According to the present estimates, Saudi Arabia contains 97 (4.25%) trees, 565 (24.73%) shrubs and about 1620 (71.02%) herbs. Flora consists of all groups of plants such as mesophytes, xerophytes, halophytes, psammophytes, hydrophytes, parasites, neutrophiles and heliophytes. Major Families of Saudi flora. Poaceae -286 spp.