IAWA Bulletin n.s., Vol. 11 (4), 1990: 319-336

COMPARATIVE WOOD ANATOMY OF AFROMONTANE AND BUSHVELD SPECIES FROM SWAZILAND, SOUTHERN AFRICA

by

J. A. B. Prior 1 and P. E. Gasson 2 1 Department of Biology, Imperial College of Science, Technology & Medicine, London SW7 2BB, U.K. and 2Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, U.K.

Summary The habit, specific gravity and wood anat­ of the archaeological research, uses all the omy of 43 Afromontane and 50 Bushveld well preserved, qualitative anatomical charac­ species from Swaziland are compared, using ters apparent in the charred modem samples qualitative features from SEM photographs in an anatomical comparison between the of charred samples. Woods with solitary ves­ two selected assemblages of trees and shrubs sels, scalariform perforation plates and fibres growing in areas of contrasting floristic com­ with distinctly bordered pits are more com­ position. Some of the woods are described in mon in the Afromontane species, whereas Kromhout (1975), others are of little com­ homocellular rays and prismatic crystals of mercial importance and have not previously calcium oxalate are more common in woods been investigated. Few ecological trends in from the Bushveld. wood anatomical features have previously Key words: Swaziland, Afromontane, Bush­ been published for southern Africa. veld, archaeological charcoal, SEM, eco­ The site of Sibebe Hill in northwest Swazi­ logical anatomy. land (26° 15' S, 31° 10' E) (Price Williams 1981), lies at an altitude of 1400 m, amidst a Introduction dramatic series of granite domes in the Afro­ Swaziland, one of the smallest African montane forest belt (White 1978). At least countries, lies in the subtropics between lati­ 1500 mm ofrain falls mainly during the sum­ tudes 25° and 27° S. Although its total area is mer months, when the mean temperature is only 17,565 Ian 2, large altitudinal differences 16.5 ° C. The high rainfall promotes the for­ from west to east result in a wide environ­ mation of a black, acidic hill peat typical of mental diversity. Ancient charcoal fragments the tropical, north-eastern mountain sourveld spanning the last 10,000 years were excavat­ (Acocks 1975). Moderate to severe frosts oc­ ed from two sites in the high, wet northwest cur during most winters, producing variable and low, dry northeast of the country, during periods of physiological drought. The lichen a multidisciplinary investigation of the covered trees and shrubs of the area cluster in detailed pattern of climatic change during the sheltered areas between the domes. They are Holocene period (Prior & Price Williams predominantly evergreen and include a high 1985). The fragments were identified by percentage of specific endemics. comparison with charred branchwood col­ Siphiso rock shelter is situated in north­ lected from 93 modern trees and shrubs of east Swaziland (26° 18' S, 31° 58' S), at an common occurrence around the two sites. altitude of 320 m. Vegetation in the area, de­ The modern taxa chosen, which represent scribed by Acocks (1975) as semiarid low­ over 60% of the woody flora of each area, veld, includes tropical bush and savanna spe­ were biassed in favour of those species cies known as Bushveld. An annual rainfall known to be carefully selected for burning varying between 500 and 700 mm and mean and for a range of utilitarian purposes today, summer temperatures in excess of 20° C lead as in the past. The present study, a byproduct to levels of evaporation which greatly exceed

Downloaded from Brill.com10/05/2021 12:37:45PM via free access 320 IAWA Bulletin n.s., Vol. 11 (4), 1990 precipitation. Upper soil levels become saline in diameter represent mature wood where and calcrete modules, composed of calcium further changes in cambial initial length and carbonate, are deposited at varying soil changes in most other cambial products are depths. Some woody species typically occur negligible. 1-2 cm3 cubes cut from each wood on the shallow, raw mineral soils or lithosols sample were embedded in washed silver sand mantling the slopes; others, particularly mi­ in crucibles and charred by heating in a muf­ crophyllous legumes, characterise the black, fle furnace at 450 0 C for 30 minutes. They alkaline, hydromorphic vertisols of the bot­ were cooled in the sand to minimise ash for­ tomlands (Young 1976). On both soil types, mation, then scored and manually fractured in a high proportion of species are deciduous three planes of section. Fractured pieces were and many show xeromorphic characters. mounted on aluminium stubs with Durofix, All the charred branch wood was examin­ desiccated for at least 24 h and coated with ed by scanning electron microscopy. The use 40 nm of gold in an atmosphere of argon, of charred material inevitably presents prob­ using a Polaron E5000 diode sputter coater. lems in the interpretation of certain wood ana­ Stubs were examined in a Philips SEM tomical characters such as the thickness of 500 and photographed at magnifications lignified walls and the number of crystals between 50 x and 6400 x. At least fifteen to present. Great care was taken to distinguish twenty photographs were taken of each charring artefacts from genuine anatomical wood. characters of taxonomic importance (Prior & For each set of photographs numbered Alvin 1983). Charring results in differential characters were recorded, according to the shrinkage of the tissues of the wood. Al­ list of microscopic features (I AW A Commit­ though this invalidates any quantitative ana­ tee 1989). Maximum and minimum ray widths tomical measurements, the large amount of were noted for most specimens and are in­ qualitative information remaining in the char­ cluded in the Appendix. The specific gravity coal enabled each wood to be clearly identi­ of most of the woods was determined either fied, using the list of microscopic features for by measuring the ratio of the oven-dry weight hardwoods recently published (IA WA Com­ to the weight of water displaced by the green mittee 1989). Only one species, the softwood volume or by reference to Kromhout (1975) Podocarpus latifolius, an important compo­ or Van Wyk (1984). The habit of each spe­ nent of the vegetation occurring amongst the cies was determined either by field observa­ granite domes of Sibebe Hill, could not be tion or by reference to Palmer (1977) or Van characterised in this way. Every wood is de­ Wyk (1984). The distinction between trees scribed in coded form in the Appendix. A and shrubs is not always clear in relation to comparison is made of the vessel, fibre, axial the species of southern Africa. In this paper, parenchyma and ray characters which pre­ plants with a woody stem of 3 m or more in dominate in the two distinct tropical montane height are called trees, though these are fre­ and tropical lowland areas. quently multi-stemmed, particularly under conditions of climatic stress, which induce Materials and Methods natural coppicing. The arrangement of the Wood samples from 43 Afromontane spe­ families and the nomenclature of species used cies and 50 Bushveld species were collected at in the Appendix follows Coates Pal grave the beginning of several dry seasons. Vege­ (1983). tative voucher specimens of each were col­ lected in duplicate for authentication at the Results Royal Botanic Gardens, Kew and at the Bo­ The habit and specific gravity of Afromon­ tanical Research Institute, Pretoria. Branch­ tane and B ushveld species are compared in wood samples were between 4 and 6 em in the table. Anatomical features of particular diameter. Wood of this size was selected ecological significance, such as the compara­ since it equates best with archaeological tive number of species with exclusively soli­ samples. Baas (1973), in his detailed study tary vessels, scalariform perforation plates, of !lex, concludes that wood samples of 5 cm fibres with distinctly bordered pits, predom-

