Am J Bot. 1997 Oct;84(10):1407.
Phylogenetic relationships were examined within the "higher" Hamamelididae using 21 species representing eight families and related outgroups. Chloroplast DNA sequences encoding the matK gene (/1 kilobase) provided 258 informative nucleotide sites. Phylogenetic analysis of this variation produced one most parsimonious tree supporting three monophyletic groups. In this tree, Nothofagus was basal to a well supported clade of remaining "higher" hamamelids, in which Fagaceae, including Fagus, were sister to a clade of core "higher" hamamelids that share wind-pollination, bicarpellate flowers, granular pollen walls, and reduced pollen apertures. Within the core "higher" hamamelids three subclades were resolved, Myricaceae, (Casuarina-(Ticodendron-(Betulaceae))), and (Rhoiptelea-Juglandaceae). Each subclade was well supported but relationships among them were not. The basal position of Nothofagus within the matK tree is consistent with the fossil record of "higher" hamamelids in which Nothofagus pollen appears earlier than microfossils with affinities to other modern "higher" hamamelids. This placement supports the exclusion of Nothofagus from Fagaceae and suggests two hypotheses for the origin of the cupule. The cupule may be ancestral within "higher" hamamelids and subsequently lost in core members of the clade or there may have been two independent origins. It is suggested that the three clades (1) Nothofagaceae, (2) Fagaceae, and (3) Juglandaceae, Rhoiptelea, Myricaceae, Casuarina, Ticodendron, and Betulaceae be considered at the ordinal level and that traditional orders, such as Fagales sensu Cronquist (Fagaceae, Nothofagaceae, and Betulaceae) be abandoned. Comparative analyses of matK sequences with previously published rbcL sequences demonstrate that for the taxa considered here matK sequences produced trees with greater phylogenetic resolution and a higher consistency index.
使用代表八个科和相关外群的 21 个物种，在“高级”Hamamelididae 中检查了系统发育关系。叶绿体 DNA 序列编码 matK 基因（/ 1kb）提供了 258 个信息性核苷酸位点。对这种变异的系统发育分析产生了一棵最简约树，支持三个单系群。在该树中，山毛榉科是其余“高级”金缕梅科的一个支持良好的分支的基础，其中壳斗科，包括山毛榉，是一个支持良好的核心“高级”金缕梅科分支的姐妹，该分支共同具有风授粉、双心皮花、颗粒花粉壁和减少的花粉孔。在核心“高级”金缕梅科中，确定了三个亚分支，杨梅科、（山龙眼科-（铁青树科））和（榆科-胡桃科）。每个亚分支都得到了很好的支持，但它们之间的关系没有得到支持。matK 树中山毛榉的基部位置与“高级”金缕梅科的化石记录一致，其中山毛榉花粉出现的时间早于与其他现代“高级”金缕梅科有亲缘关系的微化石。这种放置支持将山毛榉排除在壳斗科之外，并提出了两个关于杯状体起源的假说。杯状体可能在“高级”金缕梅科中是祖先的，随后在该分支的核心成员中丢失，或者可能有两个独立的起源。建议将三个分支（1）山毛榉科、（2）壳斗科和（3）胡桃科、榆科、杨梅科、山龙眼科、铁青树科和桦木科在目级水平上考虑，并且放弃传统的目，如 Cronquist 的 Fagales sensu （壳斗科、山毛榉科和桦木科）。matK 序列与以前发表的 rbcL 序列的比较分析表明，对于这里考虑的分类群，matK 序列产生的树具有更高的系统发育分辨率和更高的一致性指数。
