Morphological Systematics of Spathoglottis Blume (Orchidaceae: Collabieae) in Peninsular Malaysia and Borneo

Abstract

Seventy-two morphological characters and three ecological characteristics were measured to assess variation and phylogenetic relationships among twelve species and three infraspecific taxa of the genus Spathoglottis from Peninsular Malaysia and Borneo. The morphological analyses divided Spathoglottis into two main groups based on the colours of the flower: Purple-Flowered Spathoglottis and Yellow-Flowered Spathoglottis. Species within the two groupings were further classified based on the size of the plants (Large/Dwarf Purple Spathoglottis and Large/Dwarf Yellow Spathoglottis) and the shapes of the labellum (spathulate, bilobulate or narrow/thread–like). The selected morphological characters appeared to support the taxonomic boundaries between two mostly debated taxa in the genus, S. aurea and S. microchilina.

1. Introduction

Forty-nine species of the genus Spathoglottis Blume (subfamily Epidendroideae, tribe Collabieae) are recognized worldwide, and of these, forty-four species are predominantly Malesian [1] (Figure 1). There are eight species and three infraspecific taxa native to Peninsular Malaysia and Borneo, namely Spathoglottis affinis de Vriese, S. aurea Lindl., S. confusa J.J.Sm., S. gracilis Rolfe ex Hook.f., S. hardingiana C.S.P.Parish & Rchb.f., S. kimballiana Hook.f., S. kimballiana var. angustifolia Ames, S. kimballiana var. kimballiana, S. microchilina Kraenzl., S. plicata Blume and S. plicata var. alba.

In the western part of Malesia, early taxonomical works on the genus Spathoglottis have been carried out by several authors for Peninsular Malaysia [2,3,4], the Borneo Islands of Sabah and Sarawak [5,6,7,8] and from Java and Sumatra [9,10]. In spite of this, a comprehensive revision on Spathoglottis in Peninsular Malaysia and Borneo is almost unavailable, worsened by the small numbers of specimens deposited in the herbaria, some of which have been wrongly identified.

Moving northwards crossing the Peninsular Malaysia–Thailand political border, taxonomic treatments for the Indochinese Spathoglottis were made available from two prominent contributions [11,12]. Meanwhile, early taxonomic revision on this genus was first discussed for the Australian Spathoglottis, later followed by revisions for the Pacific Islands and the New Caledonian species [13,14,15]. Surprisingly, even though almost half of Spathoglottis species are concentrated in New Guinea, knowledge on the genus from this part of East Malesia is rather scarce. Similarly, Spathoglottis from central Malesia (Wallacea), which includes the Philippines, Sulawesi, Lesser Sunda Islands and Maluku Islands, has been poorly studied.

Species within the genus are morphologically still poorly defined. Classifications based on morphology have utilized both quantitative and qualitative characters for the informal groupings within Spathoglottis [3,4]. Nevertheless, this classification was made based on limited measurement of morphological characters. Species within Spathoglottis were first recognized by the colours of the flower, followed by shapes of the labellum (lip)/midlobe, size of the flowers, shapes of the sidelobes, and size of the sepals in proportion to the petals. However, a detailed study of the morphological variation, using analysis of many traits in resolving the taxonomic boundaries among species of the genus, has not previously been undertaken.

Meanwhile, analyses of independent gene regions coupled with combined dataset using molecular markers have proven that Spathoglottis is monophyletic. The phylogenetic relationships among species of Spathoglottis from Peninsular Malaysia and Borneo were successfully resolved, and species boundaries were successfully circumscribed [16,17]. At the genetic level, the split within Spathoglottis reflects an early differentiation of plant size, flower colours and flower size. Nonetheless, no attempt has ever been made to elucidate the phylogenetic patterns within the genus using a detailed study of the morphological variation. Thus, the present work aimed to explain species relationships between members of the genus Spathoglottis from Peninsular Malaysia and Borneo using morphological and ecological variation, and to resolve the taxonomic questions between the controversial narrow-lip S. aurea and S. microchilina.

2. Materials and Methods

2.1. Taxon Sampling

A total of 103 plant samples from 12 species and 3 infraspecific taxa of Spathoglottis were analysed in this present work as listed in Table 1. It was sufficient to use one outgroup only, namely Tainia paucifolia (Breda) J.J.Sm. from tribe Collabieae, as Spathoglottis is already known to be monophyletic. The plant samples were obtained from different localities throughout Peninsular Malaysia and Borneo (Sabah and Sarawak). Plant samples for the six Spathoglottis species from Thailand, Sumatra, Irian Jaya, Maluku Island and New Caledonia were provided by our collaborators. The samples were also included in this detailed study to examine discreet evolutionary relationships between members of the genus based on morphological character and ecological characteristic analyses.

The species list, localities and voucher information for all Spathoglottis species and the outgroup used are listed in Table 1. All voucher specimens were deposited in the Herbarium, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia (USMP) [18].

2.2. Species Identification and Enumeration

The Spathoglottis species were identified using the morphological characters described and identification keys prepared by preceding authors [2,3,4,5,6,7,8,9,10,11]. The scientific names adopted here are those accepted by the latest Kew’s Plants of the World Online, accessed via the web [1].

2.3. Morphological Character and Ecological Characteristic Analyses

Observations on the vegetative and reproductive macromorphological characters were made in the field. The geographical, ecological and geological attributes were also documented. For detailed micromorphological characters, specimens were examined under a stereo microscope, particularly on the parts of the flower.

In this study, morphological revision of Spathoglottis was also conducted using ordinary practices of herbarium taxonomy. The morphological characters were thoroughly examined and compiled from various literature searches [2,3,4,5,6,7,8,9,10,11,12,13,14,15] and herbarium specimen holdings of the Kew Royal Botanic Gardens Herbarium (K), Leiden University Herbarium (L), Singapore Botanic Gardens Herbarium (SING), Australian National Herbarium (CANB), Forest Research Institute Malaysia Herbarium (KEP), University of Malaya Herbarium (KLU), Universiti Kebangsaan Malaysia Herbarium (UKMB), Universiti Putra Malaysia Herbarium (UPM), Sarawak Forest Department Herbarium and Sabah Park (Mount Kinabalu) Herbarium. Collectively, more than 200 individuals of Spathoglottis have been examined in the wild. Each species is represented by at least three different flowering individuals, except for S. eburnea, S. gracilis, S. pubescens, S. unguiculata and S. vanvuurenii. This is due to the small population size (S. gracilis, for instance, is rather rare) and long dormancy period (for S. eburnea and S. pubescens, measurements were taken from flowering individuals of the whole population). From the analyses, 72 morphological characters and 3 ecological characteristics were measured quantitatively and qualitatively. These characters were gathered from the plant samples collected and all literature sources available, and by examining approximately 400 herbarium voucher specimens. Each of the characters are numerically coded as shown in Table 2.

2.4. Character Matrix and Phylogenetic Analysis

To build a phylogenetic tree based on morphological characters, the first step was to group the species by their similarities (shared characters) in order to recognize what characters they share and what characters are different. The information was then organized into a character matrix, which is a chart of characters that is important in categorizing the species and the names of the species. A phylogenetic analysis using the Maximum Parsimony method was carried out using data from the matrix in an attempt to ascertain whether these characters were phylogenetically significant, and to elucidate the relationships between members of Spathoglottis based on their morphological variation. The character matrix and phylogenetic tree were generated using Mesquite version 3.70 [19].