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Table showing comparative ecological trends in Afromontane and Bushveld species.

Qualitative character Afromontane species Bushveld species (%) (%)

Tree 58 68 Shrub 42 32

Evergreen 65 32 Deciduous 26 60 Tardily deciduous 9 8

Growth ring boundaries distinct 7 14

Basic specific gravity 0.40-0.75 21 16 Basic specific gravity> 0.75 35 56 Unknown 44 28

Vessels exclusively solitary 39 14 Perforations scalariform 19 2 Intervessel pits scalariform 12 0 Intervessel pits opposite 14 0 Intervessel pits alternate 93 100 Vestured pits 26 36 Vessel-ray pits + distinct borders 81 80 Vessel-ray pits + reduced/simple borders 21 22 Vessels + helical thickenings 5 0

Fibres with distinctly bordered pits 46 20 Septate fibres present 39 26 Fibres very thin-walled 21 14 Fibres thin- to thick-walled 91 96 Fibres very thick-walled 14 22

Parenchyma very rare 24 20 Parenchyma predominantly apotracheal 72 64 Parenchyma vasicentric to aliform and confluent 16 36 Parenchyma banded 16 30

Rays homocellular 12 28 Very narrow rays (1-3 cells wide) 84 92 Ray height> 1 mm 14 8

Crystals present 33 58 Silica bodies present 5 4

Downloaded from Brill.com10/05/2021 12:37:45PM via free access 322 IAWA Bulletin n.s., Vol. 11 (4), 1990 inantly apotracheal and paratracheal axial commonly arranged in radial multiples of parenchyma or homocellular rays are also four or more are three times more frequent in listed. Features which are of rare occurrence the cooler, Afromontane area (see Appendix). or of less ecological significance are only In this area too, 39% of all species have 90% shown in the Appendix. These include the or more of solitary vessels. The comparable storying of one or more elements, vessel figure for the semiarid Bushveld sample is grouping other than solitary and the occur­ only 14%. rence of tyloses. The comparative number of Of the Afromontane species, 88% have solitary vessels with angular outlines has also vessels with simple perforation plates and been omitted from the table, since charring 19% have vessels with scalariform plates, may result in a considerable amount of cel­ either alone or in combination with the simple lular deformation. A selection of the wide type (Figs. 4 & 13). In the Bushveld sample, range of qualitative features preserved in the the comparable percentages are 98% and 2% charcoal of Afromontane and Bushveld spe­ (Fig. 24). Alternate intervessel pitting pre­ cies is illustrated in Figures 1-14 and Figures dominates throughout. In most cases, vessel! 15-24 respectively. ray pitting is similar to intervessel pitting. The In the selected samples, 32 families are percentages of vestured pitting in the cooler represented from the Afromontane area, and and warmer areas are 26% and 36% respec­ 21 from the Bushveld. Almost twice as many tively (Fig. 23). In the cooler area however, trees and shrubs from the Afromontane area most of the woods with vestured pits belong are evergreen. A considerably higher propor­ to the Rubiaceae, whereas in the warmer, tion of woods from the Bushveld have a most are legumes. Only two Afromontane specific gravity of more than 0.75, although species, Ilex mitis and Heteromorpha arbor­ figures were not available for every species. escens, show helical thickenings throughout Only three Afromontane species, Pappea ca­ the body of the vessel elements (Fig. 7). pensis, Heteromorpha arborescens, andDom­ At Sibebe, 54% of the woods have fibres beya rotundifolia, show clear growth rings. with simple to minutely bordered pits and in In Heteromorpha, the wood is also semi­ 46%, the pitting is distinctly bordered (Fig. ring-porous. Pappea capensis is widely dis­ 11). Comparable percentages for the Bush­ tributed in Swaziland but polymorphic. The veld sample are 82% and 20% (Fig. 22). One small, sclerophyllous Bushveld form may specimen, Ekebergia capensis, has both types. not necessarily possess the same wood struc­ Septate fibres occur more frequently in Afro­ ture. Growth rings occur in seven Bushveld montane species (Fig. 7) but they often oc­ species, three of which are legumes. These cur in combination with non-septate fibres. are Acacia caffra, Acacia karroo, Dichro­ Seven Bushveld species have very thin­ stachys cinerea, Androstachys johnson ii, walled fibres (Fig. 16), and apart from three May tenus heterophylla, Ptaeroxylon obli­ members of the Anacardiaceae, all are hydro­ quum, and Grewia occidentalis. Only the philic species growing near or alongside Grewia is semi-ring-porous. In the legumes semi-permanent water courses. Conversely, generally and in the two acacias in particular, fewer Afromontane woods have fibres with growth rings are known to occur sporadically very thick walls. and when present, they may be discontinu­ The majority of the woods in the Afro­ ous (Metcalfe & Chalk 1950; Robbertse et al. montane sample have axial parenchyma with 1980). a predominantly apotracheal distribution. In Clustered or tangentially banded vessels the Bushveld species, the comparatively high occur only in the Afromontane sample, in 7% percentage of aliform or confluent parenchyma and 5% of the species respectively (see Ap­ (36%), reflects the high number of legumes pendix and Fig. 2). Vessels showing a diag­ in the sample (Fig. 15). onal and/or a radial pattern (Fig. 17), are Throughout both florulas, narrow rays recorded in 30% of Afromontane species, from 1-3 cells in width predominate and wide representing 11 families, and 38% of Bush­ veld species, representing 9 families. Vessels (text continued on page 327)

