystalline deposits extracted from mature leaves and leaf primordia of D. sanderiana were studied by scanning electron microscopy and X-ray powder diffractometry techniques, and compared with X-ray standards for calcium monohydrate and calcium oxalate dihydrate.• Intracellular calcium oxalate deposits were of two types; calcium oxalate monohydrate raphides or solitary calcium oxalate dihydrate crystals. Raphide-containing cells exhibited lamellate sheaths around the chamber walls, mucilage-like materials surrounding the developing crystal chambers, and paracrystalline bodies with closely spaced subunits within the chambers. The intracellular calcium oxalate dihydrate crystals usually displayed typical tetragonal-dipyramidal morphology, but development of some unusual crystal faces occasionally occurred.• Two intracellular hydrate forms of calcium oxalate (monohydrate and dihydrate) exist in D. sanderiana . The elaboration of crystal vacuoles derived from rough endoplasmic reticulum and modified crystals with energetically unfavourable faces suggest that precipitation of calcium oxalate dihydrate in D. sanderiana cells might be biologically controlled.