In the UAE this species is recorded from along the Arabian Gulf coast and in the northern Hajar Mountains, including Jebel Hafeet (Jongbloed et al. 2003, Al Mehairbi et al. 2019). Globally, the native range of this species spans across the Old World (Board of Trustees, RBG Kew 2019).

A detailed description of the distribution of Medicago polymorpha within the UAE is lacking, however it is known to occur within the country according to R. Western. According to Fawzi and Karim (pers. comm. 2019), this species has been recorded from Hatta and Ras al-Khaimah, in addition to Abu Dhabi Island (S. Sakkir pers. comm. 2019). Globally, the native range of this species encompasses northern and eastern Africa, Europe, the Arabian Peninsula and western and central Asia (Board of Trustees, RBG Kew 2019).

Within the UAE, this species was recently recorded from Jebel Hafeet and is also known from the Ru'us al-Jibal (Feulner 2011, Sakkir and Brown 2014). It is generally found within the Hajar Mountains, although localities may be scattered (Jongbloed et al. 2003). Globally, the native range of this species encompasses southern Africa, in addition to Macaronesia to Ethiopia and Tanzania, and on to India (Board of Trustees, RBG Kew 2019).

Within the UAE, it occurs within the Hajar Mountain range and in the Ru'us al-Jibal (Jongbloed et al. 2003, Feulner 2011, 2014). In the Ru'us al-Jibal, this species has been recorded from up to at least 1,650 m altitude (Feulner 2011). Globally, the native range of this species includes Somalia and northern Africa, through to the Arabian Peninsula and Pakistan (Board of Trustees, RBG Kew 2019).

This species is widespread but very scattered in the Hajar Mountains (Jongbloed et al. 2003), including Wadi Wurayah National Park (WWNP; Feulner 2016), and was recorded in 2018 from Jebel Hafeet (Sakkir et al. 2018). Feulner (2011) found this species at only one site (a spring, 'Ayn as-Sih) in the Ru'us al-Jibal, not in the UAE, but reported the species to be occasional in the Hajar Mountains near springs and seeps, typically among Adiantum capillus-veneris ferns. The species has also been recorded from the base of the waterfall in WWNP. Without detailed locality records (aside from Jebel Hafeet), it has not been possible to estimate the EOO and AOO. The distribution of this species is from the eastern Mediterranean and the Caucuses, through the Arabian Peninsula to eastern Africa, and east to China (Board of Trustees, RBG Kew 2018).

This species is widespread throughout the Hajar Mountains in the UAE (Jongbloed et al. 2003), including records from Wadi Wurayah National Park (Feulner 2016). Globally, this species occurs in North Africa, Southern Europe, the Middle East, Central Asia and Myanmar (Board of Trustees, RBG Kew 2018).

This is the most common species of seagrass in the UAE. In the Arabian Gulf, there are large areas of this species in inshore areas and around most, if not all, islands in Abu Dhabi Emirate, from the Abu Dhabi Islands to Ra's Hanjurah, with a total area of c.55 km² estimated and representing c. 60% of seagrass bed content (EAD 2017); seagrass was found to be much more abundant in eastern Abu Dhabi, with the highest densities occurring north of Abu Dhabi Island around Al Samaliyah Island (EAD 2008). There is estimated to be around 4,000 km² of this species within Abu Dhabi Emirate (H.S. Das pers. comm. 2019). The species also occurs in Dubai Emirate, with records of extensive seagrass beds containing this species in the Jebel Ali area, particularly between Ras Hasyan and Ras Ghantoot, with their distribution primarily linked to areas of unconsolidated, deep sand (CBD 2016), and offshore from Jumeirah Beach. The species occurs eastwards to at least Umm Al Quwain. This species has a wide Indo-Pacific distribution. In the Pacific, it is found in southern Japan, Taiwan, the Philippines, Malaysia, Indonesia, throughout the Gulf of Thailand and along the coast of Vietnam and southern China. It occurs throughout insular Southeast Asia, northeast to the Northern Mariana Islands, Micronesia, and southeast to the Fiji Islands, as well as across northern Australia and the Great Barrier Reef. In the Indian Ocean, it is found from Geographe Bay in Western Australia extending across the Timor Sea, the south coast of Indonesia, and to the Andaman Sea and extending around the Bay of Bengal and around India to the Malabar Coast. It ranges from the Persian Gulf to the Red Sea, south to the east coast of South Africa to Madagascar and the islands of the western Indian Ocean.

Within the UAE, this species is known to occur along the Arabian Gulf coast (Phillips et al. 2002). The maximum AOO of this species is estimated to be under 2,000 km², incorporating the area of this species found in Abu Dhabi and Ras al-Khaimah (H.S. Das pers. comm. 2019). Due to the occurrence of multiple seagrass meadows along the UAE coastline, there are estimated to be greater than ten threat-based locations. The native range of this species encompasses Egypt to India and the West Indian Ocean (Board of Trustees, RBG Kew 2019).

Within the UAE, this species has been recently recorded from the Ru'us al-Jibal (Feulner 2011). It is thought to generally grow at high elevations within this area, between 1,200 and 1,350 m (Feulner 2011). Globally, this species' native range spans from Tunisia to Afghanistan (Board of Trustees, RBG Kew 2019).

Avena barbata occurs in the Ru'us al-Jibal mountains in the north of the UAE (Jongbloed et al. 2003, Feulner 2011). Within this area, it has been recorded from one confirmed locality in the UAE at 900 m elevation, above bedrock on a ridge. A second record at 1,500 m elevation (Feulner 2011) may not be within the UAE. The origin and distribution of the species in the UAE requires confirmation; it may be native or be present here as a result of natural introduction, or may have been introduced alongside agriculture. Globally, this species occurs in northern, middle, east, south-east and south-west Europe, temperate Asia, Macaronesia, northern Africa and the Indian Subcontinent, and is naturalized in the Azores, Australia and the Americas (Duarte et al. 2011, Board of Trustees, RBG Kew 2018).