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Figs. 1-4. Transverse sections of Afromontane species. - 1: Psychotria capensis showing very narrow vessels and some rays damaged by charring. Scale line = 200 J..Lm. - 2: Heteromorpha arborescens showing a tangential arrangement of vessels. Scale line as 1. - 3: Combretum kraussii with an indistinct growth ring and diffuse included phloem. Scale line as 1. - 4: Eke­ bergia pterophylla showing groups of vessels, some with simple perforation plates, and charred starch grains within the ray cells. Scale line = 100 /illl.

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Figs. 5-8. Tangential longitudinal sections of Afromontane species. - 5: Faurea speciosa show­ ing very wide, fairly low rays and some uniseriate rays. Scale line = 500 /J.m. - 6: Brachylaena discolor showing low rays, predominantly 1-3 cells wide. Scale line = 200 /J.m. -7. Hetero­ morpha arborescens showing spirals throughout the body of the vessel element and a septate fibre. Scale line = 25 /J.m. - 8: Ochna arborea showing fibres with vestured pits. Scale line = 20 /J.m.

~ Figs. 9-14. Tangential longitudinal sections (9-11) and radial longitudinal sections (12-14) of Afromontane species. - 9: Ochna arborea showing high rays with idioblasts containing prismatic crystals. Scale line = 100 /J.m. - 10: Ekebergia pterophylla showing a vessel with well preserved coalescent pit apertures and ray cells containing charred, partially decomposed starch grains. Scale line = 50 /J.m. - 11: Canthium inerme showing fibres with distinctly bordered pits. Scale line = 25 /J.m. - 12: Heteropyxis natalensis showing vestured vessel-ray pitting. Scale line as 11. - 13: Apodytes dimidiata showing a scalariform perforation plate with 18 bars. Scale line as 11.- 14: Trimeria grandifolia with chambered ray cells containing prismatic crystals. Scale line as 10.

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--.~

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Figs. 15-18. Transverse sections of Bushveld species. - 15: Lonchocarpus capassa showing wide tangential bands of axial parenchyma. Scale line = 200 11m. - 16: Trema orientalis showing very thin-walled fibres and vessels. Scale line as 15. - 17: Mimusops zeyheri showing radial multiples of vessels and narrow bands of axial parenchyma. Scale line = 500 11m. - 18: Andro­ stachys johnsonii showing a growth ring, narrow vessels and moderately thick-walled fibres. Scale line = 100 11m.

Downloaded from Brill.com10/05/2021 12:37:45PM via free access Prior & Gasson - Wood anatomy of Afromontane and Bushveld species 327 and/or high rays, with or without sheath belonging to a wide range of families. Their cells, are commoner in the cooler area (Figs. woods often have more than 90% of solitary 5, 6 & 9). Homocellular rays are commoner vessels, a high incidence of scalariform per­ in the Bushveld, where they are most fre­ foration plates, fibres with distinctly bordered quent in leguminous species. At Sibebe, far pits and predominantly apotracheal paren­ more of the woods contain rays with long chyma. They seldom have homocellular rays tails or mixed cellular composition. or aliform or confluent parenchyma. Woods possessing such a combination of characters Discussion are considered by Metcalfe and Chalk (1950) The limitations of this study are obvious. and others, to show a lack of phylogenetic The use of charred material precludes the use specialisation. The correlation between such of any quantitative parameters and the select­ features and cooler, less water stressed envi­ ed samples of modem woods consisted of ronments where they are presumably not se­ branchwood only. The total sample was bias­ lected against, has been recorded many times sed in favour of trees and shrubs used either in the past. Previous studies include those as fuel or for utilitarian purposes, both today by Novruzova for Soviet Azerbaijan (1968), and in ancient times. Nevertheless, a compar­ Carlquist and Hoekman for southern Califor­ ison between the ecologically significant, nia (1985), Baas et at. (1983) and Fahn et at. qualitative wood anatomical features of the (1986) for Israel, and Baas and Schweingru­ two florulas, shown in the table, illustrates ber (1987) for Europe. the different type of wood anatomy which Hydraulic safety and efficiency are of para­ predominates in the altitudinally and ecologi­ mount importance to any plant growing in cally distinct tropical montane and tropical hot, dry regions. In the Bushveld sample lowland assemblages. only one wood, Cassine transvaalensis, has At Sibebe, climatic conditions associated scalariform perforation plates and even here, with a comparatively high altitude, high an­ there are few bars to reduce the speed of con­ nual rainfall and relative humidity and cool, duction. The legumes, which comprise nearly dry winter months during which some frosts a quarter of the sample, tend to have some always occur, promote a species-rich woody wide vessels which enhance conductive effi­ vegetation with many evergreens. This pre­ ciency (Carlquist 1975; Baas 1976; Zimmer­ dominance of evergreens (65% of the total mann 1978). These vulnerable conductors are Afromontane sample) explains the low inci­ interspersed with narrow vessel elements, dence of growth rings within the woods. In less subject to embolisms. Baas et al. (1983), the tropical lowland area known as the Bush­ in their study of ecological trends in vessel veld, the plants are water stressed for about characters of woods from many different half of the year. Much of the woody vegeta­ areas, found that the arid flora had the highest tion is xeromorphic and it is also less di­ proportion of species with a combination of verse, drought deciduous legumes being wide and narrow vessels. A different type of much in evidence (24% of the total sample). hydraulic architecture exists in Combretum Although a high proportion of the woody apicu[atum, a small, shallow rooting tree species are trees (68%), as compared to 58% which commonly grows on lithosols. Here, in the cooler area, many of these are small vessels are again of mixed sizes but vascular and multi-stemmed. The growth of most tracheids supplement the conductive tissue trees and shrubs is slow and the wood pro­ (Van Vliet 1979). Androstachys johnsonii, duced is dense, having a high proportion of with its many small vessels, shows yet an­ very thick-walled fibres (22%). A similar re­ other strategy which succeeds in a hot, dry sult is reported from Mexico, where Barajas­ region. These wide variations support the Morales (1985) found smaller trees with view of Carlquist (1980), that the presence of denser wood in a dry tropical deciduous for­ different wood anatomical patterns in the est than in a tropical rain forest. same area merely emphasises the fact that The comparatively cool, moist Afromon­ trees can exploit the environment in different tane area has many endemic trees and shrubs ways.

