BLUMEA 46 (2001) 485 - 497
Systematic leaf anatomy of
Baccaurea, Distichirhops, and Nothobaccaurea
(Euphorbiaceae)
S. Bodegom R.M.A.P. Haegens B.J. van Heuven & P. Baas
Nationaal Herbarium Nederland, Universiteit Leiden branch,
P.O. Box 9514, 2300 RA Leiden, The Netherlands
Summary
The leaf anatomical of the Baccaurea Lour. diversity genera (43 species), Distichirhops Haegens
(3 species) and Nothobaccaurea Haegens (2 species) (Euphorbiaceae)is described. Two species of
Aporosa and three species ofMaesobotrya were examined for comparison. The following characters
are important for the delimitation of species: hair types, the position ofthe glandular areason the
leaf margin, the hairiness and size of the glandular areas, the number of epidermal layers, the
of idioblasts in the the of above the presence (mucilage) epidermis, presence palisade parenchyma
vascular and the ofthe cell walls. leaf bundles, birefringence spongy parenchyma However, anatomy
for distinction between five studied. Phenetic resulted did not yield characters the genera analysis
in a grouping based on leaf anatomical similarities that corresponds to a large extent with the phylogenetic position of species based on a cladistic analysis oflargely macromorphological features
(Haegens, 2000).
Key words : Baccaurea, Distichirhops, Maesobotrya, Nothobaccaurea, Euphorbiaceae, hairs, leaf
anatomy, leaf glands, systematics.
Introduction
Little is known about leafanatomical of Lour., the allied diversity Baccaurea genera
Distichirhops Haegens and Nothobaccaurea Haegens (Euphorbiaceae), and its use
for delimitationand classification. The studies genus and species most important are:
of leafand of vascular bundles anatomy petiole Phyllanthoideae (Rothdauscher, 1896);
in Phyllanthoideae (Constantin, 1935); overall vegetative anatomy of Euphorbiaceae
(Metcalfe & Chalk, 1950); foliar stomata in Euphorbiaceae (Raju & Rao, 1977); the
indumentumofEuphorbiaceae ofNew Guinea(Airy Shaw, 1980); and leaf morphology of Phyllanthoideae (Levin, 1986a). In these studies only a few species of Baccaurea
leaf the are mentioned. However, a anatomical study comprising genera Baccaurea,
and Nothobaccaureahad been carried The Distichirhops not yet out. present compre-
taxonomic hensive study was carried out to support a phylogenetic and revision of
here these taxa (Haegens, 2000), where many ofthe data presented were incorporated
in the overall The the leaf anatomical in much analysis. present paper presents range
more detail. 486 BLUMEA Vol. 46, No. 3, 2001
MATERIALS AND METHODS
Character choice
A pilot study was carried out to explore which characters might be of diagnostic
valueand/orbe phylogenetically informative. Ten specimens ofthe following species
were used: Baccaureaangulata Merr., B. brevipes Hook. f„ B. macrophylla (Mull.Arg.)
Miill.Arg., B. motleyana Mull.Arg. and Nothobaccaurea pulvinata (A.C. Sm.)
Haegens. These species were chosen to represent the fullphylogenetic and geographical range of this clade(Haegens, 2000). Macerations, stained paradermal sections ofthe
upper and lower surface of the leaf, unstained and stained cross sections of the leaf
margin, midribandpetiole were investigated. Leaf fragments (upper and lower surface)
including the leaf margin with glandular areas, the lamina and the midrib were examined with SEM. On the basis of this pilot study and the literature a selection of
characters was made that were of promising diagnostic and systematic value, and the
sampling was extended to all species of the three genera, while at the same time the repertoire ofmicrotechnicalprocedures was limitedto observe the selected characters
efficiently.
Anatomy
Characters that could be scored directly from herbarium material were examined
with a stereomicroscope at fairly low magnification. For Light Microscopy (LM) and
Scanning Electron Microscopy (SEM) mature leaves from herbariumspecimens were rehydrated by boiling in water. Cross sections were made with a thickness of (20-)
30(-60) pm. The material for SEM was dried with a Balzers CPD 030 Critical Point
Dryer and coated with gold using the Bal-tec SCD 005 Sputter Coater. The leaf surfaces
were observed and photographed with a Jeol JSM-5300 SEM at 15 k V. The size ofthe
glandular areas on the leaf margin was measured parallel to the margin in SEM photo-
graphs. The cell walls of the spongy parenchyma, the druses and fragmented crystals, and starch grains were all observed with polarised light. Strongly birefringent secondary
walls of the spongy parenchyma are thick and appeared to be lignified (tested with
Wiesner's reagent).