The distribution of character states among the 12 species and 3 infraspecific taxa of Spathoglottis measured in this study is presented in Table 3 below:

3. Results

Morphological characters and ecological characteristics appeared to support the informal groupings in Spathoglottis. Based on the morphological variation analyses, the relationships among species of Spathoglottis in Peninsular Malaysia and Borneo are represented in a well-resolved phylogenetic tree.

3.1. Phylogeny Based on Morphological and Ecological Variation Analyses

The early groupings of Spathoglottis are suggested to be driven by the different colours of the flowers, followed by the plant size, and species are further distinguished by the shapes of the labellum/lip (Figure 2). Two main groups based on the colours of the flowers are recognized for this separation; namely Purple-Flowered Spathoglottis (Group G1) and Yellow-Flowered Spathoglottis (Group G2). A chart on the different tons of purple and yellow representing each species of Spathoglottis was prepared, as shown in Figure 3. It was observed that the character for purple colour flower was gained twice in Spathoglottis, as seen in the lilac S. hardingiana embedded within the Yellow-Flowered Spathoglottis group.

From the phylogenetic tree, it can be seen that Clade I consists of S. unguiculata, a purple-flowered Spathoglottis from the island of New Caledonia which was found to be a sister to all Spathoglottis species. The densely hairy callus and short column are characteristics unique to this species, and appeared nowhere else in any species of the genus (Figure 4).

Meanwhile in Clade II, S. parviflora from Irian Jaya appeared to be a sister to the rest of the purple-flowered Spathoglottis. The lip of S. parviflora is spathulate or almost boat-shaped, and thus is very distinctive from the broad/bilobulate lip of S. plicata, S. plicata var. alba and S. vanvuurenii from Seram (Figure 5). Generally, all members of these two clades share many similarities in vegetative habit, size and characters of the flowers. However, the clades are separated by the shapes of the lip and the sidelobes of the flower; S. parviflora has a spathulate lip, and the sidelobes are falcate, in contrast to the bilobulate lip in S. plicata, S. plicata var. alba and S. vanvuurenii (Figure 6).

Clade III contains all the purple- and yellow-flowered Spathoglottis in Peninsular Malaysia and Borneo and is monophyletic. This clade is further divided into Subclade III-A (Purple-Flowered Spathoglottis group) and Subclade III-B (Yellow-Flowered Spathoglottis group) according to their respective flower colours. The Purple-Flowered Spathoglottis group comprises the purple-flowered species, namely S. vanvuurenii, S. plicata and its white form S. plicata var. alba. Species within this group are held together by shared vegetative characters: medium-to-large-sized plants with four to five plicate leaves, having broad and coriaceous leaves, production of persistence floral bracts; and reproductive characters: flowers in the shades of pink to mauve to deep purple, thin-textured flowers, free-spreading sepals and petals, and broad midlobe with the presence of a narrow claw. However, vegetatively, it is difficult to differentiate S. vanvuurenii from S. plicata in the absence of the flowers. They are almost similar in habit, but S. vanvuurenii is less robust and has fewer leaves than S. plicata, and the inflorescence is less dense with only a few pinkish flowers blooming at one time. The shape and architecture of the sidelobes and calli (plural of callus) on the lip are different in S. vanvuurenii and S. plicata. The two species are thus separable based on the oblong vs. square sidelobes, and cuneate vs. obcuneate calli in S. vanvuurenii and S. plicata, respectively. The calli in S. plicata are also united at the base, in contrast to the calli of S. vanvuurenii which rise individually.

Meanwhile, the Yellow-Flowered Spathoglottis group is further divided into two separate groupings based on the size of the plants. Subclade III-B1 (Dwarf Yellow Spathoglottis group) houses all the dwarf-sized yellow Spathoglottis from Indo–China, whereas Subclade III-B2 (Large Yellow Spathoglottis group) comprises the large-sized species from Peninsular Malaysia and Borneo. These morphological variation analyses have shown that the Yellow-Flowered Spathoglottis group is monophyletic. Independently, the Large Yellow Spathoglottis group is also monophyletic. However, the Dwarf Yellow Spathoglottis group appears to be paraphyletic. This is due to the placement of S. hardingiana, a dwarf species with a purple flower that nests within the clade, rather than forming a distinct clade of its own.

The four species, namely S. eburnea, S. affinis, S. hardingiana and S. pubescens, are distinctly dwarf in habit. A flattened pseudobulb of irregular shape is unique to members in the Dwarf Yellow Spathoglottis group, and a white colour pseudobulb was only observed in S. eburnea and S. pubescens. The group also shows diverse similarities of characters, such as the petioles and thin leaf, the elliptic sterile bracts that are deciduous, purplish inflorescence and finely hairy throughout, bearing less than five flowers per inflorescence of which only one blooms at a time, having sepals and petals almost equal in width, and predominantly, all are lithophytic species that dwell on rocky substrates.

The Large Yellow Spathoglottis group is observed as a well-resolved clade. The group consists of species with large yellow flowers (about 5.0–8.0 cm cross), the sepals and petals of which are thick-textured; the pedicel holding the flower is glabrous as compared to the hairy one in the Dwarf Yellow Spathoglottis group and the rest of the purple lower Spathoglottis; and the floral bracts are coriaceous, persistent and ovate to triangular in shape. Species within the Large Yellow Spathoglottis group are further separated into two distinct groupings based on the shapes of the lip. Subclade III-B3 (Narrow-Lip Spathoglottis) holds together the two species with a narrow lip, namely S. aurea and S. microchilina, whereas Subclade III-B4 (Broad-Lip Spathoglottis) consists of all Spathoglottis species from Borneo with a broad lip.

In the Narrow-Lip Spathoglottis group, S. aurea and S. microchilina formed a distinct grouping, predominantly characterized by a narrow and pointed lip which is almost thread-like, in contrast to the broad, spathulate midlobe of S. gracilis, S. kimballiana and its two infraspecific taxa. Additionally, this group is separated from the broad-lip Spathoglottis by the number of leaves, which is only two to three per plant, sometimes tinged with purple (S. aurea), the arched column, and also the high percentage of fruit sets in each individual plant. Autogamy or self-pollination is also unique to this group, and swelling of the ovary is commonly observed even before the flower bud is open.

Together, S. gracilis, S. kimballiana, S. kimballiana var. angustifolia and S. kimballiana var. kimballiana form the Broad-Lip Spathoglottis group. This group consists of species that show a mixture of various vegetative characters, from the one-leaf S. gracilis to the four-leaf S. kimballiana, to the grass-like leaves of S. kimballiana var. kimballiana and S. kimballiana var. angustifolia. Despite of the differences, members of this group are all ultramafic species and are held together by many similarities in their floral characters. A pair of broad and long auriculate sidelobes is a feature special to this group, along with flowers spotted with crimson on the reverse of the sepals and the distinctive curved column.

