IAWA Journal, Vol. 18 (4), 1997: 331-368

WOOD ANATOMY OF THE HIPPOCRATEOIDEAE () by Alberta M.W. Mennega

Department of Ecology & Evolutionary Biology, Herbarium Division, University of Utrecht, Heidelberglaan 2, P. O. Box 80.102,3508 TC Utrecht, The Netherlands

SUMMARY

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 - 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 gen­ era worldwide (24), except the Asian 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 Hippocra­ teae/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 an intruding bark resulting in an in­ dented wood pattern in stern cross sections or even an intricate pattern of deep furrows. The Salacieael Salacioideae on the other hand are char­ acterized by narrow, not exceptionally high rays, absence of unlignified ray cells, the occurrence of septate fibres in a parenchyma-like dis­ tribution, and often by the presence of included phloem tissue, either as isolated strands or more often as conspicuous concentric bands, or as ir­ regular 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; fibre­ tracheids, and libriform nonseptate and septate fibres present; axial pa­ renchyma scanty paratracheal or as rare isolated strands; rays hetero­ geneous, the cell types irregularly distributed, rhombic crystals numerous, often in characteristic radial distribution. , considered in the past by some taxonornists as belonging in Celastraceae or as inter­ mediate 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.

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Key words: Celastraceae, Hippocrateoideae, Salacieae, Campylo­ stemoneae, Helictonemeae, Hippocrateae, systematie wood anatomy, in­ cluded phloem, non-lignified ray tissue.

INTRODUCTION

The Hippocrateaceae, at present by most taxonomists considered as a subfamily of the Celastraceae, are confined to the tropics and subtropics. The are for the greater part woody , occasionally or . A study ofthe New World genera (Mennega 1972, 1994) revealed the occurrence of two fundamentally different types of wood structure, running parallel with the taxo­ nomie division of the Hippocrateaceae into two groups: Hippocrateae and Salacieae. In these papers the Hippocrateaceae were still considered aseparate family of the order . It seemed worthwhile to study the wood structure worldwide to see if this bipartition is also found in genera not represented in the New World. Of particular interest was the structure of the African genera Bequaertia, Campylostemon and Tristemonanthes. Loesener, in his treatment of Hippocrateaceae (1942), considered Campylostemon as a genus of the Celastraceae, Bequaertia as a species of , and Tristemonanthes as a genus of the Hippocrateaceae. In a monograph of the West African Hippocrateaceae (1962) and in recent treatments in the Floras of Gabon and Cameroon by Halle (1986, 1990) these three genera were accommodated in the tribe Campylostemoneae of the Celastraceae. In spite of requests to several institutional wood collections no wood could be ob­ tained of Halles (1984) genus Arnicratea comprising fOUf Old World species. This genus is related to (Hou 1963), but in Halles opinion sufficiently distinct to be considered as a separate taxon. Generic delimitations vary considerably in the subfamily Hippocrateoideae accord­ ing to the taxonomic opinions of the authors. Some prefer to admit only few genera, chiefly Hippocratea and , others are in favour of splitting these large genera into several smaller taxa. For my treatment of the New World material I followed A. C. Smith (1940), who ac­ cepted several genera next to Hippocratea and Salacia. For the African sampies the identification and papers by N. Halle provided the starting-point. He is not in favour of splitting Salacia, but on the other hand recognized several genera besides Hippocratea. Finally, for the Asian material Hou's (1964) treatment in Flora Malesiana was used. He considered the genus Salacicratea Loes. as conspecific with Salacia. From the present wood anatomieal research it appears that the tribes recognized by Halle in the Flore du Cameroun, listed in Table 1, can be divided into two groups: group 1 the Salacieae; group 2 comprising Campylostemoneae, Helictonemeae and Hippocrateae. Taxa of group 2 showing the characteristic wide rays of the Hippocrateae as described in the treatment of the Guianan material (Mennega 1994) will be indi­ cated in this paper as Hippocrateae.

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Table 1. Genera with number of species recognized, based on Halle (1990) and Görts & Mennega (1994); between brackets the number of species studied.

Tribe Salacieae Campylostemoneae Helictonemeae Hippocrateae

Cheiloclinium 11 (5) Bequaertia 1 (1) Helictonema 1 (1) 2 (1) 13 (5) Campylostemon 8? (1) Apodostigma 1 (1) Salacia c. 200 (31) Tristemonanthes 2 (1) Arnicratea 3 (0) Salacighia 2 (1) 5 (1) Thyrsosalacia 4 (2) 7 (2) 31 (6) Hippocratea 3 (3) Hylenaea 3 (2) 16 (6) Prionostemma 5 (l) 24 (8) Reissantia 6 (1) Semialarium 2 (1) Simicratea 1 (l) Simirestis 6 (1)

MATERIAL AND METHODS

For the present study a good number of sampies from Africa was available, main­ ly collected by F.O. Breteler and by A.lM. Leeuwenberg in Gabon and Cameroon. These collections were cited in Halles treatments for the Flore du Gabon and Flore du Cameroun (1986, 1990), where, for a number of specimens, a drawing of a cross section of the twig or stern at natural size was given, often showing characteristic pat­ tems. Material available from Asia and Australia was rather scarce, and in the case of Australia restricted to sections forwarded by the Wood Technology and Forest Re­ search Division at Beecroft, New South Wales. All sampies .are backed by herbarium vouchers. African herbarium specimens were identified by Halle, Neotropical material by myself. Wood sampies of the genera listed in Table 1 were studied. Sections were prepared according to standard methods. Samples or slides received from other institutes are indicated by Stem's (1988) abbreviations in his Index Xylariorum 3. Descriptions mainly followed the recommendations of the IAWA (1989). Features present in all taxa of the subfamily, e. g. simple vessel perforations and vessel / ray pit­ ting similar to the intervessel pitting, were omitted in the generic descriptions. Length of elements was measured in macerations, means were based on 25 measurements of each element. For vessel elements tails were included. In the short general descriptions of wood and bark only occasionally values could be given of the wood density.

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Generic treatments follow tribai succession as listed in Table 1, and within the tribes arrangement according to alphabeticalorder. Gregory's (1994) Bibliography was helpful in complementing and checking litera­ ture references.

SURVEY OF WOOD ANATOMICAL CHARACTERS Growth rings Usually present but faint and hardly visible to the naked eye. Marked by presence of some rows of radially flattened fibres at the end of a growth period (Fig. 18,20). In several genera of the Hippocrateae (Table 2), however, the zone of flattened fibres extending in the wide rays as a V-shaped layer of unlignified cells, resulted in an unu­ sual pattern as seen in cross sections (Fig. 21,24,42). Vessels Generally for 90-95% solitary, the remainder in radial multiples of2-3; number of multiples slightly more numerous in Campylostemon and in some species of Salacia. Diffuse. Vessel frequency 4 -80 per sq. mm. The characteristic occurrence of wide and narrow vessels, Carlquist's (1985) vessel dimorphism (Fig. 1,24) is more pronounced in the lianas than in the shrubs or trees. Narrow vessels 20-50 Iffil wide, the wide ones ranging from 100-350 Iffil. Average vessel element length between 500-900 11m, mostly 600-800 Iffil. Perforations simple. Intervessel pits alternate, crowded, borders round to oval, the slits included or reaching the border or coalescent, suggesting a striated vessel surface. Pits most frequently 3 - 5 11m wide, but pits 6(-10) 11m wide occur in Bequaertia, Campylostemon, Helictonema and Tristemonanthes while in Hippocratea p. p., Loeseneriella, and Reissantia pits are 8-12 flm wide. Vessel/ ray pitting (not always present) almost identical to intervessel pitting.

Fibre tissue Ground tissue composed of fibre-tracheids, and septate and nonseptate libriform fibres. Distribution generally random and amounts variable, but in a number of genera of group 1 (Fig. 3, 5) septate fibres arranged in a parenchyma-like way, in concentric, narrow, straight or interrupted bands or vasicentric, aliform to aliform-confluent. Of­ ten, particularly in genera of group 2, septate fibres are scarce and difficult to observe. Fibre-tracheids strongly pitted with small bordered pits on both tangential and radial walls (Fig. 9, 27, 35). Walls mostly 3-4 Iffil thick, lumina 8-10 11m wide; average length varying between 700-1600 Iffil, with a most frequent range of 900-1200 11m; tending to be shorter in tribe Salacieae than in tribes constituting group 2. In both groups the longest elements occurring in shrubs and trees. Septate fibres less strongly pitted, pits simple and mostly restricted to radial walls. Walls often thin, 1-2 flm, and lumina usually slightly larger than in fibre-tracheids, length shorter. Number of septa varying from 1 to 7.

Axial parenchyma Usually parenchyma scarce or absent, if present restricted to a narrow vasicentric, often incomplete ring or to a few diffuse strands. Strands composed of 3-12 cells, mostly of 4-8 cells. No contents observed.

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Rays As stated in the introduction a striking difference exists in ray size and number between the two groups. In tribes of group 2, width of multiseriates varying from 5 - 20 (40) cells, height 8-12 mm or more, number of rays 4-8 per mm of which 1-3 are multiseriates. In Salacieae rays 1-2 cells wide, and not over 1300 llm high; number varying from 12-20 per mm. The cellular composition does not show great differences. Rays heterogeneous. Uniseriates composed of square and upright cells, occasionally with a few procumbent cells. Body of multiseriate wide rays composed of procumbent and square cells irregu­ larly mixed, the procumbent cells mostly very elongate and low; margins short to longer, uniseriate and composed of square and upright cells. Groups of stone cells occasion­ ally present in these wide rays. A striking feature of the wide rays in certain genera of the Hippocrateae (Table 2) is constituted by the rows of un1ignified cells forrning a V-shaped figure at the growth ring margins (Fig. 21, 24). Rhombic crystals almost always present, often in considerable amounts and in ra­ dial arrangement (Fig. 16), generally solitary in a ceIl, but also in radially chambered ceIls; sometimes in inflated cells in group 1 (Fig. 4). Silica bodies as weIl as rhombic crystals present in ray cells of Loeseneriella africana and Prionostemma aspera (Fig. 35).

Included phloem tissue Included phloem is restricted to the Salacieae where it is found in all genera, though not in all species, as it is usually not present in trees, cognatum except­ ed. Most commonly distributed as more or less concentric, continuous or interrupted bands composed of parenchymatous tissue, often with groups of stone ceIls, wherein islands of phloem tissue. These bands of different widths, often connected by radial or diagonal bands of parenchymatous and sclerenchymatous cells, forming characteristic patterns in cross section (Fig. 1,5). Another form of included phloem consists of isolated strands, 'islands' as seen in cross section (Fig. 2, 12). These islands having a random distribution (Cheiloclinium cognatum, Salacighia letestuana) or are arranged in concentric patterns (Cheiloclinium belizense, Salacia staudtiana, S. zenkeri, Tontelea corymbosa, T. cylindrocarpa).