Finally, 10 species were examinedfor the contents of theiridioblasts.For all exam-
half ined species, of the cross sections of the midrib were put in water and the other
half in 96% alcohol. Samples in water preserve oil and in alcohol mucilage (Bakker,
1989). Sections collected in water were stained in a 1 % aqueous solutionofchrysoidin-
for acridin red for 3 mins detection ofoil (Richter, 1977). Ifoil is present, the contents ofthe idioblasts will stain orange to red. The sections collected in alcohol were stained
in a 1%alcoholic alcian blue solutionfor 15 mins (Quintarelli et ah, 1964).Ifmucilage
is present, the contents ofthe idioblasts will stain blue.
Phenetic analyses
The following phenetic analyses were performed to check whether there is cluster-
ing: Ward's Method, Group-Average Method (Cole, 1969) and Principal Component
Analysis (PCA) (Sneath & Sokal, 1973) using Statgraphics Plus 2.1 for Windows.
Prior to the analyses the multistate character set was binarised. All the dendrograms
were created using the Squared Euclidean distance metric (Cole, 1969). 487 S. Bodegom et al.: Leaf anatomy of Baccaurea, Distichirhops, Nothobaccaurea
Collections
indicated with Collections used both for the pilot study and general study are (p), both for the contents of the idioblasts and general study with (i), for hairs only with
(h). Collections with stellate scales are indicated with (s). Five collectionsofBaccaurea
tetrandra, examined for the of druses, and starch only presence fragmented crystals
Collections without suffix grains in the idioblasts, are indicated with (t). a were only
used for the general study.
Aporosa arborea:: Lainpi 859; Rahmat si Boeea (= Rahmat si Toroes) 5376 — A. nitida: Jacobs
5196; S 33729 (Othman Ismawi).
Baccaurea angulata: Endert 4800; SAN 153763 (Wood); SF 9310 (Sinclair & Kadimbin) (p) —
B. annamensis: Harmand 1436; Poilane 1269 — B. bracteata: KEP/FRI 2527 (Kochummen)
(h, s); PBU 416 (Sidyasa); Rahmat si Boeea (= Rahmat si Toroes) 5448; SF 34745 (Henderson)
(h, s) — B. brevipes: KEP/FRI 8495 (Cockbum); Rahmat si Boeea (= Rahmat si Toroes) 5822
(i); Sangkhachand 1237 (p) — B. carinata: De Vriese Herb. Lugd. Bat. 994.355-118; Pullen
— 996 — B. costulata: S 41135 (Yii Puan Ching); Suzuki K 5554 B. courtallensis: Ridsdale 67
— (i); Ridsdale 622 — B. deflexa: BoschproefstationT3P380;Elmer 21118 (i) B. dolichobotrys:
S 41494 (Othman et al.); S 53328 (Bernard Lee Meng Hock) — B. dulcis: Dayar Arbain
DA-476 (i); Dumas 1658 — B. edulis: De Jong 341; S 31991 (Paul Chai) — B. javanica:
Rastini 217 (V11I.F.28) — B. lanceolata: De Wilde & De Wilde-Duyfjes 18860; S 2977 (Pickles)
— B. De Wilde & De Elmer 21240 —B. macrocarpa: Wilde-Duyfjes 15518; (i) macrophylla:
bb 25190; Forbes 2706 (p); SF 40743 (Sinclair& Kiah bin Salleh)— B. maingayi: KEP/FRI
10506 (Cockburn); S 41121 (Yii Puan Ching) (i) — B. microcarpa: Brass 27290 — B. minor:
KEP/FRI 7108 (Cockburn); Kostermans & Anta 657 — B. mollis: S 38495 (Yeo & Jugah);
5 3422 (Pickles) — B. motleyana: Chin See Chung 2776; De Wilde & De Wilde-Duyfjes 12781;
