1Barthlott W. Epidermal and seed surface characters of plants: systematic applicability and some evolutionary aspects[J]. Nordic Journal of Botany, 1981(1):345-355.
2Werker E. Seed Anatomy[J]. Berlin: Stuttgart Bomtraeger, 1997:1-65.
3Bouman F., Lange A. de. Structure, micromorphology of begonia seeds[J]. The Begonian, 1983(50): 70-78.