“低等”金缕梅类植物的起源和散布

本文根据植物类群的系统发育和地理分布相统一的原理，讨论了“低等”金缕梅类植物的起源和散布。“低类”金缕梅类植物包括下列７科：昆栏树科、水青树科、连香树科、折扇叶科、领春木科、悬铃木科和金缕梅科。该类群共有１３种分布区类型。东亚区的南部和印度支那区的北部是它的现代分布中心；根据化石证据及原始类群和外类群的分布分析，以上地区最有可能是这类植物的起源地。“低等”

山白树属雄蕊数目和形态的变异及其系统学意义?

该文利用扫描电镜法(SEM)研究了山白树属雄蕊的形态学特征,主要观察结果如下:多数情况下,雄蕊为5枚,其成熟花药有背腹之分,花药侧面纵向延伸的缝线在两端发生分叉;此外,还观察到4枚及6枚雄蕊的情况,有的雄蕊的花药在形态上没有背腹之分,呈四方柱状或扁平状,其侧面纵向延伸的缝线在两端不发生分叉或者仅在基部的一侧发生分叉。研究结果,山白树属雄蕊在形态分化上处于不稳定的过渡阶段,表现出和"高等金缕梅类"的联系。

Phylogenetic Relationships of the "Higher" Hamamelids Based on Chloroplast trn L-F Sequences

Phylogenetic relationships of the 'higher' hamamelids were estimated based on nucleotide sequences of the non-coding region of chloroplast trnL-F. Twenty-five species were sampled, representing 24 genera of all eight families of the 'higher' hamamelids. A parsimony analysis of data set indicated that the 'higher' hamamelids formed a strongly supported clade with 100% bootstrap value in the strict consensus tree. Nothofagus was the basal lineage and the Fagaceae was sister to a well-supported core 'higher' hamamelids clade containing Myricaceae, Rhoipteleaceae, Juglandaceae, Casuarinaceae, Ticodendraceae and Betulaceae. Three clades were recognized in the core ' higher' hamamelids: (1) Casuatina ( Ticodendron, ( Betu-laceae)), (2) Juglandaceae-Rhoipteleaceae, and (3) Myricaceae. Compared with the previous studies, familial relationships of the 'higher' hamamelids were better resolved.