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The widely different floristic composition renchyma. The percentages given by Wheeler of the two areas makes any detailed compari­ et al. for homocellular rays and crystals in a son of wood anatomical features between variety of cell types are 26% and 56% res­ individual families or genera difficult. How­ pectively. In the Bushveld sample, compar­ ever, if one examines features of members of able figures are 28% and 58%. the Celastraceae, Sapotaceae and Rubiaceae The presence of calcium oxalate crystals in from both assemblages, differences between over half the Bushveld woods is not sur­ the two groups are small. Similarly the woods prising considering the alkaline nature of the of Combretum kraussii, Ochna arborea and vertisols and their calcrete accumulations. Rhus pyroides from the tropical montane area This alkalinity, due primarily to the nature of differ little anatomically from their lowland the parent basalts, may be enhanced by the counterparts Combretum apiculatum, Ochna release of calcium oxalate from decayed natalitia and Rhus chirindensis. Baas et al. fallen leaves of drought deciduous species (1983) found that values for the length of such as acacias. The hill peats of the Afro­ vessel members in species belonging to sev­ montane area are strongly acidic. Carlquist eral genera growing in Mediterranean and (1988: 237) considers that the "preferential arid areas were more or less identical to those accumulation of calcium is not a function previously recorded for more mesic members primarily of edaphic factors," whereas Rury of the same genera. (1985) inclines towards the opposite view. In Several of the anatomical trends reported this study, it appears that the nature of the above agree closely with those computed for Bushveld soils may contribute to the increased a large database of over 5,000 world hard­ calcium oxalate accumulation in the woody woods by Wheeler et al. (1986). In general, tissues of local plants. vessel characters recorded for their large The selection of wood features for survi­ sample are most similar to those found in the val in the two groups appears to have been Afromontane woods, whereas figures given more rigorous in the species growing in the for the occurrence of homocellular rays and more arid zone. However, if there is a reten­ crystals approximate most closely to percen­ tion of large parts of the 'taxonomic' charac­ tages obtained for woods from the Bushveld. ter sets carried by members of the dominant For example, the percentages of 89% and families, it might bias the wood character dis­ 17% for simple and scalariform perforation tribution, making it hard to distinguish true plates respectively in the world woods com­ adaptations from those that are non-adaptive. pare with percentages of 88% and 19% for Climatic and edaphic factors operate on the the Afromontane sample. Vessels arranged in whole organism and distinguishing their par­ radial groups of four or more occurred in ticular effects on wood anatomy is very diffi­ 18.5% of the world sample as compared to cult. The correlations between ecology and 18.6% and 6% for the Afromontane and wood characters reported in the literature Bushveld samples respectively. In the world cited above do however, match our findings sample and in all the Swaziland woods at to a large extent. The apparently less stressed, least half had predominantly paratracheal pa- wet, montane habitat with its acid hill peats

Figs. 19-24. Tangential longitudinal sections (19-23) and transverse section (24) of Bushveld species. - 19: Bridelia cathartica showing rays of two distinct sizes, the wider rays inflated by charring. Scale line = 200 ~m. - 20: Sclerocarya caffra showing long chains of chambered axial parenchyma cells containing prismatic crystals of calcium oxalate, and a ray with a secretory canal. Scale line = 50 ~m. - 21: Rhus chirindensis showing uniseriate rays and septate fibres. Scale line = 100 ~m. - 22: May tenus heterophylla showing some fibres with distinctly bordered pits and narrow rays containing prismatic crystals. Scale line = 25 ~m. - 23: Lonchocarpus ca­ passa showing vestured intervessel pitting. Scale line = 10 11m. - 24: Mimusops zeyheri show­ ing a vessel with a simple perforation plate and silica bodies in the ray cells. Scale line = 50 Ilm.