Bark intrusion The occurrence of more or less pronounced intrusion of the bark into the wood cylinder is a feature characteristic for a great number of species of various genera of group 2. It may be present as a not very pronounced crenulation, as striking deltoid structures with step-like sides or even forming a complicate pattern dividing the stern into sections (Loeseneriella species). It is never found in the tribe Salacieae. Other genera with an intruding bark are: Apodostigma, Bequaertia, Campylostemon, Hippocratea, Reissantia, Tristemonanthes.

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Fig. 1-4. -1: Cheiloclinium anomalum (Mathias & Taylor 5114). TS, included phloem tissue in a wide continuous band, septate fibres in narrow, irregular undulating bands. - 2: Cheiloclinium cognatum (Lanjouw & Lindeman 2820). TS, included phloem as dispersed 'islands'. - 3 & 4: Peritassa huanucana (Lindeman 5774). 3: TS, regular almost straight bands of septate fibres. 4: RLS, rhombic crystals in normal, divided or inflated ray cells.

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GENERIC DESCRIPTIONS

SALACIEAE Cheiloclinium Miers - Fig. 1, 2 A genus of 11 species, restricted to the Neotropies.

Material examined: C. anomalum Miers, Surinam: Lindeman & Heyde 197; Peru: Mathias & Taylor 5114. - C. belizense (Standl.) A.C. Smith, Honduras: Macdougal et al. 3381; Guyana: Maas et al. 5921. - C. cognatum (Miers) A.c. Smith, Venezuela: Breteler 5141; Guyana, Surinam, Fr. Guiana numerous (46) collections: i.e., Guyana: A.c. Smith 2486, Surinam: Lanjouw & Lindeman 2820, Daniels & Jonker 987, Fr. Guiana: de Granville et al. 7909; Peru: Woytkowski 5750; Brazil: Irwin 48728, Krukoff 4843,6140,6188,6393,6682,8318 (USw 19633), Maguire et al. 56441, 56753.­ C. hippocrateoides (Peyr.) A.C. Smith, Costa Rica: K. Thomsen 1250; Guyana: A.c. Smith 2547 (MAD-SJRw 35600); Surinam: van Donselaar 3111. - C. serratum (Carnb.) A.C. Smith, Brazil: Reitz 15027 (USw 15092, MAD-SJRw 52080). Lianas, shrubs, or low trees. Bark thin, smooth, light greyish brown sometimes tinged with yellow. Wood light brown, in the arborescent C. cognatum occasionally with medium-brown heartwood. In the lianas sterns terete or fluted, wood with concentric rings of included phloem. Wood density of C. cognatum 0.88. Growth rings faint. Vessels diffuse, occasionally in a more or less radial arrangement due to the pres­ ence of radial streaks with few vessels and crowded rays in C. hippocrateoides, 90- 95% solitary, in C. serratum radial multiples of 2-3 more numerous. Frequency 18-40 per sq. mm in the lianas, in the arborescent C. cognatum on average 6-8 per sq. mm. Outline round to oval, diameter oftwo sizes in the lianas, widest vessels 120- 200 Jlm in diameter, the narrow ones c. 30 Jlm, in C. cognatum vessels not dimorphie, 50-70 Jlill wide. Vesse1 element length: 570 (450-640) Jlm. Intervessel pits 3-5 Jlm in diameter, elongate, the slits often coalescent. Ground tissue composed of fibre-tracheids, and septate and nonseptate libriforrn fibres. Libriforrn fibres in parenchyma-like distribution: narrow-vasicentric, aliforrn confluent to banded and in diffuse patches. Diameter of fibre-tracheids 12-20 Jlm, walls 4-5 Jlm thick with numerous small bordered pits in both radial and tangential walls; libriforrn fibres of same width but walls c. 2 Jlm thick, pits simple, confined to radial walls. Length of fibre-tracheids 832 (650-1160) Jlm. F IV ratio: 1.28-1.60. Parenchyma scanty paratracheal. Strands of 4-6 cells. Rays 15 (12-18) per mm, uniseriate and biseriate, occasionally wider near the ra­ dial conjunctive tissue in woods with banded included phloem. Square and upright cells numerous, truly procumbent cells usually scarce. Height very variable, mostly 200-500 Jlill, maximum height up to 32 cells (1300 Jlm). Contents: numerous rhombic crystals in ray cells. Included phloem always present, showing in cross sections either as isolated strands 250-800 Jlm wide, oval to round in outline, arranged randomly (c. cognatum), or in a more or less concentric way (c. belizense), or the phloem incorporated in concentric bands of conjunctive tissue, the bands interconnected by radial or diagonal bundles of conjunctive tissue. Bands mostly 300-500 Jlm wide; groups of stone cellS in the con­ junctive tissue.

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Peritassa Miers - Fig. 3, 4 A genus of 13 species, restricted to the Neotropics.

Material examined: P. bullata A.C. Smith, Peru: Mathias & Taylor 5099. - P. calypsoides (Carnb.) A.C. Smith, Brazil: Reitz 16556, Hatschbach et al. 879. - P. dulcis (Benth.) Miers, Brazil: I.N.P.A. X-3739. - P. huanucana (Loes.) A. C. Smith, Surinam: Lindeman & Stoffers 650, Lindeman 5774; Peru: Mathias & Taylor 3954. - P. pruinosa (Seern.) A.C. Smith, Venezuela: MAD-SJRw 42026.

Lianas, low shrubs (P. calypsoides) or small trees (P. dulcis). Sterns terete, bark of uniform thickness, 1-2 rum, smooth, occasionally blotched, greyish. Wood light grey­ ish brown, with widely spaced, narrow concentric bands of included phloem or with­ out included phloem. Growth rings absent or faint. Vessels diffuse, 90-95% solitary, the remainder in radial multiples of 2-3. Fre­ quency 7-20 (30) per sq. rum. Outline round to oval, diameter of two sizes, the wide vessels 80-100 (150) ~ wide, the narrow ones 10-40 ~ wide. Vessel element length: 600 (350-830) Jlm. Intervessel pits 3-4 ~ in diameter, slits enclosed, but occasion­ ally coalescent. Vessels sometimes occluded by sclerotic tyloses. Ground tissue composed of fibre-tracheids, and septate and nonseptate libriform fibres. The libriform fibres in parenchyma-like distribution: concentric bands or aliform­ confluent in species without included phloem, if included phloem is present then irregularly distributed in patches. Diameter 15-19 ~, walls 4-6 Jlm thick in the fibre­ tracheids, 1.5-2.5 Jlm in the libriform fibres. Small bordered pits in both radial and tangential walls in the fibre-tracheids, pits simple and restricted to the radial walls in the septate fibres. Length fibre-tracheids 800 (756-830) 11m. F/V ratio: 1.42 (1.23- 1.50). Parenchyma extremely scarce, scanty paratracheal, restricted to an occasional strand bordering avesseI. Strands of 4-12 cells. Rays exclusively uniseriate, though locally over a short distance two cells wide; 12-26 per rum. Composed mainly of square and upright cells, procumbent cells few or absent. Height variable, usually about 25 cells (500-700~) but in species without included phloem often up to 40 cells (2-3 rum) high. Rhombic crystals frequent, in inflated cells or in divided ray cells. Included phloem in concentric bands c. 1 rum wide without radial connections be­ tween the bands, or included phloem absent (P. dulcis).

Salacia L. - Fig. 5 -11 A pantropical genus of about 200 species, the number depending on taxonomie opin­ ions.

Material examined: S. adolfoJridericii Loes. ex Harms, Cameroon: Breteler 1718, 2830. - S. alwynii Mennega, Venezuela: Steyermark et al. 119786. - S. amplectens A. C. Smith, Brazil: Prance & Maas P 14191. - S. cauliflora A.C. Smith, Peru: Woytkowski 5346 (USw 15884). - S. cerasifera Welw. ex Oliv. var. cerasifera, Cameroon: Brete1er 1895, 2449. - S. chinensis L., Queensland: (SFCw, BG 201564 and BG 26150 V). - S. chlorantha Oliv., Liberia: (MAD-SJRw 15119, distributed as

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Fig. 5-9. - 5: Salacia germainii var. chlorion (Halle 3406). TS, banded included phloem. - 6: Salacia impressifolia (Maguire et al. 55865). TS, showing septate fibres in vasicentric-aliform and in irregularly banded position. - 7: Salacia lehmbachii (Leeuwenberg 3800). RLS. - 8 & 9: Salacia pynaertii (Breteler 866).8: TS, banded included phloem. 9: TLS, uniseriate rays, fibre­ tracheids strongly pitted.

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S. senegalensis DC.). - S. cordata (Miers) Mennega, Brazil: Prance & Maas P 11268; Surinam: Lindeman 6330. - S. crassifolia (Mart.) G. Don, Brazil: Maguire et al. 57028. - S. debilis (G. Don) Walp., Cameroon: Breteler 2190,2443. - S. disepala (C.F. Wright) Ding Hou, Queensland: (SFCw, BH 21160). - S. duckei A. C. Smith, Surinam: Lanjouw & Lindeman 2430, Lindeman 5776, 5883.­ S. elegans Welw. ex Oliv. var. elegans, Cameroon: Breteler 2868. - S. elliptica (Mart.) G. Don, Brazil: Reitz 14266 (MAD-SJRw 51996); Guyana: Jansen-Jacobs et al. 903; Bolivia: Nee 35676 (MADw 46013). - S. erecta (G. Don) Walp., Cameroon: Breteler 1693. - S. germainii Wilcz. var. chlorion (Halle) Halle, Gabon: Halle 3406. - S. impressifolia (Miers) A. C. Smith, Venezuela: Wurdack & Adderley 43182; Guyana: Jansen-Jacobs et al. 2439; Surinam: Maguire et al. 55865 (USw 3966); Brazil: Prance & Maas P 11524. - S. insignis A. C. Smith, Brazil: Krukoff 6799,6991,7043; Maguire et al. 47036; Fr. Guiana: Feuillet et al. 10308, de Granville et al. 6521, Oldeman T 372. - S. juruana Loes., Peru: Tessmann 4672; Guyana: Jansen-Jacobs et al. 2336. - S. kanukuensis A. C. Smith, Surinam: Maguire 2471 (MAD-SJRw 44231). - S. lehmbachii Loes. var. aurantiaca (Halle) Halle, Ivory Coast: Leeuwenberg 3800. - S. letestuii Pellegrin, Cameroon: Breteler 1418,2762,2828. - S. ma­ burensis Mennega, Guyana: Maas et al. 7134. - S. macrantha A.c. Smith, Peru: Maas et al. 6255, Surinam: Lindeman 6383. - S. miqueliana Loes., Surinam: Heyde 550. - S. multiflora (Larn.) DC. var. multiflora, Venezuela: LI. Williams 10332; Colombia: Cuatrecasas 17516; Surinam: Heyde 474, Lanjouw & Lindeman 2653, Maguire 24558 (MAD-SJRw 44156), Schulz 7283; var. mucronata (Rusby) Mennega, Venezuela: Breteler 3816. - S. opacifolia (Macbr.) A.C. Smith, Costa Rica: K. Thomsen 987. - S. prinoides (Willd.) DC., Indonesia: Rahmat si Boeea 52 (MICH); New Gui­ nea: CSIRO 215 (MAD-SJRw 32065). - S. pynaertii de Wild., Cameroon: Breteler 866, 1663. - S. solimoesensis A.C. Smith, Brazil: Krukoff 8174, Prance & Maas P 15104. - S. staudtiana Loes. var. staudtiana, Cameroon: Breteler et al. 2322. Lianas or trees. Sterns usually cylindrical, but sometimes, particularly old sterns, more or less deeply grooved. In cross sections concentric bands of included phloem with usually red sap, often conspicuous; rarely the induded phloem in radial arrangement. Bark thin, dark greyish, occasionally with an orange-red hue (S. adolfo-fridericii, S. cerasifera). Wood yellowish or light yellowish brown, seldom reddish brown.

