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Article

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

1
School of Biological Sciences, Universiti Sains Malaysia, Gelugor 11800, Penang, Malaysia
2
Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, Kota Samarahan 94300, Sarawak, Malaysia
3
Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
4
Faculty of Tropical Forestry, Jalan UMS, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia
*
Author to whom correspondence should be addressed.
Forests 2023, 14(5), 940; https://doi.org/10.3390/f14050940
Submission received: 21 March 2023 / Revised: 27 April 2023 / Accepted: 28 April 2023 / Published: 3 May 2023
(This article belongs to the Section Genetics and Molecular Biology)

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.

Funding

The study was funded by the USM Short Term Grant of assignment No. 304/PBIOLOGI/6315549 awarded to the corresponding author and the first author. All funders provided financial supports for the present work but did not contribute any additional role in in the research design, data collection and analysis and preparation 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.

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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 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.
Forests 14 00940 g001
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 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.
Forests 14 00940 g002
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 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.
Forests 14 00940 g003
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 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.
Forests 14 00940 g004
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 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.
Forests 14 00940 g005
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 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.
Forests 14 00940 g006
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.
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.
Forests 14 00940 g007
Table 1. Species list, collection localities and herbarium voucher numbers of the Spathoglottis species and outgroup used in this present work.
Table 1. Species list, collection localities and herbarium voucher numbers of the Spathoglottis species and outgroup used in this present work.
SpeciesCollection Number/Voucher NumberCollection LocalityAltitude (m)
  • Spathoglottis affinis de Vriese
FAN020/USMP12177Ton Nga Chang, Songkhla, Thailand100
2.
Spathoglottis affinis de Vriese
FAN023/USMP12178Fang District, Chiang Mai,
Thailand
1000
3.
Spathoglottis affinis de Vriese
FAN025/USMP12179Thailand–Myanmar Border1000
4.
Spathoglottis affinis de Vriese
FAN028/USMP12180Padang Tok Sheikh, G. Jerai,
Kedah
1131
5.
Spathoglottis aurea Lindl.
FAN006/USMP12181G. Ledang, Johor1200
6.
Spathoglottis aurea Lindl.
FAN008/USMP12182G. Lari Tembakau, Pahang1800
7.
Spathoglottis aurea Lindl.
FAN009/USMP12183G. Ulu Kali, Pahang1800
8.
Spathoglottis aurea Lindl.
FAN018/USMP12184G. Jerai, Kedah989
9.
Spathoglottis aurea Lindl.
FAN019/USMP12185Taman Rimba, G. Jerai,
Kedah
986
10.
Spathoglottis aurea Lindl.
FAN026/USMP12186Taman Rimba, G. Jerai,
Kedah
990
11.
Spathoglottis aurea Lindl.
FAN030/USMP12187Fraser’s Hill, Pahang1300
12.
Spathoglottis aurea Lindl.
FAN031/USMP12188Fraser’s Hill, Pahang1300
13.
Spathoglottis aurea Lindl.
FAN032/USMP12189Fraser’s Hill, Pahang1292
14.
Spathoglottis aurea Lindl.
FAN035/USMP12190Mile 49, Tanah Rata,
Cameron Highlands, Pahang
1400
15.
Spathoglottis aurea Lindl.
FAN036/USMP12191Mile 39, Tanah Rata,
Cameron Highlands, Pahang
1410