3.2. Delimiting Species Using Discreet Morphological Examination

Over the years, the taxonomic status between S. aurea and S. microchilina has been repeatedly questioned. The two narrow-lip, yellow-flowered Spathoglottis inhabit montane forests at 1300–2000 m asl and scarcely survive anywhere lower than 1000 m. They were separated as two different species predominantly based on the width of the lip/midlobe, which is wider in S. aurea (2.5–4.0 mm) as compared to the thread-like instances in S. microchilina (c. 1.5 mm). Spathoglottis microchilina was also reported to be autogamous, which is in contrast to the insect-pollinated S. aurea. However, this generalization is partly agreed, because self-pollination was also observed to be rather common in S. aurea. The flower of S. aurea is also relatively larger (c. 5.0–7.0 cm cross) and golden yellow as compared to the medium-sized (c. 4.0 cm cross) and pale yellow flower of S. microchilina (Figure 7).

Both S. aurea and S. microchilina share many similarities in their vegetative habits, such as size of plants, shapes of leaves and length of inflorescence. However, individuals in wild populations of S. aurea show great phenotypic variations across habitat, thus leading many authors to suggest S. microchilina as one of the highly variable forms of S. aurea. Nevertheless, the two species are well separated geographically, as S. aurea is rather common in the mountains of Peninsular Malaysia, while S. microchilina is confined to the ultramafic forests in Borneo [17].

Discreet morphological examination of the flower characters of S. aurea and S. microchilina has successfully resolved the taxonomic confusion between these two species. Spathoglottis aurea is distinguished from S. microchilina (S. aurea vs. S microchilina.) by (1) having a wider lip (c. 2.5–4.0 mm vs. <1.5 mm), (2) a triangular vs. obovate floral bract, (3) golden yellow flower vs. pale yellow flower, (4) sepals and petals almost equal in size vs. relatively larger petals, (5) falcate sidelobe vs. oblong sidelobe, (6) cuneate callus vs. falcate callus and (7) callus united at base vs. callus risen individually (Figure 4, Figure 5 and Figure 6).

4. Discussion

4.1. Morphological Variation and Phylogenetic Relationships between Species of Spathoglottis

Morphology may show prominent signals in elucidating phylogenetic relationships and phenotypic character evolution as discussed in various morphological systematics of Orchidaceae [20,21,22]. Morphological and ecological variation analyses in this present work have successfully resolved the evolutionary relationships between the eight species and three infraspecific taxa of Spathoglottis from Peninsular Malaysia and Borneo. Additionally, species boundaries within the genus have been successfully circumscribed.

Plant size, flower colours and shapes of labellum are synapomorphic characters that support monophyly in Spathoglottis.

The application of parsimony to the morphological matrix in this work reproduced the well-supported topology, and is in accordance with the early revision efforts on the classification of Spathoglottis prior to the advent of molecular phylogenetics. This genus is classified into two main groups (Purple-Flowered Spathoglottis and Yellow-Flowered Spathoglottis) based on the colours of the flower (Character 33), size of the plants (Character 1) and shapes of the labellum/lip (Character 49). The other equally important morphological characters and ecological characteristics used to identify and delimit species within Spathoglottis are: leaf shape and vernation (Character 11, 15), size of flower (Character 34), size and shape of midlobe (Character 52, 53), callus architecture (Character 69), column architecture (Character 70), pollination strategies (Character 37), ecological niches (Character 74) and geological history of the species (Character 75).

4.2. Spathoglottis aurea and S. microchilina as Two Distinguished Species

Based on the morphological variation analyses, S. aurea and S. microchilina should be accepted as two separate taxa, of which S. aurea (native to Peninsular Malaysia) has wider geographical occurrences, while S. microchilina is known only in Borneo.

The narrow lip possessed by both S. aurea and S. microchilina is suggested to appear due to a floral divergence driven by adaptation to specific pollinators in particular habitat. The much-reduced lip of S. aurea and S. microchilina, the underdeveloped rostellum, and the swollen ovary with developed pollen tubes during the floral bud stage are evidence of a self-pollination strategy. In this study, each of the individuals of S. microchilina from Borneo was observed to be completely cleistogamous or occasionally geitonogamous. The flower does not open fully, and fruit set percentage is very high; a sign of a successful self-pollination strategy. Likewise, similar observation was noticed among individuals of S. aurea from different populations in Peninsular Malaysia. A complete cleistogamous form of S. aurea is usually stunted or smaller in size, in comparison to the geitonogamous or insect-pollinated S. aurea which are vegetatively and reproductively larger in size.

4.3. Phylogenetic Relationships Based on Morphological Data and Molecular Data

Comparison-wise, the morphological tree obtained in this study appeared incongruent to the molecular trees published in separate studies [17]. The comparisons are discussed as in Table 4 below:

However, both in morphology and molecular trees, the Large Yellow-Flowered Spathoglottis have been proven to be monophyletic. In addition, the taxonomic status of the two profoundly confused narrow-lip Spathoglottis, S. aurea and S. microchilina, is now resolved and they should be considered as two separate taxa.

This phylogenetic incongruence between trees built from morphological data versus molecular data might be due to several reasons, such as homoplasious characters resulting from convergent evolution, and morphological variation across character states inflicted by environmental variation impacting on plastic morphological traits [20].

5. Conclusions

Morphological characters and ecological characteristics have been proven to show a strong taxonomic signal in elucidating evolutionary relationships within Spathoglottis. Plant size, flower colours and shapes of labellum are synapomorphic characters that support the monophyly of the groups within Spathoglottis. However, it was proven that similar morphological characters were not necessarily inherited, but could be independently derived.

Author Contributions

Data curation, F.A.N. and A.S.O.; formal analysis and investigation, F.A.N., C.S.Y.Y., A.S.O. and K.S.; methodology, F.A.N., A.S.O., A.R., R.G. and C.S.Y.Y.; resources, F.A.N., A.S.O., K.S., A.R. and R.G.; supervision, A.S.O. and K.S.; validation, A.S.O.; writing—original draft, F.A.N.; writing—review and editing, F.A.N. and A.S.O. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Data presented in this article are available on request from the corresponding authors.

Acknowledgments

The authors would like to express their deepest gratitude to the administrative and field personnel of School of Biological Sciences, Universiti Sains Malaysia; Faculty of Resource Science and Technology, Universiti Malaysia Sarawak; Department of Biology, Universiti Putra Malaysia; and Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah for the facilities and assistance provided during the study conducted. Thank you to the Forestry Department of Peninsular Malaysia, Forestry Department of Sarawak, Forestry Department of Sabah, Sabah Biodiversity Centre and Kinabalu Park for the research permits granted. Many thanks to Richard Chung (FRIM), Ong Poh Teck (FRIM), Yong Kien Thai (KLU) and Nik Norhazrina Nik Mohd Kamil (UKMB) for the assistance provided during visits to the herbaria. Special thanks to our local and overseas collaborators; Anuar, Lawrence and C. K. Lim of Suriana Botanic Conservation Gardens.

Conflicts of Interest

The authors declare no conflict of interest.

Footnotes

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Figures and Tables

Figure 1. Distribution of Spathoglottis in Indo–China and throughout Malesia. Each numbering represents individual island grouping, with almost no cross-over in species occurrences: (1) Indo–China, (2) Peninsular Malaysia and Sumatra, (3) Borneo, (4) Java, (5) Sulawesi, (6) the Philippines and (7) New Guinea. Spathoglottis plicata is a widespread species throughout Malesia.

