Department of Ecology and Evolutionary Biology, University of Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, Michigan 48108-2287 USA;
Am J Bot. 2004 Feb;91(2):262-73. doi: 10.3732/ajb.91.2.262.
Phylogenetic data from plastid (ndhF and rbcL) and nuclear (PHYC) genes indicate that, within the order Malpighiales, Elatinaceae are strongly supported as sister to Malpighiaceae. There are several putative morphological synapomorphies for this clade; most notably, they both have a base chromosome number of X = 6 (or some multiple of three or six), opposite or whorled leaves with stipules, unicellular hairs (also uniseriate in some Elatinaceae), multicellular glands on the leaves, and resin (Elatinacae) or latex (Malpighiaceae). Further study is needed to determine if these features are synapomorphic within the order. Malpighiaceae have previously been inferred as sister to Peridiscaceae based on rbcL sequence data, but the rbcL sequence of Whittonia is a chimera of two sequences, neither of which appears to be Whittonia. Our data from plastid (atpB, rbcL) and nuclear (18S rDNA) genes instead place Peridiscaeace as a member of the Saxifragales.
基于质体（ndhF 和 rbcL）和核（PHYC）基因的系统发育数据表明，在金虎尾目内，卫矛科与金虎尾科的亲缘关系最为密切。这个分支有几个假定的形态同源特征；最值得注意的是，它们的基数染色体数均为 X = 6（或三或六的倍数），具有对生或轮生的叶和托叶、单细胞毛（某些卫矛科中也有单列）、叶上的多细胞腺体和树脂（卫矛科）或乳胶（金虎尾科）。需要进一步研究来确定这些特征是否在该目中是同源的。根据 rbcL 序列数据，金虎尾科以前被推断为卫矛科的姊妹科，但 Whittonia 的 rbcL 序列是两个序列的嵌合体，这两个序列似乎都不是 Whittonia。我们从质体（atpB，rbcL）和核（18S rDNA）基因获得的数据则将 Peridiscaceae 置于虎耳草目中。