— Purseglove 5446 (p) — B. multiflora: De Wilde & De Wilde-Duyfjes 20690; Rastini 61 — B. nanihua: Mogea & Ramlanto 822; Prawiroatmodjo & Soewoko 1736 B. nesophila: Brass
28298; LAE 70905 (Katik et al.) — B. odoratissima: S 22112 (Sibat ak Luang); S 26142
— 23905 BW 4526 Carr (Banyeng ak Nudong) B. papuana: Brass 8157; Brass (i); (Lasschuit);
14260; LAE 77101 (Gideon); Lam 875; NGF 29557 (Coode); NGF 31690 (Ridsdale); NGF
41905 (Henty & Lelean); NGF 47802 (Streimann) — B. parviflora: Burley et al. 1284; De
Wilde & De Wilde-Duyfjes 12671; KEP/FRI 4008 (Whitmore); KEP/FRI 8166 (Cockbum);
KEP/FRI 13515 (Loh Hoy Shing); KEP/FRI 32616 (Wong Khoon Meng & Khairuddin) (s);
Maxwell 81-223; SAN 90925 (Termiji Arshid) — B. philippinensis: Sulit 6363; Wenzel 3007
—B. polyneura: KEP/FRI 17880 (Sohadi); SAN 89751 (Fedilis& Sumbing) — B. ptychopyxis:
1612 — 346 S 37783 — Carr Parkinson B. pubera: PBU (Sidyasa); (Paie) B. purpurea: 16270;
NGF 41916 (Henty & Lelean)— B. pyriformis: De Wilde & De Wilde-Duyfjes 13887;McDonald
6 Ismail 3484 — B. racemosa: De Wilde & De Wilde-Duyfjes 14374; KEP/FRI 16923 (Chan) — — B. ramiflora: MADw 24531 (Majumder& Islam) (i); Poilane 11696 B. reticulata: Meijer
4613; S 40571 (Yii Puan Ching) — B. sarawakensis: Leighton 378; S 24597 (Sibat ak Luang);
S 26272 (Sibat ak Luang& Jugah ak Kudi)— B. seemannii: Degener 15252; Smith 7413 (i) —
B. simaloerensis: Achmad 244; Achmad 728 — B. sumatrana: Meijer 4083; S 17010 (Paie) —
B. taitensis: Spence 516; Whistler W682 (i) — B. tetrandra: BNB 4516; BS 34768 (Ramos &
Pasgasio); Burley, Tukirin et al. 2378 (t); Celestino & Ramos 128 (t); Mabesa 2-26 (t), PNH
42094 (Mendoza); S 24262 (Paie) (t); SAN 4516 (Madani), SAN 32189 (Lajangah) (t) —
B. trigonocarpa: Elmer 21608 (s); S 19761 (Chai) — B. velutina: KEP/FRI 17318 (Loh); KEP/
FRI 10490IB (Everett).
Distichirhops megale: NGF 28659 (Streimann & Katik) — D. minor: BW 4933 (Versteegh); SAN
99863 (Sigin et al.) — D. mitsemosik: LAE 55701 (Stevens); Hartley TGH 12711.
Maesobotrya barteri: Bos 6824; Leeuwenberg 7975 — M. pauciflora: Zenker 2952 (s); Zenker
M. 3321 (s) — staudtii: Zenker 1603 (s); Zenker 1748.
Nothobaccaurea pulvinata: Gillespie 2409; Greenwood 998; Qoro & Kuruvoli 13631 — N. stylaris:
BSIP 8511 (Dennis); Tabualewa 15572. 488 BLUMEA Vol. 46, No. 3, 2001
0 II 3: 1 1I 1 0 I 0 1 0 0 0 0 0 0 I 0 1 1 1 0 0 0 N. styl (1 0 0 11 (1 (1 0
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oa 0 II II (1 (1 B. pube 1 I 1 1 1 1 0 1 1 1 0 0 1010000100 i) 1010000100 n 0 0 0 0 1) (1 (1 10000000000II II10000000 II 00000000 10000000 11 II II B. plycoa 11 1 il II 0 0 0 0 1 II 11 II II 0 0 1 0 1 0 0 II (1 Maesobotrya 1 I 0 11111 1 1 0101 00100 0000 0000 0 1 (i II 1 1 II 1 1 1 0 1) 1) 1) 0 (1 0 II B. poly 1001010111 1 0 1 001010 0 001010 0 0 0 0 0 0 00100 0/10000 1 1 03 II 0 II 1) II 1) B. phil 1 1I 1 1 1 1 1 I1 (1 0 0 0 000010 0 0 0 0 0 0 0 0/1 0 0 0
5. 1 3 oa B. parv i) 11 (i li I 0 (1 1 II 0 1 0 11 II 0 0 0 1 I1 1 1 0/10 0/10 0/1(1/1 0 0 0 0 0 0 0/1 0/1 0 10000000000000 11/ B. papu 10110100100000000010 oa 1 (1 II II I) 1 1 11 11 ti0000000100001 1 1 0 0 0 1 0 0 1 0 II II 0 0 0 0 1 0 0 0
