4. Discussion

Aniseia Choisy is a small genus of Convolvulaceae that is commonly recognized for its twining or climbing growth habit. Species in this genus are characterized by their funnel-shaped flowers and simple, undivided leaves. The plants are predominantly herbaceous. Globally, the genus is represented by only a few species, with Aniseia martinicensis (Jacq.) Choisy being the most widely recognized. In this study, A. martinicensis is the only species of the genus identified. It is an herbaceous vine, typically found as an aquatic or semi-aquatic plant.

Camonea Raf. is a genus comprising twining vines typically. Plants in this genus are often distinguished by their slender, twining stems, simple leaves, and brightly colored, funnel-shaped flowers. In the investigation conducted in Udon Thani Province, Camonea was represented by three species: C. bambusetorum (Kerr) A.R.Simões & Staples, C. kingii (Prain) A.R.Simões & Staples, and C. umbellata (L.) A.R.Simões & Staples, rendering it one of the more diverse genera in the region, following Ipomoea, Argyreia, and Merremia. Camonea and Merremia are both placed within the tribe Merremieae in the Convolvulaceae family. Camonea and Merremia are closely related but distinct lineages. In some classifications, species originally placed in Merremia have been moved to Camonea based on genetic data. They share similar floral structures, such as funnel-shaped flowers with radial symmetry, and often have white or yellow flowers. Their fruits are typically capsules with dehiscent seeds, similar to other genera in the family. Camonea is distinguished by more specific traits like flower morphology, especially in calyx and corolla structure, and the arrangement of stamens, while Merremia includes a broader diversity of species with some variation in leaf shape, floral size, and growth habit. All species within the genus often have beautifully colored flowers (yellow, yellowish, or white), and lush and green leaves, making them attractive for incorporation in gardens, landscapes, and as ornamental plants.

Decalobanthus Ooststr. is a genus consisting of twining or climbing vines. The genus is characterized by its large, heart-shaped leaves and conspicuous, funnel-shaped flowers. Its name reflects the distinctive 10-lobed (deca-lobate) structure of its floral parts in some species, though not all members exhibit this trait. In the Udon Thani Province study, only one species of Decalobanthus was recorded. One well-known species, Decalobanthus mammosus (Lour.) A.R.Simões & Staples (formerly Merremia mammosa), is recognized for its rapid growth and ability to cover large areas, which can sometimes make it invasive outside its native range.

Distimake Raf. is a genus consisting of twining vines. It was previously classified under the genus Ipomoea, but molecular studies have led to its reclassification as a separate genus. Distimake species are characterized by their climbing habit, simple leaves, and funnel-shaped flowers, which often resemble those of other genera in the family. In the investigation conducted in Udon Thani Province, three species of Distimake were recorded, including D. cissoides (Lam.) A.R.Simões & Staples, D. quinatus (R.Br.) A.R.Simões & Staples, and D. vitifolius (Burm.f.) Pisuttimarn & Petrongari. This highlights its modest representation in the region compared to more diverse genera like Ipomoea and Argyreia. Some species of Distimake are valued for their ornamental appeal, while others may have ecological roles as cover plants in natural habitats.

Evolvulus L. is a genus of herbaceous plants and small shrubs. Unlike many other members of the family that are twining vines, Evolvulus species are typically non-climbing and more compact in growth habit. Evolvulus species are distinguished by their small, often silvery or hairy leaves, and their delicate, funnel-shaped flowers, which are usually blue, white, or lavender. These flowers are smaller compared to those of genera like Ipomoea, but they still attract pollinators such as bees and butterflies. In the Udon Thani Province study, Evolvulus was represented by three species, including E. alsinoides (L.) L., E. glomeratus Nees & Mart., and E. nummularius (L.) L., making it moderately diverse compared to other genera in the region. One of the most well-known species is E. alsinoides, which has traditional medicinal uses, particularly in Ayurvedic medicine, and is believed to have cognitive and anti-inflammatory properties. Evolvulus species are also appreciated for their ornamental value, especially in rock gardens or as ground cover.

Hewittia Wight & Arn. is a small genus comprising herbaceous twining or climbing plants. The genus is relatively less diverse compared to others in the family and is characterized by its twining stems, heart-shaped or ovate leaves, and funnel-shaped flowers that are often pale yellow or white with darker centers. These plants are typically found growing along roadsides, in disturbed habitats, or in moist environments such as riverbanks and wetlands. Hewittia species are notable for their ability to rapidly colonize open or disturbed areas due to their twining nature. In the investigation of Convolvulaceae in Udon Thani Province, only one species of Hewittia (H. malabarica (L.) Suresh) was recorded, reflecting its limited diversity in the region. Its seeds, leaves, and roots have been reported to have various therapeutic properties, such as treating stomach issues and wounds.

