THAI FOR. BULL. (BOT.) 43: 4–14. 2015.

Pollen morphology of Combretaceae from Thailand and its taxonomic signifi cance

PUNTIWA KRACHAI1,2 & PIMWADEE PORNPONGRUNGRUENG1,*

ABSTRACT. The pollen morphology of 30 taxa from six genera of Thai Combretaceae, including one species each of Anogeissus and Calycopteris, two species each of Lumnitzera and Quisqualis, 11 species of Combretum and 13 species of Terminalia (including one introduced species), was investigated to determine its taxonomic signifi cance. The pollen samples were acetolyzed and investigated under light and scanning electron microscopy. Pollen morphology of Thai Combretaceae was described, compared and discussed along with its taxonomic implications. The taxonomic signifi cance of pollen morphological characters for Thai Combretaceae is limited. The pollen grains were found to be monads, radially symmetrical, isopolar, small- to medium-sized, heterocolpate (tricolporate alternating with subsidiary colpi). The taxa studied can be divided into two groups and nine subgroups according to the fusion of subsidiary colpi at the polar area and the exine sculpturing patterns. However, this grouping is not congruent with the taxonomic classifi cation of the family based on morphological as well as molecular data.

KEY WORDS: Combretaceae, Pollen, Taxonomy, Thailand.

INTRODUCTION Thailand were classifi ed into two tribes and three subtribes, including the tribe Laguncularieae con- The family Combretaceae belongs to the order taining the single genus Lumnitzera Willd.; the Myrtales, and comprises ca 20 genera and 500 species tribe Combreteae with two subtribes: Combretinae (Heywood et al., 2007; APG III, 2009). The family containing three genera: Calycopteris Lam. ex Poir., is distributed throughout the tropics, with some Combretum L oefl . a n d Quisqualis L . , and Terminaliinae extensions to subtropical and warm-temperate containing two genera: Anogeissus (DC.) Wall. ex regions (Exell & Stace, 1966; Heywood et al., Guillem. & Perr. and Terminalia L. (classifi cation 2007; Stace, 2007). The family is divided into two follows Stace, 1966). subfamilies, Strephonematoideae and Combretoideae. The fi rst one contains the single genus Strephonema Studies of pollen morphology of Combretaceae Hook.f., and the latter contains most of the genera. were carried out by a number of previous authors. The subfamily Combretoideae was previously divided Erdtman (1966) stated that pollen grains of into four tribes: Calycopter-ideae, Combreteae, Combretaceae are tricolporate or tricolporate with Laguncularieae and Terminalieae (Exell, 1954). pseudocolpi, prolate to prolate-spheroidal in shape, More recently, the subfamily was divided into only with the sexine evidently thinner than the nexine. two tribes, Laguncularieae and Combreteae, and The pollen grains of this family are similar to those the latter tribe was subdivided into three subtribes: of Melastomataceae but differ from Myrtaceae, Combretinae, Pteleopsidinae and Terminaliinae (Exell Punicaceae and Sonneratiaceae, which are all clas- & Stace, 1966; Stace, 2007). Only the subfamily sifi ed in the same order Myrtales according to APG Combretoideae is present in Thailand, with seven III (2009). A more detailed study was produced by genera and 47 species (Nanakorn, 1985, 1986; Pooma Patelet al. (1984), who recognized the Combretaceae & Suddee, 2014). The member of Combretaceae in pollen to be isopolar, radially symmetrical,

1 Applied Taxonomic Research Center, Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand 2 present address: Program of Biology, Department of Science, Faculty of Science and Technology, Loei Rajabhat University, Loei 42000, Thailand *Correspondent author: [email protected]