■5 oa 11 1) II II (1 0 II 0 II II II II 0 0 B. odor 1 1 1 1 1 1 1 1 1 00000 0 I] 0 111 0 110 001 0 1110/11 0 000 1) II I) 1) (1 (1 0 0 n 0 1 B. neso 1 1 1 1 1 1 1 oa il 0 Q 0 0 0 0 0 00000 0 00000 10000 00010 00000 Distichirhops, 1 B. nanioa 0 0 1 1 11 1 0 II I 0 11 1) 1) 011 1 (1 II II 0 1 1 1 0 0 0 0 1 0 0 0 0 1 0/1i)/ 1 B. mull II 11 1) II II 1 1 1 1 0000000000000000000 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11 0 0 II
0 0 II 0 B. molloa 1 l I 1 1 1 1 1 (i li 0 0 11 0 0 000000000(1 (1 0 II 0 0 0 0 0 0 0 0 0000001111 II II (1 11 II I) 11 (1 (1 0 0 11 i 1 0 1 1 1 1 1 0 1 0 1 II 0 0 I 1 0 B. mollioa 1110 1 1111 1001 1001 00000000000 1011 0001
1 1 0001000000000000 1 1 1 0001100000000000 II 1 11 (1 11 0 1" 0 0 0 0 11 11 1) 0 0 0 (1 II 0 0 0 0 0 B. mino05 0 1 0/10100 00000 00000
5 (1 II 1 II 1 I) 0 0 II Baccaurea, microB. 0 1 1 0 0 10001000000010001000 I1 1 0 11 0001100 0 11 0 0 0 0 0 0 1 1 0/1 0 10 i II 0 0 0 0 II II II I) 0 B. main 1 0 1 (l n 0 1 0 1 1 0 0 1 0 11 0 000000000010 0 0 0 I) 00 1 00 macrop= aj II (1 0 II 0 0 0 II 11 II (1 (1 0 0 0 0 11 1 1 1 I1 I1 1 11 11 1 0/10 B. 0 000 0 101 0 0 11/ macroc 1 0/100 1 1) II II (1 0 (1 II B. 11 1 1 1 1 1 1 1 1 1 p.p., 0 II 0 0 0 0 0 0 0 (1 0 0 0 000000000000000000000000000000 1000000100 1000000000 0/1 oa B. lanc II 1.1 II 1 0 0 0 0 II II 1) II 1 I) 0 1 1 II 0 1) (1 0 0 1 1 0 1 10000 000 1 0 1 oa 11 01 111 01 (1 II II II 11 1) B. java 0 1 11111 1001 11111 1 0 0 1 0 1 0 0101 0 0 1 0 (1 il 0 1 0 0000 00000 edul B.Oa 001 0 0 0 II 1) II 1 1 1 1 0 0 1 0 0 0 1 0 0 0 1) II II (1 0 0 0 0 II II 10I0110010100001001010000II0111010I 0/10/1 Aporosa B. dulc 1 1 1 1 1 1 1 1) II (1 II (1 II II (1 1) 10000010100100000111 I1 I 0 0 0 00000001000000000000000000000000 1 0 0 0 0 0 0 0 1 Q -5 B. doli II (1 0 0 II 0 1) II II (1 (1 II II 0 (1 1 II II of 1 0 1 1 1 1 1 1 1 0 0 0 II 1 1 1 1 0 () (i ii 0 D (i Q D B. defl 1 1 I 1 0 0 010000000 ii 0 0 0 000000000 0001000000 0 0 0 0 0 0 0 (1 0 0 0 0 II 0 II 0 1) II II (1 (1 (1 0 0 1 0 0 1 1 1 0 1 0 0 0101000 1 I1 1 B. cour 01001 11011 00100 11110 00001 00000 00000 1 1 II 11 II00010000000000000000000000000000000000000000000 II 1) (1 1) 1) II (1 (1 (1 0 I 1I Q 0 1 I1 0 0 0000000000000000000000000000000000000000000000 1 0 0 0 1 0 I 0 B. costoa 0000000 000011
II I I (1 (1 (1 I I 0 0 0 1 1I 11 II 1 0 1 II II 0 II II 1 1 1 1 (l.'l B. carioa 0 00000000000010000000000001001011010111 0 0 0 0 0/1 0
characters 1 1 1 1! I) 0 1) 0 0 (1 0 0 (1 0 0 0 0 B. brevz. 1 1 1 II (1 0 0 0 1 0 1 1 1000000000000000 0 11 0 0 I! il 0 1 1 1I 1 1 1 1 1 1 1 1 0 0 0 B. brac I) 1) 1) 0 0 0 1) 0 II (1 0 000000000000000000000000 111 1 1 1 1 1 1 (1 1 (1 I 0 1 Q 1) II 0 (I 0 (1 (1 0 0 (1 0 B. anna03 00/10011000110000 0 1 0 0 0 000000 00000 01000 00000 1100 1110 1001 1101 10 1111 0 (1 (1 (1 (I 1 1 0 0 0 1 1 0 0 1 1 I 1 0 (i 1 0000010000010000 0 0 0 1 i) Q ii ii 0 000010001000000 B. angunq 000000000100 00001 00010 0/10000 000100000000 l 10 000000000 1 |i () 0 II 1) 1) 0 (i a 071 0 00000000 1 0 l 1 0 0 1 0 0 0 0 1 0 0 0 1 on 0 nili A.■*: 001011 000010 000000 11 00 00 00 00 01 00 00 0 0 o 0 0 anatomical 1 1 11 1 1 0 (l (i a u l) 0 0 (i (i (i 0 0 0 0 0 0 0 0 1} A."£arbo l