16.
Spathoglottis aurea Lindl.
FAN037/USMP12192G. Brinchang, Pahang1800
17.
Spathoglottis aurea Lindl.
FAN038/USMP12193G. Brinchang, Pahang1600
18.
Spathoglottis aurea Lindl.
FAN039/USMP12194G. Ulu Kali, Pahang1800
19.
Spathoglottis aurea Lindl.
FAN040/USMP12195G. Chin Chin, Pahang1800
20.
Spathoglottis aurea Lindl.
FAN041/USMP12196G. Brinchang, Pahang1800
21.
Spathoglottis aurea Lindl.
FAN044/USMP12197Padang Tok Sheikh, G. Jerai, Kedah1200
22.
Spathoglottis aurea Lindl.
FAN052/USMP12198G. Ulu Kali, Pahang1800
23.
Spathoglottis aurea Lindl.
FAN053/USMP12199G. Ulu Kali, Pahang1800
24.
Spathoglottis aurea Lindl.
FAN054/USMP12200Padang Tok Sheikh, G. Jerai, Kedah1200
25.
Spathoglottis aurea Lindl.
FAN057/USMP12201G. Bunga Buah, Selangor1400
26.
Spathoglottis aurea Lindl.
FAN058/USMP12202G. Bunga Buah, Selangor1400
27.
Spathoglottis aurea Lindl.
FAN059/USMP12203G. Bunga Buah, Selangor1400
28.
Spathoglottis aurea Lindl.
FAN060/USMP12204G. Bunga Buah, Selangor1400
29.
Spathoglottis aurea Lindl.
FAN069/USMP12205Tanah Rata, Cameron
Highlands, Pahang
1419
30.
Spathoglottis aurea Lindl.
FAN070/USMP12206Tanah Rata, Cameron
Highlands, Pahang
1419
31.
Spathoglottis aurea Lindl.
FAN071/USMP12207Huta Tinggi, Samarindo,
Samosir, North Sumatra
1400
32.
Spathoglottis aurea Lindl.
FAN098/USMP12208Tanah Rata, Cameron
Highlands, Pahang
1419
33.
Spathoglottis aurea Lindl.
FAN099/USMP12209Tanah Rata, Cameron
Highlands, Pahang
1419
34.
Spathoglottis eburnea Gagnep.
FAN022/USMP12210Fang District, Chiang Mai,
Thailand
1000
35.
Spathoglottis gracilis Rolfe ex Hook.f.
FAN094/USMP12211
KIP1266f
Kg. Liposu, Ranau, Sabah850
36.
Spathoglottis hardingiana
C.S.P.Parish & Rchb.f.
FAN016/USMP12212G. Baling, Kedah450
37.
Spathoglottis hardingiana
C.S.P.Parish & Rchb.f.
FAN056/USMP12213G. Pong, Kenering, Perak420
38.
Spathoglottis hardingiana
C.S.P.Parish & Rchb.f.
FAN105/USMP12214
K20160013
Tg. Asan, Pulau Timun,
Langkawi, Kedah
200
39.
Spathoglottis kimballiana
Hook.f.
FAN085/USMP12215Ranau, Sabah1300
40.
Spathoglottis kimballiana var.
angustifolia Ames
FAN076/USMP12216
THH13 6 99
Bidu Bidu FR, Telupid,
Sabah
71
41.
Spathoglottis kimballiana var.
angustifolia Ames
FAN077/USMP12217Bidu Bidu FR, Telupid,
Sabah
71
42.
Spathoglottis kimballiana var.
angustifolia Ames
FAN104/USMP12218Sungai Tongod, Telupid,
Sabah
60
43.
Spathoglottis kimballiana var. kimballiana
FAN067/USMP12219Mt. Kinabalu, Ranau, Sabah1300
44.
Spathoglottis kimballiana var. kimballiana
FAN092/USMP12220Kota Belud, Sabah800
45.
Spathoglottis kimballiana var. kimballiana
FAN093/USMP12221Pekan Nabalu, Ranau, Sabah1400
46.
Spathoglottis microchilina
Kraenzl.
FAN082/USMP12222Bundu Tuhan View Trail,
Kinabalu Park, Sabah
1601
47.
Spathoglottis microchilina
Kraenzl.
FAN083/USMP12223Kinabalu Park Research
Centre, Sabah
1599
48.
Spathoglottis microchilina
Kraenzl.
FAN084/USMP12224Kinabalu Park, Sabah850
49.
Spathoglottis microchilina
Kraenzl.
FAN086/USMP12225Mamut Copper Mine, Sabah1324
50.
Spathoglottis microchilina
Kraenzl.
FAN087/USMP12226Mamut Copper Mine, Sabah1485
51.
Spathoglottis microchilina
Kraenzl.
FAN088/USMP12227Mamut Copper Mine, Sabah1372
52.
Spathoglottis microchilina
Kraenzl.
FAN089/USMP12228Mamut Copper Mine, Sabah1405
53.
Spathoglottis microchilina
Kraenzl.
FAN091/USMP12229Sg. Lohan, Ranau, Sabah1375
54.
Spathoglottis microchilina
Kraenzl.
FAN095/USMP12230Tambunan, Sabah1000
55.
Spathoglottis microchilina
Kraenzl.
FAN096/USMP12231Ranau, Sabah850
56.
Spathoglottis parviflora
Kraenzl.
FAN061/USMP12232Wamena, Irian Jaya1679
57.
Spathoglottis plicata Blume
FAN001/USMP12233Peak of G. Ledang, Johor1000
58.
Spathoglottis plicata Blume
FAN002/USMP12234Peak of G. Ledang, Johor1100
59.
Spathoglottis plicata Blume
