The aim of this study was historically and pharmacologically reviewing almost all the known medicinal trees mentioned in classical texts of Persian traditional herbal medicine, which are not present or do no longer grow in Iran today. We have reviewed all important historical and modern literature about the medicinal trees and shrub used in Iranian traditional medicine. Then we selected the major references and collected the data. All plants, which were mentioned in classical texts of Iranian traditional herbal medicine, but do not occur or no longer grow in Iran at present. We compared the modern and traditional documented herbal medicine of our country and edited them as follow. All data about the terminology (if necessary some etymological information have been provided), local and native names, comparison the modern and traditional terminology and postulations about the plants, description about the medicinal parts of the plant, and finally the proposed medicinal and pharmacological activities of the trees have been presented. The collected data were represented as twenty-three species of trees and shrubs which were mentioned in classical texts of Iranian traditional herbal medicine, but are not reported as spontaneous in Iran at present. It is interesting that almost all of these plants have been described in the classical texts of Iranian herbal medicine. These data show that Persian scholars knew these trees in the earlier times. We may suppose the following probabilities for this controversy. The Persian scholars may were aware of these plants from Arabic, Indic or Greek-Roman tradition without seeing them closely. But it is known that the usage of the plants was common among Iranian herbalists and scholars in the past centuries. We propose more researches about these plants and the exact cause of their earlier presence and accessibility to the Persians in the history and the lack of their presence today in Iran.