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would not be suitable for the species adapted Carlquist, S. 1975. Ecological strategies of to clay-rich vertisols and high temperatures. xylem evolution. Univ. California Press, Similarly, the calcifuges of the montane soils Berkeley, Los Angeles, London. would be ill suited to the lower areas, where Carlquist, S. 1980. Further concepts in eco­ water stress is frequent and upper soil levels logical wood anatomy, with comments on are alkaline. The indications are that there is a recent work in wood anatomy and evolu­ correlation between wood anatomical charac­ tion. Aliso 9: 499-553. ters and the sum of ecological factors expres­ Carlquist, S. 1988. Comparative wood anat­ sed in the two sites. omy. Systematic, ecological and evolution­ ary aspects of dicotyledon wood. Springer Acknowledgements Verlag, Berlin, Heidelberg, New York, The Anglo American de Beer's Chairman's London, Paris, Tokyo. Fund, the Swaziland National Trust Commis­ Carlquist, S. & D.A Hoekman. 1985. Eco­ sion and the Central Research Fund, Univer­ logical wood anatomy of the woody sity of London, kindly provided financial southern Californian flora. lAW A Bull. support for charcoal studies and for field­ n.s. 6: 319-347. work in Swaziland. The authors would like Coates Palgrave, K. 1983. Trees of Southern to thank Dr. David Cutler and Dr. Paula Africa. Ed. 2. C. Struick, Cape Town, Jo­ Rudall of the Jodrell Laboratory, Royal Bo­ hannesburg. tanic Gardens, Kew, for their help, particu­ Fahn, A, E. Werker & P. Baas. 1986. Wood larly for their constructive criticism of the anatomy and identification of trees and manuscript, and the Kew Photographic De­ shrubs from Israel and adjacent regions. partment, for the preparation of many of The Israel Academy of Sciences and Hu­ the photographic reproductions used in this manities, Jerusalem. paper. IAWA Committee. 1989. IAWA list of mi­ croscopic features for hardwood identifi­ References cation. IAWA Bull. n.s. 10: 219-332. Acocks, J.P.H. 1975. Veld types of South Kromhout, c.P. 1975. 'n Sleutel vir die mi­ Africa. Ed. 2. Mem. Bot. Surv. South kroscopiese uitkenning van die vemaam­ Africa, 40. Govt. Printer, Pretoria. ste inheemse houtsorte van Suid Afrika. Baas, P. 1973. The wood anatomy of Ilex Bull. 50, Dept of Forestry, Pretoria. (Aquifoliaceae) and its ecological and Metcalfe, C. R. & L. Chalk. 1950. Anatomy phylogenetic significance. Blumea 21: of the Dicotyledons. Clarendon Press, Ox­ 193-258. ford. Baas, P. 1976. Some functional and adaptive Novruzova, Z.A. 1968. The water conduct­ aspects of vessel member morphology. In: ing complex of trees and shrubs as related Wood structure in biological and techno­ to ecology. Izg. Akad. Nauk. Azerb. SSR. logical research (eds. P. Baas, AJ. Bol­ Baku. Original in Russian, information ton & D.M. Catling): 157-181. Leiden taken from English abstract in BioI. Ab­ Bot. Series No.3. Leiden Univ. Press, stracts 51: 12186. The Hague. Palmer, E. 1977. A field guide to the trees of Baas, P. & F.H. Schweingruber. 1987. Eco­ southern Africa. Collins, London, Johan­ logical trends in the wood anatomy of nesburg. trees, shrubs and climbers from Europe. Price Williams, D. 1981. A preliminary re­ IAWA Bull. n.s. 8: 245-274. port on recent excavations of middle and Baas, P., E. Werker & A. Fahn. 1983. Some late stone age levels at Sibebe shelter, ecological trends in vessel characters. north-west Swaziland. S. Afr. Archaeol. IAWA Bull. n.s. 4: 141-159. Bull. 36: 22-28. Barajas-Morales, 1. 1985. Wood structural Prior, 1. & K. Alvin. 1983. Structural changes differences between trees of two tropical on charring woods of Dichrostachys and forests in Mexico. lAW A Bull. n. s. 6: Salix from southern Africa. IA WA Bull. 355-364. n.s.4: 197-206.

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Prior, J. & D. Price Williams. 1985. An in­ White, F. 1978. The Afromontane region. In: vestigation of climatic change in the Holo­ Biogeography and ecology of southern cene epoch using archaeological charcoal Africa (ed. M.J.A. Werger): 463-513. from Swaziland, southern Africa. J. Ar­ Junk, The Hague. chaeol. Sci. 12: 457-475. Wyk, P. van. 1984. Field guide to the trees Robbertse, P.J., G. Venter & H.J. van of the Kruger National Park. C. Struick, Rensburg. 1980. The wood anatomy of Cape Town. the South African acacias. lAWA Bull. Young, A. 1976. Tropical soils and soil sur­ n.s. 1: 93-103. vey. Cambridge Univ. Press, Cambridge, Rury, P.M. 1985. Systematic and ecologi­ London, New York, Melbourne. cal wood anatomy of the Erythroxylaceae. Zimmermann, M.H. 1978. Structural require­ IAWA Bull. n.s. 6: 365-397. ments for optimal water conduction in tree Vliet, G.J.C.M. van. 1979. Wood anatomy stems. In: Tropical trees as living systems oftheCombretaceae. Blumea25: 141-223. (ed. P.B. Tomlinson & M.H. Zimmer­ Wheeler, E.A., R.G. Pearson, C.A. La­ mann): 517-532. Cambridge Univ. Press, Pasha, T. Zack & W. Hatley. 1986. Com­ Cambridge. puter-aided wood identification. North Carolina Agric. Res. Servo Bull. 474. Raleigh, North Carolina.

