ABSTRACT

Juglans, consisting of deciduous trees, belongs to the family Juglandaceae. The most closely related genus, of Asian origin, is Pterocarya. 7 At least 12 Juglans species are recognized, all deciduous, with edible fruit, some of considerable value for timber. Many species of Juglans are still found wild in many parts of the world. Species are classified mainly on the basis of leaf, nut, and fruit characteristics. Juglans regia L., the Persian walnut, has by far the greatest economic importance. It is native to a wide region from northern India, southern Russia, Afghanistan, Iran, Iraq, Turkey, and extending to the Carpathian mountains.8 J. regia trees have been grown since antiquity from seed and are still propagated thus in certain regions. This is due, at least in part, to difficulties in budding or grafting. Grafting has been in use probably only the last 200 years. The presence of numerous seedlings in many countries contributes to floral diversity and span of period of flowering.23 , 31 , 53 Most of our information on flower biology, including dichogamy, originates from observations on J. regia, but native American species have also been observed.39