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tricolporate (rarely tetracolporate), or heterocol- kept at Queen Sirikit Botanic Garden Herbarium pate with three colporate alternating with three (QBG). The list of voucher specimens included in subsidiary colpi, and subsidiary colpi united or this study is given in Appendix 1. The pollen grains separated at the polar area, spheroidal to subprolate were acetolyzed following the methods described shape in equatorial view, circular or hexagonal by Erdtman (1966). For light microscopy, the ace- outline in polar view, with the exine sculpturing tolyzed pollens were mounted in silicone oil and GLYHUVH IURP VWULDWH SVLODWH ¿QHO\ UXJXODWH WR sealed with paraplast. Permanent slides are kept at rugulate. These authors also suggested that the Khon Kaen University Herbarium (KKU). At least &RPEUHWDFHDHSROOHQFDQEHGLYLGHGLQWR¿YHSROOHQ 15 pollen grains per taxa were used to measure the groups based on the presence of subsidiary colpi polar axis (P), equatorial axis (E), exine thickness and exine sculpturing. El Ghazali et al. (1998) in polar view (EX) and colpus length (CL). For investigated 18 genera and 130 species of scanning electron microscopy, acetolyzed pollen Combretaceae and reported that the pollen are grains were suspended in a drop of absolute alcohol, monads, isopolar, radially symmetrical, tricolporate then transferred to aluminum stubs, air-dried and or heterocolpate. Nine pollen types and two subtypes coated with gold-palladium. SEM micrographs were were recognized based on pollen class, aperture taken with a Leo 1450VP SEM. The terminology types, thickening of the exine around the endoaper- and pollen size classes follow Walker & Doyle tures, costae endopori, pollen size, exine sculpturing (1975) and Punt et al. (2007). and shape in polar view. They reported that pollen morphological data do not support the current RESULTS taxonomic treatment of the family. Stace (2007) reported two pollen types: tricolporate and hetero- The description of pollen morphological FROSDWHWKH¿UVWW\SHIRXQGLQBuchenavia Eichler, characters is provided in alphabetical sequence by Laguncularia C.F.Gaertn. and Strephonema, while tribe, subtribe and genera, while the characters of the latter type is found in the other genera including the taxa are summarized in Table 1. Anogeissus, Calycopteris, Combretum, Conocarpus Tribe Combreteae: subtribe Combretinae L., Guiera Adans. ex Juss., Lumnitzera, Macrop- teranthes F.Muell ex Benth., Pteleopsis Engl. and Calycopteris (Fig. 2D–F): Terminalia. He pointed out that the exine sculpturing Monads, radially symmetrical, isopolar, P = varies between species in the group with tricolporate 18–23 μm, E = 18–23 μm, small, prolate-spheroidal, grains but quite similar in the group with hetero- heterocolpate, colpus length 13–18 μm, subsidiary colpate grains. Moreover, the pollen morphology colpi separated at the polar area, exine thickness cannot be used for clarifying the relationship 1–2 μm, perforate-microrugulate between genera. However, these characters might KHOS LQ LGHQWL¿FDWLRQ RI VRPH WD[D 7KH SROOHQ Combretum (Figs. 1A–C, 2G–I): morphology of the family has never been studied in Thailand. The aims of the present work were Monads, radially symmetrical, isopolar, P = to classify, describe, and illustrate the pollen char- 14–30 μm, E = 14–29 μm, small to medium, spherical, acteristics of Thai Combretaceae and to assess the prolate-spheroidal, subprolate, oblate-spheroidal, taxonomic value of these characters. heterocolpate, colpus length 11–27 μm, subsidiary colpi fused or separated at the polar area, exine thickness 1–2 μm, perforate-microrugulate, striate MATERIAL AND METHODS or microrugulate. The pollen of 30 taxa of Combretaceae in Quisqualis (Figs. 1D–F, 2J–L): Thailand (including one introduced species, Terminaia ivorensis A.Chev.) was examined using Monads, radially symmetrical, isopolar, P = light microscopy (LM) and scanning electron 28–40 μm, E = 29–42 μm, medium, oblate-spheroidal microscopy (SEM). Pollen samples were collected or prolate-spheroidal, heterocolpate, colpus length IURP WKH ¿HOG FROOHFWLRQV DURXQG 7KDLODQG DQG 24–33 μm, subsidiary colpi fused or separated at the some taxa were taken from herbarium specimens polar area, exine thickness 2–3 μm, microrugulate or reticulate.

