LI, JIANHUA* AND A. LINN BOGLE. Harvard University Herbaria, 22 Divinity Ave., Cambridge, MA 02138 and Department of Plant Biology, University of New Hampshire, Durham, NH 03824. - Comparative embryology and floral ontogeny of the Corylopsis complex (Hamamelidaceae).
Comparative embryology and floral ontogeny were studied for the four
genera in the Corylopsis complex (Hamamelidoideae,
Hamamelidaceae) including Corylopsis, Eustigma,
Fortunearia, and Sinowilsonia). Conservative
embryological character states in this complex are the following: the
Glandular type of tapetum, the Simultaneous type of microsporogenesis,
two-celled pollen grains, Crassinucellate ovule, the Polygonum type of
megasporogenesis, the Nuclear type of endosperm formation, and a
transverse division of the zygote. In contrast, variable
characteristics include: tempo of microsporogenesis, number of ovules
per carpel, presence of caruncle, embryogeny, and polyembryogeny.
Sinowilsonia is the most specialized genus among the genera and
early initiation of stamen is responsible for the reduction and loss
of petals in this genus. Corylopsis is embryologically and
ontogenetically distinct from Eustigma, Fortunearia, and
Sinowilsonia, thus supporting the taxonomic treatment that
separates Corylopsis from the latter three genera. This study
was partially supported by Summer Teaching Assistant Fellowships of
the University of New Hampshire to JLi.
Key words: embryology, Corylopsis, Eustigma, floral ontogeny, Fortunearia, Sinowilsonia