Figure 2. A majority rule consensus of 100 equally parsimonious trees of Spathoglottis species based on morphological and ecological sequence data. Tree length = 251; CI = 0.51; RI = 0.54. Groups G1 and G2 denote the Purple-Flowered Spathoglottis and Yellow-Flowered Spathoglottis, respectively. Numbers at nodes represent the informal groupings in Spathoglottis from Peninsular Malaysia, Borneo, Thailand, Sumatra, Irian Jaya, Maluku Island and New Caledonia.

Figure 3. A chart on the different shades of purple and yellow representing each species of Spathoglottis. The chart was prepared from the correct colours of Spathoglottis flowers, taken in natural light.

Figure 4. Column (Characters 70–72), side view of (A) S. microchilina (scale bar 1 mm, 4× magnification); (B) S. aurea (scale bar 0.5 cm, 4× magnification); (C) S. unguiculata (scale bar 0.5 cm, 4× magnification); (D) S. pubescens (scale bar 2000 µm, 4× magnification); (E) S. hardingiana (scale bar 2000 µm, 4× magnification); (F) S. plicata (scale bar 2000 µm, 4× magnification); and dorsal view of (G,H) S. affinis (scale bar 2 mm, 4× magnification). Photos: Farah Alia Nordin.

Figure 5. Labellum/lip (Characters 49–56) of (A) S. microchilina; (B) S. aurea; (C) S. unguiculata; (D,E) S. affinis; (F) S. eburnea; (G,H) S. plicata; (I) S. plicata var. alba; and (J) S. parviflora. Scale bar 2 mm, 4× magnification. Photos: Farah Alia Nordin.

Figure 6. Sidelobes (Characters 57–61) of (A) S. microchilina; (B) S. aurea; (C) S. hardingiana; (D) S. plicata; (E,F) S. affinis; (G) S. kimballiana var. kimballiana; (H) S. kimballiana var. angustifolia; and (I) S. gracilis. Scale bar 2 mm, 4× magnification. Photos: Farah Alia Nordin.

Figure 7. Spathoglottis aurea (A) habit; (C) flower; (F) inflorescence and (G) self-pollinated flowers and fruits, and S. microchilina (B) habit; (D) flower; (E) inflorescence; (H) self-pollinated flowers and fruits. Photos: Farah Alia Nordin.

Table 1

Species list, collection localities and herbarium voucher numbers of the Spathoglottis species and outgroup used in this present work.

