The first list is obtained from an EIA study for an oil exploration project in Block 5B in the swamps of the upper stretch of the White Nile in the former southern Sudan WNPOC [2] .

The list in Table 1 will have to be looked upon in the light of the paucity of aquatic plants lists [3] .

The second list (Table 2) describes the flora in the desert zone obtained during an EIA study for the proposed Kajbar Hydropower project [4] . The plants were classified into trees, shrubs, grasses and forbes.

The third list of plants (Table 3) was assembled during an EIA study tour for an oil development project in Western Kordofan State where a pipeline was proposed to transport crude oil [5] .

The area in which the proposed oil pipeline crosses is known for its good vegetation cover especially during the rainy season. Harrison and Jackson [6] classified the vegetation of this area as Combretum glutinosum-Dalbergia melanoxylon-Albizia amara Savannah woodland as sub-division of the low rainfall woodland savannah on sand. This sub-division occurs in areas of rainfall ranging between 450 - 600 mm/year. The dominant woody species were mostly broad-leafed non-thorny such as: Combretum glutinosum, D. melanoxylon, A. amara, Guirea senegalensis, Sclerocarya birrea, Commiphora africana, Lannea humilis, Terminalia laxiflora, Terminalia brownii, Dalbergia melanoxylon and Adansonia digitata. Currently C. africana and L. humilis are decreasing due to their intensive use by the pastoralists and agro-pastoralists for robes making, buildings materials etc. while G. senegalensis, C. glutinosum and Terminalia spp. are increasing due to less destruction. Dichrostachys cinerea is found to increase along animal tracks, night camps and roads sides. Dalbergia melanoxylon is severely decreasing due to the high run-off, on the bare areas around the small savannah deciduous tree causing root system desiccation and also the human intensive use of the wood.

*Nomen novum.

The previous ground cover was mentioned to be composed of Brachiarra xantholeuea, Eragrostis termula, Cenchrus biflorus, Aristidapallidac, Andropogan gayanus, Pennsetium pedicellatum, Blepharis linariifolia, Zornia glochidiata and Monechma hispidum. Currently, C. biflorus (Huskaneit) and B. linariifolia were not observed and the

people met confirmed their disappearance. List of the current natural vegetation in the project area is given in Table 3.

Belpharis persica (Burm.f.) kuntze. Synonym: Belpharis edulis

This is an annual woody herb, with spiny leaf margin of the family Acanthaceae. The green and dry plant is a very valuable camel fodder while sheep, goats and cattle relish the plant when green. It is found in the semi-desert ecological zones of Butana plain of eastern Sudan, Erkawit and khor Dahand in the Red Sea State [7] . It was not specifically

mentioned in the flora of the desert ecological zone. Long drought spells after germination may cause complete disappearance of the plant from the rangeland. At present the plant has disappeared from many grazing areas of Butana. There is only one area from which seed stock can be collected for regeneration (reseeding) which is Jebel Elmundra in the Butana plain, where stands of under-grazed plants are found due to limited resources of livestock drinking water. Light clay soils are suitable for germination and establishment of uncovered mature seeds.

During an EIA survey for the proposed Kajbar hydropower dam, Belpharis was found in one of the seasonal water courses draining into the western bank of the River Nile. This could be the first record of the species in the desert zone of Sudan (Figure 1 & Figure 2).

Medemia argun (Martius) Wuttt. ex H. A. Wendi Family: Arecaceae (Figures 3-5).

Medemia is a monotypic genus endemic to the upper valley of the River Nile in Egypt and Sudan. Nowadays, there are only a few localities in which this palm is found, and in most cases the populations there consist of very few individuals. The Sudanese Nubian Desert east of the River Nile is the only region where the plant is now naturally growing. This region is so arid that consecutive years pass without any rain falling. Though the terrain is harsh with many rocky features, the Nubian Desert is characterized by a network of seasonal water courses that drain into and form the large WadiGabgaba. These wadis could run with flash floods coming from seasonal rainfall in the Red Sea Hills. According to the International Union for the Conservation of Nature (IUCN) Red list Category and Criteria [8] , the “Argoun Palm” is critically endangered.

During two visits to the eastern Nubian Desert in 2011 and 2015, several populations of Medemia have been encountered. The findings have manifested not only that Medemia still exists, but it inhabits many locations. Most striking is that the tree is in good condition and many fruiting trees and several young trees at different stages of growth have been encountered [9] . Nevertheless, the criterion upon which IUCN has categorized the Argoun palm as critically endangered―small and fragmented populations―is still valid.

During a multidisciplinary expedition organized in 1979 by the Hydrobiological Research Unit (Later on amalgamated in the IES) of University of Khartoum to study the expected environmental and social impacts of the proposed Jonglei Canal in southern Sudan, a plant was observed growing in swamps at the joining of Bahr el Zeraf and a side lake. It was first taken to be a member of the Araceae family due to the sagitate shape of the leaf base. When several specimens were taken to Kew, London, it was discovered that the plant is not only a new species but a new genus of the poaceae (Graminae) family! It was aptly named Suddia sagitifolia. The discovery was considered as the declaration that Suddia sagitifolia is the only endemic aquatic plant in the Sudan (Figure 6) [10] . Endemic plants and animals are those that are unique to a specific geographic region. This makes them incredibly special and more vulnerable to extinction. Because they are only found in certain locations, they require special conservation efforts.

The plant was encountered by the author during a later field work mission in 2005 organized by the IES as part of an EIA study for Block 5B for the White Nile Petroleum Operating Company within Bahr el Zeraf Basin [2] . Very recently the same plant was found in some wetlands in Uganda and the plant was rated as a near endemic species. Nevertheless, the credit for this contribution of international dimension still remains to the EIA of seventies of the last century. Within the same region the smallest floating plant (Wollfia hyaline) in the former Sudan was also reported.

The available information on the distribution of flora on Sudan is old and limited. The EIA studies have availed valuable chances for the flora expert within the EIA team to visit many sites within Sudan. Some of these sites fall in regions which are otherwise inaccessible hadn’t it been for the EIA missions. The lists are not exclusive yet useful for future monitoring and for providing a base to revise and update the flora list. The identification of the plants was not an easy task due to the paucity in taxonomy references as well as national taxonomists. So far the only available references are the three volumes of Andrews in the fifties of the last century [11] [12] . However, recently a significant contribution to alleviate this situation is the publishing of an annotated checklist on the plants of Sudan and South Sudan [13] .