These are four consecutive leaves (numbered fols. 237-241) from an illustrated manuscript of the Arabic version of De materia medica by Dioscorides, copied in the seventh century AH / thirteenth CE in Iran. Pedanius Dioscorides wrote his treatise on medicinal plants in the first century CE. It was translated into Syriac and then Arabic in Baghdad in the third century AH / ninth CE. De materia medica by Dioscorides was one of the earliest scientific manuscripts to be translated from Greek to Arabic. The Walters' leaves illustrate five plants: wild cucumber, mezereon (spurge-olive), and three varieties of thymelaea (spurge-laurel).
For full description, see http://www.thedigitalwalters.org/Data/WaltersManuscripts/html/W750/description.html