Growth rings faint or absent, boundaries formed by 3-7 layers of flattened fibres. Vessels diffuse, in S. cordata, S. gennainii and S. juruana in radial stripes, 80-90% solitary, the remainder in radial multiples of 2-3, occasionally in clusters, usually 6-25 per sq. mm, but far more numerous (70-90 per sq. mm) in S. elegans, S. lehmbachii (a ) and S. staudtiana. Outline oval to round, wide and narrow vessels mixed, diameter of the wide ones 150-250 Jlm, less wide in the species with numerous ves­ sels, and in the New World species: S. elliptica, S. insignis and S. maburensis (a ); the narrow vessels 30-60 Jlm wide. Vessel element length on average 590 (387-773) Jlill. Intervessel pits smalI, 3-5 Jlm wide, exceptionally in S. chinensis 7-8 Jlm wide, the slits induded or coalescent; vessel-ray pitting also often with coalescent apertures. Occasionally with reddish or orange gum or resin. Ground tissue composed of fibre-tracheids, and septate and nonseptate libriform fibres. The septate fibres arranged in concentric bands and in patches, also often vasi­ centric, suggesting parenchyma, the bands either regular or interrupted and sinuous. Diameter of all fibrous elements 15-20 Jlm. Fibre-tracheids radially and tangentially strongly pitted, walls c. 4 Jlm thick, libriform fibres with numerous small simple pits in the 2-3 Jlm thick walls. Length offibre-tracheids 855 (614-1135) Jlm, longest in the trees and shrubs. F IV ratio: 1.44 (1.29-1.69). Parenchyma, if present, scarce, vasicentric, strands of 4-9 cells.

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Rays 12-22 per IllIll. Generally uniseriate or rarely with short biseriate portions, in other species, such as S. cerasifera, S. chinensis, S. disepala, S. elliptica, S. elegans, S. germainii, and S. letestuii, biseriates of general occurrence; aggregate rays or rays up to 8 cells wide rather frequently present, particu1arly in species with included phloem, in the radial conjunctive tissue. Procumbent, square and upright cells present, irregu­ larly distributed, the procumbent cells often rather short in radial direction, and the upright cells rather low. Height variable from 2-15 cells, up to 600 jlm. Crystals abun­ dant, often in inflated cells, about 30 jlm in diameter. Included phloem nearly always present in the lianas, absent in some of the shrubby or tree species, such as S. cordata, S. elliptica, S. insignis, S. lehmbachii, S. maburensis. Usually occurring in concentric rings, with or without radial or oblique connections, exceptions are found in S. opacifolia and in S. staudtiana. In the latter species the included phloem bundles connected in radial direction by conjunctive tissue without stone cells giving a misleading impression of intrusive growth of the outer phloem into the woody cylinder. Obaton (1960) mentioned as a third type the occurrence of iso­ lated islands of included phloem in S. zenkeri Loes. (See also note). Note: In my earlier paper (Mennega 1972) I described the same special type of distri­ bution of the included phloem as occurs in S. opacifolia and S. staudtiana for Tontelea corymbosa, and I considered it erronously as related to the type of wedge-like in­ vaginations of the bark into the woody cylinder occurring in Hippocrateae. The same was done by Obaton (1960) who described sterns of Salacia staudtiana var. tsopouhensis and S. nitida (Benth.) N. E. Brown var. bipidensis (Loes.) N. Hallt\ Though I have not seen material of the latter species, her explicit description and the accompanying drawing clearly indicate that here the same type of included phloem is present. From stern drawings in the paper by Hall and Lock (1975), who studied the anatomy of Salacias of Ghana, it appears that S. laterita N. Halle and S. whytei Loes. also belong to this category. The third type, the isolated strands, described by Obaton as lacunose for S. zenkeri, was also found in the Ghanaian woods studied by Hall and Lock in S. howesii Hutch. & Moss. The wood of the Asian S. reticulata studied by Chalk and Chattaway (1937) shows the most frequent pattern of concentric rings of conjunctive tissue with included phloem and fascicular bundles.

Salacighia Loes. - Fig. 12, 13 A genus of 2 species, restricted to tropical Africa.

Material examined: S. letestuana (Pellegr.) Blake!., Cameroon: Breteler 1645. Lianas. Sterns cylindrical. Bark thin, greyish brown, finely striate. Wood yellowish. Growth rings not noticed. Vessels diffuse, 95% solitary, the remainder in radial multiples of 2-3. Frequency 13.5 (10-18) per sq. IllIll. Outline round to oval, wide and narrow vessels mixed, the wide ones 80-120 jlm wide, the small ones 30 jlm wide. Vessel element length on

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Fig. 10-14. - 10 & 11: Salacia staudtiana (Brete1er et al. 2322). 10: TS, showing numerous, small vessels, bundles of inc1uded phloem tissue arranged in radial strands. 11: TLS, normal uniseriate rays and part of enlarged ray containing phloem bundles. -12 & 13: Salacighia letestuana (Breteler 1645). 12: TS, showing inc1uded phloem 'islands'. 13: TLS, showing long uniseriate or partially biseriate rays. - 14: Tontelea mauritioides (Heyde 639). TS, showing a wide band of inc1uded phloem.

Downloaded from Brill.com10/07/2021 06:13:28AM via free access Mennega - Wood anatomy of the Hippocrateoideae 343 average 473 (340-620) 11m. Intervessel pits alternate, about 4 11m in diameter. Orange resin occasionally present. Ground tissue composed of fibre-tracheids and septate libriform fibres, the latter in rather irregular concentric bands 3-4 cells wide. Diameter of both types of fibres c. 12 !lill, walls of the fibre-tracheids 3.5 11m thick, strongly pitted in radial and tangential walls, the walls of the septate fibres 1.5 11m thick, with small bordered pits in the radial walls. Septate fibres often with brown contents. Length of fibre-tracheids 746 (560- 970) 11m. F IV ratio: 1.58. Parenchyma scanty paratracheal in an usually incomplete ring one cell wide. Strands of 2-6 cells. Rays 24 per mm, uni- and biseriate. Composed mainly of square and upright cells. Width 12-24 11m, height variable, from 100-1500 11m. Contents: abundant rhombic crystals mostly in square cells, occasionally in divided cells. Included phloem present as numerous isolated strands with round or elliptic outline and a tangential diameter of 200-350 !lill. Note: Obaton (1960) mentioned the occurrence of included phloem in isolated strands in astern of S. malpighioides, a species considered by Halle (1986) as a synonym of S. letestuana.

Thyrsosalacia Loes. An African genus of 4 species.

Material examined: T. racemosa (Loes. ex Harms) N. Halle, Cameroon: Leeuwenberg 9117, W. de Wilde 1454. - T. nematobrachion Loes., Cameroon: Leeuwenberg 5334, W. de Wilde 1756. Only thin twigs were available, about 3 mm wide, taken from herbarium specimens of low shrubs. Low shrubs or smalllianas. Growth rings not observed. Vessels 90% solitary, the remainder in radial multiples of 2-3 or in small clusters, over 100 per sq. mm, slightly angular in outline, 20-35 11m wide.Vessel element 1ength 750 (706-810). Intervessel pits 4 !lill wide, the border e10ngate, the slits included. Ground tissue composed of fibre-tracheids 12 11m wide, the walls 4-5 11m thick, both radial and tangential walls strongly pitted, length 990 (980 -10 10) !lill. Septate libriform fibres in parenchyma-like arrangement, vasicentric in complete or incom­ plete rings, occasionally aliform and forming irregular bands; width 14-20 11m, the walls 2.5 !lill thick, pits restricted to radial walls. F IV ratio: 1.32. Parenchyma almost absent. Rays 14-16 per mm; uniseriate or locally biseriate, juvenile, composed of very tall upright cells and square cells, procumbent cells absent. Height 600-1000 11m. Rhom­ bic crystals numerous. Included phloem not (or not yet) present. Note: Due to the extremely small size of the sampies a comparison with other genera of the Salacieae is somewhat difficult, but the structure seems to fit very weIl within the rather homogeneous tribe.

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Tontelea AubI. - Fig. 14 A neotropical genus of 31 species.

Material examined: T. corymbosa (Huber) A.C. Smith, Peru: Tessmann 4720 (Bw 2862). - T. cy­ lindrocarpa A. C. Smith, Brazil: Irwin & Westra 47488; Guyana: Ursum & Potters 43; Surinam: WesseIs Boer 1500. - T. glabra A.C. Smith, Surinam: van Donselaar 3511. - T. mauritioides A.C. Smith, Surinam: Heyde 639. - T. micrantha (Mart.) A.C. Smith, Brazil: I. Gottsberger 279 R-28972. - T. nectandrifolia (A.C. Smith) A.C. Smith, Surinam: Maguire 24871 (MAD-SJRw 44279).

