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

<div>A new fern species, <em>Tectaria</em> <em>danangensis</em> (Tectariaceae) is described and illustrated from Vietnam, which had long been misreported as <em>T</em>. <em>crenata</em>. The new species somewhat resembles <em>T</em>. <em>poilanei</em>, 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 <em>T</em>. <em>danangensis</em> has close affinity to <em>T</em>. <em>harlandii</em>. <em>Tectaria</em> <em>danangensis</em> appears to be an intermediate species between <em>T</em>. <em>harlandii</em> and <em>T</em>. <em>poilanei</em>.</div>