1 =1= margin I1
margin = Leaf ■ leaf I1 1 obt./ac. leaf margin manymany leaf = = vascular the less asas in 1. && hairshairs the more in the leaf cells nerve to on aboveabove below thethe ac./obt.ac-/obt. blade adnateadnate on the below below parenchyma and crystals hairs areas onon pmjim fragments Table leaf areas layers layers above cells infrequentinfrequent 0;0; recurrent layerslayers layers secondary 1I partly layers, epidermal secondary = partly 2 layers, layers, = free areasareas 22 spongy and grains the epidermisepidermis spongy 12-2512-25 and 0; 0; of ofof infrequent on glandular epidermis of glandular = = 0; fragmented crystalscrystals Obtuse glandular epidermal epidermal druses starch obt./obt.obl./obt. from = pmum pm Mmum parenchyma = urn in enlarged hairs hairs of hairyhairy hairy pmurn adaxialadaxial epidermal epidermal infrequent of glandular of lowermost 0:0; tuft of margin lamina of aboveabove below druses and && pmnm grains of Mm in = of consisting consistingconsisting Jim of inin above of the the both both enlarged marginmargin -249 - 349 -640 640640 layerlayer layer bundles Birefringence enlarged Fragmented Position Densely 100-164100-164 Number as Palisade Birefringence Fragmented Numerous Numerous Angle AcuteAcute Ac./ac. TVpes"types Solitary Stellate Position DecurTentDecurrent Hairiness Glabrous SparselySparsely Size 165165-249 250-349 .150-640 Number Idioblasts OnlyOnly Palisade Size 12-25 Druses Druses Starch Starch Tuft Tuft Size > In In Tuft Tuft On On 250 350 1 1 In In CharacterCharacter >
1 9 2 3 4 5 6 7 8x 10 11 12 S. al.: Nothobaccaurea 489 Bodegom et Leaf anatomy of Baccaurea, Distichirhops,
RESULTS
Survey of the leaf anatomicalcharacters (Table 1)
The leafanatomical diversity ofAporosa p.p., Baccaurea, Distichirhops, Maesobotrya
p.p. and Nothobaccaurea is summarised in Table 1 using binary coding. The rangeof
variation of the most salientfeatures is surveyed below.
Lowermost pair of secondary nerves (Fig. 1a)
The angle formed between the lowermost pair of secondary nerves and the midrib
(consistent with the angles formed by the other lower secondaries, more acute, or
more obtuse) was suggested to be a good character by Levin (1986a).
Indumentum(Plate 1a-c)
All the leaves ofthe studied species ofAporosa, Baccaurea, Distichirhops, Maeso-
botrya and Nothobaccaurea have unicellular solitary hairs, but several species have
inaddition tuftedhairs. These tuftedhairs are divided into 3 types: tufts consisting of
formed Fig. 1. a. The angle between the lowermost pair of secondary nerves and the midrib in comparison with other secondaries; b. the position of the glandular areas in the leaf margin. 490\1 BLUMEA Vol. 46, No. 3, 2001
Plate 1. a. Baccaurea macrocarpa, tuft consisting of free hairs; b. B. nanihua, stellate tuft; c. B.
stellate d. B. the leaf parviflora, scale; purperea, glandular area on margin glabrous; e. Aporosa arborea, glandular area on the leaf margin with intermediate hairiness; f. B. deflexa, glandular
the leaf — Scale bars: b 10 c-f 100 area on margin abundantly hairy. a, = μm; = μm.