Lianas or low shrubs (T. micrantha), occasionally low trees with scandent branches. Sterns terete or slightly compressed in the middle. Bark thin, smooth or finely striate, light greyish to brownish, often blotched with light patches. Wood brown. In some species with concentric rings of included phloem with or without radial connections. Growth rings absent or faint. Vessels diffuse, exclusively solitary, or with a few clusters of 2-3, from 10-30 per sq. mm in most species, but over 100 per sq. mm in the shrubby T. micrantha. Outline round or oval, diameter of wide vessels usually from 100-160 /-Im, but up to 280 /-Im in T. nectandrifolia; in T. micrantha no differentiation in narrow and wide vessels, largest width 50 /-Im. Average vessel element length 547 (360-650) /-Im. Intervessel pits scarce, small, 2-5 /-Im wide, the slits sometimes coalescent. Ground tissue of fibre-tracheids and septate libriforrn fibres, the latter in parenchy­ ma-like distribution, in concentric bands 2-3 cells wide or aliforrn-confluent. Diam­ eter 12-18 /-Im, walls in the fibre-tracheids 2.5-6 /-Im thick, in the libriforrn fibres 1- 2.3 /-Im thick; small bordered pits numerous in both radial and tangential walls in the fibre-tracheids, simple pits in radial walls in the libriforrn fibres. Length on average 920 (787-1080) /-lffi. F/V ratio: 1.48 (1.33-1.59). Parenchyma scanty paratracheal and apotracheal as isolated strands, difficult to distinguish from the septate fibres. Strands of 8 cells. Rays 12-18 per mm, all uniseriate (T. glabra, T. nectandrifolia), or uni- and biseriate, in T. cylindrocarpa aggregate rays conspicuous. Composed of taU upright cells, cells grading to square cells, truly procumbent cells scarce. Height from 2-18 cells (up to 1200 /-Im). Contents: rhombic crystals numerous. Included phloem noticed in all species except in the thin stern of T. glabra. In T. cy­ lindrocarpa as roundish phloem islands in concentric arrangement separated by wide aggregate rays often containing groups of stone cells; in T. mauritioides as concentric rings without radial connections; in the other species as concentric rings with radial or oblique interconnections of conjunctive tissue of parenchyma and sclerotic ceUs.

CAMPYLOSTEMONEAE

Bequaertia Wi1cz. - Fig. 15, 16 A monotypic genus of tropical Africa.

Material examined: B. mucronata (ExeIl) Wilcz., Ivory Coast: N. Halle 227 (P).

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Liana, stern cylindrical. Bark of irregular width, 1-3 mm thick, with step-like indenta­ tions into the woody cylinder, composed of unlignified tissue with groups of stone cells arranged in concentric bands. Growth rings inconspicuous, marked by a number of rows of radially compressed fibres. Vessels diffuse, 92% solitary, the remainder in radial multiples of 2-3. Frequency 31 (25-37) per sq. mm. Relatively few narrow vessels among the wide ones, wide ves­ sels mostly 150-200 Jlm wide. Vessel element length on average 728 (590-830) Jlffi. Intervessel pits 6-8 Jlm, the borders elongate, the slits enclosed, seldom coalescent; vessel-ray pitting rare. Lignified tyloses often present. Ground tissue composed of mixed septate and nonseptate libriform fibres and fibre­ tracheids, diameter c. 18 Jlm, walls c. 2.5 Jlffi thick, length on average 1030 (790-1300) Jlffi. Both radial and tangential walls of the fibre-tracheids strongly pitted with small bordered pits. Parenchyma very scarce, restricted to a few cells bordering avessei; strands of 4-8 cells. Rays 10-12 per mm, of which two are multiseriate. The uniseriates composed of upright cells, 1-8 cells high, the multiseriates 5-14 cells (100-120 Jlffi) wide, and over 7 mm high, the body composed of narrow procumbent cells, the uniseriate exten­ sions of few upright cells. Contents: numerous rhombic crystals in procumbent ray cells, mostly arranged in radial series.

Campylostemon Welw. ex Hook. f. - Fig. 17 An African genus of 8 species, perhaps fewer.

Material examined: C. angolense Welw. ex Oliv., Cameroon: Breteler 1714, 2978. Large lianas, at least 50 m long, sterns cylindrical. Bark smooth or somewhat fissured, the inner bark with a regular pattern of deltoid indentations, up to 4 mm deep. Growth rings very faint. Vessels diffuse, 72% solitary, the remainder in short radial multiples, 34 (24-45) per sq. mm. Outline round to oval, most vessels 100-170 Jlffi wide; narrow vessels, 20-60 Jlffi wide, rather scarce. Vessel element length 607 (350-820) Jlm. Intervessel pits 8-10 Jlm, the borders angular, slits included; vessel-ray pitting rare. Ground tissue mainly composed of strongly pitted fibre-tracheids, intermingled with some septate fibres. Diameter 18-22 Jlm, walls of the fibre-tracheids 3-4 Jlffi thick. Occasionally with reddish contents. Length on average 1000 (750-1200) Jlffi. F/V ratio: 1.66. Parenchyma rare or absent; strands of 3-6 cells. Rays 7-8 per mm, of which 2-3 are multiseriates. The uniseriates composed of 1-6 upright cells; the multiseriates 3-13 cells (up to 150 Jlffi) wide and over 12 mm high. Multiseriates with the body part composed of elongate procumbent cells mixed with square cells, the uniseriate tails short, composed of upright cells. Numerous rhombic crystals present, 2-4 in divided procumbent cells and these cells in radial alignment.

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Fig. 15-20. - 15 & 16: Bequaertia mucronata (Halle 227). 15: TS, ingrowth ofbark tissue into wood. 16: RLS, radial alignment of crystal-bearing cells. - 17: Campylostemon angolense (Breteler 1714). TS, step-like intrusion ofbark into wood. - 18: Tristemonanthes nigrisilvae (Leeuwenberg 3758). TS, intruding bark as a gap in the wood, and two wide rays. - 19 & 20: Helictonema velutinum (Breteler 2929). 19: TS, slight intrusion of bark, striking vessel dimorphism, and one wide ray. 20: TS, basal part of seetion with wood structure in the non-climbing stage, above first ring after climbing has started.

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Note: At the time when were still unknown, Loesener (1942) considered Campylostemon to belong to the Celastraceae in a subfamily of its own on account of the structure of the . Later Lawalree (1947), who had seen fruits of the plant, preferred a position in Hippocrateaceae. In Hou's (1964) opinion the genus is interme­ diate between the two families. Robson (1965) considered Campylostemon as a genu­ ine, though reduced Hippocratea. Finally Halle (1962, 1986, 1990) also treated the taxon as a member of the Hippocrateaceae, but in aseparate tribe: Campylostemoneae. The anatomy of the wood supports a close affinity with Hippocratea and related genera (see also Introduction and Table 2).

Tristemonanthes Loes. - Fig. 18 A genus of 2 species of tropical Africa.

Material examined: T. nigrisilvae (N. HaIle) N. HaIle, Ivory Coast: Leeuwenberg 3758. Large , at least 50 m long, stern cylindrical. Bark scaly, strongly fissured and of irregular width, the inner bark penetrating more or less deeply into the wood; light greyish brown. Wood ochraceous, hard. Growth rings present, the boundaries formed by a few rows of radially flattened fibres. Vessels 70% solitary, the remainder in radial multiples or in clusters. Frequency 15 (10-22) per sq. mm. Outline circular, occasionally elliptic; most vessels 140-250 /lm wide, the narrow ones 60-80 /lm in diameter. Vessel element length on average 910 (760-1020) /lm. Intervessel pits 8-10 /lm in diameter, the slits often coalescent. Ves­ sel-ray pitting rare. Ground tissue of fibre-tracheids mixed with some septate libriform fibres. Diameter 18-20 /lffi, the walls 3 /lm thick, average length 1270 (800-1700) /lm. Fibre-tracheids with numerous small bordered pits in both radial and tangential walls, the libriform fibres with small simple pits restricted to the radial walls. F IV ratio: 1.40. Parenchyma scanty paratracheal; strands of 2-7 cells. Rays uni- and multiseriate. Number 5-9 per mm of which 1 or 2 are multiseriate. Uniseriates composed of upright and square cells, 2-20 cells (1000 /lm) high. Multi­ seriates up to 25 cells (350 /lm) wide and over 10 mm tall, composed in the middle part of low procumbent cells, the uniseriate tails short to extremely long. Rhombic crystals often present, solitary, paired or three to four in a divided procumbent cell, these cells in radial alignment. Note: The wood resembles Bequaertia and Campylostemon, except for the less nu­ merous, wider vessels, the longer vessel elements and longer fibres.

HELICTONEMEAE

Helictonema Pierre - Fig. 19,20 A monotypic genus of tropical Africa.

Material examined: H. velutinum (AfzeI.) Pierre ex N. HaIle, Cameroon: Breteler 1550, 1658,2929.

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Fig. 21-24. - 21 & 22: Anthodon decussatum (Woytkowski 5666). 21: TS, showing wide rays with V-shaped bands of non-lignified ray cells. 22: RLS, wide ray with non-lignified cells and numerous crystal-bearing cells at the border of the bundle of non-lignified cells. - 23: Apodostigma pallens (Halle 131). TS. - 24: Cuervea kappleriana (Heyde 452). TS, showing unlignified parts of the wide rays.

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Liana up to 25 m long. Outer bark yellowish with longitudinal fissures and transverse­ ly crackled, inner bark dark brown when dry, superficially intruding into the woody cylinder, with large cavities where the phloem strands capped the wood. Wood pale brown, hard. Growth rings inconspicuous, the boundary formed by a couple of rows with radially flattened fibres and a slight bulging of the wide rays. Vessels over 85 - 95% solitary, the remainder in radial pairs or in clusters, diffuse. Number 5 (2-8) per sq. mm. Outline round to elliptic, the large vessels 200-350 /Jm wide, the narrow ones 20-120 /Jm wide. Vessel element length on average 800 (450- 1210) /Jill. Intervessel pits rare, elongate, 6-8 /Jm in diameter, the slits enclosed. Ves­ sel-ray pitting similar or larger and confluent. Occasionally red resin present. Ground tissue composed of fibre-tracheids, nonseptate and septate libriform fibres, the septate fibres scattered, numerous. Diameter of both fibre types 16-26 /Jm, walls 3-4 /Jm thick, lumen large. Fibre-tracheids with numerous small bordered pits in both radial and tangential walls. Septate fibres with 2-7 septa, often with amorphous con­ tents. Average length ofthe fibres 1440 (1000-2000) /Jm. F/V ratio: 1.80 (1.74-1.85). Parenchyma paratracheal in an often incomplete ring one cell wide, occasionally diffuse. Strands of 4-12 cells. Rays 7 (5-10) per mrn ofwhich one is multiseriate. The uni- or occasionally biseriates composed of square and low upright cells, up to 25 cells (700 /Jill) high. The multiseriates composed of long and low procumbent cells mixed with some square and upright cells, tails short to long. Width up to 40 cells (600 /Jm), height over 1 cm. Contents: rhombic crystals numerous in both types of rays. Occasionally a few non-lignified cells present at the growth ring boundary in the wide rays. Note: The wood shows a close resemblance to Hippocratea volubilis.

HIPPOCRATEAE

Anthodon Ruiz & Pavon - Fig. 21, 22 A genus of 2 species of Central and South America.