FAN003/USMP12235Penang Hill, Penang686
60.
Spathoglottis plicata Blume
FAN004/USMP12236Penang Hill, Penang735
61.
Spathoglottis plicata Blume
FAN005/USMP12237Sungai Rui, Kedah700
62.
Spathoglottis plicata Blume
FAN007/USMP12238K. Kubu Bharu, Selangor1392
63.
Spathoglottis plicata Blume
FAN010/USMP12239G. Ulu Kali, Pahang1800
64.
Spathoglottis plicata Blume
FAN011/USMP12240G. Jerai, Kedah980
65.
Spathoglottis plicata Blume
FAN012/USMP12241G. Jerai, Kedah1200
66.
Spathoglottis plicata Blume
FAN015/USMP12242Gerik, Perak1100
67.
Spathoglottis plicata Blume
FAN017/USMP12243Baling, Kedah650
68.
Spathoglottis plicata Blume
FAN021/USMP12244Peak of G. Jerai, Kedah1210
69.
Spathoglottis plicata Blume
FAN027/USMP12245G. Jerai, Kedah1000
70.
Spathoglottis plicata Blume
FAN029/USMP12246G. Jerai, Kedah1100
71.
Spathoglottis plicata Blume
FAN033/USMP12247Raub, Pahang1000
72.
Spathoglottis plicata Blume
FAN042/USMP12248Taiping Hill, Perak1200
73.
Spathoglottis plicata Blume
FAN043/USMP12249G. Jerai, Kedah926
74.
Spathoglottis plicata Blume
FAN046/USMP12250Taman Negara
Endau Rompin, Johor
78
75.
Spathoglottis plicata Blume
FAN047/USMP12251Taman Negara
Endau–Rompin, Johor
80
76.
Spathoglottis plicata Blume
FAN048/USMP12252Kota Tinggi Waterfall, Johor100
77.
Spathoglottis plicata Blume
FAN049/USMP12253Ladang Lok Heng, Kota
Tinggi, Johor
40
78.
Spathoglottis plicata Blume
FAN050/USMP12254Jalan Mersing, Kahang,
Johor
76
79.
Spathoglottis plicata Blume
FAN051/USMP12255Peak of G. Ledang, Johor1200
80.
Spathoglottis plicata Blume
FAN055/USMP12256G. Jerai, Kedah1200
81.
Spathoglottis plicata Blume
FAN063/USMP12257Lata Chemerong,
Terengganu
200
82.
Spathoglottis plicata Blume
FAN064/USMP12258Lata Chemerong,
Terengganu
70
83.
Spathoglottis plicata Blume
FAN065/USMP12259Lata Chemerong,
Terengganu
110
84.
Spathoglottis plicata Blume
FAN066/USMP12260Lata Chemerong,
Terengganu
70
85.
Spathoglottis plicata Blume
FAN072/USMP12261Tasik Kenyir, Terengganu30
86.
Spathoglottis plicata Blume
FAN073/USMP12262Mile 49, Tamparuli to Ranau Road, Sabah839
87.
Spathoglottis plicata Blume
FAN074/USMP12263Jalan Kaung to Ranau, Kota
Belud, Sabah
880
88.
Spathoglottis plicata Blume
FAN075/USMP12264Kg. Labong–Labong, Kota Belud, Sabah800
89.
Spathoglottis plicata Blume
FAN078/USMP12265Sg. Keripir, 45 miles to Tambunan, Sabah750
90.
Spathoglottis plicata Blume
FAN079/USMP12266Tambunan Road, Sabah757
91.
Spathoglottis plicata Blume
FAN080/USMP12267Tambunan Road, Sabah757
92.
Spathoglottis plicata Blume
FAN081/USMP12268Tambunan Road, Sabah468
93.
Spathoglottis plicata Blume
FAN090/USMP12269Mamut Copper Mine, Sabah1405
94.
Spathoglottis plicata Blume
FAN097/USMP12270Hulu Telom, Pahang708
95.
Spathoglottis plicata Blume
FAN100/USMP12271Semengoh Nature Reserve, Sarawak46
96.
Spathoglottis plicata Blume
FAN101/USMP12272Semengoh Nature Reserve, Sarawak50
97.
Spathoglottis plicata Blume
FAN102/USMP12273Bario, Sarawak1065
98.
Spathoglottis plicata Blume
FAN103/USMP12274Long Baleh, Sarawak944
99.
Spathoglottis plicata var. alba
FAN034/USMP12275Lata Tembakah, Terengganu36
100.
Spathoglottis plicata var.
alba
FAN045/USMP12276Lata Tembakah, Terengganu36
101.
Spathoglottis pubescens Lindl.
FAN068/USMP12277Fang District, Chiang Mai, Thailand800
102.
Spathoglottis unguiculata
(Labill.) Rchb.f.
FAN024/USMP12278Isle of Pines, New Caledonia200
103.
Spathoglottis vanvuurenii
J.J.Sm.
FAN062/USMP12279Seram, Maluku Island834
104.
Tainia paucifolia (Breda) J.J.Sm.
FAN597/USMP12280Taman Rimba Kenong, Pahang20 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.
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.
CharacterCharacter 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.
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.
