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A new route to oxide synthesis on semiconductors, via optimally oxidized metal superstructures, is established. The result is a radical transformation of the oxide film from a polycrystal to a single crystal.

2D magnets have recently emerged as a host for unconventional phases and related phenomena. An intrinsic exchange bias effect accompanies the dimensional crossover indicating coexisting magnetic orders.

Light-induced magnetization response unfolding on a temporal scale down to femtoseconds presents a way to convey information via spin manipulation.

The inherent malleability of 2D magnetism provides access to unconventional quantum phases, in particular those with coexisting magnetic orders. Incidentally, in a number of materials, the magnetic state in the bulk undergoes a fundamental change when the system is pushed to the monolayer limit. Therefore, a competition of magnetic states can be expected in the crossover region. Here, an exchange bias state is observed at the crossover from 3D antiferromagnetism to 2D ferromagnetism driven by the number of monolayers in the metalloxene GdSi

Bulbophyllum phanquyetii, from Lai Chau Province was found and described as a new species for science. The new species looks similar to B. guttulatum and B. umbellatum but differs in the connate upper margin of lateral sepals, verruculose sepals and petals, and triangular stelidia. In addition, B. tianguii found in Ha Giang Province is firstly recorded for the orchid flora of Vietnam.

Relevance. Unreasonably high pollutant emissions into the environment, the ill-considered use of natural resources and the raw material orientation of exports have led to an environmental crisis in many areas.Purpose. To study the effect of ecotoxicants on the histochemical structure of tooth and jaw germs in laboratory rats and ways to reduce this effect during perinatal prevention.Materials and methods. The experiment included 50 white outbred rats weighing 180-250 grams. All animals formed five groups: 1 control and four experimental. All animals of the experimental groups were subject to gasoline and formaldehyde vapours inhalation exposure; Group 1 (control) was subject to only poisoning with ecotoxicants, Group 2 had peptinsorbent associated with ecotoxicant poisoning, Group 3 – a membrane protector – magnolia vine, Group 4 – beet, Group 5 – peptinsorbent, membrane protector and beet.Results. The histochemical study of tissues around the tooth germs in pup rats born from the control group rats after poisoning with ecotoxicants revealed an increased mast cell number in the tissues compared to intact rats. The samples of Group 2 rats showed that the mast cell number and characteristics practically did not differ from the control group after ecotoxicant poisoning. In the rats of Group 3, the number of mast cells was slightly lower than in the control group. In Group 4, the number of mast cells was not significantly lower than in the control group. In the rats of Group 5, the number of mast cells significantly decreased compared to the control and other experimental groups.Conclusion. Thus, during subchronic poisoning of pregnant female rats with ecotoxicants, the number of mast cells in the gingiva of rat pups increases against the background of microcirculation disorders. The number of mast cells in gingiva significantly decreases and approaches the normal values in rat pups after feeding pregnant rats with the combined mixture (peptinsorbent+membrane protector Schisandra+beetroot).

The paper provides a short annotated taxonomic review of Bulbopyllum sect. Tripudianthes from the flora of Vietnam along with a species-level key for identification. The section in Vietnam includes five species, one of which is a new species for science and described under the name, B. viridipallidum. The new species was found recently from Kon Tum Province of southern Vietnam. It is similar to B. kanburiense, B. khaoyaiense, and B. wallichii, but clearly differs by having pale greenish lateral sepals and two rounded calli at the lip base fused distally into a single prominent longitudinal keel; this is inflated at the lip apex into prominent half ovoid callus. In addition, we confirm the occurrence of B. wallichii in the flora of Vietnam. The taxonomic description, data on distribution, ecology, phenology, proposed conservation status, taxonomic notes, and the comparison of the new species with morphologically similar species are reported.

A new species of Bulbophyllum (Orchidaceae), named as B. sondangii discovered in Da Lat Plateau (Da Lat Town area, Lam Dong Province of southern Vietnam) is described and illustrated. The new species is similar to B. andersonii and B. trongsaense, but can be distinguished by a short seta at the apex of median sepal and petals; almost entire margin of petals except the fimbriate apex; lip with auricles at base; and stelidia apiculate at apex. The paper presents the taxonomical description, data on distribution, ecology, phenology and conservation status, as well as notes and the comparison of the newly described plant with morphologically similar species.