Material examined: A. decussatum Ruiz & Pavon, Peru: Woytkowsky 5666 (USw 16016). Lianas, stern terete, bark fissured, c. 2 mm thick, not intruding into the woody cylinder. Wood greyish brown. Growth rings inconspicuous to the naked eye, but conspicuous in sections due to a row of marginal parenchyma cells with unlignified cell walls extending into a V-shaped pattern in the wide rays. Vessels diffuse, 95% solitary, the remainder in short multiples, Frequency 13 (9-22) per sq. mrn. Outline round to oval, wide vessels 160-200 /Jm wide, the narrow ones 16 - 60 /Jill wide. Vessel-element length 803 (580 -1000) /Jill. Intervessel pits very scarce, 5 - 8 /Jm in diameter, the slits usually enclosed. Vessel-ray pitting slightly larger. Thin tyloses and resin occasionally present.

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Ground tissue composed of fibre-tracheids and septate libriform fibres, the two types mixed without pattern. Diameter 15-18 flIll, walls of the septate fibres 1 ).Im thick, of the fibre-tracheids 2 ).Im; the septate fibres with numerous simple pits and the fibre­ tracheids with numerous small bordered pits in both radial and tangential walls. Length of the fibre-tracheids 1380 (1100-1650) flIll. FN ratio: 1.70. Parenchyma scanty paratracheal and diffuse, terminal as an unlignified band one cell wide. Strands of 4-6 cells. Rays 4 per mm, one of which is multiseriate. The uniseriates composed of square and upright cells, occasionally procumbent cells also present, 1-30 cells high; the multiseriates heterogeneous, in the middle part composed of low procumbent cells, at the margins with square cells, up to 28 cells (400 flIll) wide and over 3 mm high, the tails short. At the growth ring border a number of rows of unlignified cells form a V­ shaped pattern as seen in cross section. Numerous rhombic crystals present, mainly in the unlignified cells and in the marginal cells of the wide rays, also in some uniseriates.

Apodostigma Wilcz. - Fig. 23 A monotypic genus of Africa and Madagascar.

Material examined: A. paUens (Planeh. ex Oliv.) Wilcz., Ivory Coast: N. Halle 131 (P). Liana, stern cylindrical. Bark thin, indentations into the woody cylinder shallow and inconspicuous. Wood greyish yellow. Growth rings faint, formed by 3-8 rows of radially compressed fibres and by a V-shaped zone of unlignified cells in the rays. Vessels diffuse, c. 95% solitary, the remainder in short radial multiples. Frequency 15 (11-20) per sq. mm. Outline round; wide and narrow vessels mixed, the wide ones 100-230 flIll wide, the narrow ones 60-80).lm wide. Vessel element length 807 (630- 1000) flIll. Intervessel pits 5 -7 flIll, the slit-like apertures generally confluent resulting in a striate appearance of the vessel wall. Vessel-ray pitting very scarce because rays seldom border on vessels, of the same size as the intervessel pitting. Lignified tyloses occasionally present. Ground tissue composed of septate libriform fibres and fibre-tracheids, the two types mixed without pattern. Diameter 20-25 ).Im, walls of septate fibres very thin, c. 2 flIll, walls of the fibre-tracheids 3 ).Im, strongly pitted. The septate fibres with 2-7 septa, on average 860 (710-1040) flIlllong; the fibre-tracheids on average 1264 (970-1540»).Im long. F/V ratio: 1.47. Parenchyma scanty paratracheal in incomplete rings one cell wide; strands of 4-8 cells. Rays 8 per mm, of which 2 are wide multiseriates. The uniseriates rather numerous, composed of 1-16 upright cells; the wide rays up to 18 cells (280 ).Im) wide and 3-7 mm high, most of the body cells procumbent, the tails usually short. A V-shaped zone of unlignified cells present at the growth ring border. Crystals numerous in the wide rays, single or in multiples in divided procumbent cells.

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Cuervea (Benth. & Hook. f.) Triana ex Miers - Fig. 24

A genus of 5 species in tropical South America and tropical Africa.

Material examined: C. kappleriana (Miq.) A.C. Smith, Panama: Cooper 474 (MAD-SJRw 12092); Surinam: Heyde 452.

Lianas of moderate size, c. 6 m long or low trees, sterns terete, bark light greyish brown, smooth. Wood yellowish.

Growth rings present, the boundaries formed by a narrow band of unlignified paren­ chyma in the wide rays, and by dilation of the wide rays. Vessels diffuse, 99% solitary, 8 (5-11) per sq. mm. Outline roundish, with a striking difference in width, the wide ones 120-260 11m in diameter, the narrow ones 30- 60 !lill. Vessel element length 770 (500-1140) !lill. Intervessel pits scarce, elongate, 5-6 11m wide. Ground tissue composed of fibre-tracheids and septate libriform fibres, the latter arranged in numerous thin, more or less concentric bands. Diameter 16-22 !lill, the fibre-tracheids with walls 3-4 11m thick and with small bordered pits in both radial and tangential walls; the septate fibres with walls 1-2 !lill thick and simple pits in both walls. Length of fibre-tracheids on average 1310 (880-1700) !lill. F IV ratio: 1.65. Parenchyma scanty paratracheal. Strands of 3-10 cells. Rays 5-10 per mm of which 2-4 wide multiseriates. The uniseriates heterogeneous with square and upright cells, 1-10 cells high; the multiseriates homogeneous, com­ posed of procumbent cells up to 18 cells (300 !lill) wide and over 8 mm (650 cells) high. At the growth ring boundary a number of rows with unlignified cells resulting in a V-shaped pattern. Numerous rhombic crystals present in the procumbent cells of the wide rays, few in the upright cells of the uniseriates. The crystals in the wide rays often in radial alignment. Note: No wood of the two African species was available. Record and Hess' (1943) statement that included phloem strands occur in a concen­ tric band of conjunctive tissue in the sampie (Cooper 474) described above, is incor­ rect, because included phloem is absent in this specimen.

Elachyptera A. C. Smith - Fig. 25

A genus on species, of tropical Africa (3), Madagascar (1), and tropical South Amer­ ica (3).

Material exaruined: E.floribunda (Benth.) A.C. Sruith, Colombia, VaIIe: Cuatrecasas 19960 (MAD­ SJRw 44400); Peru: Tessmann 4917 (RBHw); Surinam: LBB (Maas) 10891 - E. parvifolia (Oliv.) Halle, Cameroon: Breteler 1821 (see note).

Lianas of moderate size, the sterns cylindrical. Bark thin, dark brown, with yellowish hue, in E. floribunda regular and of equal width, in the sample of E. parviflora irregu­ larly intruding into the wood (see note).

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Fig. 25-29.- 25: Elachyptera floribunda (Cuatrecasas 19960). TS, showing extremely wide rays wherein narrow zones of compressed cells demarcating the growth ring border. - 26: Hippocratea myriantha (Breteler 1709). TS, wide rays, large vessels and on the upper side intruding bark with large stone cells. - 27 & 28: Hippocratea vignei (Leeuwenberg 41OT,. 27: TLS, showing uniseriate rays and part of a wide ray, fibres with numerous bordered pits. 28: RLS, showing radially paired crystals in square ray cells. - 29: Hippocratea volubilis (Lindeman 5403). TS.

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Growth rings absent or faint, boundary forrned by a few rows of radially compressed fibres and slightly widened rays. Vessels diffuse, 95% solitary, the remainder in radial multiples of 2-3; 11 (8-14) per sq. mm. Diameter of two sizes, the wide vessels 100-230 jlm wide. Average vessel element length 680 (500-800) jlm. Intervessel pits 3-5 (7) jlm, elongate, the slits often coalescent resulting in a striate appearance, alternate to opposite; vessel-ray pitting often with reduced borders. Ground tissue of fibre-tracheids and few septate libriforrn fibres, the two types mixed without pattern. Diameter 15-20 Jlffi, walls c. 3 Jlffi thick in both types, the fibre-tra­ cheids with numerous small bordered pits in both radial and tangential walls. Length of fibre-tracheids on average 1020 (800-1260) Jlffi. F IV ratio: 1.52. Parenchyma absent or very scarce, diffuse and scanty paratracheal. Strands of 2-7 cells. Rays 4-8 per mm of which 1-3 are wide multiseriates, the uniseriates composed of upright and square cells. The wide rays up to 25 cells (450 jlm) wide, the body com­ posed mainly of low procumbent cells mixed with few square cells, the tails short. Rhombic crystals numerous in radial pairs in divided cells of the wide rays.

Note: The wood sampie, Breteler 1821, belonging to a fruiting liana identified by Halle (1986) as E. parvifolia, is not included in the generic description. It differs in several respects from E. floribunda, e. g. the intruding inner bark, the more numerous smaller vessels, the less wide rays, and the occurrence of both rhombic crystals and silica globules in the rays. These characters are suggestive of Loeseneriella africana.

Hippocratea L. - Fig. 26 - 29 A genus of 3 species, 1 in tropica1 America, 2 in tropical Africa.

Material examined: H. myriantha Oliv., Cameroon: Breteler 1709. - H. vignei Hoyle, Ivory Coast: Leeuwenberg 4107. - H. volubilis L., numerous collections (21) from Brazil, Colombia, Guyana, Surinam, French Guiana, Peru, Venezuela. Among others Venezuela: Breteler 3869; Colombia: MAD­ SJRw 28455; Guyana: MAD-SJRw 35524, Maas et al. 7413; Surinam: Heyde 526, Lindeman 4951, 5403; Brazil: Lindeman & de Haas 3483; Peru: Mathias & Taylor 4098. Lianas, often 1arge, with a trunk up to 10 cm thick. Sterns cylindrical, occasionally with a few deep grooves. Bark 5-10 mm thick, rhytidome smooth, greyish brown, inner bark penetrating irregularly wedge-like into the wood in H. vignei and H. volu­ bilis, without wedges in H. myriantha. In cross section red, exudating a red sap with resinous threads in H. myriantha. Wood pale yellow in H. vignei, pinkish brown to red in the other species; hard. Wood density of H. volubilis 0.84. Growth rings inconspicuous, the boundaries forrned by a few rows of radially com­ pressed fibres. Vessels diffuse, about 95% solitary, the remainder in radial multiples. Number 5-10 (3-15) per sq. mm. Outline round to oval, diameter oftwo sizes, the wide ones 150- 300 jlm wide, the narrow ones 50-100 Jlffi. Vessel element length on average 780

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Fig. 30-33. - 30: Hylenaea comosa (Heyde 451). TS. - 31: Loeseneriella apiculata (Breteler 2977). TS, showing few very wide vessels. - 32: Loeseneriella apocynoides (Breteler 1767). TS, showing numerous narrow vessels and intruding bark. - 33: Loeseneriella crenata (Breteler 2450). TS.

