Department of Botany, Stockholm University, SE-106 91 Stockholm, Sweden, and Molecular Systematics Laboratory, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden;
Am J Bot. 2002 Mar;89(3):506-17. doi: 10.3732/ajb.89.3.506.
A phylogenetic framework is developed for the clubmoss family Selaginellaceae based on maximum parsimony analyses of molecular data. The chloroplast gene rbcL was sequenced for 62 species, which represent nearly 10% of living species diversity in the family. Taxa were chosen to reflect morphological, geographical, and ecological diversity. The analyses provide support for monophyly of subgenera Selaginella and Tetragonostachys. Stachygynandrum and Heterostachys are polyphyletic. Monophyly of Ericetorum is uncertain. Results also indicate a large number of new groupings not previously recognized on morphological grounds. Some of these new groups seem to have corresponding morphological synapomorphies, such as the presence of rhizophores (distinctive root-like structures), aspects of rhizophore development, and leaf and stem morphology. Others share distinctive ecological traits (e.g., xerophytism). For many groups, however, no morphological, ecological, or physiological markers are known. This could reflect patchy sampling and a lack of detailed knowledge about many species. Despite a lengthy fossil record dating from the Carboniferous Period, cladogram topology indicates that most of the living tropical species are probably the products of more recent diversifications. Resurrection plants, extreme xerophytes characterized by aridity-driven inrolling of branches and rapid revival on rehydration, have evolved at least three times in quite different clades.
基于分子数据的最大简约分析，为石松科（Selaginellaceae）建立了系统发育框架。对代表该科近 10%现存物种多样性的 62 种植物的叶绿体基因 rbcL 进行了测序。所选择的分类群反映了形态、地理和生态多样性。分析结果支持石松亚属和四齿石松亚属的单系性。穗叶藤属和异穗藤属是多系的。拟卷柏属的单系性不确定。研究结果还表明了大量以前基于形态学原因未被识别的新分组。其中一些新分组似乎具有相应的形态学相似性，例如根状茎（独特的根状结构）、根状茎发育的某些方面以及叶和茎的形态。其他分组则具有独特的生态特征（例如，耐旱性）。然而，对于许多分组，没有已知的形态、生态或生理标记。这可能反映了样本的不完整和对许多物种缺乏详细了解。尽管化石记录可以追溯到石炭纪时期，但系统发育图的拓扑结构表明，大多数现存的热带物种可能是最近多样化的产物。复活植物，即特征为干旱驱动的分支内卷和重新水合后迅速复苏的极端耐旱植物，已经在相当不同的分支中至少进化了三次。
