Bremer Kåre
Department of Systematic Botany, Evolutionary Biology Centre, Uppsala University, Sweden.
Evolution. 2002 Jul;56(7):1374-87. doi: 10.1111/j.0014-3820.2002.tb01451.x.
Phylogenetic interrelationships among all 18 families of Poales were assessed by cladistic analysis of chloroplast DNA rbcL and atpB sequences from 65 species. There are two well-supported main clades; the graminoid clade with Poaceae (grasses), Anarthriaceae, Centrolepidaceae, Ecdeiocoleaceae, Flagellariaceae, Joinvilleaceae, and Restionaceae; and the cyperoid clade with Cyperaceae, Juncaceae, and Thurniaceae. A sister group relationship between Poaceae and Ecdeiocoleaceae is identified with strong support. The sister group of this pair is Joinvilleaceae. These relationships help in elucidating the evolution of grasses and the grass spikelet. Dating of the tree was done by nonparametric rate smoothing of rbcL molecular evolution. Most Poales families date back to the Cretaceous >65 million years ago (mya). Dispersal-vicariance analysis indicates that the Poales originated in South America, the cyperoid clade in West Gondwana (South America or Africa), and the graminoid clade in East Gondwana (Australia). The Trans-Antarctic connection between South America and Australia, and its breakup about 35 mya, probably influenced the evolution of the Poales and the graminoid clade in particular, leading to vicariance between the continents, but the separation of Africa from the other Gondwanan areas, completed about 105 mya, is too old for such a relation.
通过对65个物种的叶绿体DNA的rbcL和atpB序列进行分支分析，评估了禾本目所有18个科之间的系统发育相互关系。有两个得到充分支持的主要分支；禾本科分支，包括禾本科（禾本科植物）、无节草科、刺鳞草科、旱叶草科、鞭藤科、苞穗草科和帚灯草科；以及莎草科分支，包括莎草科、灯心草科和杜若科。禾本科和旱叶草科之间的姐妹群关系得到了有力支持。这一对的姐妹群是苞穗草科。这些关系有助于阐明禾本科植物和禾本科小穗的进化。通过对rbcL分子进化进行非参数速率平滑处理来确定树的年代。大多数禾本目科可追溯到6500万年前（百万年前）的白垩纪。扩散-隔离分析表明，禾本目起源于南美洲，莎草科分支起源于西冈瓦纳（南美洲或非洲），禾本科分支起源于东冈瓦纳（澳大利亚）。南美洲和澳大利亚之间的跨南极联系及其在约3500万年前的分裂，可能影响了禾本目的进化，尤其是禾本科分支，导致了各大洲之间的隔离，但非洲与其他冈瓦纳地区在约1.05亿年前完成的分离，对于这种关系来说太过久远。