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(450-1100) 11m. Intervessel pits 9-10 11m in H. myriantha and H. vignei, 4-7 11m in H. volubilis. Apertures encIosed or coalescent giving a striate appearance to the wall. Vessel-ray pits rare. Sometimes resin present in avesseI, but not occIuding the lumen. Ground tissue composed of fibre-tracheids, septate and nonseptate libriform fibres, intermingled. In H. myriantha with a preponderance of septate fibres, in H. vignei septate fibres scarce. Diameter 20-25 Jlffi, the fibre-tracheids with numerous small bordered pits in radial and tangential walls, the libriform fibres with simple pits in the radial walls. Length on average 1325 (800-2100) Jlffi. F/V ratio: 1.52 (1.48-1.58). Parenchyma scanty paratracheal or vasicentric as a ring one cell wide in H. vignei or as a few strands bordering avesseI; strands of 4-15 cells. Rays 5-7 per mm of which 2-3 wide. The uniseriates composed of upright cells, few to about 20 cells high in H. vignei; the large rays 3-17 cells (up to 300 Jlffi) wide and over 10 mm high. The body composed of low procumbent cells, the short tails of square und upright cells. The wide rays with numerous rhombic crystals, often in ra­ dially divided cells. Occasionally a few non-lignified cells present in the region of the growth ring boundary. Note: Sections labelled Hippocratea macrantha, received from Beecroft, New South Wales, Australia, differed in several respects from the sampies described above, e. g. in the more numerous and narrower vessels. The sections matched much better the wood of Loeseneriella, and in accordance with A. C. Smith's transference of Hippocratea macrantha to Loeseneriella macrantha (Korth.) A.c. Smith, the material at hand was also considered as belonging to the latter genus.

Hylenaea Miers - Fig. 30 A neotropical genus of 3 species.

Material examined: H. comosa (Sw.) Miers, Surinam: Heyde 45 I. - H. praecelsa (Miers) A. C. Smith, Panama: WL. Stern et al. 942 (MO) (USw 16539). Rather slender lianas, low or high cIimbing. Sterns cylindrical. Bark c. 3 mm thick, smooth, greyish brown, of regular width. Wood yellow.

Growth rings indistinct, the margin formed by a narrow zone of radially flattened fibres and by the presence of more numerous crystals in the cells of the wide rays; unlignified cells absent or obscure. Vessels diffuse, for over 95% solitary. Frequency 12-16 per sq. mm. Outline roundish, wide vessels 100-200 Jlffi wide, the narrow ones about 40 11m. Vessel element length on average 775 (630-960) Jlffi. Intervessel pits elongate, 3-4 Jlffi wide, slits encIosed or coalescent, resulting in striations on the vessel wall. Ground tissue of fibre-tracheids, and septate and nonseptate libriform fibres inter­ mingIed. Diameter 18-20 11m, the walls ofthe fibre-tracheids 4 Jlffi thick, of the libriform fibres 2-3 Jlffi; numerous small bordered pits in both radial and tangential walls of the fibre-tracheids, simple pits in radial walls of the fibres. Length fibre-tracheids 1180 (840-1300) 11m, length of libriform fibres 800 (670-900) Jlffi. F IV ratio: 1.52.

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Parenchyma scarce, vasicentric as a sheath one cell wide. Strands of 6-12 cells. Rays uni- and multiseriate, 6 per mm of which 2-3 are multiseriates. Both types heterogeneous. The uniseriates 6-16 cells (450 J.Iffi) high, the multiseriates up to 22 cells (300 11m) wide, the body of low procumbent cells intermingled with square cells, short tails of square and upright cells; up to 12 mm high. Rhombic crystals numerous in the wide rays, with a concentration at the growth ring margin.

Loeseneriella A. C. Smith - Fig. 31-33 An Old World genus of 16 species, of which 10 occur in Africa, 2 in Madagascar, the others in the Far East and Australia.

Material examined: L. africana (WilId.) Wilcz. ex N. Halle var. africana, Cameroon: Breteler 1813, 1821,2083 (see note). - L. apiculata (Welw. ex Oliv.) Halle ex Wilcz., Cameroon: Breteler 1523 (see note), 1576, 1901,2047,2686,2977. - L. apocynoides (Welw. ex Oliv.) N. Halle ex J. Raynal var. apocynoides, Cameroon: Breteler 1767,2782,2817,2928. - L. apocynoides (Welw. ex Oliv.) N. Halle exJ. Raynal var. guineensis (Hutch. & Moss) Halle, Cameroon: Breteler 1692. -L. clefYU1toi­ des (Loes.) Wilcz. ex N. Halle, Cameroon; Breteler 2115, 2415, 2451. -L. crenata (Klotzsch) Wilcz. ex N. Halle var. crenata, Cameroon: Breteler 2450. - L. crenata (Klotzsch) Wilcz. ex N. Halle var. loandensis (ExeIl) Halle, Cameroon: Breteler 1750. - L. fYU1crantha (Korth.) A.C. Smith, Australia: (SFCw 20128 V). Lianas, often high climbing with a base up to 20 cm in diameter. Young sterns usually terete, older sterns grooved, particularly in L. apiculata with four deeply suIcate grooves. Transverse sections of the sterns of L. apiculata and of L. clematoides show an intri­ cate pattern of inner bark intruding into the woody cylinder, dividing the wood into four coherent parts. This pattern is less pronounced in the other species or even absent. In freshly cut specimens the bark is pinkish red with white resinous threads; the outer bark smooth, brown with a purplish hue. Wood yellowish brown, hard. Growth rings faint, the boundaries formed by a few rows of radially flattened fibres. Vessels diffuse, for 90-95% solitary, in L. crenata var. loandensis for 80% solitary, the remainder in radial pairs, or a few in clusters or tangentially pairs; from 22-80 per sq. mm in L. africana, L. apocynoides, L. crenata and L. macrantha, but 4-8.5 per sq. mm in L. apiculata and L. clematoides; wide and narrow vessels mixed, the wide ones in the species with few vessels 250-400 11m wide. Vessel element length on aver­ age 560-950 J.Iffi. Intervessel pits 10-12 11m, the slits enclosed, occasionally coales­ cent, the borders narrow, elongate. Ground tissue composed of fibre-tracheids and some septate libriform fibres dis­ tributed without pattern and in various amounts. Fibre-tracheids with walls 3-4 11m thick, and a diameter of 15-20 11m; numerous bordered pits in both radial and tangen­ tial walls. The pits simple in the septate fibres. Length on average 1140 (930-1390) J.Iffi. F IV ratio: 1.45 (1.24-1.84). Parenchyrna scanty paratracheal. Strands of 4-6 cells. Rays 7-10 per mm, of which 2-3 (4) are multiseriates. The uniseriates composed of upright cells or of procumbent, square and upright cells, usually not over 12 cells high; the multiseriates mostly 5 -12 (16) cells (100-240 11m) wide, less wide in L. cle-

Downloaded from Brill.com10/07/2021 06:13:28AM via free access Mennega - Wood anatomy of the Hippocrateoideae 357 matoides, L. crenata var. loandensis, and over 10 mm high, composed mainly of low procumbent cells. Contents: numerous large rhombic crystals, often clustered. Silica grains frequent particularly in uniseriate rays. Orange substance in some ray cells in L. africana.

Note: The intricate pattern of four deep ingrowths of phloem combined with subse­ quent sinuous phloem intrusions is characteristic for L. apiculata and L. clematoides. In the other species investigated the division into four parts is less pronounced or ab­ sent, but phloem ingrowth is always present. Though in general the vessels are rather numerous and not over 200 11m wide, L. apiculata and L. clematoides are exceptional in this respect with fewer than 10 vessels per sq. mm that are often 300-400 11m wide. The herbarium voucher of Breteler 1523 was cited by Halle (1990) as Pristimera preussii. The wood sampie, however, exactly matches Loeseneriella apiculata in ma­ croscopic as weIl as microscopic characters, and does not fit at all in Pristimera (see note under Pristimera). Breteler 2083, identified by Halle as Elachyptera parviflora, neither resembles Elachyptera but belongs according to the wood anatomy in Loesen­ eriella africana. For the specimen L. macrantha see also the note under Hippocratea.

Prionostemma Miers - Fig. 34, 35

A tropical genus of 5 species, 3 occurring in Africa, 1 in Asia and 1 in America.

Material exarnined: P. aspera (Larn.) Miers, Venezuela: Breteler 3437,3880,3991; Guyana: Maas & Westra 3838, Jansen-Jacobs et al. 1078; Surinarn: van Donselaar 3117, Heyde 461, 605, Lindeman 5170,5226, Lindernan & Görts 31, Lindernan & Heyde 35, 47,116.

Usually long lianas with a trunk up to 20 cm diameter. Bark of uniform thickness, 3-5 mm wide; inner bark exuding a sticky red sap, outer bark light yellowish brown, blotchy, longitudinally slightly fissured. Wood yellowish brown, hard, straight-grained.

Growth rings indistinct, if present, the margins formed by a narrow zone with fewer vessels. Vessels diffuse, almost exclusively solitary, occasionally a radial pair present. Fre­ quency 9.5 (5-14) per sq. mm. Outline round to oval, wide vessels 100-250 11m wide. Vessel element length on average 875 (830-920) 11m. Intervessel pits rare, elongate, about 5 !lffi wide, the slits often coalescent. Ground tissue offibre-tracheids and septate libriform fibres interrningled. Diameter of both types 20-24 11m, the walls of the fibre-tracheids c. 4 11m thick, with numerous small bordered pits in both radial and tangential walls. Septate fibres less numerous, the walls c. 2 11m thick and pits restricted to the radial walls. Length of fibre-tracheids 1550 (1480-1620) 11m. F/V ratio: 1.76 (1.66-1.83). Parenchyma scanty paratracheal. Strands of 8-12 cells. Rays uni- and multiseriate, 6-9 per mm of which 2-3 very wide multiseriates; het­ erogeneous; the uniseriates of square and upright cells, the multiseriates of rather 10w

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Fig. 34-38. - 34 & 35: Prionostemma aspera (Breteler 3437). 34: TS. 35: LRS, showing ray cells with silica globules and a few with rhombic crystals. - 36 & 37: Pristimera nervosa (Linde­ man & Heyde 292). 36: TS, showing wide rays with zones ofunlignified cells. 37: TLS, showing extremely long rays. - 38: Reissantia indica var. astericantha (Brete1er 1672). TS, showing layered intruding bark tissue.

Downloaded from Brill.com10/07/2021 06:13:28AM via free access Mennega - Wood anatomy of the Hippocrateoideae 359 procumbent ceHs intermingled with square and intermediately sized ceHs, over 750 ceHs (12 mm) high, and 6-10 (100-160 /lm) ceHs wide. Large silica bodies present in numerous ceHs of the wide rays, occasionaHy also some ceHs with a rhombic crystal.