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Tribe Combreteae: subtribe Terminaliinae subtribe Terminaliinae have only a small sized-grains whereas subtribe Combretinae and Laguncularieae Anogeissus (Fig. 2A–C): have a small to medium sized-grains. The largest Monads, radially symmetrical, isopolar, P = size was found in Q. indica (P = 37–40 μm, E = 38– 12–14 μm, E = 11–14 μm, small, prolate-spheroidal, 42 μm) and the smallest was found in A. acuminata heterocolpate, colpus length 9–11 μm, subsidiary (P = 12–14 μm, E = 11–14 μm). The pollen shape in colpi separated at the polar area, exine thickness equatorial view varied among species. Most species 1–1.5 μm, microechinate. are prolate-spheroidal in pollen shape and a few species are oblate-spheroidal, subprolate and spherical. Terminalia (Figs. 1G–L, 3G–L): The amb outline is circular or hexagonal. Monads, radially symmetrical, isopolar, P = Even though the pollen morphological char- 13–21 μm, E = 12–19 μm, small, prolate-spheroidal DFWHUVDUHLQVXI¿FLHQWWRLGHQWLI\DOOVSHFLHVVWXGLHG or subprolate, heterocolpate, colpus length 9–18 μm, the exine sculpturing is possibly a helpful character subsidiary colpi fused or separated at the polar area, for distinguishing some species because it varies exine thickness 1–2 μm, perforate-microrugulate DPRQJ VSHFLHV DQG VRPH VSHFLHV KDYH VSHFL¿F or microrugulate. features. Most species of Thai Combretaceae have Tribe Laguncularieae perforate-microrugulate, microrugulate or striate exine sculpturing, while reticulate a type was found Lumnitzera (Fig. 3A–F): in two species, Q. conferta and L. racemosa, and a Monads, radially symmetrical, isopolar, P = microechinate and scabrate exine was found only in 20–30 μm, E = 21–35 μm, small to medium, oblate- a single species each, A. acuminata and L. littorea spheroidal, heterocolpate, colpus length 16–24 μm, respectively. exine thickness 1–4 μm, scabrate or reticulate. Lacking a shared character among taxa in the same genus led to pollen morphological characters DISCUSSION AND CONCLUSION to be a considered of less taxonomic value for Thai Combretaceae. However, the pollen characters can The study showed that the pollen grains of be used to divide the Thai Combretaceae into two Thai Combretaceae are quite uniform. The basic main groups with nine subgroups based on the fu- pollen characters of the family are monads, isopolar, sion of subsidiary colpi at polar area and the exine radially symmetrical, heterocolpate, (tricolporate sculpturing patterns. alternating with subsidiary colpi), colpus 9–33 μm in length, subsidiary colpi shorter or longer than Group I (Fig. 1): this group is characterized by the colpi. Our results agree with the previous reports presence of subsidiary colpi fused at the polar area. for the general characters of Combretaceae pollen There are three subgroups according to exine by Erdtman (1966), Huang (1972), Patel et al. sculpturing patterns. (1984), El Ghazali et al. (1998) and Stace (2007), Subgroup I-A: a group of microrugulate except that the tricolpate grains were not observed exine sculpturing. This subgroup contains Q. indica in Thai Combretaceae. Patel et al. (1984) and El and T. catappa. Ghazali et al. (1998) reported the fusion of subsid- iary colpi at the polar area in some species of Subgroup I-B: a group of perforate-microru- Bucida L., Calopyxis Tul. and Quisqualis. We also gulate exine sculpturing. This subgroup contains observed these characters in some taxa of C. chinense, T. alata, T. calamansanai, T. corticosa Combretum, Terminalia and Quisqualis. and T. glaucifolia. Pollen size and shape varied among species Subgroup I-C: a group of striate exine but did not appear to be diagnostic characters for sculpturing. This contains only a single species, C. the generic and infrageneric levels of this family. pilosum. The size of pollen grains varied from small to medium Group II (Figs. 2–3): this group is characterized (P = 12–40 μm, E = 11–42 μm). The members of

