Understanding the ecosystem services provided by urban green spaces, in terms of their environmental, economic, and social benefits, is essential for a better management of area. Chulalongkorn University Centenary Park (CU 100) was established to mitigate the effects of climate change, especially flood prevention. This study focused on quantifying the ecosystem services provided by the trees in the park in terms of regulating and provisioning services. A publicly available tool, the i-Tree Eco international software, was used with data obtained from a local weather station as proxies to determine the accuracy of the analysis. Services, quantified in terms of monetary value, included avoided runoff, carbon storage, carbon sequestration, pollution removal, and timber price. The total monetary benefits, obtained from 697 trees (56 species, 49 genera, and 22 families), were estimated at USD 101,400. Of the total services, provisioning services contributed 75% to the total monetary value. Among all regulating services, the avoided runoff contributed about 60%, which was considered as the goal achieved by the park design. Azadirachta indica A. Juss (USD 518.75/tree⁻¹/year⁻¹), Shorea roxburghii G. Don (USD 417.17/tree⁻¹/year⁻¹) and Millettia leucantha Kurz (USD 414.87/tree⁻¹/year⁻¹) provided the greatest benefit, as indicated by a high value of provisioning services in terms of a high timber quality. These results can be used when planning the composition of trees to be planted in urban areas to increase both green spaces and maximize ecosystem services to improve the vitality of human well-being.

A revision of the genus Mitragyna (Rubiaceae) in Thailand is reported. Four species, i.e. M. diversifolia, M. hirsuta, M. rotundifolia, and M. speciosa are described in this taxonomic treatment. A summary of taxonomic history, detailed morphological descriptions, distributions, ecology, phenology, vernacular names, uses, IUCN conservation status, specimens examined, photographs and a key to the species are proposed. Two names are lectotypified: M. rotundifolia and M. speciosa.

We present the results of classifying plants at species level that can tolerate air pollution, provide cooling, and simultaneously survive and thrive in urban environments. For this purpose, we estimated the air pollution tolerance index (APTI) and anticipated performance index (API) of several species growing in a park located in central Bangkok, Thailand. The cooling effect was quantified by calculating the reduction in soil and air temperatures. Melaleuca quinquenervia (Cav.) S.T. Blake, Albizia saman (Jacq.) Merr., Chukrasia tabularis A. Juss. had the highest API score and were able to substantially reduce the temperature and were in a group of highly recommended species which also included other species like A. saman, C. tabularis, Tabebuia rosea (Bertol.) Bertero ex A. DC., Dalbergia cochinchinensis Pierre etc. Species from both evergreen and deciduous habitat were able to provide ambient cooling but were vulnerable to air pollution and included Elaeocarpus grandifloras Sm. and Bauhinia purpurea L. However, there were other species which had a high air pollution tolerance but failed to provide adequate cooling, such as Hopea odorata Roxb. and Millingtonia hortensis L.f. The results would be of interest to urban greenspace landscapers in such climates while selecting suitable species that can provide multiple ecosystem services ranging from air pollution tolerance to temperature reduction without reducing plant vitality.

In this paper, we present the morphology, taxonomy, anatomy, and palynology of Papaver somniferum. A detailed morphological description and illustrations of the species are provided, along with information about the identification, distribution, cultivation areas, habitats, pollinators, specimens examined, growing periods, phenology, etymology, vernacular name, and uses. The species can be characterized as a glabrous and glaucous herb with unlobed or pinnately lobed leaves, and an amplexicaul base; variations in color and morphological characteristics of petals; and white filaments, occasionally purple with a white basal part, broadened at the apical part. Two rings of discontinuous and widely spaced collateral vascular bundles are recognized in the transverse section of the stems. The shape of epidermal cells on the adaxial surface is polygonal, while that on the abaxial surface is polygonal or irregular. The anticlinal cell walls of the epidermal cells on the adaxial surface are straight or slightly curved, while those on the abaxial surface are straight, slightly curved, sinuate, or strongly sinuate. The stomata are anomocytic and are confined to the lower epidermis. The stomatal density is 54–199/mm² (with a mean of 89.29 ± 24.97). The mesophyll is not distinctly differentiated into palisade and spongy regions. Laticifers are found in the phloem areas of the stems and leaves. The pollen grains can be spheroidal or prolate spheroidal in shape, sometimes oblate spheroidal [polar axis (P) diameter/equatorial axis (E) diameter ratio = 0.99–1.12 (with a mean of 1.03 ± 0.03)]. The pollen aperture is tricolpate and the exine sculpturing is microechinate.

In this paper, we present the morphology, taxonomy, anatomy, and palynology of Arundo donax. A detailed morphological description and illustrations of the species are provided, along with information about the identification, distribution, the specimens examined, habitat and ecology, the International Union for Conservation of Nature (IUCN) conservation assessment, phenology, etymology, vernacular name, and uses. The species can be distinguished by its large, tall rhizomatous perennial reed; cauline leaves; an open, large, plumose panicle inflorescence; subequal glumes as long as the spikelets; glabrous rachilla; all bisexual florets; and a lemma with a straight awn and with long white hairs outside below the middle part. In this study, two names were lectotypified: Arundo bifaria and A. bengalensis, which are synonyms of A. donax. The culm internodes in the transverse section have numerous vascular bundles scattered in the ground tissue, and the parenchyma cells have significantly lignified cell walls. Vascular bundles are composed of phloem and xylem and are enclosed in a continuous sclerenchymatous bundle sheath. The chloroplasts in the transverse section of the leaf blades are found only in the mesophyll cells but are absent in the bundle sheath cells, which indicates that it is a C3 grass. The leaves have stomata on both surfaces and are confined to the intercostal zones. The stomata are typically paracytic, with two lateral subsidiary cells placed parallel to the guard cells. The stomatal density is higher on the abaxial surface [450–839/mm² (606.83 ± 72.71)] relative to the adaxial surface [286–587/mm² (441.27 ± 50.72)]. The pollen grains are spheroidal or subspheroidal [polar axis length/equatorial axis length ratio (P/E ratio) = 0.89–1.16 (1.02 ± 0.07)] with a single pore surrounded by a faint annulus, and the exine sculpturing is granular.