NEW AND RARE ORCHIDS (ORCHIDACEAE) IN THE FLORA OF CAMBODIA AND LAOS

Herbarium material collected in 2009–2013 in Cambodia and Laos provides 240 new localities for 156 orchid species (from 73 genera). Among them, 13 and 45 species respectively are new for the flora of each country. One species (Bulbophyllum konstantinovii) discovered in Cambodia is described as new for science. Eight genera (Acanthephippium, Didymoplexiopsis, Eclecticus, Herpysma, Hetaeria, Lecanorchis, Neuwiedia, and Trichosma) were found in Laos at first.


Introduction
The orchid flora of Cambodia and Laos still remains one of the less studied orchid floras in Tropical Asia. In comparison to other countries of Indochina Peninsula, such as Thailand or Vietnam each including at least 1100 species (Seidenfaden, 1992;Averyanov, 2003;Pedersen et al., 2011), about 200 orchid species totally were recorded for Cambodia (Seidenfaden, 1992;Averyanov, 2013;Leti et al., 2013;Schuiteman et al., 2015Schuiteman et al., , 2016Tagane et al., 2015) and about 530 species for Laos (Newman et al., 2007;Schuiteman et al., 2008;Averyanov, 2013). Meanwhile, according to their square and various natural conditions all countries of Indochina should certainly conceal similar orchid richness and diversity. Present paper summarizes some consequent steps in studies of the orchid flora of Cambodia and Laos based on herbarium specimens collected by different collectors in the field mainly during 2013-2015.
The paper provides 298 new localities for 167 species (from 57 genera) among which 8 species are new for the flora of Cambodia and 43 species represent new records for Laos. One genus -Didymoplexis is recorded for the Laotian flora at first. Mentioned new records (see table 1) represent sig- Table 1 New records of orchids in the flora of Cambodia and Laos Names of new species for science and species new for the flora are marked with bold font (additionally, new species for science are marked with asterisk "*", new species for Cambodia and Laos are marked with superscript letters " C " and " L " respectively) -valid name and main synonyms, occurring in regional literature; -maximally abbreviated and unified text of herbarium labels including geographical locality, collection date, collectors' names, collection number and acronym of Herbarium where mentioned specimen is housed; -living form, summarized available data on ecology, habitat elevation, phenology and observed rarity; -general distribution and distribution in studied countries (by listing of the country provinces).
Color and line illustrations as well as taxonomic notes are additionally provided for new and most significant species. The names of orchid species and genera reported for Cambodia and Laos at first are marked in the list with superscript letters " C " and " L " respectively, and species described as a new for science are marked with asterisk "*".
The following Herbarium acronyms are used in the text: CPC -Herbarium of the Center for Plant Conservation, Vietnam Union of Science and Technology Associations, Hanoi, Vietnam.
LE -Herbarium of Komarov Botanical Institute, Russian Academy of Sciences, St. Petersburg, Russian Federation.
HNL -Conseil National des Sciences, National Herbarium of Laos, Vientiane, Lao PDR.
FOF -Herbarium of National University of Laos, Vientiane, Lao PDR.
Prefixes "CPC" and "LA-VN" at some collecting numbers represent abbreviations of "The Center for Plant Conservation" (CPC) and "Laos -Vietnamese expedition" (LA-VN). Both collecting series are attributed to herbaria collected in expeditions managed by the Center for Plant Conservation (Vietnam Union of Science and Technology Associations) with main collectors -Leonid V. Averyanov and Nguyen Tien Hiep. Prefixes "K" and "TM" at plant collecting numbers designate herbarium collections of Eugene L. Konstantinov and Tatiana V. Maisak with their co-workers.
Attractive species highly desirable for cultivation are indicated in the list as "ornamental". Almost all these species fast become very rare due to commercial collecting even on protected areas and badly need conservation to prevent their full extinction in nature.

12
This species considered earlier as endemic of Hong Kong (Barretto, Cribb, Gale, 2011) has actually broad distribution in limestone areas of northeastern Laos and northwestern Vietnam. It is noteworthy that in Indochina the species was observed exclusively in forests on rocky limestone.  T. Hiep, L. Averyanov, N. S. Khang et al., LA-VN 1157 (HNL, FOF, LE).
Epiphyte. Primary and secondary broad-leaved evergreen dry forests on rocky limestone, commonly on hill and mountain tops, 600-700 m. Fl. April -May. Not common.