Species	Collection Number/Voucher Number	Collection Locality	Altitude (m)
Spathoglottis affinis de Vriese	FAN020/USMP12177	Ton Nga Chang, Songkhla, Thailand	100
2. Spathoglottis affinis de Vriese	FAN023/USMP12178	Fang District, Chiang Mai,Thailand	1000
3. Spathoglottis affinis de Vriese	FAN025/USMP12179	Thailand–Myanmar Border	1000
4. Spathoglottis affinis de Vriese	FAN028/USMP12180	Padang Tok Sheikh, G. Jerai, Kedah	1131
5. Spathoglottis aurea Lindl.	FAN006/USMP12181	G. Ledang, Johor	1200
6. Spathoglottis aurea Lindl.	FAN008/USMP12182	G. Lari Tembakau, Pahang	1800
7. Spathoglottis aurea Lindl.	FAN009/USMP12183	G. Ulu Kali, Pahang	1800
8. Spathoglottis aurea Lindl.	FAN018/USMP12184	G. Jerai, Kedah	989
9. Spathoglottis aurea Lindl.	FAN019/USMP12185	Taman Rimba, G. Jerai,Kedah	986
10. Spathoglottis aurea Lindl.	FAN026/USMP12186	Taman Rimba, G. Jerai,Kedah	990
11. Spathoglottis aurea Lindl.	FAN030/USMP12187	Fraser’s Hill, Pahang	1300
12. Spathoglottis aurea Lindl.	FAN031/USMP12188	Fraser’s Hill, Pahang	1300
13. Spathoglottis aurea Lindl.	FAN032/USMP12189	Fraser’s Hill, Pahang	1292
14. Spathoglottis aurea Lindl.	FAN035/USMP12190	Mile 49, Tanah Rata,Cameron Highlands, Pahang	1400
15. Spathoglottis aurea Lindl.	FAN036/USMP12191	Mile 39, Tanah Rata, Cameron Highlands, Pahang	1410
16. Spathoglottis aurea Lindl.	FAN037/USMP12192	G. Brinchang, Pahang	1800
17. Spathoglottis aurea Lindl.	FAN038/USMP12193	G. Brinchang, Pahang	1600
18. Spathoglottis aurea Lindl.	FAN039/USMP12194	G. Ulu Kali, Pahang	1800
19. Spathoglottis aurea Lindl.	FAN040/USMP12195	G. Chin Chin, Pahang	1800
20. Spathoglottis aurea Lindl.	FAN041/USMP12196	G. Brinchang, Pahang	1800
21. Spathoglottis aurea Lindl.	FAN044/USMP12197	Padang Tok Sheikh, G. Jerai, Kedah	1200
22. Spathoglottis aurea Lindl.	FAN052/USMP12198	G. Ulu Kali, Pahang	1800
23. Spathoglottis aurea Lindl.	FAN053/USMP12199	G. Ulu Kali, Pahang	1800
24. Spathoglottis aurea Lindl.	FAN054/USMP12200	Padang Tok Sheikh, G. Jerai, Kedah	1200
25. Spathoglottis aurea Lindl.	FAN057/USMP12201	G. Bunga Buah, Selangor	1400
26. Spathoglottis aurea Lindl.	FAN058/USMP12202	G. Bunga Buah, Selangor	1400
27. Spathoglottis aurea Lindl.	FAN059/USMP12203	G. Bunga Buah, Selangor	1400
28. Spathoglottis aurea Lindl.	FAN060/USMP12204	G. Bunga Buah, Selangor	1400
29. Spathoglottis aurea Lindl.	FAN069/USMP12205	Tanah Rata, Cameron Highlands, Pahang	1419
30. Spathoglottis aurea Lindl.	FAN070/USMP12206	Tanah Rata, CameronHighlands, Pahang	1419
31. Spathoglottis aurea Lindl.	FAN071/USMP12207	Huta Tinggi, Samarindo,Samosir, North Sumatra	1400
32. Spathoglottis aurea Lindl.	FAN098/USMP12208	Tanah Rata, CameronHighlands, Pahang	1419
33. Spathoglottis aurea Lindl.	FAN099/USMP12209	Tanah Rata, CameronHighlands, Pahang	1419
34. Spathoglottis eburnea Gagnep.	FAN022/USMP12210	Fang District, Chiang Mai,Thailand	1000
35. Spathoglottis gracilis Rolfe ex Hook.f.	FAN094/USMP12211KIP1266f	Kg. Liposu, Ranau, Sabah	850
36. Spathoglottis hardingiana C.S.P.Parish & Rchb.f.	FAN016/USMP12212	G. Baling, Kedah	450
37. Spathoglottis hardingiana C.S.P.Parish & Rchb.f.	FAN056/USMP12213	G. Pong, Kenering, Perak	420
38. Spathoglottis hardingiana C.S.P.Parish & Rchb.f.	FAN105/USMP12214K20160013	Tg. Asan, Pulau Timun,Langkawi, Kedah	200
39. Spathoglottis kimballiana Hook.f.	FAN085/USMP12215	Ranau, Sabah	1300
40. Spathoglottis kimballiana var. angustifolia Ames	FAN076/USMP12216THH13 6 99	Bidu Bidu FR, Telupid,Sabah	71
41. Spathoglottis kimballiana var. angustifolia Ames	FAN077/USMP12217	Bidu Bidu FR, Telupid,Sabah	71
42. Spathoglottis kimballiana var. angustifolia Ames	FAN104/USMP12218	Sungai Tongod, Telupid,Sabah	60
43. Spathoglottis kimballiana var. kimballiana	FAN067/USMP12219	Mt. Kinabalu, Ranau, Sabah	1300
44. Spathoglottis kimballiana var. kimballiana	FAN092/USMP12220	Kota Belud, Sabah	800
45. Spathoglottis kimballiana var. kimballiana	FAN093/USMP12221	Pekan Nabalu, Ranau, Sabah	1400
46. Spathoglottis microchilina Kraenzl.	FAN082/USMP12222	Bundu Tuhan View Trail,Kinabalu Park, Sabah	1601
47. Spathoglottis microchilina Kraenzl.	FAN083/USMP12223	Kinabalu Park ResearchCentre, Sabah	1599
48. Spathoglottis microchilina Kraenzl.	FAN084/USMP12224	Kinabalu Park, Sabah	850
49. Spathoglottis microchilina Kraenzl.	FAN086/USMP12225	Mamut Copper Mine, Sabah	1324
50. Spathoglottis microchilina Kraenzl.	FAN087/USMP12226	Mamut Copper Mine, Sabah	1485
51. Spathoglottis microchilina Kraenzl.	FAN088/USMP12227	Mamut Copper Mine, Sabah	1372
52. Spathoglottis microchilina Kraenzl.	FAN089/USMP12228	Mamut Copper Mine, Sabah	1405
53. Spathoglottis microchilina Kraenzl.	FAN091/USMP12229	Sg. Lohan, Ranau, Sabah	1375
54. Spathoglottis microchilina Kraenzl.	FAN095/USMP12230	Tambunan, Sabah	1000
55. Spathoglottis microchilina Kraenzl.	FAN096/USMP12231	Ranau, Sabah	850
56. Spathoglottis parviflora Kraenzl.	FAN061/USMP12232	Wamena, Irian Jaya	1679
57. Spathoglottis plicata Blume	FAN001/USMP12233	Peak of G. Ledang, Johor	1000
58. Spathoglottis plicata Blume	FAN002/USMP12234	Peak of G. Ledang, Johor	1100
59. Spathoglottis plicata Blume	FAN003/USMP12235	Penang Hill, Penang	686
60. Spathoglottis plicata Blume	FAN004/USMP12236	Penang Hill, Penang	735
61. Spathoglottis plicata Blume	FAN005/USMP12237	Sungai Rui, Kedah	700
62. Spathoglottis plicata Blume	FAN007/USMP12238	K. Kubu Bharu, Selangor	1392
63. Spathoglottis plicata Blume	FAN010/USMP12239	G. Ulu Kali, Pahang	1800
64. Spathoglottis plicata Blume	FAN011/USMP12240	G. Jerai, Kedah	980
65. Spathoglottis plicata Blume	FAN012/USMP12241	G. Jerai, Kedah	1200
66. Spathoglottis plicata Blume	FAN015/USMP12242	Gerik, Perak	1100
67. Spathoglottis plicata Blume	FAN017/USMP12243	Baling, Kedah	650
68. Spathoglottis plicata Blume	FAN021/USMP12244	Peak of G. Jerai, Kedah	1210
69. Spathoglottis plicata Blume	FAN027/USMP12245	G. Jerai, Kedah	1000
70. Spathoglottis plicata Blume	FAN029/USMP12246	G. Jerai, Kedah	1100
71. Spathoglottis plicata Blume	FAN033/USMP12247	Raub, Pahang	1000
72. Spathoglottis plicata Blume	FAN042/USMP12248	Taiping Hill, Perak	1200
73. Spathoglottis plicata Blume	FAN043/USMP12249	G. Jerai, Kedah	926
74. Spathoglottis plicata Blume	FAN046/USMP12250	Taman Negara Endau Rompin, Johor	78
75. Spathoglottis plicata Blume	FAN047/USMP12251	Taman NegaraEndau–Rompin, Johor	80
76. Spathoglottis plicata Blume	FAN048/USMP12252	Kota Tinggi Waterfall, Johor	100
77. Spathoglottis plicata Blume	FAN049/USMP12253	Ladang Lok Heng, KotaTinggi, Johor	40
78. Spathoglottis plicata Blume	FAN050/USMP12254	Jalan Mersing, Kahang,Johor	76
79. Spathoglottis plicata Blume	FAN051/USMP12255	Peak of G. Ledang, Johor	1200
80. Spathoglottis plicata Blume	FAN055/USMP12256	G. Jerai, Kedah	1200
81. Spathoglottis plicata Blume	FAN063/USMP12257	Lata Chemerong, Terengganu	200
82. Spathoglottis plicata Blume	FAN064/USMP12258	Lata Chemerong,Terengganu	70
83. Spathoglottis plicata Blume	FAN065/USMP12259	Lata Chemerong,Terengganu	110
84. Spathoglottis plicata Blume	FAN066/USMP12260	Lata Chemerong,Terengganu	70
85. Spathoglottis plicata Blume	FAN072/USMP12261	Tasik Kenyir, Terengganu	30
86. Spathoglottis plicata Blume	FAN073/USMP12262	Mile 49, Tamparuli to Ranau Road, Sabah	839
87. Spathoglottis plicata Blume	FAN074/USMP12263	Jalan Kaung to Ranau, KotaBelud, Sabah	880
88. Spathoglottis plicata Blume	FAN075/USMP12264	Kg. Labong–Labong, Kota Belud, Sabah	800
89. Spathoglottis plicata Blume	FAN078/USMP12265	Sg. Keripir, 45 miles to Tambunan, Sabah	750
90. Spathoglottis plicata Blume	FAN079/USMP12266	Tambunan Road, Sabah	757
91. Spathoglottis plicata Blume	FAN080/USMP12267	Tambunan Road, Sabah	757
92. Spathoglottis plicata Blume	FAN081/USMP12268	Tambunan Road, Sabah	468
93. Spathoglottis plicata Blume	FAN090/USMP12269	Mamut Copper Mine, Sabah	1405
94. Spathoglottis plicata Blume	FAN097/USMP12270	Hulu Telom, Pahang	708
95. Spathoglottis plicata Blume	FAN100/USMP12271	Semengoh Nature Reserve, Sarawak	46
96. Spathoglottis plicata Blume	FAN101/USMP12272	Semengoh Nature Reserve, Sarawak	50
97. Spathoglottis plicata Blume	FAN102/USMP12273	Bario, Sarawak	1065
98. Spathoglottis plicata Blume	FAN103/USMP12274	Long Baleh, Sarawak	944
99. Spathoglottis plicata var. alba	FAN034/USMP12275	Lata Tembakah, Terengganu	36
100. Spathoglottis plicata var. alba	FAN045/USMP12276	Lata Tembakah, Terengganu	36
101. Spathoglottis pubescens Lindl.	FAN068/USMP12277	Fang District, Chiang Mai, Thailand	800
102. Spathoglottis unguiculata (Labill.) Rchb.f.	FAN024/USMP12278	Isle of Pines, New Caledonia	200
103. Spathoglottis vanvuurenii J.J.Sm.	FAN062/USMP12279	Seram, Maluku Island	834
104. Tainia paucifolia (Breda) J.J.Sm.	FAN597/USMP12280	Taman Rimba Kenong, Pahang	20 m

Table 2

Morphological characters and ecological characteristics measured in this present work. The characters were measured quantitatively and qualitatively. Each of the character states are represented by a numerical code.