free hairs, tufts ofpartly adnatehairs (less than 1/3 of their lengths adnate) and stel-
late tufts (more than 1/3 adnate). There is no evidence that they are fundamentally
differentsince no basal cells were found for the adnatehairs. Yet these types are used
for the phenetic analyses since they are easily recognisable in surface view, and
the hairs with more than 1/3 of their parts adnate are always smaller. Five species S. al.: Nothobaccaurea 491\2 Bodegom et Leaf anatomy of Baccaurea, Distichirhops,
Plate 2. a. Baccaurea piriformis, idioblasts (arrows) in both epidermal layers, in abaxial layer
of less than in adaxial layer; b. B. multiflora, birefringence the spongy parenchyma; c. B. nesophila, in cells; d. numerous druses and fragmented druses (arrows) present enlarged epidermal B. tetrandra,
cells; e. odoratissima, numerous starch grains (arrows) present in enlarged epidermal B. starch
grains (arrow) infrequent in enlarged epidermal cells. — Scale bars: a-e = 100 μm.
were found with stellate scales: B. bracteata,B. parviflora, B. trigonocarpa,M. pauci- flora and M. staudtii. Since theirpresence was highly variablebelow the species level
and only a few collections possessed them, this character was not used for further
analysis. 492 BLUMEA Vol. 46, No. 3, 2001
the Plate Glandular areas on leaf margin (Fig. 1b, 1d-f)
leaf situated leaf Glandular areas in the vicinity of the margin are on the margin
itself, parallel to the leaf margin, alternating, or decurrent from and recurrent to the
the leaf divided into 5 size leaf margin (Fig. lb). The glandular areas on margin are
classes (Table 1). The hairiness of the glandular areas is scored as (sub)glabrous,
sparsely hairy, and densely hairy.
Epidermis (Plate 2a, c-e)
The number of epidermal layers is divided into 3 states: one adaxial epidermal
layer and one abaxial epidermal layer; two adaxial and one abaxial epidermal layer;
two adaxial and two abaxial epidermal layers. InAporosa nitida some epidermal cells
are divided into two daughter cells giving the appearance of being two-layered. The presence of idioblastsin the epidermis is scored as: absent; present only in the adaxial
epidermal layer; present in both epidermal layers with as many in the abaxial layer as
in the adaxial layer; present in both epidermal layers with less in the abaxial layer.
The idioblasts of seven species tested positive formucilage, one species tested negative
for both idioblasts. The and mucilage and oil, and 2 species had no druses fragmented
classes: and crystals in enlarged epidermal cells are divided into 5 druses fragmented
crystals absent; druses infrequent; druses numerous; fragmented crystals infrequent; and fragmented crystals numerous. The starch grains in the enlarged epidermal cells
are divided into 3 classes: starch grains absent; starch grains infrequent; starch grains abundant. Aporosa, Distichirhops, Maesobotrya and Nothobaccaureado not contain
druses, fragmented crystals, or starch grains in enlarged epidermal cells, except for
Nothobaccaurea stylaris which has some druses and fragmented crystals in enlarged
epidermal cells. Crystals and similar inclusions occur in some plants in ordinary cells,
in others in certain tissues only, and a third group only in special cells called crystal
idioblasts (Clowes & Juniper, 1968). In the epidermis of Baccaurea and Notho- baccaurea stylaris the druses are situated in special enlarged epidermal cells.
Mesophyll (Plate 2b)
dorsiventral Palisade The mesophyll of all species studied is ofthe common type.
parenchyma is present or absent above the vascular bundles. The birefringence of the
spongy parenchyma is absent to weak, or strong. Druses in ordinary cells found in the
mesophyll are divided into 2 size classes (Table 1).
Summary of varying leafanatomicalcharacters in Baccaurea
Leaf surface
The angle formed between the lowermostpair ofsecondary nerves and the midrib
is more acute, or more obtuse than the angle between the other secondaries and the
midrib, or the same (Fig. la). The indumentum consists of unicellular solitary hairs and in addition sometimes of tufted hairs (Plate la, b), and exceptionally of scales
Glandular scattered lamina sometimes (Plate lc). areas on the are present; they are
usually situated on the leaf margin (Fig. lb). Their diameter varies from 100-640 pm, rarely bigger, and they are glabrous to densely hairy (Plate ld-f). S. Bodegom et al.: Leaf anatomy of Baccaurea, Distichirhops, Nothobaccaurea 493
Epidermis
The epidermis usually consists ofone adaxial and abaxial layer, rarely two adaxial
and one abaxial, or two adaxial andtwo abaxial layers. Mucilaginous idioblasts usually
occur only in the adaxial epidermis or in adaxial and abaxial epidermis, but then with
fewer and smaller idioblasts in the abaxial layer than in the adaxial layer (Plate 2a).
There rarely are as many idioblasts in both epidermal layers or rarely the idioblasts
are absent. Druses, fragmented crystals, and starch grains are rarely present in enlarged
epidermal cells (Plate 2c-e).
Mesophyll
The palisade parenchyma is usually interrupted above the vascular bundles. Some-
times the cell walls of the spongy parenchyma are strongly birefringent (Plate 2b).