APPENDIX

AFROMONT ANE SAMPLE

Family / Species Qualitative microscopic features (numbers as in lAWA List, 1989)

Myricaceae Myrica pilulifera 2,5,9, 13, 14, 16,20,21,22,30,62,63,66,75,97, 109, 190 Evergreen Proteaceae F aurea speciosa 2, 5, 6, 13, 22 (coalescent apertures), 30, 62, 66, 69, 83, 85, 88, 91, 92, 99, Deciduous 102, 103, 104, 136, 138, 189 Trimeniaceae Xymalos monospora 2,5,7, 12, 14, 16,21,22,32,62,65,68,69,75,78,98, 102, 103, 108, 109, Evergreen 110, 189, 194 Pittosporaceae Pittosporum viridiflorum 2, 5, 12, 13, 22 (coalescent apertures), 30, 61, 65, 66, 69, 78, 97 (1-4), 106, Tardily deciduous 107, 189 Hamamelidaceae TrichocIadus grandiflorus 2,5,9, 12, 14, 16,21,31,61,66,69,76,78,97 (1-2), 108, 109, 136, 142, Deciduous 189 Erythroxylaceae Erythroxylum emarginatum 2,5, 13,22,31,62,66,69,70,76,78,97 (1-2), 108, 109, 136, 137, 189, 195 No information Rutaceae F agara davyi 2, 5, 7, 13, 22, 30, 61, 66, 68, 69, 85, 89, 97 (1-2), 104, 106, 136, 142, 189, Deciduous 195 Calodendrum capense 2,5,13,22,30,61,66,69,70,79,83,98,104,106,136,137, 138, 189, 194 Deciduous Clausena anisata 2, 5, 7, 13, 22, 30, 61, 65, 66, 69, 80, 81, 83, 84, 89, 91, 92, 97 (1-2), 104, Deciduous 190

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Meliaceae Ekebergia pterophyUa 2,5,7, 13,22 (coalescent apertures), 30,61,65,66,68,69,78,97 (1-2), 106, Evergreen 189, 194 Anacardiaceae Protorhus longifolia 2,5, 12 (thin-walled), 13, 14, 15,22,31,61,65,66,68,69,78,97 (1-2), 106, Evergreen 107, 189, 194 Rhus pyroides 2,5, 13,22 (coalescent apertures), 31, 32, 61, 65, 66, 68, 69, 78, 97 (1-2), 107, Evergreen 108, 110, 190 Aquifoliaceae /lex mitis 2, 5, 11, 12, 14, 17, 21, 30, 36, 37, 61, 64, 66, 69, 78, 97, 98, 103, 107, 110, Evergreen 189, 194 Celastraceae Catha edulis 2,5,9, 13,22,30,62,66,69,85,97 (1-2), 108, 109, 190, 195 Evergreen Pteroeelastrus eehinatus 2,5,9, 13,22,30,62,66,69,85,97 (1-2), 108, 109, 190 Evergreen Cassine eucleiformis 2,5,9, 13,22, 30, 62, 66, 69, 85, 97 (1-2), 108, 109, 189 Evergreen Icacinaceae Apodytes dimidiata 2, 5, 12, 14, 16,22, 30, 62, 66, 68, 69, 76, 78, 97 (1-4), 108, 109, 136, 138, Evergreen 189, 195 Sapindaceae Pappea eapensis 1, 5, 7, 13,22,30 (coalescent apertures in narrow vessels), 61, 65, 66, 69, 70, Evergreen 78, 85, 86, 89, 92, 97 (1-2), 106, 136, 137, 138, 142, 189, 195 Sterculiaceae Dombeya rotundifolia 1,5,7, 10, 13,22,30,61,66,69,70,83,97 (1-4), 106, 189, 195 Deciduous Ochnaceae Oehna arborea 2,5,9, 13,22,29,30,62,66,69,70,76,78,93,98, 108, 109, 110, 136, 138, Evergreen 156, 189, 195 Flacourtiaceae Seolopia mundii 2,5,7, 10, 12, 13,22 (coalescent apertures), 30, 62, 65, 69, 75, 97 (1-4), 108, Evergreen 109, 189, 195 Trimeria grandifolia 2, 5, 7, 10, 12, 13,22,30,62,65,75,97 (1-2), 108, 109, 136, 137, 140, 190 Evergreen Combretaceae Combretum kraussii 2,5,9,13,22,29,30,62,65,66,69,80,81,83,96,105, 134, 189, 195 Deciduous Combreturn moUe 2, 5, 9, 13,22,29, 30,61,66,69,80,81,83,96, 109, 134, 136, 137, 138, Deciduous 156, 189, 195 Myrtaceae Eugenia eapensis 2,5,9, 13,22,29,30,62,66,76,93,97 (1-3), 108, 136, 138, 189 Evergreen Heteropyxis natalensis 2, 5, 7, 10, 13,22, 29, 30, 61, 65, 66, 69, 76, 78, 91, 92, 97 (1-4), 106, 107, Deciduous 136, 138, 189, 195 Araliaceae Cussonia spicata 2,5, 13, 14, 15,20,21,22,30,61,65,66,68,69,78,98, 102, 106, 107, 110, Evergreen 130, 189, 194 Apiaceae Heteromorpha arboreseens 1,4, 6, 11, 12, 13, 20, 22, 31, 32, 36, 37, 61, 65, 66, 69, 78, 97 (1-3), 106, Deciduous 107, 109, 190