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by the presence of subsidiary colpi that separated at ACKNOWLEDGEMENTS the polar area. It can be divided into six subgroups We would like to thank the Graduate School, based on exine sculpturing patterns. Khon Kaen University (52131111) and the TFR/ Subgroup II-A: a group of microechinate BIOTEC Special Program for Biodiversity Research exine sculpturing. This contains only a single species, and Training Grant BRT T_152127 for supporting A. acuminata. this study. Subgroup II-B: a group of perforate-microru- gulate exine sculpturing. This contains C. griffi thii, REFERENCES C. prosurcum, C. punctatum ssp. punctatum, C. APG (Angiosperm Phylogeny Group) III (2009). punctatum ssp. squamosum, C. quadrangulare, C. An update of the Angiosperm Phylogeny sundaicum, Ca. fl oribunda, T. bellirica, T. chebula Group classifi cation for the orders and families var. chebula, T. chebula var. nana, T. pedicellata, T. of fl owering plants: APG III. Botanical Journal pierrei and T. triptera. of the Linnean Society 161: 105–121. Subgroup II-C: a group of microrugulate El Ghazali, G.E.B., Tsuji, S., El Ghazaly, G.A. & exine sculpturing. This contains C. deciduum, C. Nilsson, S. (1998). Combretaceae R.Brown. trifoliatum and T. ivorensis. World Pollen and Spore Flora 21: 1–40. Subgroup II-D: a group of striate exine Erdtman, G. (1966). Pollen Morphology and Plant sculpturing. This subgroup contains C. latifolium Taxonomy: Angiosperms. Hafner Publishing and T. arjuna. Company, New York. Exell, A.W. (1954). Combretaceae. In: G.G.G.J. Subgroup II-E: a group of reticulate exine van Steenis (ed.), Flora Malesiana, Ser. I, 4: sculpturing. This subgroup contains L. racemosa 533–589. Noordhoff-Kolff, Djakarta. and Q. conferta. Exell, A.W. & Stace, C.A. (1966). Revision of the Subgroup II-F: a group of scabrate exine Combretaceae. Boletim da Sociedade Broteriana sculpturing. This subgroup contains only a single sér. 2, 40: 5–26. species L. littorea. Heywood, V.H., Brummitt, R.K., Culham, A. & These grouping, however, are not congruent Seberg, O. (2007). Flowering plant families of with the taxonomic groups based on macromor- the world. Royal Botanic Gardens, Kew. phological data (Exell & Stace, 1966; Stace, 2007). Huang, T.-C. (1972). Pollen Flora of Taiwan. National This is also in agreement with El Ghazali et al. Taiwan University, Botany Dept. Press, Taipei. (1998) who reported that the pollen characters cannot Nanakorn, W. (1985). The genus Terminalia help in clarifying the taxonomic relationship in (Combretaceae) in Thailand. Thai Forest Bulletin Combretaceae. (Botany) 15: 59–107. The taxonomic signifi cance of pollen morpho- ______. (1986). The genus Combretum (Combreta- logical characters in Thai Combretaceae is limited. ceae) in Thailand. Thai Forest Bulletin (Botany) Using the pollen characters alone does not help in 16: 154–204. resolving the classifi cation of the family as well as Patel, V.C., Skvarla, J.J. & Raven, P.H. (1984). they cannot be used to identify all species but they Pollen characters in relation to the delimitation provide some information for distinguishing some of Myrtales. Annals of the Missouri Botanical taxa. Moreover, using these characters in combination Garden 71: 858–969. with other characters such as anatomical or molecular data may help in clarifying the relationship between Pooma, R. & Suddee, S. (eds.) (2014). Tem the closely related taxa and may help to further Smitinand’s Thai Plant Names, revised edition understandd the taxonomic relationship within the 2014. The Offi ce of the Forest Herbarium, family. Department of National Parks, Wildlife and Plant Conservation, Bangkok. 826 pp.