A species, new to science, is described from Son La province, Vietnam. The new species is similar to B. yongtaiense, B. layae and B. sridithii in the hairy lip at base but clearly differs by the papillose margin and inner surface of dorsal sepal and petals, lip without mid keel and dense hairs on lateral keels, stelidia 2 times longer than 3 similar species.

The paper presents a taxonomic review of Bulbophyllum section Rhytionanthos for the flora of Vietnam and provides the key for its species’ identification. A new species, B. truongtamii and a new variety, B. taeniophyllum var. denticulatoalatum are described for science. Bulbophyllum nodosum is reported for the first time from the country. Bulbophyllum strigosum, described 20 years ago based on cultivated plant of uncertain origin was rediscovered in NE Vietnam. For this species, location and detailed description are reported. Analytical photos, data on phenology, ecology, and distribution are presented for all studied species. The morphological comparison table of the new species, new variety and newly recorded species segregating them from similar species are presented.

Gastrochilus pankajkumarii, found in the Central Highlands of Vietnam, is described as a new species for science. The protologue includes color analytical photos of the new species and data on phenology, ecology, and distribution. Morphological comparisons with similar species are presented.

2D magnetic materials are at the forefront of research on fundamentals of magnetism; they exhibit unconventional phases and properties controlled by external stimuli. 2D magnets offer a solution to the problem of miniaturization of spintronic devices. A technological target of materials science is to find suitable magnetic materials and scale their thickness down as much as possible, a single monolayer being a natural limit. However, magnetism does not halt at one monolayer - it may persist beyond this boundary, to sparse but regular lattices of magnetic atoms. Here, we report 2D magnetic phases of Eu on the Ge(110) surface. We synthesized two submonolayer structures Eu/Ge(110) employing molecular beam epitaxy. The phases, identified by electron diffraction, differ in the surface density of Eu atoms. At low temperature, they exhibit magnetic ordering with magnetic moments lying in-plane. Strong dependence of the effective magnetic transition temperature on weak magnetic fields points at the 2D nature of the observed magnetism. The results are set against those on the Eu/Si system. The study of Eu/Ge(110) magnets demonstrates that a variety of substrates of different structure and symmetry can host submonolayer 2D magnetic phases, suggesting the phenomenon to be rather general.

This paper continues the publication of new data obtained during field studies in remote and poorly studied regions of Laos in 2017–2022. It provides descriptions of one species and one variety new for science (Oberonia sinuata Aver. and Cleisostoma fuerstenbergianum Kraenzl. var. minutiflorum Aver.) and reports five species newly recorded in the flora of Laos (Liparis balansae Gagnep., Oberonia trochopetala Gagnep., Paphiopedilum coccineum Perner et R. Herrm., P. sukhakulii Schoser et Senghas, and Uncifera dalatensis (Guillaumin) Seidenf. et Smitinand). Appropriate citations of regional literature, color illustrations, data on types and distribution, descriptions and etymology (for new taxa), as well as notes on taxonomy and related species are provided for the studied taxa.

The electron state in intercalated silicene stacks evolves from chiral anomalies in multiple layers to 3 types of localization in a few monolayers.

AVERYANOV, LEONID V., THAI, TRAN HUY, NGUYEN, VAN CANH, TRUONG, BA VUONG, MAISAK, TATIANA V., DOAN, NGA THI, NGUYEN, KHANG SINH (2023): Averyanov L.V. et al.: (2022): New orchids in the flora of Vietnam (Orchidaceae, Aeridinae). Phytotaxa 572 (1): 043-060. Phytotaxa 579 (1): 70-70, DOI: https://doi.org/10.11646/phytotaxa.579.1.9, URL: http://dx.doi.org/10.11646/phytotaxa.579.1.9

Common variable immunodeficiency (CVID) is a rare immunodeficiency, the classic manifestation being recurrent infections. Other lesions are often found in CVID patients, such as malignant neoplasms, autoimmune conditions caused by abnormal cellular immunity, in addition to infectious complications. Usually, the pathological process involves the lungs. This article presents a clinical case of a patient with CVID complicated by granulomatous lymphocytic interstitial lung disease.