Ipomoea L. is a highly diverse genus of plants known as morning glories. In the investigation of Convolvulaceae in Udon Thani Province, Ipomoea was noted as the most diverse genus with 17 species identified, including I. alba L., I. aquatica Forssk., I. asarifolia (Desr.) Roem. & Schult., I. batatas (L.) Lam., I. cairica (L.) Sweet, I. carnea Jacq., I. campanulata L., I. coptica (L.) Roth, I. holubii Baker, I. nil (L.) Roth, I. obscura (L.) Ker Gawl., I. pes-tigridis L., I. pileata Roxb., I. purpurata (L.) Roth, I. quamoclit L., I sagittifolia Burm.f., and I. triloba L. This diversity underscores its ecological importance and adaptability in the region. Notable species include Ipomoea aquatica, generally referred to as morning glory or Pak Bung, which is a rapidly growing aquatic or semi-aquatic plant, recognized for its consumable branches and foliage; it also has significant horticultural potential beyond its edible purposes. Ipomoea batatas or sweet potato is primarily cultivated for its edible tubers, but it also has significant horticultural potential. Sweet potatoes provide both ornamental value and nutritional benefits, rendering them ideal for use in edible landscaping schemes. Ipomoea purpurea, known as the common morning glory, is a rapidly growing and twining annual vine, popular for its distinctive trumpet-shaped blossoms (purple color), that is often planted for ornamental purposes. And Ipomoea carnea, referred to as bush morning glory or pink morning glory, is a rapidly growing perennial shrub, popular for its distinctive trumpet-shaped blossoms (pink color), that is also planted for ornamental purposes.

Jacquemontia Choisy is a genus consisting of twining vines and small shrubs. Plants in this genus are typically characterized by their delicate, twining stems, small, simple leaves, and attractive, often small, funnel- or bell-shaped flowers, usually blue, white, or purple. In this study, only one species was recorded, J. paniculata (Burm.f.) Hallier f., indicating its limited presence in the region.

Lepistemon Blume is a genus of plants generally characterized by their twining or climbing habit, with leaves and flowers typical of the family. In this study, Lepistemon binectarifer (Wall.) Kuntze is the only species identified.

Merremia Dennst. is another significant genus within the Convolvulaceae family, known for its twining vines and beautiful flowers. The flowers are large, showy, and funnel- or bell-shaped. They usually have five petals that are fused into a corolla. The color of the flowers varies widely, usually white, yellow, or pink. The flowers are usually solitary or in small clusters. In this study, Merremia was identified as the third most diverse genus, comprising five species: M. gemella (Burm.f.) Hallier f., M. hederacea (Burm.f.) Hallier f., M. hirta (L.) Merr., M. thorelii (Gagnep.) Staples, and M. verruculosa S.Y.Liu, demonstrating its adaptability and ecological significance in the area. All Merremia species in this study produce attractive trumpet-shaped flowers in vibrant colors such as yellow, white, and purple, making them ideal for ornamental use in gardens, trellises, and fences.

Operculina Silva is a genus typically consisting of climbing or trailing vines with a vigorous twining habit. The leaves are simple, large, and either heart-shaped or ovate, arranged alternately along the stems. Depending on environmental conditions, some species may exhibit lobed or slightly divided leaves. The flowers, one of the genus’s most striking features, are large, funnel-shaped, and commonly white or pale yellow. They consist of five fused petals forming a broad, bell-like corolla and are typically solitary or found in small clusters at the leaf axils. The genus name Operculina refers to the “lid-like” (operculate) structure that sometimes covers the fruit capsule. In Udon Thani Province, this genus is represented by two species: O. petaloidea (Choisy) Ooststr. and O. turpethum (L.) Silva Manso. Both species feature large, funnel-shaped flowers in shades of white, cream, or yellow, making them striking additions to gardens.

Porana Burm.f. is a genus known for its ornamental value; it features dense clusters of white flowers and a twining growth habit, making it a notable part of the local flora during its flowering season. In Udon Thani Province, Porana volubilis Burm.f. is the only species in this genus.