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Punt, W., Hoen, P.P., Blackmore, S., Nilsson, S. & Foi Lom Forest Park, Krachai 504 (KKU); C. pro- Le Thomas, A. (2007). Glossary of pollen and surcum, Kanchanaburi, Sai Yok, Chongko 698 spore terminology. Review of Palaeobotany (QBG); C. punctatum ssp. punctatum, Chiang Mai, and Palynology 143: 1–81. Doi Inthanon, Norsaengsri 3736 (QBG); C. punc- Stace, C.A. (1965). The signifi cance of the leaf tatum ssp. squamosum, Chiang Mai, Mae Rim, epidermis in the taxonomy of the Combretaceae Pongamornkul 677 (QBG); C. quadrangulare, Nakhon I. A general review of tribal, generic and specifi c Ratchasima, Non Sung, Krachai 248 (KKU); C. characters. Botanical Journal of the Linnean sundaicum, Loei, Nong Hin, Krachai 560 (KKU); Society 59: 229–252. C. trifoliatum, Udon Thani, Ban Phue, Krachai 461 (KKU); Lumnitzera littorea, Trat, Ko Chang, ______. (1966). The use of epidermal characters Krachai 515 (KKU); L. racemosa, Prachuap Khiri in phylogenetic considerations. New Phytologist Khan, Khao Ta Mong Lai Forest Park, Krachai 518 65: 304–318. (KKU); Quisqualis conferta, Surat Thani, Phanom, ______. (2007). Combretaceae. In: K. Kubitzki Gardner ST2672 (QBG); Q. indica, Chanthaburi, (ed.), The families and genera of vascular plants Pong Nam Ron, Krachai 549 (KKU); Terminalia 9: 68–82. Springer Verlag, Berlin, Heidelberg alata, Sakhon Nakhon, Phu Phan National Park, etc. Krachai 521 (KKU); T. arjuna, Khon Kaen, Walker, J.W. & Doyle, J.A. (1975). The bases of Muang, Krachai 562 (KKU); T. bellirica, Kamphaeng angiosperm phylogeny: palynology. Annals of Phet, Khlong Lan National Park, Krachai 230 the Missouri Botanical Garden 62: 664–723. (KKU); T. calamansanai, Chachoengsao, Phanom Sarakham, Krachai 610 (KKU); T. catappa, Khon APPENDIX 1 Kaen, Muang, Krachai 511 (KKU); T. chebula var. chebula, Khon Kaen, Muang, Krachai 305 (KKU); Specimens examined T. chebula var. nana, Khon Kaen, Muang, Krachai Anogeissus acuminata, Phetchabun, Nam Nao 280 (KKU); T. corticosa, Khon Kaen, Muang, National Park, Krachai 445 (KKU); Calycopteris Krachai 602 (KKU); T. glaucifolia, Khon Kaen, fl oribunda, Ubon Ratchathani, Khong Chiam, Muang, Krachai 571 (KKU); T. ivorensis, Maha Krachai 5477 (KKU); Combretum chinense, Nan, Sarakham, Muang, Krachai 611 (KKU); T. pedi- Doi Phu Kha National Park, Srisanga 17066 (QBG); cellata, Ubon Ratchathani, Pha Taem National C. deciduum, Chiang Mai, Fang, Srisanga et al. Park, Krachai 5466 (KKU); T. pierrei, Sakhon 3132 (QBG); C. griffi thii, Chiang Mai, Hang Nakhon, Phu Phan National Park, Krachai 730 Dong, Watthana & Pongamornkul 239 (QBG); C. (KKU); T. triptera, Prachuap Khiri Khan, Sam Roi latifolium, Khon Kaen, Nam Phong National Park, Yot, Krachai 5277 (KKU). Krachai 601 (KKU); C. pilosum, Udon Thani, Phu