In the last years several studies have shown that mesenchymal stem cells (MSCs) are able to reduce the systemic inflammatory response and mortality in experimental models of sepsis. As recently found, the surface of MSCs have receptors for erythropoietin (EPO). So we hypothesized that the introduction of EPO together with MSCs may enhance their effect and improve the results of sepsis treatment. Aim: То evaluate morphologic and immunologic effects of combined treatment with EPO and MSC in an experimental LPS sepsis model in rats. Methods: 50 Wistar rats were randomized into 5 groups: Group 1 - the healthy controls, Groups 2-5 were intraperitoneally introduced bacterial LPS 20 mg/kg. Two hours after LPS injection animals received the following intravenous treatments: Group 3 - 4xl05 allogeneic MSCs, Group 4 - 8.5 pg of recombinant EPO-beta, Group 5 - MSCs and EPO in the same doses. Surviving animals were euthanased on the 4th day. The morphological study of the liver, spleen, thymus, lungs, kidney tissues was performed. We analyzed the tissue changes, white blood cells count and serum level of IL-l, IL-2, IL-6, TNF-. Results: Mortality in LPS groups did not differ. The highest white blood cells count was found in the group of combined treatment EPO+MSCs (8.15x106 cells/ml) compared with controls (2,15x10s cells/ml) and LPS controls (6,52x10s cells/ml). There were no differences in levels of TNF-, IL-2 and IL-6 between the groups, but serum IL-1 level in groups 2 and 4 was significantly higher than in treated with MSCs and MSCc + EPO animals. Histologically in the group 5 we observed significantly less leukocyte lung interalveolar septal infiltration and kidney tubular dystrophy. The most significant differences in group LPS + EPO were found in the lymphoid tissue - considerable hyperplasia of spleen white pulp and thymus cortex, whereas in the other groups different degrees of atrophy of the corresponding zones were noted. Conclusions: Combined treatment with EPO and MSCs can reduce acute lung injury and kidney damage, cause hyperplasia of lymphoid tissue and enhance the immune response more than separate treatment in an experimental model of sepsis in rats.

Hemiboea chanii, a new species of Gesneriaceae from Ha Giang Province, northern Vietnam, is here described and illustrated. It has many branched stems, diamond-shaped involucre with two cirrose opposite apices, a pink corolla, red spotted inside, and a flowering time in January-February. Among congeners with an externally hairy corolla, this new species is morphologically close to H. crystallina and H. sinovietnamica. Diagnostic discriminative characters in all mentioned species are discussed. The conservation status of this species is considered to be “Critically endangered” (CR) according to the IUCN Red List Categories and Criteria.

This paper presents new data on the orchid diversity of Vietnam obtained in 2020–2022. It comprises descriptions of two species new for science (Cleisostoma tatonii and Sarcoglyphis hiepii) and descriptions of four species new for the flora of Vietnam (Cleisostoma aspersum, Gastrochilus nanus, Micropera mannii and Trichoglottis ramosa). All species found for the first time in Vietnam are morphologically slightly different from the individuals in their main distribution area. Data on accepted names, main synonyms, etymology (for newly described species), morphological description, studied specimens, ecology, phenology and distribution, conservation status assessment, brief taxonomic notes, and illustrations are provided for each species listed.

Bulbophyllum sect. Brachyantha Reichenbach (1861: 264). Type: B. umbellatum Lindley (1830: 56)., Published as part of Dang, Minh Quan, V. Averyanov, Leonid, Dang, Van Son, Maisak, Tatiana, Bui, Van Huong, Tu, Bao Ngan, Nguyen, Van Canh & Truong, Ba Vuong, 2022, A new species, Bulbophyllum phanquyetii and a new national record of B. tianguii (Orchidaceae) from the limestone area of northern Vietnam, pp. 227-232 in Phytotaxa 566 (2) on page 228, DOI: 10.11646/phytotaxa.566.2.7, http://zenodo.org/record/7119218, {"references":["Lindley, J. (1830) The genera and species of orchidaceous plants. Ridgeways, London, 553 pp. https: // doi. org / 10.5962 / bhl. title. 499"]}

