Wood anatomy of the Euphorbiaceae, in particular of the subfamily Phyllanthoideae. The great variety in wood structure of the large family Euphorbiaceae makes it impossible to describe briefly a général wood pattern. Nevertheless, a more or less clear division into four anatomical groups can be made. A short overview is given of the wood structure of the uni‐ovulate subfamilies Acalyphoideae, Crotonoideae, and Euphorbioideae, following the classification by Webster. These subfamilies cannot be distinguished by their anatomy. The paper is mainly devoted to the bi‐ovulate subfamily Phyllanthoideae. Within this subfamily, two groups can be recognized on the basis of their wood anatomy: the Aporusa type with a great number of primitive characters, and the Glochidion type, in which primitive features such as scalariform vessel perforation plates are absent. A short description of the 13 tribes is given as well as suggestions for rearrangement of the succession of the tribes. In several tribes some taxa are anomalous and, on anatomical evidence, exclusion of some genera, sometimes with assignment to another tribe, is suggested.

Cool temperate rainforests growing on the flanks of the Andes and along the Coastal Range in Valdivia (Chile) today provide the closest analogue for the fossil floras of Antarctica during the Eocene. This paper records key Valdivian elements in a Maastrichtian to Eocene wood flora that extends the evidence for a Valdivian analogue back as far as possibly the Late Cretaceous. Here we record the first occurrences of myrtaceous and eucryphiaceous wood taxa from the Maastrichtian^Palaeocene sediments of the James Ross Basin. In addition, a previously unrecorded morphotype is described and assigned to the form genus Antarctoxylon which Poole and Cantrill erected for fossil angiosperm woods of Antarctica with uncertain taxonomic affinities. This increases the number and range of the described morphotypes from the Antarctic Peninsula and helps further our understanding of the southern high latitude angiosperm dominated floras. ß

The wood anatomy was studied of 82 species from 34 out of 54 genera in the subfamily Euphorbioideae, covering all five tribes recognized in this subfamily. In general the woods show a great deal of similarity. They are characterized by a relative paucity of vessels, often arranged in short to long, dumbbell-shaped or twin, radial multiples, and by medium-sized to large intervessel pits; fibres often have gelatinous walls; parenchyma apotracheal in short, wavy, narrow bands and diffuse-in-aggregates; mostly uni- or only locally biseriate rays, strongly heterocellular (except Hippomane, Hura and Pachystroma). Cell contents, either silica or crystals, or both together, are nearly always present and often useful in distinguishing between genera. Radiallaticifers were noticed in most genera, though they are scarce and difficult to trace. The laticifers are generally not surrounded by special cells, except in some genera of the subtribe Euphorbiinae where radiallaticifers are comparatively frequent and conspicuous.

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In this paper the wood anatomy of the subfarnily Hippocrateoideae of the Celastraceae is treated. Halle's division (1986, 1990) of the subfarnily into four tribes, chiefly based on material of tropical Africa: viz. Salacieae, Campylostemoneae, Helictonemeae and Hippocrateae is followed. In a recent issue of the Flora of the Guianas the Hippocrateaceae - there treated as aseparate farnily - were divided into Hippocrateoideae and Salacioideae. This bipartition was reflected in the wood structure of the genera studied (Mennega 1994). Here the wood structure of all genera worldwide (24), except the Asian genus Arnicratea, is described. It appeared that again a subdivision into two distinct anatomical groups could be made, with the three last tribes mentioned above showing the same characteristic structure as found before in New World Hippocrateae/Hippocrateoideae. The most important features of this group are the presence of very wide and very high rays, in a number of genera with unlignified ray cells at the growth ring border, the absence of included phloem tissue, and in many species an intruding bark resulting in an indented wood pattern in stern cross sections or even an intricate pattern of deep furrows. The Salacieae/Salacioideae on the other hand are characterized by narrow, not exceptionally high rays, absence of unlignified ray cells, the occurrence of septate fibres in a parenchyma-like distribution, and often by the presence of included phloem tissue, either as isolated strands or more often as conspicuous concentric bands, or as irregular bands with radial connections. Features present in all genera are: vessels with simple perforation plates, preponderance of solitary vessels, wide and narrow vessels distributed at random, alternate pitting; fibretracheids, and libriform nonseptate and septate fibres present; axial parenchyma scanty paratracheal or as rare isolated strands; rays heterogeneous, the cell types irregularly distributed, rhombic crystals numerous, often in characteristic radial distribution. Campylostemon, considered in the past by some taxonornists as belonging in Celastraceae or as intermediate between Hippocrateaceae and Celastraceae, closely resembles Hippocrateae in its wood anatomy. And it is especially this group that by its characteristic features -like the wide rays - is more different from Celastraceae in general than Salacieae, which have several features in common with genera of Celastraceae.

Abstractgiven.The relation of these three genera with the two other members of the tribe in South America, Orites and Gevuina, is discussed.

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