Note: The occurrence of incIuded phloem islands as mentioned by Record aand Hess (1943) must be based on misidentified material.

Pristimera Miers - Fig. 36, 37 A genus of about 24 species, 9 in the New World, 14 in Africa, 1 in Asia (Indonesia).

Material examined: P. aruiina Miers, Brazil (parana): Lindeman & de Haas 1248, 1567. - P. graciliflora (Welw. ex Oliv.) Halle, Cameroon: Breteler 2826 (see note). - P. holdeniana A.C. Smith, Guyana: A.C. Smith 2630 (MAD-SJRw 35641). - P. nervosa (Miers) A.C. Smith, Surinam: Lindeman & Heyde 292. - P. paniculata (Vahl) Halle, Ivory Coast: N. Halle 338 (P). - P. preussii (Loes.) Halle, Cameroon: Breteler 1523 (see note). - P. tenuiflora (Mart.) A.C. Smith, Colombia: van Rooden et al. 674. - P. verrucosa (Kunth) Miers, Colombia: Record 65 (MAD-SJRw 16464). Sterns cylindrical, bark uniform in width, thin in the New World species, of medium thickness in African material; wood yellowish. Growth rings inconspicuous, boundaries formed by a couple of rows of radially flat­ tened fibres and in the wide rays by a V-shaped pattern of unlignified cells. Vessels diffuse, for about 80-92% solitary, the remainder in short radial multiples. Frequency ranging from 14-100 per sq. mm, most numerous in P. verrucosa. Outline round, diameter of wide vessels usually 70-150 (180) /lm, the narrow vessels about 50 /lm wide. Vessel element length on average 605 (400-725) Jlffi. Intervessel pits 4-8 /lm, elongate with encIosed slits. Vessel-ray pitting rare, similar to the intervessel pits, but sometimes also with confluent slits. Ground tissue composed of fibre-tracheids and septate libriform fibres, the latter type often scarce. Diameter of fibre-tracheids 15-18 (20) Jlffi, walls 2-3 /lm thick, both radial and tangential walls strongly pitted. Length on average 830 (640-1100) Jlffi. F IV ratio on average 1.53 (1.26-1.90). Parenchyma scanty paratracheal, usually present as an incomplete vasicentric ring; strands of 4-8 cells. Rays 3-8 per mm, uniseriate and multiseriate, ofwhich 2 (4) are multiseriates. The uniseriates usuaHy rather low, composed of square and/or upright ceHs, the multiseriates up to 35 ceHs (500 Jlffi) wide. Heterogeneous, the body composed of irregular low pro­ cumbent cells interspersed with square cells, occasionally some sheath cells present. In the wide rays at the growth ring border a V-shaped zone of unlignified cens is present in an species studied. Rhombic crystals numerous, often more numerous in the uni­ seriates and in the sheath cens.

Note: The description of the wood is mainly based on New World species. Of the three African species available P. paniculata fits very wen in the genus concept of Pristimera. The anatomy of the sampIe of two other species, P. graciliflora and P. preussii is so different in several aspects from the generic concept of Pristemera that they are ex-

Downloaded from Brill.com10/07/2021 06:13:28AM via free access 360 IAWA Journal, Vol. 18 (4),1997 cluded from my survey. Pristimera gracijlora (Breteler 2826) resembles Reissantia; P. preussi (Breteler 1523) might belong in Loeseneriella. The similarity of flower structure of Pristimera and Simirestis induced Robson (1965) to consider them as synonyms, a conclusion supported by the wood anatomy.

Reissantia N. Halle - Fig. 38 A genus of 6 species restricted to the tropics of the Old World, 3 in Africa, 3 in Asia.

Material examined: R. indica (Willd.) N. Halle var. astericantha (N. Halle) N. Halle, Cameroon: Breteler 1650, 1672, 1688. - R. indica var. loeseneriana (Huteh. & Moss) N. Halle, Cameroon: Breteler 1722, 2936 (see note); Liberia: (MAD-SJR w 15278). Large lianas, up to 30 m. Sterns cylindrical, bark yellowish brown, superficially fissured, 2-4 mm thick, inner bark penetrating with numerous rather short wedges into the woody cylinder. Wood pale brown or yellow with a light brown hue, hard, straight-grained. Growth rings inconspicuous or absent. Vessels diffuse, 80-90% solitary, the remainder in radial multiples of 2-3. Fre­ quency 16-19 per sq. mm. Outline round to oval; wide and narrow vessels intermixed, the wide ones 130-200 flm in diameter, the narrow ones 50-70 flm wide. Vessel ele­ ment length on average 656 (583-730) flm. Intervessel pits 10-12 flm wide, the slits included. Vessel-ray pitting similar. Ground tissue mainly composed offibre-tracheids and some septate libriform fibres scattered in between. Diameter of fibre-tracheids 20 (16-25) flm, the walls 3-4 flm thick. Small bordered pits in both radial and tangential walls. Length: 1106 (670- 1520) flm. F/V ratio: 1.70 (1.50-1.93). Parenchyma very scanty paratracheal. Strands of 4-8 cells. Rays uniseriate and multiseriate, 5-9 per mm of which 3 are multiseriates. The uniseriates composed of 2-16 upright cells, the multiseriates 5-16 cells (200-400 flm) wide and over 13 mm high, composed of low procumbent cells mixed with square cells, the tails usually very short. Rhombic crystals numerous in the wide rays, often 2-4 in radial alignment in divided cells. Note: The sampie Breteler 2936 of R. indica var. loeseneriana is not included in the generic description because its structure is different from the other taxa in several aspects. The bark is of uniform width, without indentations; unlignified cells occur in the wide rays at the growth ring border, the distinction between wide and narrow ves­ sels is inconspicuous, the intervessel pits are c. 8 f.lill wide and the widest rays not over 4 cells wide. This species, originally described by Linnaeus as Hippocratea indica, was transferred by A.C. Smith (1945) to Pristimera. Halle (1962) did not consider the species as belonging in Pristimera, but accommodated it in Reissantia. Hou (1964) shared his opinion. The anatomy of the wood, so different from the other material of Reissantia examined, supports the assignment üf the species to Pristimera. In 1984 Halle transferred three Asian species considered by Hüu (1963, 1964) as belonging in Reissantia to a new genus Arnicratea, of which no wood was available for study.

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Semialarium N. Halle - Fig. 39,40 A New World genus of 2 species.

Material examined: S. mexicanum (Miers) Mennega, Mexico: (MAD-SJRw 47935; MADw 13466). Shrubs or low trees, up to 10 m high, occasionally large lianas. Sterns terete, bark fissured, dark grey. Wood light yellowish brown, fine-textured; density 0.67. Growth rings present, the boundaries composed of a few rows of radially compressed fibres. Vessels diffuse, solitary. Frequency 9 (6-12) per sq. mm. Outline round to oval. Large vessels 100-140 lffi1 wide, narrow ones 30-60 lffi1 wide. Vessel element length on average 540 (360-760) /lm. Intervessel pits rare, 5-6 /lm wide, the slits included. Vessel-ray pits crowded. Ground tissue composed of fibre-tracheids, and septate and nonseptate libriform fibres, the fibres arranged in often interrupted bands one cell wide, suggesting paren­ chyma. Diameter of both types 16 -19 /lm, walls of fibre-tracheids 2.5 lffi1 thick, of the libriform fibres 1.5 /lm. Fibre-tracheids with few small bordered pits in radial and tan­ gential walls, fibres with the pits mainly restricted to the radial walls. Length of fibre­ tracheids 1610 (1080 -2000) 1ffi1, of septate fibres 680 (500- 810) 1ffi1. F IV ratio: 3.00. Parenchyma scanty paratracheal. Strands of 4--8 cells. Rays 6-9 per mm, ofwhich 2-3 multiseriates. The uniseriates composed ofupright cells, 2-12 cells high. The multiseriates 10-12 cells (100-150 1ffi1) wide, the body composed of procumbent and square cells, the uniseriate tails often long; sheath cells occasionally present; height 3-7.5 mm. Contents: numerous rhombic crystals, mostly arranged in radial series.

Simicratea N. Halle - Fig. 41 A monotypic genus of tropical Africa.

Material examined: S. welwitschii (Oliv.) N. Halle. Cameroon: Breteler 1448, 1898. Lianas. Sterns cylindrical, bark scaly, greyish brown, c. 2 mm thick, the inner bark with a ring of large phloem gaps; the wood yellowish, hard. Growth rings defined by a boundary of a number of radially compressed fibres and by a V-shaped zone with unlignified cells in the wide rays. Vessels about 95% solitary, the remainder in radial pairs, and occasionally in small clusters. Frequency 5 (1-9) per sq. mm, wide and narrow vessels mixed, the wide ves­ sels 180-350 lffi1 wide, the narrow ones 30-80 1ffi1, outline round. Vessel element length 880 (700-1100) /lm. Intervessel pits elongate, generally with included slits, 5 1ffi1; vessel-ray pitting scarce. Ground tissue mainly composed of fibre-tracheids, septate libriform fibres scarce, scattered. Diameter 20-25 /lm, the walls 2.5-4 lffi1 thick, length of fibre-tracheids on average 1364 (1000-1900) /lm, with numerous small bordered pits in both radial and tangential walls. F IV ratio: 1.54.

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Fig. 39-42. - 39 & 40: Semialarium mexicanum (MADw 13466). 39: TS, showing relatively few vessels of different widths. 40: TLS, showing uni- and multiseriate rays and septate fibres. - 41: Simicratea welwitschii (Breteler 1898). TS, showing intruding bark. - 42: Simirestis tis­ serantii (N. Halle 345). TS, showing rays with unlignified celllayers.

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Parenchyma scanty paratracheal. Strands of 4 cells. Rays uniseriate and multiseriate, 2-3 per mm, of which one is multiseriate. The uniseriates scarce, composed of procumbent and upright cells or exc1usively of up­ right cells, 2-18 cells high (500 !l1Il); the multiseriates with a body of low procumbent cells and short tails of a type of cells intermediate between procumbent and square; up to 30 cells (600 /lm) wide and over 10 mm high. Rhombic crystals numerous, 1 to 4 in divided ray cells, the cells procumbent or intermediate.

Simirestis N. Halle - Fig. 42 A genus of 6 species of tropical Africa.