B. parviflorum
Creeping epiphyte and lithophyte. Primary and secondary dry evergreen forests on any kind of soil, commonly on large rocks along streams, 300-350 m. Fl. November -December. Not rare.
Epiphyte. Primary and secondary broad-leaved evergreen and semideciduous dry forests on any kind of soil, 1200-1400 m. Fl. June -July. Occasional.
Terrestrial semi-woody herb. Primary and secondary broad-leaved evergreen dry forests on rocky limestone, usually in humid shady depressions and stream valleys with rich soil, 300-800 m. Fl. May -July. Occasional.

D. loddigesii
Tropical and subtropical mainland Asia, Ryukyu Islands, Malay Archipelago to New Guinea. Laos: Xiangkhouang.
Lithophyte and occasionally epiphyte. Primary and secondary broad-leaved evergreen dry forests on rocky limestone, commonly on shady mossy rocks on mountain tops, 600-700 m. Fl. September -November. Rare.
Epiphyte. Primary and secondary broad-leaved evergreen dry forests on rocky limestone, commonly on shady humid places on hill and mountain tops, 800-1200 m. Fl. March -May. Not common. Ornamental.
Terrestrial and occasionally lithophytic herb in open wet mossy places on any kind of soil and in any plant communities, commonly along sandy banks of streams, wet rocks and rocky waterfalls, 400-900 m. Fl. March -May. Not rare.
Epiphyte. Primary and secondary broad-leaved evergreen dry forests on rocky shale and limestone, 1100-1200 m. Fl. August -October. Rare.
Miniature canopy and branch epiphyte. Submontane broad-leaved primary and old secondary humid cloud forest on granite, usually along small streams, 1000 m. Fl. February -December. Very rare. Species epithet refers resemblance of the flowers with traditional capuchin monk wear.
Miniature branch and trunk epiphyte. Primary and secondary dry semideciduous broad-leaved lowland forests on alluvial soils derived from limestone, 150-200 m. Fl. August -September.

Rare.
Laos: Khammouan. Endemic. Newly discovered plant belongs to group of species with hysteranthous inflorescence appearing from the apex of mature pseudobulb. From all representatives of this group new species strikingly differs in disproportionally long and broad lateral sepals (twice longer than median sepal) strongly bent down, almost round petals connivent with their apices at front of column and simple lip slightly undulate along the margin and notched at the base. Small population of this curious plant was found in canopy of lone remnant expiring tree remaining in almost completely deforested area, hence species should be regarded as crotically endangered. (Rchb. f.) Rolfe, 1908, Orchid Rev. 16: 8;Newman et al., 2007, Checklist Vasc. Pl. Lao PDR: 279;Schuit. et al., 2008, Nord. Journ. Bot. 26: 307;Aver., 2013, Turczaninowia 16, 4: 42. Central Laos, Vientiane province, Phou Khao Khouay National Protected Area to about 40 km NE of Vientiane, 9 December 2015, L. Averyanov,T. Maisak,AL 153 (LE).
Miniature trunk epiphyte and lithophyte. Primary and secondary dry evergreen broad-leaved lowland forests on sandstone, commonly along streams and small rivers, 350-400 m. Fl. March -April. Locally common.
Laos: Vientiane. Endemic. New plant belongs to group of species with proteranthous inflorescence appearing from the base of mature pseudobulb. From all species of this group new plant well differs in glabrous narrow flowers, free narrowly lanceolate finely papillulate petals involute along the margin and in short simple rectangular lip with acute-triangular apex. New species in its locus classicus was observed as common plant with large visually stable population.
Creeping miniature epiphyte. Primary and secondary broad-leaved evergreen dry forests on rocky limestone, commonly on shady cliffs near hill and mountain tops, 600-700 m. Fl. May -June. Very rare. Ornamental.
Miniature epiphyte. Primary and secondary broad-leaved evergreen dry forests on rocky limestone, commonly on shady cliffs near hill and mountain tops, 1200-1450 m. Fl. May -June. Very rare. Ornamental.
Creeping epiphyte. Primary and secondary broad-leaved evergreen forests on rocky limestone, commonly on hill and mountain tops, 1100-1750 m. Fl. April -May. Occasional.
Miniature canopy and branch epiphyte. Primary and old secondary lowland broad-leaved evergreen dry forests on rocky limestone, usually on old mossy trees in shady, humid places near mountain tops, 600-700 m. Fl. August -September. Rare.
Miniature epiphyte and occasionally lithophyte. Primary and secondary broad-leaved evergreen forests on any kind of soil, often on rocky limestone