The size of druses in the mesophyll varies from 12-50 pm.
The vascular system of the midrib and the petiole is of the simple closed type.
Midriband petiole hardly differfromeach other in this respect and do not vary for the
different species (as judged from the pilot study).
Phenetic analysis
The results of the phenetic analysis based on Ward's Method is illustrated in Fig. 2.
Some collectionsof one species are never clustered. These species are: B. parviflora
(which splits up into 3 groups, with one group consisting of B. parviflora s.str. and
the former species B. scortechinii), B. tetrandra (which always splits up according
to B. tetrandra s.str. and the former species B. stipulata), Distichirhops minor and
D. mitsemosik.
In some cases the collections ofdifferentspecies are always put together: Baccaurea
dolichobotrys and B. maingayi (and in most dendrograms also B. polyneura), B. dulcis and B. lanceolata, B. odoratissima and B. parviflora (one collection), B. parviflora
(the groupwith B. parviflora s. str. and the former species B. scortechinii) and B. pty-
chopyxis, and B. sumatrana and B. trigonocarpa. These species pairs show no or little
variation in leaf anatomical characters.
In the PCA (not shown) based on the data in Table 1, the first component only accounted for 11.3% ofthe total variance. This is probably due to the lack ofinforma-
tion in the binarised characters. There is, however, an indication that the hair type is
an important character. The results of the Group-Average Method and of the PCA
were similar to the Ward's dendrogram with respect to the clustering of specimens and species.
DISCUSSION
The results of this leaf anatomical study have to be interpreted with caution, since
only 2 collections have been used for most species. For several species, however, up
to 10 collections have been used to study the variation within one species. Generally
there is very little infraspecific variation, but that does not mean thateach species of
Baccaurea shows a constant leaf anatomy. 494 BLUMEA Vol. 46, No. 3, 2001
B. pyriformis (2)
A. arborea (2)
B. motleyana (3)
B. bracteata (2)
B. carinata (3)
D. megale (1)
A. nitida (2)
B. minor(2)
B. multiflora(2)
D. minor A (1)
B. dulcis (2)
B. lanceolata (2)
B. parviflora A (2)
D. mitsemosik A (1)
B. sarawakensis (2)
B. tetrandra A (2)
B. polyneura (2)
B. dolichobotrys (2)
B. maingayi (2)
D. minor B (1)
B. brevipes (3)
B. javanica (2)
B. courtallensis (2)
B. microcarpa'(1)
B. seemannii (2)
N. stylaris (2)
B. papuana (10)
B. philippinensis (2)
M. pauciflora (2)
B. deflexa (2)
B. simalourensis B (1)
D. mitsemosik B (1)
B. simaloerensis A(1)
N. pulvinata (3)
B. taitensis (2)
M. barteri (2)
B. ramiflora (2)
B. odoratissima (2)
B. parviflora B (1)
M. staudtii (2)
B. parviflora C(4)
B. parviflora D (1)
B. ptychopyxis'(1)
B. racemosa (2)
B. purpurea (2)
B. nesophila (2)
B. velutina(2)
B. sumatrana (2)
B. trigonocarpa (2)
B. costulata (2)
B. edulis (2)
B. nanihua (2)
B. pubera (2)
B. reticulata (2)
B. macrocarpa (2)
B. macrophylla (3)
B. mollis (2)
B. angulata (3)
B. annamensis (2)
B. tetrandra B (2)
Fig. 2. The dendrogram obtained with Ward’s Method, Squared Euclidean, shows groupingbased on similarities between specimens, giving no indication about the extent of similarity between
within of which do specimens a group (* = specimens one species not group together). S. Bodegom et al.: Leaf anatomy of Baccaurea, Distichirhops, Nothobaccaurea 495
with Characters comments on their diagnostic significance
formedbetween of midrib The angle the lowermost pair secondary nerves and the
be variable character, makes distinction proved to a very which the ofcharacter states
very difficult. For this reason it was decided to run all the phenetic (and in Haegens,
2000, also the phylogenetic) analyses without this character.
The type of hairs is the most diagnostic character for distinctionof species according
to the PCA. This distinctive character has been used for the first lead in the general
key to the species of Baccaurea (Haegens, 2000).
The position of the glandular areas on the leaf margin can be established directly
from herbariummaterial. This character has two states which are common among the
species studied, causing a segregation into two groups. The other two states are more
uncommon and occur only in a few species. The glandular area on the leaf margin is
very easy to measure when glabrous, but when densely hairy it becomes more compli-
cated. In this study the glandular area with surrounding hairs was measured, probably
overestimating the size in some species. However, the size and hairiness ofthe glandular
area are reliable diagnostic characters, which provide informationbecause ofthe large
differences between individual species.
