The study of the flora located in the central part of the Hoàng Liên Sơn Range in the northern region of Indochina has revealed 279 species of liverwort and hornwort, 26 of which are newly reported for the flora of Vietnam. The uniqueness and peculiarity of the studied flora are explained by the significant altitudinal range in the area treated and its position in the contact zone of the Sikang-Yunnan floristic province of the East Asian Floristic Region with the Indochina Floristic Region. The checklist includes data on the distribution of each species in the studied region, habitats, and accompanying taxa. The high disunity of the regional floras of the southern tip of the East Asian region compared to the lesser disunity of the regional floras in the north of the East Asian region is shown. In general, the studied flora possess Sino-Himalayan mountain subtropical characteristics with the large participation of tropical elements.

Abies delavayi subsp. fansipanensis is classified as a highly endangered plant in the Vietnam Red Data Book (2007) and a critically endangered species in IUCN red list (2012). This species distributed at the altitudes of 2600-2680 m and 2750-2950 m above sea level (a.s.l) on Fansipan-mountain, Lao Cai province, Vietnam. However, to date there is still a lack of information on the bio-ecological and genetics characteristics of Abies delavayi subsp. fansipanensis indifferent altitudinal conditions, which helps to conserve and promote this precious genetic resource in Vietnam. In this study, climate conditions, soil property, vegetation and genetic structure of two populations of Abies delavayi subsp. fansipanensis distributed in two altitudinal belts on Fansipan-mountain were investigated. The research results have shown that Abies delavayi subsp. fansipanensis is distributed in the ecological conditions including temperature: 1.6-29.3°C, rainfall: 26.8-500 mm, humidity: 65%-95%, sunshine: 90-130 h sunshine, pH: 4-5, and the total organic carbon value 34-73%. The importance value index (IVI) and the correlation coefficient of the relationship of tree height and diameter at breast height values of Abies delavayi subsp. fansipanensis distributed in the altitudes of 2600-2680 m a.s.l. were 4.72% and 0.2749, while those of this species in the altitudes of 2750-2950 m a.s.l. were 42.24% and 0.6824, respectively. The DNA analysisof Abies delavayi subsp. fansipanensis also indicated that the genome of individuals in the higher altitude is more diverse than those lived in the lower altitude. This is the first study of the bio-ecological and genetic structure characteristics of Abies delavayi subsp. fansipanensis distributed on Fansipan-mountain. The study provides valuable data for proposing solutions to conserve and promote this rare genetic resource for Vietnam as well as for the world. Keywords: Abies delavayi subsp. fansipanensis, altitudinal conditions, bio-ecological characteristics, Fansipan-mountain, genetic characteristics.

Ongoing studies on the Lepidoziaceae in East Indochina have yielded new information on the distribution and morphology of a number of family representatives. This study aimed to provide new data in this regard. The latter task looks quite justified, taking into account the fact that East Indochina houses a notable portion of the worldwide Lepidoziaceae diversity, especially in the genus Bazzania. The materials for the paper were 48 specimens collected throughout East Indochina. The cited specimens contain 18 taxa, discussed in respect of their ecology, distribution, and morphology. All the taxa discussed in this paper are supplemented with illustrations, and their morphological descriptions based on the Indochinese materials are also included in most cases. One taxon (Bazzania appendiculata subsp. cambodiana subsp. nov.) is described as new-for-science. Six species are new to Indochina, three species are new to East Indochina, one species is new to Vietnam, and three species are new to Cambodia. A comparison of the currently known taxonomic diversity with that of Malaysia, which borders East Indochina, reveals that the diversity of Lepidoziaceae in East Indochina is still clearly understudied, and further research is likely to yield new discoveries. The final target in this field is the creation of a thorough taxonomic revision of the family in this region in the future.