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Cornaceae Curtisia dentata 2, 5, 9, 12, 14, 17,20,21, 30, 62, 66, 69, 78, 97 (1-4), 108, 109, 136, 137, Evergreen 189, 195 Ericaceae Erica drakensbergensis 2,5,9 (thin-walled), 12, 13,20,22,30,61,66,68,75,98, 102, 103, 109, 190 Evergreen Myrsinaceae Maesa lanceolata 2, 5, 12 (thin-walled), 13, 22, 31, 32,61, 65, 68, 69, 75, 78, 97 (1-4), 102, Evergreen 108, 109, 110, 190 Sapotaceae Bequaertiodendron nagalis­ 2,5,7, 10, 13,22, 31, 32, 61, 66, 69,77,86,87,97 (1-2), 106, 107, 108, montanum; Evergreen 159, 160, 189, 194 Ebenaceae Diospyros whyteana 2, 5, 7, 10, 12, 13, 22 (coalescent apertures), 30 (also coalescent), 62, 66, 69, Evergreen 77, 78, 97 (1-2), 109, 159, 160, 190, 194 Loganiaceae Nuxia congesta 2,5,7, 10, 12, 13,22,30,61,65,69,75,97 (1-3), 1l0, 189, 195 Evergreen Apocynaceae Carissa bispinosa 2,5,9, 13,22,29,30,62,66,69,76,78,97 (1-2), 107, 190 No information Solanaceae Solanum aculeastrum 2,5, ll, 13,22,30,31,61,66,69,78,91,97 (1-2), 106, 109, 190 Deciduous Scrophulariaceae Halleria lucida 2, 5, 7, 10, 13, 22, 30, 62, 65, 69, 75, 98 (4-10), 102, 103, 108, 109, 1l0, Evergreen 190, 194 Rubiaceae Cephalanthus natalensis 2, 5, 9, 12, 13,22,29, 30, 61, 66, 69, 76, 97 (1-3), 108, 190 No information Burchellia bubalina 2,5,9, 12, 13,22,29,30,62,66,69,97 (1-2), 108, 190 Evergreen Rothmannia capensis 2,5,9, 12, 13,22,29,30,62,66,69,76,97 (1-3), 108, 190, 195 Evergreen Canthium inerme 2, 5, 9, 12, 13, 22, 29, 30, 62, 66, 69, 75, 76, 97 (1-4), 108, 136, 137, 190, No information 195 Psychotria capensis 2,5,9 (minute vessels), 12, 13,22,29,30,61,65, 69, 75, 97 (1-4), 108, 190 Evergreen Compositae Brachylaena discolor 2, 5, 13, 22 (coalescent apertures), 30,61, 66, 69, 70, 80, 81, 83,97 (mostly Evergreen 1-3), 104, 118, 120, 121, 122, 189, 195

BUSHVELD SAMPLE Salicaceae Salix woodii 2,5,13,22,31,56,61,66,68,69,75,78,96,106,107,189 Deciduous Ulmaceae Trema orientalis 2, 5, 9 (thin-walled), 13,22, 32,61, 66, 68, 75, 78, 97 (1-3), 103, 107, 109, Deciduous 189, 194 Moraceae Ficus sycomorus 2,5 (thin-walled), 13,22,30,31, 32,61,65,66,68,69,85,98, 108, 189, 194 Tardily deciduous

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Leguminosae (Mimosaceae) Acacia cajJra 1, 2, 5,9, 13,22,29, 30, 61, 66, 69, 80, 81, 83, 89, 92, 97 (1-3), 104, 136, Deciduous 142, 189, 195 Acacia karroo 1,2, 5, 9 (thin-walled), 13,22,29,30,61,66,69, 70, 80, 81, 83, 89,91,92, Deciduous 97,98, 104, 136, 142 (long chains), 189, 195 Acacia nigrescens 2,5, 13,22,29,30,61,66,69,80,81,83,85,92,93,97 (1-4), 104, 136, 142 Deciduous (long chains), 189, 195 Acacia nilotica 2, 5, 13,22,29, 30, 61, 66, 69, 70, 80, 81, 83, 90, 91, 97, 98, 104, 136, 142, Deciduous 189, 195 Acacia tortilis 2, 5, 13, 22, 29, 30,61, 66, 69, 80, 81, 83, 85, 91, 92, 97 (1-4), 102, 104, Deciduous 136, 142 (long chains), 189, 195 Acacia xanthophloea 2,5, 13,22,29,30,61,65,66,69,83,98, 104, 136, 142, 189, 195 Deciduous Dichrostachys cinerea 1,2,5, 13,22,29,30,61,66,69,70,80,81,83,92,97 (1-3), 104, 136, 142, Deciduous 189, 195 Leguminosae (Caesalpiniaceae) Schotia brachypetala 2,5, 13,22,29,30,61,66,69,80,81,83,85,86,90,91,97 (1-3), 106, 136, Tardily deciduous 142 (long chains), 189, 195 A/zelia quanzensis 2, 5, 13, 22 (coalescent apertures), 29, 30, 61, 65, 66, 69, 80, 81, 83, 85, 91 Deciduous 97 (1-2), 104, 106, 136, 142 (long chains), 189, 195 Peltophorum a/ricanum 2, 5, 13, 22 (not vestured), 30,61, 65, 69, 80, 81, 83, 85, 92, 93, 97 (1-3), Deciduous 104, 136, 142, 190, 194 Leguminosae (Papilionaceae) Bolusanthus speciosus 2, 5, 13,22, 29, 30,61,66, 69, 78, 83, 84, 91, 92, 97 (1-3), 104, 106, 118, Deciduous 120, 136, 142, 189, 195 Lonchocarpus capassa 2, 5, 13, 22, 29, 30, 61, 66, 69, 83, 85, 93, 94, 97 (1-4), 104, 120, 136, 142, Deciduous 189, 195 Meliaceae Ekebergia capensis 2,5, 13,22 (coalescent apertures), 30, 61, 62, 66, 69, 78, 89, 92, 97 (1-3), 104, Evergreen 106, 189, 194 Trichelia ernetica 2, 5, 7 (thin-walled), 13, 22, 30, 61, 66, 68, 69, 78, 92, 97 (1-2), 106, 107, Evergreen 159, 160, 189, 194 Euphorhiaceae Securinega virosa 2,5,7, 13,22,31,61,65,66,69,75,78,97 (1-3), 102, 108, 190 Deciduous Bridelia cathartica 2,5,7, 13,22,29,30,61,66,69,75,78,97 (1-4), 103, 108, 189 Deciduous Androstachys johnsonii I, 2, 5, 13, 22, 30, 62, 66, 69, 70, 75, 78, 96, 104, 189, 195 Evergreen Spirostachys africana 2,5,7,13,22,30,61,66,69,77,78,92,97 (1-2), 106, 107, 113, 136, 137, Deciduous 138, 189, 195 Anacardiaceae Sc/erocarya caffra 2,5,7, 13,22,31,56,61,65,68,69,78,97 (1-2), 106, 130, 136, 137,138, Deciduous 140, 142, 189, 194 Ozoroa engleri 2,5,7, 13,22,31,61,65,68,69,78,97 (1-2), 107, 190, 195 Tardily deciduous Rhus chirindensis 2,5,7, 12 (thin-walled), 13,22 (coalescent apertures), 31, 61, 65, 68,69,78,96, Deciduous 109, 130, 190, 195 Celastraceae May tenus heterophylla 1,5, 13,22,30,62,65,66,69,85,97 (1-2), 108, 136, 137, 138, 190 Evergreen