Bulbophyllum phanquyetii Vuong, Aver. & V.S.Dang sp. nov. (Fig. 1) Type:— VIETNAM. Herbarium specimen is prepared from plant cultivated in private Phan Trong Quyet garden in Lam Dong Province on 21 March 2022 by Truong Ba Vuong, Bui Van Huong, Dang Van Son, Phan Trong Quyet, BV 1349 (holotype: VNM 00069948, analytical photos: LE 01123075 https://en.herbariumle.ru/?t=occ&id=132346), originated from Lai Chau Province, Sin Ho District, Xa De Phin Commune. Etymology:—The species name honors Mr. Phan Trong Quyet, who cultivated the plant and provided material for the description and type specimen preparation. Description:—Branched epiphyte. Pseudobulbs 1-leaved, yellowish-green, ovoid to narrowly ovoid, 3–3.5 cm high, young pseudobulbs outside with fibrous sheath remnants and 2 thin brown narrowly elliptic bracts, 1.4–1.6 cm long, ca. 9 mm wide, old pseudobulbs clearly 4-angles, distant on 1–2.7 cm on creeping brown rhizome ca. 4 mm in diameter covered by brown to dark brown bracts. Leaves petiolate; petiole 1–1.3 cm long; leaf blade oblong-lanceolate, slightly arching, grassy green adaxially, pale green abaxially, 6–18.5 cm long, 2.9–3.5 cm wide, apex rounded, slightly retuse. Inflorescence erect; scape from the base of pseudobulbs, erect, 10–11 cm long, yellowish-green with many small purple streaks and marks, at base with 2 overlapping tubular bracts, above with a single tubular bract, ca. 1 cm long, apex obtuse to subacute; rachis very short, ca. 1.5 mm long, with 6 flowers in subumbellate raceme; floral bracts narrowly ovate, 3–8 mm long, acute to shortly acuminate; pedicel and ovary ca. 2 cm long, pedicel greenishyellow, with many small purple marks, ovary green, sparely verruculose. Flowers opening simultaneously, with light unpleasant smell; sepals and petals pale yellow, with many small red lines; lip adaxially purple, with many dark purple spots in the middle, abaxially almost white with many purple dots; column pale yellow with many small redpurple dots. Median sepal broadly ovate to almost circular, 7–8 mm long, 6–6.5 mm wide, concave, apex rounded, mucronate, forward directed, adaxially verruculose in apical half. Lateral sepals obliquely triangular, 1.5–1.6 cm long, 5–6 mm wide, acute, adaxially densely verruculose in apical half and sparely verruculose near the base; twisted at middle; upper margin connate in middle part, free at base and apex; lower margin free. Petals oblique, narrowly ovate to ovate, 5–6 mm long, 3–4 mm wide, apex truncate with small seta, adaxially in apical half densely verruculose. Lip simple, fleshy, slightly recurved, 6–7 mm long, 2–2.5 mm wide, apex truncate or rounded, adaxially sparsely verruculose, glossy, shallowly grooved; abaxially with 2 low keels. Column short and stout, 2–3 mm tall, on sides with low half round wings; column foot ca. 5 mm long, upcurved; stelidia triangular, ca. 1 mm long, somewhat oblique, pointing forward, apex blunt; stigma concave, narrowly obovate, ca. 1.5 mm long; anther cap yellow, rectangular, ca. 1.2 mm long and wide, glossy in middle, frontal margin ciliate; pollinaria 2, each with 2 unequal half-globular pollinia. Fruits not seen. Habitat and phenology:—Branch epiphyte in broad-leaved evergreen montane forest at elevation of 1400 m a.s.l. Flowers in March–April. Distribution:—Known from the type locality only. Proposed conservation status:—According to presently available data, the new species is very rare and found only at one site. More field studies are necessary for its conservation assessment. In view of lack of current data and in accordance with IUCN criteria (IUCN, 2019), the species should be assessed as “Data Deficient” (DD). Notes:—The new species belongs to the group of similar species including B. chyrmangensis, B. guttulatum, B. putaoense, B. salweenensis, and B. umbellatum. The detailed morphological comparison of these species and our plant is presented on Table 1. According to the concept of Vermeulen et al. (2014), all mentioned species belong to B. sect. Brachyantha characterized by subumbellate inflorescence and commonly entire margin of sepals and petals. At the same time, B. chyrmanensis has somewhat