Rivea Choisy is a genus known for its climbing habit and ornamental flowers, making it a significant species in both natural and cultivated landscapes. The flowers are funnel-shaped with a broad, open corolla, and the fused petals form a tubular structure, which is typical of the family. They are usually white or pale in color, often fragrant, and bloom in clusters. In Udon Thani Province, Rivea ornata (Roxb.) Choisy is the only species present.

Xenostegia D.F.Austin & Staples is a genus represented in Udon Thani Province by a single species, Xenostegia tridentata (L.) D.F. Austin & Staples, a climbing herbaceous plant. The specific epithet “tridentata” refers to the tooth-like lobes at the base of the leaves; typically, the plant features three lobes on each side. The plant’s modest flowers and climbing habit make it a notable element of the local flora, particularly in areas with open or disturbed vegetation. The smooth edges of its leaves further enhance its delicate appearance.

The findings of this study provide valuable insights into the diversity and ecological roles of the Convolvulaceae family in Udon Thani Province. This region, with its varied species, serves as an important site for further research into the potential uses of these plants in both ornamental and practical applications. The unique distribution of species within the family and their diverse habitats suggest that Udon Thani’s Convolvulaceae flora could be a promising resource for both ecological conservation and the development of new horticultural practices. Future studies may explore the genetic relationships among these species, especially within genera like Camonea and Merremia, to better understand their evolutionary adaptations and potential for future cultivation.

This ecological flexibility underscores the importance of Convolvulaceae in habitat restoration and ecosystem management. Future studies should explore their specific ecological roles and adaptive strategies to better understand their contributions to ecosystem resilience and biodiversity conservation.

The Convolvulaceae family in Udon Thani Province is widely distributed, with 16 species across six genera recorded throughout the region. Most species were observed in multiple districts, while Argyreia lanceolata was uniquely found in Ban Phue, suggesting localized habitat preferences. High species diversity in districts such as Ban Phue, Ban Dung, Kumphawapi, Mueang, and Na Yung underscores their significance for Convolvulaceae biodiversity. This diversity is likely due to the varied ecological conditions, including wetlands, forests, and grasslands, which support a wide range of species. Differences in elevation, microclimates, and water availability further create distinct habitats, fostering species adaptation and specialization.

The aquatic areas and DDF show the highest similarity in species diversity, forming the closest cluster in the dendrogram. This strong connection can likely be explained by overlapping environmental conditions, such as seasonal water availability and comparable vegetation structures. Species adapted to periodic moisture are common in both settings, leading to significant overlap in species composition. These habitats may function as ecological buffers, supporting species that thrive under similar climatic and soil conditions.

The MDF exhibits a moderate similarity to the aquatic and DDF clusters, reflecting some shared species due to transitional ecological features. This forest type acts as a bridge, blending traits of both deciduous and aquatic environments. Species capable of tolerating variable levels of moisture and canopy cover are often found in these zones. However, MDF also has distinct ecological characteristics, such as increased competition for resources and specific soil properties, which contribute to its unique diversity.

Open areas and roadsides form a separate cluster that shows moderate similarity to forested habitats but diverges notably due to human influence. Activities such as road construction and land clearing create disturbed environments that favor resilient, fast-growing Convolvulaceae species. These areas are dominated by plants that can adapt to high levels of sunlight, compacted soils, and frequent disturbances, emphasizing the impact of human-modified environments on plant diversity.

Cultivated areas form the most distinct cluster, differing substantially from the natural habitats. This divergence is primarily due to the intentional selection of species in cultivation, often for aesthetic or economic purposes. As a result, cultivated areas typically have reduced species diversity, focusing on a limited number of plants with specific characteristics. The separation highlights how horticultural and horticultural practices alter natural ecosystems.

Interestingly, cultivated areas still show some similarity to aquatic habitats in species diversity. This connection arises from the conditions created in cultivation, such as irrigation systems that replicate wetland environments. Species like Ipomoea aquatica, which thrive in moist conditions, are often selected for cultivation due to their ornamental and horticultural value. These species bridge the gap between natural aquatic habitats and managed environments.

Aquatic habitats, with their wet and humid conditions, naturally support species adapted to creeping growth forms, waterlogged soils, and fluctuating environments. These traits also make such plants suitable for cultivated settings. In contrast, species from DDF and MDF tend to have stricter ecological requirements and are less suited to managed environments. This adaptability of aquatic species strengthens their association with cultivated areas.