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(CelastnlCeae) Cassine transvaalensis 2, 5 (mainly in fibre bands), 14, 15,22, 30, 62, 65, 69, 70, 85, 97 (1-3), 108, Tardily deciduous 136, 137, 138, 190 Ptaeroxylaceae Ptaeroxylon obliquum 1,5,7, 10, 13,22,30,61,66,69,78,89,96, 104, 136, 142, 190, 195 Deciduous Rhamnaceae Ziziphus mucronata 2,5,7, 13,22,30,61,66,69,76,78,92,96, 105, 136, 137, 189, 195 Deciduous Berchemia zeyheri 2,5,7, 13,22,30,61,66,69,75,78,97 (1-2), 106, 107, 136, 137, 138, 189, Deciduous 195 Tiliaceae Grewia monticola 2, 5, 13, 22 (coalescent apertures), 30,61,66,69, 70, 77, 78, 83, 90, 91, 92, Deciduous 97 (1-4), 106, 107, Ill, 136, 138, 140, 190 Grewia occidentalis I, 4, 5, 13, 22 (coalescent apertures), 30, 56, 61, 66, 69, 78, 92, 98, 103, 109, No infonnation 110, 11 I, 136, 140, 142, 190 Grewia villosa 2, 5, 13, 22, 30, 61, 66, 69, 78, 97, 106, 107, 109, Ill, 136, 137, 138, 190 No infonnation Ochnaceae Ochna natalitia 2, 5, 12, 13, 22, 29, 30, 62, 66, 69, 75, 78, 92, 93, 97 (1-4), 102, 105, 190 Evergreen Flacourtiaceae Kiggelaria africana 2,5,7, 10, 13,22,31,61,65,69,75,97 (1-3), 107, 108, 136, 137, 138, 189, Tardily deciduous 194 Combretaceae Combretum apiculatum 2, 5, 9, 13, 22, 29, 30, 61, 66, 69, 80, 81, 83, 96, 109, 134, 136, 137, 138, Deciduous 156, 189, 195 Combretum imberbe 2, 5,9 (large & sparse), 13,22,29, 30,61,65,66,69,79,96, 109, 136, 137, Deciduous 138, 156, 189, 195 Terminalia sericea 2, 13,22,29,30,61,66,69,80,81,83,97 (1-2), 109, 189, 195 Deciduous Myrtaceae Syzygium guineense 2,5, 13,22,29,31,32,61,66,83,93,97, 106, 107, 189 Evergreen Myrsinaceae Rapanea melanophloeos 2,5,7, 13,22,30,61,65,69,75,78,98, 102, 109, 110, 189, 194 Evergreen Sapotaceae Mimusops zeyheri 2,5,7, 10, 13,22 (coalescent apertures), 31,61,66,69,70,77,78,93,94,97, Evergreen 108, 109, 159, 160, 189, 195 Sideroxylon inerme 2,5,7, 8, 13,22 (coalescent apertures), 31, 33, 61, 66, 69, 70, 78, 83, 86, 92, Tardily deciduous 97 (1-3), 107, 108, 109, 189, 195 Ebenaceae Euclea crispa 2, 5,7, 13,22 (coalescent apertures), 30, 62, 66, 69, 70, 76, 77, 78, 97 (1-2), Evergreen 109, 136, 142, 190, 195 Euclea schimperi 2,5,7, 12, 13,22,30,61,66,69,77,78,96 (1-2), 105, 136, 137, 190 Evergreen Diospyros mespiliformis 2, 5, 7, 13, 22, 30, 62, 66, 69, 77, 78, 91, 92, 93, 97 (1-2), 108, 109, 136, Deciduous 137, 138, 189, 195 Diospyros natalensis 2,5,7, 13,22,30,62,66,69,77,78,97 (1-3), 108, 109, 136, 142, 190 Deciduous

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Oleaceae Olea capensis 2, 5, 13,22, 3D, 61, 66, 69, 70, 78, 89, 97 (1-3), 107, 189, 195 Evergreen Olea africana 2,5,7,13,22,30,61,66,69,70,78,91,97 (1-2), 107, 189, 195 Evergreen Rubiaceae Breonadia microcephala 2, 5, 9, 12, 13,22,29, 3D, 62, 66, 69, 76, 97 (1-2), 108, 189, 195 Evergreen Kraussia jloribunda 2, 5, 9, 12, 13,22, 3D, 61, 66, 69, 76, 97 (1-2), 108, 190 No information Canthium cilia/um 2, 5, 12, 13, 22, 3D, 62, 66, 69, 75, 97 (1-2), 108, 152, 154, 190 No information

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