A taxonomic revision of Garcinia section Xanthochymus (Clusiaceae) in Thailand.

Garcinia section Xanthochymus (Clusiaceae) is revised for Thailand with four native species, i.e., G. dulcis, G. nervosa, G. prainiana, and G. xanthochymus. All species are described with updated morphological descriptions, illustrations, and an identification key, together with notes on distributions, distribution maps, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. Four taxa, G. andamanica, G. andamanica var. pubescens, G. cambodgiensis and G. vilersiana, are synonymized under G. dulcis, and two taxa, G. nervosa var. pubescens and G. spectabilis, are newly synonymized under G. nervosa. Nine names are lectotypified: G. dulcis and its associated synonyms (G. cambodgiensis and G. vilersiana), G. nervosa and its associated synonyms (G. andersonii, G. nervosa var. pubescens, and G. spectabilis), G. prainiana, and G. xanthochymus. All species have a conservation assessment of Least Concern (LC). The fruits of all species are edible and have a sour or sweet-sour taste.

A taxonomic revision of Thai Fernandoa Welw. ex Seem. (Bignoniaceae).

A taxonomic revision of Fernandoa Welw. ex Seem. (Bignoniaceae) in Thailand is presented. Two species, F.adenophylla (Wall. ex G. Don) Steenis and F.collignonii (Dop) Steenis, are enumerated with updated morphological descriptions, illustrations and a taxonomic identification key, together with notes on distributions, distribution maps, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. The collection of Wallich Cat. 6502A from Myanmar, Ava at G [G00133642] is designated here as the lectotype of F.adenophylla in a second step lectotypification. F.collignonii has a conservation status of Endangered [EN]. The leaf, stem, and wood anatomy and pollen morphology of F.adenophylla are also reported in this study.

A taxonomic revision of Cenchrus L. (Poaceae) in Thailand, with lectotypification of Pennisetummacrostachyum Benth.

A revision of the genus Cenchrus (Poaceae) in Thailand is reported. Seven species, i.e. C.brownii, C.ciliaris, C.clandestinus, C.echinatus, C.pedicellatus, C.purpureus and C.setosus are described in this taxonomic treatment. This genus is an exotic species and distributed throughout the floristic regions. All the species have become naturalised to Thailand as a weed and found growing in wastelands, open areas by the roadside, disturbed sites, the edge of rice fields and the edge of deciduous and evergreen forests at elevations between 0 and 2,650 m alt. Pennisetummacrostachyum, a synonym of Cenchruspurpureus is lectotypified. Detailed morphological descriptions, illustrations and a key to the species are presented, along with information on distributions, habitats, ecology, phenology, vernacular names and specimens examined.

Morphology, Taxonomy, Anatomy, and Palynology of the Opium Poppy (Papaver somniferum L.) Cultivation in Northern Thailand.

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.

Morphology, Taxonomy, Culm Internode and Leaf Anatomy, and Palynology of the Giant Reed (Arundo donax L.), Poaceae, Growing in Thailand.

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.

Variations in mitragynine content in the naturally growing Kratom (Mitragyna speciosa) population of Thailand.

We analyzed the content of mitragynine (MG) found in kratom leaves (Mitragyna speciosa) and the influence of different environmental conditions (air and soil variables) on the yield in various regions of Thailand. The content of MG in kratom leaves ranged from 7.5 - 26.6 mg g-1 of dry leaf weight. Canonical correspondence analysis showed that the most significant environmental variables affecting the MG content among the various regions were light intensity, relative humidity, soil volumetric water content (VW), soil pH, and calcium. This study is a first step towards providing information about environmental conditions suitable to maximize the quality and quantity of bioactive alkaloids in kratom. Future studies should focus on leaf collection and the post-harvest processes in order to assure the desired alkaloidal content in finished products, when produced under suitable environmental conditions identified in this study.

Dolichos kongkandae sp. nov. and lectotypification of D. fragrans (Leguminosae, Papilionoideae) from Asia.

Dolichos kongkandae is described as a new species from Asia and includes a line drawing, photographs and information on its distribution and ecology. The morphological differences between D. kongkandae and the morphologically similar D. tenuicaulis are highlighted and clarified. Additionally, a lectotype for D. fragrans is designated.