SpeciesCharacters and Character States
123456789101112131415161718192021
S. affinis012011011010000100001
S. aurea100000011001012023311
S. eburnea012211101000011002111
S. gracilis111100010101012003100
S. hardingiana010011101112101112201
S. kimballiana110010002001012003310
S. kimballiana var.
angustifolia
110011001010000100110
S. kimballiana var.
kimballiana
110011001010000101110
S. microchilina100000001001012003310
S. parviflora110010013001012003310
S. plicata100010003001012003310
S. plicata var. alba100010003001012003310
S. pubescens012211101110000000010
S. unguiculata110010002001012103300
S. vanvuurenii100010003001012003310
Tainia paucifolia101110100100003003211
222324252627282930313233343536373839404142
S. affinis100101110011020000100
S. aurea011211001111120113101
S. eburnea100101110011000000100
S. gracilis011011000111220001000
S. hardingiana100101110013031002010
S. kimballiana011000000111220000001
222324252627282930313233343536373839404142
S. kimballiana var.
angustifolia
011000000111220001001
S. kimballiana var.
kimballiana
011000000111120000001
S. microchilina011010001111110113001
S. parviflora011101110113230200000
S. plicata011101111113130210000
S. plicata var. alba011100110110030000110
S. pubescens100101110011030000110
S. unguiculata011101110113030000001
S. vanvuurenii011101110112130010000
Tainia paucifolia0011011111231300?0021
434445464748495051525354555657585960616263
S. affinis200010101310102200000
S. aurea002000001001003000010
S. eburnea010010501110001200010
S. gracilis000010111310001201001
S. hardingiana021011001001100210010
S. kimballiana000010111310004201100
S. kimballiana var.
angustifolia
100000411112004201110
S. kimballiana var.
kimballiana
100010110310002200000
S. microchilina100010001001002000010
S. parviflora100010301110013100010
S. plicata100000101310001200000
S. plicata var. alba101010101310111100000
S. pubescens111110201210002200010
S. unguiculata120000200110112100010
S. vanvuurenii100010101310002200010
Tainia paucifolia123202212112002010010
646566676869707172737475
S. affinis010201211101
S. aurea011000011002
S. eburnea013011211101
S. gracilis010001211003
S. hardingiana104001110111
S. kimballiana010001211003
S. kimballiana var.
angustifolia
010000211023
S. kimballiana var.
kimballiana
010000211003
S. microchilina013001011003
S. parviflora104011211000
S. plicata012200211010
S. plicata var. alba012210211020
S. pubescens102011211111
S. unguiculata104111201010
S. vanvuurenii010001211000
Tainia paucifolia2?????011020
Table 4. Phylogenetic relationships between species of Spathoglottis compared from morphological data and molecular data.
Table 4. Phylogenetic relationships between species of Spathoglottis compared from morphological data and molecular data.
Relationships from Morphological DataRelationships 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.
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Nordin, F.A.; Raffi, A.; Go, R.; Seok Yien Yong, C.; Saibeh, K.; Othman, A.S. Morphological Systematics of Spathoglottis Blume (Orchidaceae: Collabieae) in Peninsular Malaysia and Borneo. Forests 2023, 14, 940. https://doi.org/10.3390/f14050940

AMA Style

Nordin FA, Raffi A, Go R, Seok Yien Yong C, Saibeh K, Othman AS. Morphological Systematics of Spathoglottis Blume (Orchidaceae: Collabieae) in Peninsular Malaysia and Borneo. Forests. 2023; 14(5):940. https://doi.org/10.3390/f14050940

Chicago/Turabian Style

Nordin, Farah Alia, Akmal Raffi, Rusea Go, Christina Seok Yien Yong, Kartini Saibeh, and Ahmad Sofiman Othman. 2023. "Morphological Systematics of Spathoglottis Blume (Orchidaceae: Collabieae) in Peninsular Malaysia and Borneo" Forests 14, no. 5: 940. https://doi.org/10.3390/f14050940

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