isolated position in this group having erose or dentate margin of median sepal and petals. According to this character, this species should be rather placed to B. sect. Cirrhopetaloides than Brachyantha. In the other hands the other morphological features show similarity to the B. umbellatum group, which belongs to B. sect. Brachyantha. As the result, this species in its morphology demonstrates obviously intermediate position between sections Cirrhopetaloides and Brachyantha. Plant data based on Seidenfaden (1973), Chen & Vermeulen (2009), Verma et al. (2015), Zhou & Jin (2015), and Liu et al. (2017). Additional specimens examined: Bulbophyllum umbellatum: — VIETNAM, plant cultivated in Ho Chi Minh City, originated from Lam Dong Province, 31 December, 2018, Truong Ba Vuong, BV 537 (VNM); VIETNAM, Lam Dong Province, 21 January, 2019, Truong Ba Vuong, Ngo Quang Dang BV 538 (VNM); VIETNAM, Lam Dong Province, Lac Duong District, 1997, Averyanov & Nguyen Quoc Binh, VH 3838 (LE 01057984, https://en.herbariumle. ru/?t=occ&id=8484); VIETNAM, Lam Dong Province, Lac Duong District, 1997, Averyanov, Nguyen Quoc Binh, Nong Van Duy, Phan Ke Loc, VH 2771 (LE 01057983, https://en.herbariumle.ru/?t=occ&id=8483); VIETNAM, Dak Lak Province, Chu Yang Sin Mt., 2011, Petrov, A., s.n. (LE 01057977, https://en.herbariumle.ru/?t=occ&id=8478); VIETNAM, Ha Giang Province, Quan Ba District, Bat Dai Son Mountains, 2019, Averyanov et al., VR 321 (LE 01048452, https://en.herbariumle.ru/?t=occ&id=1842). Bulbophyllum guttulatum:— LAOS, Vientiane Province, Pa Chao Mountain, 2017, Averyanov et al. LA-VN 1743, (LE 01087488, https://en.herbariumle.ru/?t=occ&id=40533); INDIA, Sikkim Himalaya, 1892, R. Pantling, 53 (MNHN-P-P00348039, http://coldb.mnhn.fr/catalognumber/mnhn/ p/p00348039);— INDIA, Darjeeling W. Griffith, 5180 (MNHN-P-P00348038, http://coldb.mnhn.fr/catalognumber/ mnhn/p/p00348038); INDIA. Sikkim Himalaya, 1899, R. Pantling, 53 (L.1484588, https://data.biodiversitydata. nl/naturalis/specimen/ L.1484588); NEPAL, 1819, N. Wallich, s.n. (isotype, BM000516909, https://data.nhm.ac.uk/ object/c860a835-66fc-452c-a09e-fbac1b9ae651)., Published as part of Dang, Minh Quan, V. Averyanov, Leonid, Dang, Van Son, Maisak, Tatiana, Bui, Van Huong, Tu, Bao Ngan, Nguyen, Van Canh & Truong, Ba Vuong, 2022, A new species, Bulbophyllum phanquyetii and a new national record of B. tianguii (Orchidaceae) from the limestone area of northern Vietnam, pp. 227-232 in Phytotaxa 566 (2) on pages 228-230, DOI: 10.11646/phytotaxa.566.2.7, http://zenodo.org/record/7119218, {"references":["IUCN Standards and Petitions Subcommittee. (2019) Guidelines for using the IUCN Red List categories and criteria. Version 14. Available from: https: // cmsdocs. s 3. amazonaws. com / RedListGuidelines. pdf (accessed 28 March 2022).","Vermeulen, J. J., Fischer, G., Smidt, E. de C., Stern, W. L, Pridgeon, A. M., Veitch, C., Siederm, A., Vugt, R. van & Gravendeel, B. (2014) Bulbophyllum. In: Pridgeon, A. M., Cribb, P. J., Chase, M. W. & Ramussen, F. N. (eds.) Genera Orchidacearum. Vol. 6, Epidendroideae. Pt. 3. Oxford University Press. pp. 4 - 51.","Seidenfaden, G. (1973) Notes on Cirrhopetalum Lindl. Dansk Botanisk Arkiv 29 (1): 1 - 260.","Chen, X. & Vermeulen, J. J. (2009) Bulbophyllum. In: Wu, Z. Y., Raven, P. H. & Hong, D. Y. (Eds.) Flora of China. Vol. 25. (Orchidaceae). Science Press, Beijing and Missouri Botanical Garden Press, St. Louis, pp. 404 - 440.","Verma, D., Lavania, S. & Singh, S. K. (2015) Bulbophyllum chyrmangensis (Orchidaceae: Epidendroideae), a new species from Meghalaya, Northeast India. Phytotaxa 195 (1): 94 - 97. https: // doi. org / 10.11646 / phytotaxa. 195.1.9","Zhou, T. T. & Jin, X. H. (2015) Bulbophyllum salweenensis (Orchidaceae; Epidendroideae; Malaxideae), a new species from Yunnan, China. Phytotaxa 234 (1): 95 - 97. https: // doi. org / 10.11646 / phytotaxa. 234.1.8","Liu, Q., Zhou, S. S., Li, R., Zhang, M. X., Zyaw, M., Lone, S. & Quan, R. C. (2017) Bulbophyllum putaoensis (Orchidaceae: Epidendroideae; Malaxideae), a new species from Kachin State, Myanmar. Phytotaxa 305 (1): 57 - 60. https: // doi. org / 10.11646 / phytotaxa. 305.1.9"]}

