Tectaria danangensis (Tectariaceae), a new fern species from Vietnam

A new fern species, Tectaria danangensis (Tectariaceae)
is described and illustrated from Vietnam, which had long been
misreported as T. crenata. The new species somewhat
resembles T. poilanei, a species long neglected in the
fern flora of Indochina, in the frond shape and sori arrangement
but differs by its sori irregularly in two rows (versus regularly
2-rowed, distantly and evenly arranged) between lateral veins of
pinnae, fronds being more or less dimorphic (versus monomorphic), and
basal pinnae each having a base-joined (versus free) branch. Phylogenetic
analyses of selected sequences of cpDNA suggested T.
danangensis has close affinity to T.
harlandii. Tectaria danangensis appears to be
an intermediate species between T.
harlandii and T. poilanei.

本文记述并图示了产自越南的蕨类新种——岘港三叉蕨（Tectaria danangensis，三叉蕨科Tectariaceae），该类群曾长期被误定为圆齿三叉蕨（T. crenata）。该新种在叶形与孢子囊群排布特征上，与印支蕨类区系中长期被忽视的波氏三叉蕨（T. poilanei）较为相似，但存在如下差异：羽片侧脉间的孢子囊群呈不规则两列排布，而波氏三叉蕨的孢子囊群为规则两列，间距疏远且排列均匀；叶或多或少呈二型，相较之下波氏三叉蕨为单型叶；基部羽片均具基部连合的分枝，而波氏三叉蕨的分枝则为分离状态。对选取的叶绿体DNA（cpDNA）序列开展系统发育分析结果表明，岘港三叉蕨与哈氏三叉蕨（T. harlandii）亲缘关系密切，且似乎是哈氏三叉蕨与波氏三叉蕨之间的过渡类群。