The evolutionary relevance of vegetative long-shoot, short-shoot differentiation in gymnospermous tree species

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This well-illustrated monograph explores the relationship between deciduousness (the seasonal shedding of leaves) and long-shoot/short-shoot differentiation in gymnosperm tree species. While most gymnosperms are evergreen, deciduousness is typically viewed as a derived trait. Comparative studies of angiosperms show a strong correlation between vegetative long-shoot/short-shoot differentiation and deciduousness. Specifically, the total leaf area of a short shoot matches that of a single long-shoot leaf lamina, indicating a replacement process in subsequent seasons. However, this correlation is only observed in Ginkgo among the studied gymnosperms, suggesting a distinct evolutionary path for long-shoot/short-shoot differentiation in gymnosperms compared to angiosperms. The research reveals that some evergreen gymnosperms may have evolved from deciduous ancestors, while others maintain a primitive deciduous state. The monograph is divided into two parts: the first investigates various gymnospermous and angiospermous species morphologically, anatomically, and physiologically, while the second maps these findings onto paleobotanical and paleogeographic data to assess the hypothesis that deciduousness was historically more prevalent among gymnosperms than current diversity indicates. This work will appeal to botanists and researchers studying both angiospermous and gymnospermous trees.