Bulbophyllum tianguii K.Y.Lang & D.Luo, J. Wuhan Bot. Res. 25: 558 (2007); Chen & Vermeulen, 2009, Flora of China 25: 424; Zhou et al., Updated Checklist Orch. China: 22 (2016) (Fig. 2) Type:— CHINA. Guangxi, Leye, Huapingzen, Yachang orchid nature reserve, on the rock, alt. 970 m a.s.l., 2007, Liu S. Y . & Deng Z. H. 010 (PE 01432249, PE 01432250, PE 01432251). Note. The discovery of this species in northern Vietnam is quite expected, due to the area of Ha Giang Province has similar habitat conditions observed in Guangxi where the species was firstly found. In the original description the authors did not mention the triangular acute teeth on the upper margin of stelidia, which are clearly seen in Vietnamese plants. Species examined: — VIETNAM, Ha Giang Province, Dong Van District, lithophyte on mossy rocks at about 1400 m a.s.l. 24 March 2022 Truong Ba Vuong, Bui Van Huong, BV 1350 (VNM 00069943), 24 March 2022 Truong Ba Vuong, Bui Van Huong, BV 1352 (VNM 00069939), 24 March 2022 Truong Ba Vuong, Bui Van Huong, BV 1353 (VNM 00069940), 24 March 2022 Truong Ba Vuong, Nguyen Van Canh, BV 1351 (VNM 00069944). Analytical photos: — VIETNAM, Ha Giang Province, Dong Van District, lithophyte on mossy rocks at about 1400 m a.s.l. 24 March 2022 Truong Ba Vuong, Bui Van Huong, BV 1350 (VNM 00069943), 24 March 2022 (VNM 00069944) – LE 01123074 (https://en.herbariumle.ru/?t=occ&id=132345)., Published as part of Dang, Minh Quan, V. Averyanov, Leonid, Dang, Van Son, Maisak, Tatiana, Bui, Van Huong, Tu, Bao Ngan, Nguyen, Van Canh & Truong, Ba Vuong, 2022, A new species, Bulbophyllum phanquyetii and a new national record of B. tianguii (Orchidaceae) from the limestone area of northern Vietnam, pp. 227-232 in Phytotaxa 566 (2) on page 232, DOI: 10.11646/phytotaxa.566.2.7, http://zenodo.org/record/7119218, {"references":["Chen, X. & Vermeulen, J. J. (2009) Bulbophyllum. In: Wu, Z. Y., Raven, P. H. & Hong, D. Y. (Eds.) Flora of China. Vol. 25. (Orchidaceae). Science Press, Beijing and Missouri Botanical Garden Press, St. Louis, pp. 404 - 440."]}

