The present flora thoroughly covers the bryophytes of the Arabian Peninsula and Socotra island, with keys to all species, notes on the occurrence of the species in the different countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates, Yemen) and distribution maps. In contrast, the arid and semi-arid parts of inner Arabia (winter rainfall area) are dominated by drought-adapted and drought-tolerant taxa of probably xerothermic-Pangaean and circum-Tethyan origin. They show a number of xeromorphic adaptations (xeropottioid and xerothalloid life syndrome) for life under desert conditions. The phytogeographical analysis of the bryoflora, as well as the distribution of thalloid and leafy liverworts, respectively acrocarpous and pleurocarpous mosses, demonstrate that there is a clear phytochorial border across the Peninsula, frequently correlated with climatic conditions (winter rainfall/summer rainfall line).

Examining all the native flowering plants and ferns (3500-4000 species), as well as major crop and amenity plants of economic importance, the Flora covers Saudi Arabia, Yemen, Oman, the United Arab Emirates, Qatar, Bahrain and Kuwait.

With the sixth volume of 'Bryophyte locality data from the Near and Middle East' (Pottiaceae “Eucladium – Z” till Trachypodaceae ; families in alphabetical order), consequently all published data of mosses between are presented to provide ‒ in addition to volume 5 (Neckeraceae till Pottiaceae “A – Didymodon”) ‒ a complete data base and background for the whole area. Starting with the beginning of the collection activities (e.g., Forsskål 1775) it covers the whole period till the end of 2019 and is the first comprehensive catalogue for these organisms including Afghanistan, Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Sinai Peninsula, Syria, Turkey, United Arab Emirates and Yemen (incl. Socotra). With the sixth volume, the catalogue of 'Bryophyte locality data from the Near and Middle East' allows an easy access to what is recorded and known from the different countries of the Near and Middle East.

With the first volume of 'Bryophyte locality data from the Near and Middle East', all published data of hornworts (Anthocerotophyta) and liverworts (Marchantiophyta) are presented to provide a solid data base and background for the whole area. Starting with the beginning of the collection activities (e.g., Forsskål 1775) it covers the whole period till the end of 2019. It is the first comprehensive catalogue for these organisms including Afghanistan, Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Sinai Peninsula, Syria, Turkey, United Arab Emirates and Yemen (incl. Socotra). Knowledge of species and its distribution is essential for floristic inventories, species catalogues, and further tools such as community structure, composition, biomonitoring, nature conservation, life history traits (morphological, anatomical and physiological adaptations), biochemical compounds (secondary metabolits, antimycotica). In addition, species distribution and occurrence today and in former time, is of basic importance in understanding plant diversity and eco-system processes, development, function and changes, especially with regard to the present increasing human influence and global warming and future tools. Although hornworts and liverworts belong to a group of mostly very small organisms that often are neglected and/or overlooked, they play an important and outstanding role in many habitats in nearly all countries and landscapes of the Near and Middle East as they are found in the understory of forests and woodlands, as pioneers on soil and rock, in steppes and deserts (organisms of "harsh environment"), in swampy areas and bogs, or as epiphytes on tree trunks. As scientific interest in plant diversity drastically increases recently, the ongoing interest stimulated us, to prepare this kind of data base to provide a solid background of what is known in the different countries of the Near and Middle East. It is a further step to integrate this large area into the Global Network of floristic knowledge and the tools of the Global Strategy for Plant Conservation.

Although the unique flora of the Socotra Archipelago with its high degree of endemism has received much attention recently, little information is available on the vegetation and related ecological aspects. Based on their extensive field experience of the region, the authors have assimilated a vast amount of knowledge to produce this book, which gives a detailed insight into the plant ecology of Socotra, designated as a World Heritage Site by UNESCO in 2008. The book is divided into seven chapters. After a brief introduction and overviews of important abiotic features, various aspects of the vascular flora are presented in Chapter 4, together with accounts of the bryophyte and lichen flora. Ecology and adaptive strategies of the plants are dealt with in Chapter 5, and Chapter 6 gives a concise description of the main vegetation units. Finally, important management issues of the vegetation are discussed, an essential topic to ensure preservation of the natural heritage of the archipelago.

This bryophyte flora of Southwest Asia is the first comprehensive, structured synthesis of the current knowledge available on the liverworts, mosses and hornworts of this region. The area covers Afghanistan, Bahrain, Iraq, Iran, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Sinai Peninsula, Syria, Turkey, United Arab Emirates, and Yemen (incl. Socotra Island), summarized to a great extent as 'Asia 5' in the 'Index Muscorum'. In total, 1193 taxa (229 liverworts, 959 mosses, 5 hornworts) and nearly 2000 names and synonyms were treated in the dichotomous keys presented, including annotations to critical, doubtful or erroneously recorded species. 14 taxa represent new country/regional records and are listed together with their collecting data in a separate paragraph. The book includes all bryophytes known to date within the large and geomorphologically varied area. Many of the species are important initial colonizers of bare rocks, crusts and soil surfaces of steppes and deserts of this region and therefore forerunners in vascular plant colonization and succession. Because they serve as indicators of ecological disturbances and air quality, their knowledge is of fundamental importance for understanding phytodiversity and ecosystem evolution. This flora provides users with an up to date tool for at least a preliminary identification of any bryophyte in the area and may stimulate and promote greater interest in this often neglected or overlooked plant group. The flora is recommended to all botanists and ecologists, interested in bryophyte flora and vegetation, biodiversity, and nature conservation.