Character	Character States
Vegetative Characters
Plant size	0 = dwarf (≤ 30 cm tall), 1 = large (≥ 30 cm up to 2 m tall)
2. Root shape	0 = thick, 1 = filiforme
3. Pseudobulb shape	0 = ovoid, 1 = conical, 2 = flattened
4. Colour of pseudobulb	0 = green, 1 = purple, 2 = white
5. Fibres enclosing pseudo. bulb	0 = presence, 1 = absence
6. Stem appearance	0 = distinct, 1 = indistinct
7. Stem sheath	0 = presence, 1 = absence
8. Stem colouration	0 = greenish, 1 = tinged with purple
9. Number of leaves per pseu dobulb	0 = 1, 1 = 2–3, 2 = 4, 3 = > 4
10. Leaf sheath attachment	0 = sheath clasping the stem, 1 = petiolated
11. Leaf vernation	0 = plicate with strong midrib, 1 = non-plicate
12. Leaf texture	0 = thin, 1 = coriaceous (tough), 2 = velvety
13. Leaf ornamentation	0 = glabrous, 1 = pubescent
14. Leaf margin	0 = entire, 1 = crisp
15. Leaf shape	0 = linear (grass-like), 1 = linear–lanceolate, 2 = lanceolate, 3 = broadly elliptic
16. Leaf apex	0 = acute, 1 = acuminate
17. Leaf colouration	0 = greenish throughout, 1 = greenish-grey, 2 = green tinged with purple
18. Leaf width	0 = grass-like (≤ 1.0 cm wide), 1 = narrow (c. 1.1–2.0 cm wide), 2 = medium (2.1–5.0 cm wide), 3 = very broad (>5.1 cm wide)
19. Leaf length	0 = short (≤15.0 cm long), 1 = medium (15.1–50.0 cm long), 2 = long (50.1–100 cm long), 3 = very long (>100.1 cm long)
Reproductive Characters
20. Inflorescence habit	0 = shorter than plant, 1 = longer than plant
21. Inflorescence colouration	0 = green, 1 = purple
22. Inflorescence ornamentation	0 = glabrous, 1 = covered with fine hairs
23. Sterile bract shape	0 = elliptic, 1 = obovate
24. Floral bract senescence	0 = deciduous, 1 = persistent
25. Floral bract shape	0 = obovate, 1 = elliptic, 2 = triangular with wavy margin
26. Floral bract attachment	0 = free, 1 = clasping the peduncle
27. Floral bract colour	0 = green, 1 = purple
28. Floral bract texture	0 = hard, 1 = soft
29. Pedicel ornamentation	0 = glabrous, 1 = covered in fine hairs
30. Ovary swelling	0 = upon flower senescence, 1 = flower still in bud stage
31. Number of flowers per rachis	0 = 2–3 (<5 flowers), 1 = many up to 20 flowers
32. Flower development	0 = determinate (terminal flower mature first), 1 = indeterminate (flower at the bottom mature first), 2 = all bloom at once
33. Flower colour	0 = white, 1 = yellow, 2 = pink, 3 = mauve to deep purple
34. Flower size (when open)	0 = small (c. 3.0 cm in dimension), 1 = medium (c. 3.1–5.0 cm in dimension), 2 = large (>5.1 cm in dimension)
35. Shades of yellow	0 = creamy yellow, 1 = pale yellow, 2 = golden yellow, 3 = other shades (not yellow)
36. Flower resupination	0 = presence (resupinate), 1 = absence (non resupinate)
37. Flower pollination strategy	0 = insect pollinated, 1 = dimorphic cleistogamy, 2 = geitonogamy
38. Fruit set percentage	0 = 50% set into fruit, 1 = almost 100% set into fruit
39. Sepal and petal architecture	0 = spreading, 1 = drooping, 2 = turned backwards, 3 = remained closed
40. Sepal and petal size	0 = different in size, 1 = almost equal in width
41. Sepal shape	0 = ovate, 1 = elliptic, 2 = narrow–elliptic
42. Sepal texture	0 = thin, 1 = tough
43. Sepal colouration	0 = flush red or brown on the outer part, 1 = no colouration, 2 = streaks with red in the inner part
44. Sepal ornamentation	0 = hairy at base, 1 = hairy on the entire outer part, 2 = glabrous
45. Sepal apex	0 = obtuse, 1 = tapering towards end, 2 = thickened, 3 = mucronate
46. Lateral sepal arrangement	0 = free, 1 = concave, 2 = curved backwards
47. Sepal carination	0 = presence, 1 = absence
48. Petal shape	0 = obtuse, 1 = elliptic, 2 = oblong–elliptic
49. Labellum/lip shape	0 = narrow, 1 = spathulate, 2 = obcordate, 3 = oblong–obovate, 4 = fiddle-shaped, 5 = square
50. Lip size	0 = length half of the sepals, 1 = length as long as sepals
51. Lip margin	0 = incurved, 1 = entire, 2 = wavy
52. Midlobe of lip	0 = thread-like, 1 = almost rounded, 2 = square, 3 = bilobulate
53. Width of midlobe	0 = mesochile narrow towards the end (≤4.0 mm wide), 1 = mesochile broad (c. 4.1–15 mm wide)
54. Lip apex	0 = dilate, 1 = pointed, 2 = truncate
55. Lip ornamentation	0 = keels or raised ridges presence, 1 = keels or raised ridges absence
56. Lip colouration	0 = spotted red or purple, 1 = splashed with yellow/white at the base
57. Sidelobe shape	0 = triangular, 1 = square, 2 = oblong, 3 = falcate, 4 = auriculate
58. Sidelobe colouration	0 = flushed with purple or crimson, 1 = splashed in yellow at base, 2 = spotted red or crimson or purple
59. Sidelobe ornamentation	0 = sparsely hairy at base, 1 = glabrous
60. Sidelobe length	0 = half as the width, 1 = almost double as wide
61. Sidelobe width	0 = half as the length, 1 = almost similar to the length
62. Lip claw	0 = presence, 1 = absence
63. Position of lip claw	0 = on one plane, 1 = bending at an acute angle to the left
64. Auricles (teeth) of lip	0 = distinct, 1 = indistinct, 2 = absence
65. Auricles shape	0 = small appendages, 1 = triangular
66. Callus shape	0 = oblong, 1 = cuneate, 2 = obcuneate, 3 = falcate, 4 = rounded
67. Callus ornamentation	0 = sparsely hairy at base, 1 = hairy entirely, 2 = hairy on top surface
68. Callus colouration	0 = spotted red or purple, 1 = yellow
69. Callus architecture	0 = united at base, 1 = risen individually
70. Column architecture	0 = arched, 1 = slender, 2 = curved
71. Column size	0 = shorter than the lip, 1 = as long as the lip
72. Column cap shape	0 = almost tubular, 1 = broadly winged
Ecological Characteristics
73. Habit	0 = terrestrial, 1 = lithophytic
74. Ecological niches	0 = montane forest above 900 m, 1 = lowland to hill forest (0–700 m asl), 2 = riverside
75. Geology	0 = multisubstrates, 1 = limestone/quartzite, 2 = granite, 3 = ultramafic

Table 3

Distribution of character states measured from the 12 species and 3 infraspecific taxa of Spathoglottis. A ‘?’ symbol denotes a missing or not applicable character.