The number of has character the other epidermal layers one common state, two
states occur less frequently. This character is not useful for segregation ofthe species
into but be used for the delimitationof large groups, can some species. This character
was one ofthe 20 phylogenetically most informative characters (out of 102 characters)
(Haegens, 2000). The presence ofidioblastsin the epidermis has two common character
which distinction into The other states, cause a two groups. two character states are
useful for the few distinction between a species. Druses and fragmented crystals in
cells sometimes be found, but tend to much within enlarged epidermal can vary a
single species. The type of starch grains can be an important character at family level
(Czaja, 1978). Starch grains probably are only temporary food reserves in the higher
plants (Clowes & Juniper, 1968). Since theamount might be dependent upon ecological
it variables, cannot be regarded as a reliable diagnostic character.
The presence ofpalisade parenchyma above the vascular bundles and the birefrin-
gence of the spongy parenchyma each have one common character state, while the other state only characterises a few species. These characters are thus useful for recog-
nition of these few species. There are two sizes of the druses in the mesophyll. The
species under investigation always possess small druses, and in additionmany species also containbigger ones. Since there is a gradual increase ofsize, this is not considered
to be a good diagnostic character.
Phenetic analysis
In some cases the specimens ofdifferent species are always put together, therefore
leafanatomy alone is not sufficientfor distinction between these species.
Baccaurea dolichobotrys and B. maingayi have female inflorescences and fruits
which are similar for the two species; and they are also very closely related according
to a phylogenetic analysis based on macromorphological and leafanatomical charac-
ters, but the leaves are very different. Baccaurea dolichobotrys, B. maingayi and
form characters B. polyneura a cladebased on 6 in phylogenetic analyses. The number ofepidermal layers is one of the three most important characters (Haegens, 2000). 496 BLUMEA Vol. 46, No. 3, 2001
Baccaurea dulcis and B. lanceolata differ macromorphologically in many charac-
related ters. Still, they are closely according to a phylogenetic analysis based onmacro-
morphological and leaf anatomical characters (Haegens, 2000).
Baccaurea odoratissima and B. parviflora look very similar vegetatively.
Baccaurea and B. related sister sumatrana trigonocarpa are very closely species, which have similar maleinflorescences and fruits. The numberof epidermal layers is
an apomorphy for this clade in the phylogenetic analyses (Haegens, 2000).
The of specimens some species never occur side by side in the phenetic analyses.
Baccaurea is parviflora macromorphologically a variable species in fruit characters:
B. parviflora s. str. has fruits without ridges, and the synonymised former B. scortechinii
has ridged fruits. Further complication lies in the position of the male inflorescences
as B. ptychopyxis, sister species ofB. parviflora, which has ridged Iruits, has axillary
inflorescences, and B. parviflora is cauliflorous. The differences found in the leaf
anatomical study do not split B. parviflora and B. ptychopyxis according to the macro-
morphological differences. So both macromorphological and leafanatomical characters
indicate for a heterogeneous gene pool B. parviflora and B. ptychopyxis.
Baccaurea tetrandra can be split leafanatomically into two forms, namely B. tetran-
dra str. and former s. species B. stipulata, based on the presence of druses and frag-
mented in and the of in crystals enlarged epidermal cells, presence starch these cells.
However, the four specimens examined were the extreme macromorphological forms:
B. tetrandra s.str. occurs only in the Philippines and the leaves dry brown, and B.
stipulata only occurs in Borneo and has a white wax on the dried leaves. Examining
more specimens revealed intermediatesfor both macromorphological and leaf ana-
tomical characters, indicating that a distinction will not be possible. Moreover, the
two leaf separating anatomical characters are diagnostically not very reliable.
The examined in this genera study are very closely related (Haegens, 2000; Levin,
1986b; Webster, 1994) and belong to subtribe Scepinae of subfamily Phyllanthoi-
deae. The few studied of and specimens Maesobotrya Aporosa are leaf anatomically
not distinguishable from Baccaurea, Distichirhops and Nothobaccaurea. Thus leaf anatomy yields no characters to distinguish between generain this subtribe. Metcalfe
& Chalk (1950) encountered the same problem for tribes. However, some leafanatom-
ical characters can be used for the delimitationof species and are phylogenetically
informative demonstrated as by Haegens (2000).
ACKNOWLEDGEMENTS
The authors would like to thank Dr. G.D.E. Povel for his help with the phenetic analyses. The
Curators of the herbaria: P and WAG of following A, DS, L, kindly provided part the research
materials.
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