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g e T T S S xin PM PM PM PM PM PM PM MR culp- urin e t s . ------+ + olpi c ubsidiary s ) 15.4 18.06 21.53 16.2 22.06 23.8 15.33 20.53 20.13 12.4 ( ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) ) (μm 1.40 1.16 0.74 0.67 1.69 2.19 0.72 1.45 1.80 0.63 olpus length c 13–18 ± 16–21 ± 20–22 ± 15–17 ± 20–27 ± 20–27 ± 14–16 ± 17–23 ± 17–22 ± 11–13 ±

) e ess ) 1.7 ± 1.63 ± 1.73 ± ( ( ( kn 1.53 ± 1.7 ± 1.46 ± 1.53 ± 1.6 ± 1.33 ± xin c ( ) ( ) ) ) ( ) ( ) ) ( ) ( ) (μm e hi 1 ± 0 t ( 1–2 0.29 1–2 0.31 1.5–2 0.25 1.5–2 0.22 1–2 0.22 1–2 0.12 1 1.5–2 0.25 1–2 0.38 1–2 0.30 sses ize m m m m m m S

la c s s, s, s s, s, s s, s, s e e e e e e e e e e lat lat lat lat lat lat lat lat Shap o o o o o o o o blate pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal Pr s Pr s Pr s Pr s Pr s Subprolat Pr s O s Pr s Pr s ) ) 20.53 21.06 23.06 18.53 24.06 23.16 15.93 24.8 23.33 15.2 ( ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) ) E (μm ean ± SD 1.24 1.03 1.09 1.06 1.65 1.52 0.88 1.69 1.39 0.86 (Range and m 18–23 ± 19–23 ± 21–25 ± 17–21 ± 21–27 ± 21–27 ± 14–17 ± 22–28 ± 22–26 ± 14–17 ± ) ) 20.73 21.2 24.86 19.53 24.93 26.8 17.46 24.13 23.4 15.46 ( ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) ombretinae ) C P (μm P ean ± SD 1.53 1.42 0.91 0.51 1.98 1.79 0.83 1.06 1.4 0.51 (Range and m 23–26 15–16 18–23 ± 19–25 ± 23–26 ± 19–20 ± 23–30 ± 24–30 ± 16–19 ± ± ± ± 21–25

.

& rz e e u e b m m K u rai u b. e ollett x C oribunda fl Roxb. ex C an Heurck . o Bl ( V Lam. ex Poir Species ombreteae: subtribe ombreteae: ) . Exell thii l ) C s b. x m e o Roxb. ombretum chinens ombretum . deciduum ( sp. punctatum quamosum R H & Müll.Arg Calycopteris C C C. grif fi C. latifolium C. pilosum R C. prosurcum C. punctatum Bl s C. punctatum ssp. s C. quadragular Tribe Tribe G.Don Table 1. Pollen morphological characters of Combretaceae in Thailand (E = equatorial axis, P = polar axis, Size classes: M = medium sized-grains and sized-grains medium = M classes: Size axis, polar = P axis, equatorial = (E Thailand in Combretaceae of characters morphological Pollen 1. Table S = small sized-grains, exine sculpturing: ME = microechinate, MR = microrugulate, PM = perforate-microrugulate, RE = reticulate, SC = scabrate, polar area, - = subsidiary colpi separated at the area) = striate, Subsidiary colpi: + subsidiary colpi fused at the ST

SW 8736-p004-014-G8.indd 9 12/1/58 BE 8:59 PM 10 THAI FOREST BULLETIN (BOTANY) 43 B C A B B D A B B A - - - - I-E I- I- I- I- I- I- I I I I I I I I I I I Group g e T S xin RE PM PM PM PM PM ME MR MR MR culp- urin e t s ------+ + + + olpi c ubsidiary s 22.2 27.46 30.6 16.26 13.33 13.8 11.93 16 ± 12.4 12.33 ( ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) 10.2 ± ( ) ) (μm) 1.01 0.91 2.44 1.72 1.16 0.61 1.01 0.70 0.81 –11 –11 olpus length c 1.25 20–23 ± 11–15 ± 24–31 ± 28–33 ± 9 15–18 ± 12–14 ± 12–15 ± 10–13 ± 13–18 11–14 ± 0.70