Species	Characters and Character States
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21
S. affinis	0	1	2	0	1	1	0	1	1	0	1	0	0	0	0	1	0	0	0	0	1
S. aurea	1	0	0	0	0	0	0	1	1	0	0	1	0	1	2	0	2	3	3	1	1
S. eburnea	0	1	2	2	1	1	1	0	1	0	0	0	0	1	1	0	0	2	1	1	1
S. gracilis	1	1	1	1	0	0	0	1	0	1	0	1	0	1	2	0	0	3	1	0	0
S. hardingiana	0	1	0	0	1	1	1	0	1	1	1	2	1	0	1	1	1	2	2	0	1
S. kimballiana	1	1	0	0	1	0	0	0	2	0	0	1	0	1	2	0	0	3	3	1	0
S. kimballiana var.angustifolia	1	1	0	0	1	1	0	0	1	0	1	0	0	0	0	1	0	0	1	1	0
S. kimballiana var.kimballiana	1	1	0	0	1	1	0	0	1	0	1	0	0	0	0	1	0	1	1	1	0
S. microchilina	1	0	0	0	0	0	0	0	1	0	0	1	0	1	2	0	0	3	3	1	0
S. parviflora	1	1	0	0	1	0	0	1	3	0	0	1	0	1	2	0	0	3	3	1	0
S. plicata	1	0	0	0	1	0	0	0	3	0	0	1	0	1	2	0	0	3	3	1	0
S. plicata var. alba	1	0	0	0	1	0	0	0	3	0	0	1	0	1	2	0	0	3	3	1	0
S. pubescens	0	1	2	2	1	1	1	0	1	1	1	0	0	0	0	0	0	0	0	1	0
S. unguiculata	1	1	0	0	1	0	0	0	2	0	0	1	0	1	2	1	0	3	3	0	0
S. vanvuurenii	1	0	0	0	1	0	0	0	3	0	0	1	0	1	2	0	0	3	3	1	0
Tainia paucifolia	1	0	1	1	1	0	1	0	0	1	0	0	0	0	3	0	0	3	2	1	1
	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42
S. affinis	1	0	0	1	0	1	1	1	0	0	1	1	0	2	0	0	0	0	1	0	0
S. aurea	0	1	1	2	1	1	0	0	1	1	1	1	1	2	0	1	1	3	1	0	1
S. eburnea	1	0	0	1	0	1	1	1	0	0	1	1	0	0	0	0	0	0	1	0	0
S. gracilis	0	1	1	0	1	1	0	0	0	1	1	1	2	2	0	0	0	1	0	0	0
S. hardingiana	1	0	0	1	0	1	1	1	0	0	1	3	0	3	1	0	0	2	0	1	0
S. kimballiana	0	1	1	0	0	0	0	0	0	1	1	1	2	2	0	0	0	0	0	0	1
	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42
S. kimballiana var.angustifolia	0	1	1	0	0	0	0	0	0	1	1	1	2	2	0	0	0	1	0	0	1
S. kimballiana var.kimballiana	0	1	1	0	0	0	0	0	0	1	1	1	1	2	0	0	0	0	0	0	1
S. microchilina	0	1	1	0	1	0	0	0	1	1	1	1	1	1	0	1	1	3	0	0	1
S. parviflora	0	1	1	1	0	1	1	1	0	1	1	3	2	3	0	2	0	0	0	0	0
S. plicata	0	1	1	1	0	1	1	1	1	1	1	3	1	3	0	2	1	0	0	0	0
S. plicata var. alba	0	1	1	1	0	0	1	1	0	1	1	0	0	3	0	0	0	0	1	1	0
S. pubescens	1	0	0	1	0	1	1	1	0	0	1	1	0	3	0	0	0	0	1	1	0
S. unguiculata	0	1	1	1	0	1	1	1	0	1	1	3	0	3	0	0	0	0	0	0	1
S. vanvuurenii	0	1	1	1	0	1	1	1	0	1	1	2	1	3	0	0	1	0	0	0	0
Tainia paucifolia	0	0	1	1	0	1	1	1	1	1	2	3	1	3	0	0	?	0	0	2	1
	43	44	45	46	47	48	49	50	51	52	53	54	55	56	57	58	59	60	61	62	63
S. affinis	2	0	0	0	1	0	1	0	1	3	1	0	1	0	2	2	0	0	0	0	0
S. aurea	0	0	2	0	0	0	0	0	1	0	0	1	0	0	3	0	0	0	0	1	0
S. eburnea	0	1	0	0	1	0	5	0	1	1	1	0	0	0	1	2	0	0	0	1	0
S. gracilis	0	0	0	0	1	0	1	1	1	3	1	0	0	0	1	2	0	1	0	0	1
S. hardingiana	0	2	1	0	1	1	0	0	1	0	0	1	1	0	0	2	1	0	0	1	0
S. kimballiana	0	0	0	0	1	0	1	1	1	3	1	0	0	0	4	2	0	1	1	0	0
S. kimballiana var.angustifolia	1	0	0	0	0	0	4	1	1	1	1	2	0	0	4	2	0	1	1	1	0
S. kimballiana var.kimballiana	1	0	0	0	1	0	1	1	0	3	1	0	0	0	2	2	0	0	0	0	0
S. microchilina	1	0	0	0	1	0	0	0	1	0	0	1	0	0	2	0	0	0	0	1	0
S. parviflora	1	0	0	0	1	0	3	0	1	1	1	0	0	1	3	1	0	0	0	1	0
S. plicata	1	0	0	0	0	0	1	0	1	3	1	0	0	0	1	2	0	0	0	0	0
S. plicata var. alba	1	0	1	0	1	0	1	0	1	3	1	0	1	1	1	1	0	0	0	0	0
S. pubescens	1	1	1	1	1	0	2	0	1	2	1	0	0	0	2	2	0	0	0	1	0
S. unguiculata	1	2	0	0	0	0	2	0	0	1	1	0	1	1	2	1	0	0	0	1	0
S. vanvuurenii	1	0	0	0	1	0	1	0	1	3	1	0	0	0	2	2	0	0	0	1	0
Tainia paucifolia	1	2	3	2	0	2	2	1	2	1	1	2	0	0	2	0	1	0	0	1	0
	64	65	66	67	68	69	70	71	72	73	74	75
S. affinis	0	1	0	2	0	1	2	1	1	1	0	1
S. aurea	0	1	1	0	0	0	0	1	1	0	0	2
S. eburnea	0	1	3	0	1	1	2	1	1	1	0	1
S. gracilis	0	1	0	0	0	1	2	1	1	0	0	3
S. hardingiana	1	0	4	0	0	1	1	1	0	1	1	1
S. kimballiana	0	1	0	0	0	1	2	1	1	0	0	3
S. kimballiana var.angustifolia	0	1	0	0	0	0	2	1	1	0	2	3
S. kimballiana var.kimballiana	0	1	0	0	0	0	2	1	1	0	0	3
S. microchilina	0	1	3	0	0	1	0	1	1	0	0	3
S. parviflora	1	0	4	0	1	1	2	1	1	0	0	0
S. plicata	0	1	2	2	0	0	2	1	1	0	1	0
S. plicata var. alba	0	1	2	2	1	0	2	1	1	0	2	0
S. pubescens	1	0	2	0	1	1	2	1	1	1	1	1
S. unguiculata	1	0	4	1	1	1	2	0	1	0	1	0
S. vanvuurenii	0	1	0	0	0	1	2	1	1	0	0	0
Tainia paucifolia	2	?	?	?	?	?	0	1	1	0	2	0

Table 4

Phylogenetic relationships between species of Spathoglottis compared from morphological data and molecular data.