The findings emphasize the importance of conserving natural habitats, as each contributes uniquely to the overall diversity of Convolvulaceae in Udon Thani Province. Aquatic areas, DDF, MDF, and roadside habitats each play a critical role in maintaining biodiversity. At the same time, encouraging sustainable and diverse cultivation practices can help reduce the ecological gap between natural and managed ecosystems. By preserving genetic and species diversity, these efforts can support ecological balance and contribute to long-term biodiversity management in the region.

Moderate agreement was observed in categories like the respiratory system (IAR = 0.82) and the obstetrics, gynecology, and urinary System (IAR = 0.82), suggesting some variability in informants’ plant choices for these conditions. The lower IAR of 0.81 in the antipyretic category further reflects the diversity of plant species used for fever treatment, possibly due to a wider range of options available. These findings emphasize the value of traditional ecological knowledge, with the need for continued research to document and preserve this knowledge for both health care and biodiversity conservation in Udon Thani Province.

The varying Cultural Importance (CI) values of Ipomoea species highlight their diverse roles as food sources within local communities. I. batatas exhibited the highest CI value of 1.93, reflecting its significant use as a food source, particularly for its edible tubers and leaves. In contrast, I. aquatica, with the lowest CI value (0.85), is utilized for its nutritional value but holds a relatively lesser cultural significance in the diet. Other species, such as I. obscura (CI = 1.45) and I. alba (CI = 1.35), are also consumed for their edible parts, but their cultural importance as food sources is more limited compared to I. batatas.

The varying Cultural Importance (CI) values of Convolvulaceae species underscore their diverse roles in traditional medicine within local communities. Ipomoea batatas exhibited the highest CI value of 1.93, reflecting its significant use in treating various ailments throughout its entire plant. In contrast, Hewittia malabarica, with a lower CI value of 0.50, contributes to traditional healing practices in more specific or localized contexts. Other species, such as I. alba (CI = 1.35) and I. obscura (CI = 1.45), are also valued for their medicinal properties, though their significance is more moderate compared to I. batatas.

The Convolvulaceae family plays a significant role in horticultural practices, with various species being cultivated for their multiple uses. These plants are fully utilized in farming, with each part of the plant serving different purposes. The Cultural Importance (CI) values of the species in this study indicate their varying roles in horticultural systems, ranging from high-value plants like Ipomoea batatas (CI = 1.93) to those with more localized horticultural roles such as Hewittia malabarica (CI = 0.50). Plants with higher CI values are integral to farming systems, contributing to soil health, crop rotation, and fodder production, while those with lower CI values often serve specialized or regional functions.

The utilization of entire plants in horticulture reflects their significance, with a majority being traded as whole plants. While some parts such as stems and leaves are also traded for medicinal or cultural uses, the inflorescences and roots are less commonly used. The varying parts of the plant are traded depending on their cultural, medicinal, or horticultural value, which supports local markets. The emphasis on whole plants highlights the comprehensive role these species play in both local economies and horticultural systems.

Economic values from these plants are diverse, with species like Ipomoea quamoclit generating substantial income for traders, reaching up to THB 85,500 annually. Conversely, species like Argyreia osyrensis offer lower returns, around THB 46,200. These variations in economic returns reflect not only the demand in specific markets but also the availability and utility of these plants in horticultural cultivation, medicine, and ornamentation. Despite differences in income, all these species contribute significantly to the livelihoods of traders, reinforcing their value in both economic and horticultural contexts.

The price data collected for the plants in this study also reveal significant insights into their economic value and potential for horticultural development. Plants with higher economic values are typically in greater demand, as reflected in their price fluctuations over the year. This trend suggests that such plants have high potential in horticulture, both as ornamental species and for other local uses. The price data indicate that plants with strong market demand can be cultivated more extensively to help balance supply and demand. This could benefit local farmers by improving their income opportunities while also ensuring a more sustainable supply of these species for the market.

Furthermore, the high economic value of these plants not only highlights their importance in local trade but also points to their potential for wider horticultural use. The balance between supply and demand could be achieved through strategic cultivation and promotion, ensuring that these species are not only preserved but also economically viable for long-term growth. Expanding cultivation efforts may also increase the diversity of plants available in the horticultural market, thus contributing to biodiversity conservation and enhancing the sustainability of local agricultural practices.

As such, it is essential to consider the economic implications of cultivating high-value plants. The cultivation of plants with high market value offers an opportunity to meet market needs, improve local livelihoods, and ensure that the plants continue to be available for future generations. Further studies on cultivation techniques, market trends, and sustainable practices will be crucial in realizing the full potential of these species in horticultural and economic development.