) e ess 1.1 ± 2.06 ± 1.3 ± 1.13 ± 1.2 ± 1.06 ± 1.33 ± 1.16 ± ( ( ( ( ( ( ( ( kn 1.93 ± 2.4 ± 1.26 ± xin c ( ) ) ) ( ) ) ( ) ) ) ) ) ) (μm e hi t 0.25 0.20 0.17 0.50 0.25 0.31 0.22 0.25 0.17 0.24 0.24 1–2 1–1.5 2–2.5 2–3 1–1.5 1–2 1–1.5 1–1.5 1–1.5 1–1.5 1–1.5 sses ize S la c m s m m s s s s s s s e e e e e e e e e e lat lat lat lat lat lat lat lat lat Shap o o o o o o o o o blate pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal Spherical Pr s Pr s O s Pr s Pr s Pr s Pr s Pr s Pr s Pr s ) ) 26.8 15 ± 30.4 40.6 16.86 13.93 16.86 13.26 17.2 13.3 12.8 ( ( ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) ) ) E (μm ean ± SD 1.42 0.98 1.40 1.01 0.83 0.59 0.91 0.59 0.67 0.72 (Range and m 25–29 ± 14–16 0.75 29–32 ± 38–42 ± 11–14 ± 15–18 ± 13–15 ± 16–19 ± 12–14 ± 16–18 ± 12–14 ± ) 26.86 15.53 32.4 38.73 13.2 19.13 15.86 16.93 14.46 18.4 15.13 ( ( ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) ) ) P (μm) P ean ± SD 0.91 1.18 2.26 1.33 0.67 1.12 0.51 0.59 0.74 0.98 0.83 (Range and m 12–14 17–21 28–35 25–28 ± 14–19 ± ± 37–40 ± ± ± 15–17 ± 16–18 ± 13–16 ± 17–20 ± 14–16 ±

. . ) . ar . v Wall.

) ent Perr. . e s V tz &

. e Gaertn. ( alata .

Roxb. ex R Rolf ( L ontinued ) Specie ombreteae: subtribe Terminaliinae subtribe ombreteae: ica C Exell r ) C uillem. . b. G x minalia o belli calamansanai chebula r Jack Roxb. ex DC. Blanco

uisqualis conferta . indica ombretum sundaicum ombretum ( ( ( chebula . . . e

ex C C. trifoliatum Q Q Tribe T B.Heyne ex Roth arjuna T. T R T catappa L T. T Miq DC.) Wight & Arn & Wight DC.) Anogeissus acuminata Table 1. Table

SW 8736-p004-014-G8.indd 10 12/1/58 BE 9:00 PM POLLEN MORPHOLOGY OF COMBRETACEAE FROM THAILAND AND ITS TAXONOMIC SIGNIFICANCE 11 (P. KRACHAI & P. PORNPONGRUNGRUENG) F B C B B B B B - - I- I-E I- I- I- I- I- I I I I I I I I I Group g e SC xin RE PM PM PM PM PM PM MR culp- urin e t s ------+ + olpi c ubsidiary s ) 16.86 13.46 12.6 14.8 22.4 17.13 12.73 13 ± ( ( ( ( ( ( ( ( 10.46 ) ) ) ) ) ) ) ) ( ) (μm 0.79 0.91 0.83 0.82 0.94 0.91 1.45 0.83 –12 olpus length c 11–14 11–14 ± 16–18 ± 12–15 ± 12–15 ± 13–17 ± 11–14 9 ± 19–24 ± 16–19 ± 0.92