	Relationships from Morphological Data	Relationships from Molecular Data
1.	Species were first separated according to the colour of the flowers.	Groupings of Spathoglottis were first made according to plant size.
2.	The Dwarf Spathoglottis is nested within the Yellow-Flowered Spathoglottis group.	The Dwarf Spathoglottis formed a separate group from the Large Spathoglottis group.
3.	The Large Yellow-Flowered Spathoglottis group is well resolved, and species are grouped according to the shapes of labellum.	Species are arranged based on their geographical distribution, ecological niches and flower size.
4.	Spathoglottis kimballiana is well placed within the Large Yellow-Flowered Spathoglottis group with other Spathoglottis species from Borneo.	Spathoglottis kimballiana is nested within the Large Purple Spathoglottis group.

References

1. POWO, Plants of the World Online (Facilitated by the Royal Botanic Gardens, Kew). Available online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:325895- (accessed on 20 January 2023).

2. Ridley, H.N.; Hutchinson, J. The Flora of the Malay Peninsula Vol. 4; A. Asher & Co.: Utrecht, Holland, L. Reeve & Co.: London, UK, 1924.

3. Holttum, R.E. A Revised Flora of Malaya: Orchids of Malaya Vol. 1; 3rd ed. Government Printing Office: Singapore, 1964.

4. Seidenfaden, G.; Wood, J.J. The Orchids of Peninsular Malaysia and Singapore: A Revision of R.E. Holttum: Orchids of Malaya; Olsen and Olsen in association with The Kew Royal Botanic Gardens, and Singapore Botanic Gardens: Fredensborg, Denmark, 1992.

5. Chan, C.L.; Lamb, A.; Shim, P.S.; Wood, J.J. Orchids of Borneo Vol. 1 Introduction and a Selection of Species; The Sabah Society in Association with the Bentham—Moxon Trust, England: Kota Kinabalu, Malaysia, 1994.

6. Wood, J.J. Orchids of Borneo Vol. 3: Dendrobium, Dendrochilum and Others; The Sabah Society in Association with the Bentham Moxon Trust, England: Kota Kinabalu, Malaysia, 1997.

7. Wood, J.J. Orchids of Borneo Vol. 4; The Sabah Society in Association with the Bentham—Moxon Trust, England: Kota Kinabalu, Malaysia, 2003.

8. Beaman, T.E.; Wood, J.J.; Beaman, R.S.; Beaman, J.H. Orchids of Sarawak; Natural History Publications in Association with the Royal Botanic Gardens, Kew: Kota Kinabalu, Malaysia, 2001.

9. Comber, J.B. Orchids of Java; The Royal Botanic Garden’s Kew, Bentham Moxon Trust: London, UK, 1999.

10. Comber, J.B. Orchids of Sumatra; Natural History Publications in Association with the Royal Botanic Gardens, Kew and Botanic Gardens, Singapore: Kota Kinabalu, Malaysia, 2001.

11. Seidenfaden, G.; Smitinand, T. The Orchids of Thailand: A Preliminary List; The Siam Society: Bangkok, Thailand, 1959.

12. Schuiteman, A.; de Vogel, E.F. Orchid Genera of Thailand, Laos, Cambodia and Vietnam; Nationaal Herbarium Nederland: Leiden, The Netherlands, 2000.

13. Dockrill, A. Australian Indigenous Orchids Vol. 1. Spathoglottis (Orchidaceae) in Australia and the Pacific Islands; Cribb, P.J.; Tang, C.Z. Springer: Berlin/Heidelberg, Germany, 1969; 36, pp. 721-729.

14. Cribb, P.J.; Tang, C.Z. Spathoglottis (Orchidaceae) in Australia and the Pacific Islands. Kew Bull.; 1981; 36, pp. 721-729. [DOI: https://dx.doi.org/10.2307/4117913]

15. Hallê, N. Flore de la Nouvelle Calêdonie et Dêpendances and Orchidacées. Spathoglottis (Orchidaceae) in Australia and the Pacific Islands; Cribb, P.J.; Tang, C.Z. Springer: Berlin/Heidelberg, Germany, 1977; 36, pp. 721-729.

16. Ginibun, F.C.; Saad, M.R.M.; Hong, T.L.; Othman, R.Y.; Khalid, N.; Bhassu, S. Chloroplast DNA barcoding of Spathoglottis species for genetic conservation. Acta Holtic.; 2010; 878, pp. 453-459. [DOI: https://dx.doi.org/10.17660/ActaHortic.2010.878.58]

17. Nordin, F.A.; Saibeh, K.; Go, R.; Mangsor, K.N.A.; Othman, A.S. Molecular Phylogenetics of the Orchid Genus Spathoglottis (Orchidaceae: Collabieae) in Peninsular Malaysia and Borneo. Forests; 2022; 13, 2079. [DOI: https://dx.doi.org/10.3390/f13122079]

18. Thiers, B. Index Herbariorum: A Global Directory of Public Herbaria and Associated Staff. Available online: https://sweetgumnybg.org/science/ih (accessed on 14 March 2023).

19. Maddison, W.P.; Maddison, D.R. Mesquite: A Modular System for Evolutionary Analysis. Version 3.70 Available online: http://mesquiteproject.org (accessed on 10 December 2022).

20. Bateman, R.M.; Murphy, A.R.M.; Hollingsworth, P.M.; Hart, M.L.; Denholm, I.; Rudall, P.J. Molecular and Morphological Phylogenetics of the Digitate–Tubered Clade within Subtribe Orchidinae s.s. (Orchidaceae: Orchideae). Kew Bull.; 2018; 73, 54. [DOI: https://dx.doi.org/10.1007/s12225-018-9782-1]

21. Venhuis, C.; Venhuis, P.; Oostermeijer, J.G.B.; van Tienderen, P.H. Morphological Systematics of Serapias L. (Orchidaceae) in Southwest Europe. Plant Syst. Evol.; 2007; 265, pp. 165-177. [DOI: https://dx.doi.org/10.1007/s00606-007-0519-0]

22. Devey, D.S.; Bateman, R.M.; Fay, M.F.; Hawkins, J.A. Friends or Relatives? Phylogenetics and Species Delimitation in the Controversial European Orchid Genus Ophrys. Ann. Bot.; 2008; 101, pp. 385-402. [DOI: https://dx.doi.org/10.1093/aob/mcm299] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/18184645]