关键词: 银杏, 叶生拟胚珠, 形态发育

Abstract: Many features of Ginkgo biloba var. epiphylla Mak. , the one which was firstly found at Yiyuan
County of Shandong Province in China, were continually observed and the comparative morphology research
was conducted, including the variation characteristics, the morphological development of ovule-like organ on
the leaf blade and veins of leaf. The results of analysis showed that the development of the ovule-like organ on
the leaf blade is comp rised of initial stage, formation stage, expansion stage and mature stage. There were one
to eight ovule2like organs on each leaf, but only one developed normally. The leaves were divided into five
types, i. e. multilobed type, nonlobed type, bilobed type, the leaf with ovule-like organ and deformation
leaf, leaf color into two types, i. e. green and variegated types. Compared with normal ovules, ovule-like
organ on the leaf blade disp layed variation in insertion, heterochrony and hysteresis in development of ovule-
like organ on the leaf blade, which was reported for the first time. The ovule2like organ lagged behind the nor-
mal ovule for fifteen days at initial stage, moreover no pollination drop was found on the ovule2like organ. The
ovule2like organ on the leaf blade was divided into five types according to the insertion on the leaf, i. e. uni-
lobed solitary type, unilobed clustered type, bilobed clustered type, multilobed solitary type and adsperse
type. The vein of normal leaf could be separated into four types according to anastomoses, i. e. closed type,
W type, V +W type and double V +W type. And that of the phyllosporous leaf was classified into three
types, i. e. uni-arcuate, biarcuate and mutli-arcuate type. The variation characteristics and the phylogeny of
Ginkgo biloba var. epiphylla Mak. were discussed in the paper.

Key words: Ginkgo biloba, Ovule-like organ on the leaf, Morphological development