J Syst Evol ›› 1996, Vol. 34 ›› Issue (5): 538-546.

• Research Articles • Previous Articles     Next Articles

The Seed Morphology in Hamamelidaceae and Its Systematic Evaluation

Zhang Zhi-yun, Wen Jie   

  • Published:1996-09-10

Abstract: The seed coat of 41 species and one variety, representing six subfamilies in the family Hamamelidaceae, was examined using light microscope (LM) and scanning electron microscope (SEM). The results indicate that there are some differences between the subfamilies in characters such as seed shape, color, size and hilum, but the subfamily Disanthoideae and most genera in the subfamily Hamamelidoideae have similar seed motphology.The above-mentioned characters are,therefore,of certain value for classification between subfamilies. The seed coat morphology under SEM could be mainly divided into five types: (1)Smooth or only striate at the margin of seeds, e.g., Disanthoideae and most genera in Hamamelidoideae (in Ostrearia,Parrotia and Matudaea,seed coat was almost smooth,but with irregular tuber-projection); (2) Striate,with striae undulate-thickened or raised, e.g., Exbucklandioideae;(3) Tuberculate or striate-tuberculate, e.g., Rhodo1eioideae;(4)Striate-reticular,e.g.,Mytilarioideae; (5)Reticular,e.g.,Liquidambaroideae,The seed coat sculpture could be served as an important criterion of distinguishing subfamilies.The testa structure of this family was also minutely studied in the present paper.The study shows that seed coat is composed of identical testa (it consisting of exotesta, mesotesta and endotesta) and tegmen,and is confirmed to be a constant sturcture in the Hamamelidaceae.In addition,some differences were reported in number of cell layers of the testa in the different genera,but according to our study,these differences seemed to be not significant for the delimitation of genera or subfamilies in this family. Notably, the subfamily Liquidambaroideae differs distinctly from the other subfamilies in seed morphology. The systematic position of the Liquidambaroideae needs to be further studied.

Key words: Hamamelidaceae, seed morphology, systematic evaluation