A database containing information on the trait complex for terminal phloem of dicots leaf having been created during the last thirty years was analyzed. The typology of terminal phloem was verified. The monotypy of plant taxa up to the family level was confirmed. For orders and subclasses, the wide distribution of structural parallelisms was demonstrated. The lists of plant families with similar structures of the phloem terminals was elaborated. As a result of comparative analysis of these lists and paleobotanic data on the age of plant families, the specificity of the types of terminal phloem and the associated morphological and functional characteristics of the groups of families of the same evolutionary, age were revealed. Ancestral type prevails among the families belonging to Prodicots, which were emerged during Cretaceous. Symplastic type is characteristic to the families of Eudicots and biomes appeared in Paleogene, while the apoplastic type is characteristic to the families and biomes of Neogene. For each group to taxa, plant stem and root parasitism is characteristic for the crown taxa completing the structural sequences of trees and herbs. All these data allow discussion of the questions of climatic adaptogenesis of the character complex studied here, the impossibility of structural iterations in morphological evolution, and the reasons of similarities and differences in the evolutionary and contemporary zonal series of the terminal phloem in Dicots.
Gamalei, YV; Pakhomova, MV; Scheremet'ev, SN
Dicotyledons of Cretaceous, Palaeogene, and Neogene. Adaptogenesis of the terminal phloem
Zhurnal Obshchei Biologii