Intron distribution in relevant taxa.

*<p>trnV introns in <i>Cuscuta</i> subg. <i>Monogyna</i> have deletions that may render them pseudogenes.</p><p>Intron presence or absence is shown for <i>Nicotiana tabacum</i> (Solanaceae), <i>Ipomoea purpurea</i> and <i>Cuscuta</i> spp. (Convolvulaceae), and <i>Epifagus virginiana</i> (Orobanchaceae). <i>Nicotiana</i>, <i>Ipomoea</i>, and <i>Cuscuta</i> are classified in the order Solanales, while <i>Epifagus virginiana</i> is in the closely related order Lamiales. Subgeneric taxonomic classifications are listed for <i>Cuscuta</i> spp. <i>Nicotiana</i> intron distribution is typical of most angiosperms. “+” indicates intron present, “−” indicates precise intron loss from an intact gene, and “X” indicates loss of gene (and intron) from the plastid genome. Intron data for <i>Nicotiana</i>, <i>Ipomoea</i>, <i>Cuscuta exaltata</i>, <i>Cuscuta reflexa</i>, <i>Cuscuta gronovii</i>, <i>Cuscuta obtusiflora</i>, and <i>Epifagus</i> were gleaned from complete genome sequences available on genbank; all other data are based on PCR and PCR sequencing assays.