) e ess ) ) 1.26 ± 1.3 ± 1.2 ± 1.1 ± ( ( ( ( kn 1.36 ± 2.9 ± 1.66 ± xin c ( ) ) ) ) ( ) ( ) (μm e ) hi 1 ± 0 1 ± 0 t ( ( 0.35 0.25 0.25 0.25 0.2 0.43 0.36 1–2 1–1.5 1–1.5 1 1–1.5 1–1.5 1 2–4 1–2 sses ize m S

la c s s s s s s s m s, e e e

e e e e e lat lat lat lat lat Shap o o o o o blate blate pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal pheroidal Subprolat Pr s Pr s Pr s Pr s Subprolat Pr s O s O s ) ) 13.66 17.4 15.06 14.13 17.33 13.66 12.33 29.66 23.66 ( ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) E (μm ean ± SD 0.81 0.91 0.59 0.74 0.89 1.04 0.48 2.63 1.34 (Range and m 12–15 ± 16–19 ± 14–16 ± 13–16 ± 16–19 ± 12–16 ± 12–13 ± 27–35 ± 21–26 ± ) 15.93 19.6 16.13 18.6 15.8 13.53 28.6 22.06 ( ( ( ( ( ( ( ( ) ) ) ) ) ) ) ) ) P (μm) P ean ± SD 0.88 0.98 0.51 0.74 1.12 0.86 0.63 0.81 1.09 (Range and m 27–30 14–17 ± 18–21 ± 15–17 ± 14–17 15.53 ± 17–21 ± 14–17 ± 13–15 ± ± 20–24 ± n r o . . b . . ea r hev rai nana illd f ticosa ess.

C . C r Nanak

W

ar litto co

A. v

a r ontinued . x Lan Species e e C

z ensis e r rr acemosa e minalia chebula ivo r r

umnit . . . e Gagnep T Pi glaucifolia T. T pedicellata T. Gagnep pierrei T. triptera Stap T. Laguncularieae Tribe L Voigt (Jack) L T Table 1. Table

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A B C

D EF

G H I

J K L

Figure 1. SEM micrographs of pollen grains. Group I: A–C: Combretum chinense; D–F: Quisqualis indica; G–I: Terminalia alata; J–L: T. calamansanai. A, D, G, J polar view; B, E, H, K equatorial view; C, F, I, L details of exine sculpturing. Scale bar = 10 μm (A, B, D, E, G, H, J, K), 1 μm (C, F, I, L); arrowheads indicate subsidiary colpi.

SW 8736-p004-014-G8.indd 12 12/1/58 BE 9:00 PM POLLEN MORPHOLOGY OF COMBRETACEAE FROM THAILAND AND ITS TAXONOMIC SIGNIFICANCE 13 (P. KRACHAI & P. PORNPONGRUNGRUENG)

A B C

D EF

G H I

J K L

Figure 2. SEM micrographs of pollen grains. Group II: A–C: Anogeissus acuminata; D–F: Calycopteris fl oribunda; G–I: Combretum latifolium; J–L: Quisqualis conferta. A, D, G, J polar view; B, E, H, K equatorial view; C, F, I, L details of exine sculpturing. Scale bar = 10 μm (A, B, D, E, G, H, J, K), 1 μm (C, F, I, L); arrowheads indicate subsidiary colpi.

SW 8736-p004-014-G8.indd 13 12/1/58 BE 9:00 PM 14 THAI FOREST BULLETIN (BOTANY) 43

A B C

D EF

G H I

J K L

Figure 3. SEM micrographs of pollen grains. Group II: A–C: Lumnitzera littorea; D–F: L. racemosa; G–I: Terminalia chebula var. chebula; J–L: T. triptera. A, D, G, J polar view; B, E, H, K equatorial view; C, F, I, L details of exine sculpturing. Scale bar = 10 μm (A, B, D, E, G, H, J, K), 1 μm (C, F, I, L); arrowheads indicate subsidiary colpi.

SW 8736-p004-014-G8.indd 14 12/1/58 BE 9:00 PM