The paper provides a short review of Bulbophyllum species recorded in Laos and Vietnam during the two last decades and continues the publication of results of our successive studies of the genus in this area. It presents data on two new species for science discovered in Laos (Bulbophyllum pachypodum) and Vietnam (B. neglectipetalum), one lesser known species for the flora of Laos (B. microtepalum), two new records for the flora of Vietnam (B. echinulus, B. setilabium), and new illustrated data on B. secundum insufficiently known in the flora of Vietnam. Bulbophyllum fascinator earlier accepted in specific rank reduced into the synonymy of B. putidum on the base of studies of newly obtained materials. Taking into consideration the new data presented in this paper, the flora of Laos presently includes 85, and flora of Vietnam 151 Bulbophyllum species, excluding Monomeria, Trias, and Sunipia. It is the largest genus in the orchid floras of both countries.

Peliosanthes longiracemosa, a new species from limestone areas of northern Vietnam, is described and illustrated. It is most similar to P. macrostegia in having a distally incurved staminal corona and a distinct pyramidal style, but clearly distinguishable chiefly by the broader leaf blades with more longitudinal veins and closer transverse veinlets, relatively longer, more slender raceme, more numerous widely expanded flowers with recurved perianth segments, and more incrassate, depressed globose staminal corona. Information on the habitat and phenology as well as notes on the taxonomic relationships with other congeners is also provided.

Dendrobium parahendersonii discovered in southern Vietnam is described as new species to science. It belongs to D. sect. Crumenata, and resembles D. hendersonii and D. exile in having a filiform, reed-like stem swollen at the base into a quadrangular ellipsoid pseudobulb and flowering from the leafless part of stem but differs clearly in the details of its tepals and lip. A morphological description, illustrations, data on habitat, phenology, and conservation status for the new species are provided.