Material examined: S. tisserantii N. Halle, Ivory Coast: N. Halle 345 (P). Liana. Stern cylindrical, bark thin, the wood superficially indented. Growth rings mainly indicated by V-shaped zones of unlignified cells in the wide rays. Vessels diffuse, exc1usively solitary. Frequency 9 (5-14) per sq. mm, wide and nar­ row vessels mixed, the wide ones 100-200 /lm wide, the (scarce) narrow ones c. 50 !l1Il wide. Outline round. Vessel element length 552 (420-680) !l1Il. Intervascular pits rare, 5 !l1Il, elongate, the slits often coalescent, vessel-ray pits also rare, similar. Tyloses sometimes present. Ground tissue mainly composed of fibre-tracheids, septate libriform fibres scarce, scattered, diameter 16-20!l1Il, walls 2.5!l1Il thick, length on average 552 (820-1250) !l1Il; the fibre-tracheids pitted with small bordered pits in both radial and tangential walls. F/V ratio: 1.91. Parenchyma vasicentric, scanty, in a partial or occasionally a complete ring one cell wide; strands of 4-6 cells. Rays uni- (and bi-)seriate and multiseriate, 4 per mm of which 1 multiseriate. Uni­ seriates composed of few upright cells, 1-6 cells high; the multiseriates composed of low, elongate procumbent cells, up to 24 cells (400 Jlm) wide and over 8 mm high, the tails very short. Rhombic crystals present, often congested in the unlignified ray cells, not in radial alignment. Note: As mentioned in the introduction, no wood was available of the genus Arnicratea, described by Halle (1984) as a new genus based on three species related to Simirestis and Reissantia.

DISCUSSION

Based mainly on Hou's studies (1963, 1964) of Asian material, the former family Hippocrateaceae is now generally considered as a subfamily of the Celastraceae. The same view was held by Robson (1965, 1966) and by Halle in his later studies of Afri­ can taxa (1984, 1986, 1990). anatomical evidence also supports a broad family concept for the Celastraceae (Den Hartog-Van Ter Tholen & Baas 1978), and Savolainen et al. (1994, 1997) found members of the Celastroideae and Hippocrateoideae united in the same c1ade in their molecular phylogenetic analyses. In the present paper Hou's

Downloaded from Brill.com10/07/2021 06:13:28AM via free access 364 IAWA Journal, Vol. 18 (4), 1997 opinion is followed, though in my previous treatments of the wood anatomy of the New World genera (Mennega 1972, 1994) I still adhered to the concept of Hippo­ crateaceae as a family of its own, mainly because among the New World genera no intermediate taxa occur linking Hippocrateaceae with Celastraceae. Furthermore, Ameri­ can taxonomists, such as Cronquist (1981), are still in favour of two families. In my paper mentioned above, the anatomy of the New World genera, Semialarium excepted, was treated. In the present paper an account is given of all genera recognized in the subfamily except one*, amounting to a total of 23. This figure is based on modem treatments by Halle (1986, 1990), Hou (1964) and A.C. Smith (1940). How­ ever, taxonomists hold different opinions on the concept of genera, and the number of genera varies accordingly. Robson (1965, 1966) was in favour of considering Salacia and Hippocratea in a broad sense. The division of the Hippocrateoideae into two distinct groups, according the na­ ture of the fruits, as also noted be fore in the wood anatomical study of the New World species, was confirmed by the present study of worldwide material. According to Halle (1986, 1990) these groups are the Salacieae on one hand and Hippocrateae, Helictonemeae and Campylostemoneae on the other. Genera of the Salacieae with drupaceous fruits and wingless are anatomically characterized by a rather thin bark of uniform thickness, narrow rays, presence of septate fibres often arranged in a parenchyma-like banded pattern, and by the frequent presence of included phlo­ em, either as concentric bands or as isolated strands. Genera of the Hippocrateae, Helictonemeae and Campylostemoneae, with dry dehiscent apocarpic fruits, and often winged seeds, possess sterns which in cross section show a thick bark, more or less deeply intruding into the woody cylinder, irregularl y, or as regular deltoid intrusions. In the wood wide rays are characteristic, whereas included phloem tissue is never present.

In the Salacieae six genera are recognized, though not by all taxonomists. In Smith's (1940) opinion the New World species belong to four genera: Cheiloclinium, Peritassa, Salacia and Tontelea. Halle (1962, 1986, 1990) recognized three genera in his African material, viz. Salacighia, Salacia and Thyrsosalacia. Hou (1964) in his treatment of Asian species incorporated them all in Salacia, including Loesener's (1942) genus Salacicratea. The overall wood structure shows a certain similarity to other taxa of the Celastraceae as revealed from treatments by Record (1938), Metcalfe and Chalk (1950), Archer and Van Wyk (1993), and personal, unpublished studies (see also Zhang et al. 1990). In particular the narrow rays and the septate fibres in a parenchyma-like configuration indicate relationships. For this reason Salacieae are treated first in the present paper. The wood structure of the six genera is remarkably similar. It is not possible to dis­ tinguish any individual genus, though recognition of certain species is occasionally possible, mainly due to the pattern of included phloem. The included phloem is present in allliana species, absent in some of the trees. It is also absent in saplings before these have reached the climbing stage.

*) Of Halle's Malaysian genus Arnicratea no material was available.

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In a previous paper (1972) I described four types of abnormal growth: 1) Wedge-like invaginations of the bark into the woody cylinder as characteristic for Hippocratea. 2) More deeply penetrating narrower inc1usions as occurring in Tontelea corymbosa. 3) Concentric bands of inc1uded phloem. 4) Isolated strands of inc1uded phloem. Of these four types the invaginations of the bark restricted to the group of Hippocrateae (type 1) are of a totally different than the inc1uded phloem s. str. My second type seems superficially related to the first type, but on inspection of sectioned wood sampies it turns out that centres of phloem are radially connected by conjunctive tissue without vessels, initiated from the cambial zone, or starting at some distance from the bark (Fig. 10, 11). Obaton (1960) in her study of 15 species of Hippocrateaceae from tropical Africa recognized three types of abnormal growth: 1) furrowed sterns (Hippocratea species, and Salacia bipindensis), 2) inc1uded strands of phloem (Salacia zenkeri, Salacighia malpighioides), and 3) concentric bands of inc1uded phloem (several Salacias). The type of abnormal growth occurring in Salacia bipindensis is according to Obaton's description and illustration, similar to that of S. staudtiana var. tsopouhensis, described here, and also to that of S. laterita, and S. whytei, both depicted as stern cross sections by Hall and Lock (1975). Tontelea corymbosa from South America be10ngs also in this category of inc1uded phloem distribution.

In the other group, consisting of the tribes Hippocrateae, He1ictonemeae and Campy10- stemoneae, the anatomy is 1ess uniform than in the Sa1acieae. However, it was impos­ sible to find characters to distinguish the tribes. In Tab1e 2 data are listed for the tribes Campylostemoneae and Helictonemae. Of the tribe Campy10stemoneae, Bequaertia and Campylostemon are almost identica1 in wood characteristcs as weIl as in configuration of the sterns. The third genus, Tris­ temonanthes differs in vesse1 features, 1ength of fibres, width of the rays, and by the deeper intrusions of the outer bark into the wood. Helictonema, characterized by a few very wide vessels, very wide rays and a superficially indented bark, c1ose1y resemb1es the genus Hippocratea of the Hippocrateae. In the Hippocrateae some genera stand apart by their wood characters, 1ike Loesen­ eriella with its strong1y indented bark, absence of unlignified cells in the wide rays and the moderately 1arge intervesse1 pits. The presence of these features in the material received under the name of Hippocratea macrantha support the transfer of this taxon to Loeseneriella macrantha as was done by A.c. Smith (1941). Other specimens which might belong in Loeseneriella are Brete1er 1523, in the Flore du Gabon 1isted under Pristimera preussii, and Breteler 1821, listed under Elachyptera parvifolia as discussed in the notes accompanying the treatment of Pristimera, and Elachyptera respectively. Other genera of this tribe are much more homogeneous. Apart from the presence or absence of rows of un1ignified ray cells on the growth ring border as noticed in Anthodon, Apodostigma, Cuervea, Pristimera, Simicratea, and Simirestis (Tab1e 3), it is impos-

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Table 2. Wood characters of the tribes Campylostemoneae and Helictonemeae.

Campylostemoneae Helictonemeae

Characters Bequaertia Campylostemon Tristemonanthes Helictonema

Bark not intruding + slightly intruding + + strongl y intruding +

Vessels number per sq. mm 31 (25-37) 34 (24-45) 15 (10-22) 4 (2-6) percentage solitary 92 72 70 90 tangential width of wide vessels <1=) 100-150 100-170 140-250 250-350 element length (firn) 728 (590-830) 650 (350-930) 908 (750-1020) 850 (450-1210) intervessel pits (flill) 6-8 6-8 8-10 6-8

Fibre tissue septate fibres few + + + length 1030 (790-1300) 1000 (750-1300) 1270 (800-1799) 1440 (1000-2000)

Rays unlignified cells absent absent absent absent number per mm 2-4 8 8 7 width of wide rays (in cells) 5-14 4-18 4-15 20-40 width (flill) 60-120 100-180 100-300 100-600

+ = present; - = absent.

Table 3. Presence or absence of unlignified ray cells at the growth ring border in the genera of group 2.

Present Absent

Anthodon Bequaertia Apodostigma Campylostemon Cuervea Elachyptera Pristimera Helictonema Reissantia (only noticed as rare cells Hippocratea in R. indica var. loeseneriana) Hylenaea Simicratea Loeseneriella Simirestis Prionostemma Semialarium Tristemonanthes

Downloaded from Brill.com10/07/2021 06:13:28AM via free access Mennega - Wood anatomy of the Hippocrateoideae 367 sible to find distinguishing characters. The wood structure of e.g. Anthodon, a New Wo"ld genus, and the African genus Apodostigma is essentially the same, whereas they are essentially different in flower and fruiting characters. The occurrence of silica ~rains as weIl as rhombic crystals in separate cells in Prionostemma aspera and L6eseneriella africana is remarkable. In other species of Loeseneriella only rhombic crystals were observed; African or Asian species of Prionostemma were not available for study. Amos (1952) in his overview of wood with silica inc1usions listed both Celastraceae and Hippocrateaceae as lacking silica. The species of Hippocratea show a discrepancy in diameter of the vessel pits. In the American species H. volubilis pits are 4-7 flm wide, whereas in the two African species studied, H. myriantha and H. vignei, pits are 9-10 flill wide. In the monotypic genus Helictonema, considered by Halle as belonging in subtribe Helictonemeae, the wood structure differs from Hippocratea by the absence of wedge­ shaped intruding bark. Instead, in dry material the cambial zone shows a ring of gaps due to the shrivelling of large masses of phloem tissue overlying the wide rays.

ACKNOWLEDGEMENTS

Thanks are due to Mr. B.J.H. ter Welle for valuable comments, and to Mr. L.Y.Th. Westra for his critical review of the English text. I am most grateful for Mrs. L.A.M. Hesselman's transcription of my type-written manuscript on diskette. The technical assistance of Mr. D. Makhan in making wood sections is greatly appreciated as weil as Mr. H. Rypkema's careful arrangement of the photographs.

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