作 者 ：Wang Xian-Zeng
期 刊 ：植物分类学报 1992年 2期
Keywords:Hamamelidaceae, Palynology,
Abstract:
This paper deals with evolution, classification and pollen morphology of the
Hamamelidaceae, an important family in phylogeny of angiosperms.
I. Pollen morphology and systematics of modern Hamamelidaceae.
The pollen morphology of the family may be divided into the following four types: (1)
Tricolpate: Hamamelis, Loropetalum, Mytilaria, Corylopsis, Sysopsis, and Distylum etc.;
(2) Tricolpate with operculum: Disanthus; (3) Tricolporate: Rhodoleia; (4) Pantoporate:
Liquidambar.
The tricolpate pollen of the Hamamelidaceae is a primitive type in angiosperms, but the
most ancient type is monocolpate pollen. Therefore, the family might have evolved from the
Magnoliaceae of the monocolpate pollen. The pantoporate pollen is an evolutionary type in
the family. It might have evolved from the tricolpate pollen.
II.The fossil pollen of the Hamamelidaceae
1 .General introduction of the fossil pollen of the family Hamamelidaceae
The most’ancient fossil pollen belonging to the family was found in the middle-late Ear-
ly Cretaceous. Palynologists call the fossil pollen of the Hamamelidaceae Retitricolpites,
which consists of three genera: Hamamelis L.,Corylopsis Sieb. et Zucc and Fothergilla
Murr. Liquidambar is of an advanced type in the fossil pollen of the Hamamelidaceae. It
was found in the period from the Palaeogene to the Neogene in China.
2. The geological history of the Hamamelidaceae may be divided into the following four
stages:
(A) The Early Cretaceous stage or origination stage. The family may be evolved from
Magnoliales in the middle-late Early Cretaceous. (B)the Late Cretaceous stage or forma-
tion stage. The family is much developed in the period. (C) The Tertiary stage or develop-
ment stage. The family was a much developed one among angiosperms. (D)The Neogene to
modern stage or perfection stage. The evolutionary type, the Liquidambar type of the
Hamamelidaceae, was much developed in the Neogene.
III. The palaeopalynological evidence of evolution of the Hamamelidaceae
The earliest fossil pollen of angiosperms was found in the Barremian (Early Cretaceous)
in England, Israel, the United States of America etc., and was named as Clavatipollenites by
Couper (1953). In recent years, Clavatipollenites was also found in the middle-late Early
Cretaceous in Nei Monggol and Jiangxi Province of China. We also found Retitricolpites in
the middle-late Early Cretaceous in Nei Monggol and Jiangxi Province. Retitricolpites, be-
longing to the Hamamelidaceae, is a primitive type among angiosperms, but it is younger
than Clavatipollenites. Therefore, the pollen of Hamamelidaceae may have evoloved from
Clavatipollenites, which may have evoloved in turn from that of Magnoliales.