New species of Begonia L. in the flora of Laos presented in this paper were mainly found in the course of botanical surveys made in Hin Nam No National Protected Area, Nam Phouy National Protected Area, Khammouane Karst Forest, and Phou Khao Khouay National Protected Area.Additionally, herbaria presently available in Laos (HNL, FOF, NUoL, FRC), living plants, and alcohol preserved material at Pha Tad Ke Botanical Garden and the data accessible online at BM, E, K, LE, NY, P, and PE Herbaria were critically studied. The study conducted during 2012–2019 reveals seven new species for science and seven species newly recorded for the flora of Lao PDR. Species described as new for science are: B. glabritepala (found in Khammouane Province; it is most close to B. pierrei but differs in glabrous outer tepals of staminate flowers, pistillate flowers, capsules, petioles, peduncles and pedicles), B.heterocantha (found in Sainyabuli Province; most close to B. depingiana but differs in reddish purple, glandular pubescent abaxial leaf surface, glandular pubescent pedicel, and outer tepals of pistillate flowers sparsely white glandular pubescent), B. lanxangensis (found in Vientiane Province; most close to B.paleacea but differs in elongate tubers, ovate-lanceolate, obscurely asymmetrical to symmetrical leaves, and glabrous pedicels), B. parviglandulosa (found in Vientiane Province; most close to B. martabanica but differs in smaller habit, reniform-cordate leaves and glandular indumentum on peduncle, pedicle and capsules), B.pseudobrandisiana (found in Khammouane Province; most close to B. brandisiana but differs in pistillate flowers with five elliptic-oblanceolate tepals), B. tripartifolia (found in Khammouane Province; most close to B. tricuspidata but differs in leaves palmate triangular-ovate, with deeply lobed lacerate margin, pistillate flower of five tepals, and ovary with unequal wing), and B. viriditenebris (found in Khammouane Province; most close to B. sinuata but differs in single leaf, indumentum of bristle hairs and reddish or bronzy green adaxial leaf surface, and three styles). The following species discovered and recorded for the flora of Laos at first are: B. hatacoa (known in Nepal, Bhutan, NE India, Myanmar, Thailand, and Vietnam), B.hemsleyana (China, Vietnam), B. labordei (NE India, Myanmar, S China, Vietnam), B.longifolia (tropical zone from NE India to Indonesia), B. minuscula (Vietnam), B. parvula (S China), and B. subperfoliata (Myanmar, Thailand, S Vietnam). Descriptions and line drawings are provided for all newly described species. Photographic illustrations, data on phenology, habitat, and notes on morphological variations and relations are given for all studied species., Виды бегоний (Begonia L.), новые для флоры Лаоса, были найдены большей частью при проведении ботанических исследований на территориях заповедников Хин Нам Но, Нам Фоу, Карстовый лес Кхаммуан и Фоу Кхао Кхоай. В дополнение к полевым исследованиям критически изучены гербарные коллекции, имеющиеся в настоящее время в Лаосе (HNL, FOF, NUoL, FRC), живые растения и заспиртованные образцы ботанического сада Фа Тад Ке, а также данные гербариев BM, E, K, LE, NY, P и PE, доступные on-line. Исследование, проведенное в 2012–2019 гг., выявило семь новых видов для науки и семь видов, новых для флоры страны. Видами, новыми для науки, являются: Begonia glabritepala (найден в провинции Кхаммуан; наиболее близок к B. pierrei, но отличается голыми чашелистиками тычиночных цветков и полностью голыми пестичными цветками, плодами, черешками листьев, цветоносами и цветоножками), B. heterocantha (найден в провинции Сайнябули; наиболее близок к B.depingiana, но отличается пурпурной, железисто опушенной нижней стороной листа, железистым опушением цветоноса, беловатым, рассеянно железистым опушением чашелистиков пестичных цветков), B.lanxangensis (найден в провинции Вьентьян; наиболее близок к B. paleacea, но отличается удлиненными клубнями, узкояйцевидными симметричными или слегка асимметричными листьями и голыми цветоножками), B. parviglandulosa (найден в провинции Вьентьян; наиболее близок к B.martabanica, но отличается маленькими размерами, почковидно-сердцевидными листьями и железистым опушением цветоноса, цветоножек и плодов), B.pseudobrandisiana (найден в провинции Кхаммуан; наиболее близок к B. brandisiana, но отличается пестичными цветками, имеющими 5 узкоэллиптических листочков околоцветника), B. tripartifolia (найден в провинции Кхаммуан; наиболее близок к B.tricuspidata, но отличается глубоко рассеченными, яйцевидно-треугольными листьями c выгрызенным краем, 5-лепестковыми цветками и завязью с отчетливо неравными крыльями) и B. viriditenebris (найден в провинции Кхаммуан; наиболее близок к B. sinuata, но отличается наличием только одного щетинисто опушенного листа, бронзово-зеленовытым с верхней стороны и тремя столбиками рыльца). Следующие семь видов приводятся для флоры Лаоса впервые: B. hatacoa (область распространения вида: Непал, Бутан, С.-В. Индия, Мьянма, Таиланд и Вьетнам), B. hemsleyana (Ю. Китай, Вьетнам), B.labordei (С.-В. Индия, Мьянма, Ю.Китай, Вьетнам), B. longifolia (тропическая зона Азии от С.-В. Индии до Индонезии), B. minuscula (Вьетнам), B. parvula (Ю. Китай) и B.subperfoliata (Мьянма, Таиланд и Ю. Вьетнам). Детальные описания и черно-белые рисунки приводятся для видов, новых для науки. Для всех изученных видов приведены фотографии, данные о фенологии, экологии, морфологической изменчивости и предполагаемом ближайшем родстве.

Intrinsic two-dimensional (2D) magnetism has been demonstrated in various materials scaled down to a single monolayer. However, the question is whether 2D magnetism extends beyond the monolayer limit, to chemical species formed by sparse but regular 2D arrays of magnetic atoms. Here we show that sub-monolayer superstructures of Eu atoms self-assembled on the silicon surface exhibit strong magnetic signals. Robust easy-plane magnetism is discovered in both one- and two-dimensionally ordered structures with Eu coverage of half monolayer and above. The emergence of 2D magnetism manifests itself by a strong dependence of the effective transition temperature on weak magnetic fields. The results constitute a versatile platform for miniaturization of 2D magnetic systems and seed an expandable class of atomically thin magnets for applications in information technologies.