Plastid DNA sequence data of the extinct <i>Logania depressa</i> (Loganiaceae) from New Zealand confirm its generic placement

The generic placement of the enigmatic and extinct <i>Logania depressa</i> from New Zealand has been uncertain due to the paucity of available plant material. This diminutive plant has only been collected once from the central North Island, New Zealand, by William Colenso on 22 February 1847. <i>Logania depressa</i> is dioecious and the single collection comprises only male flowers and does not include female flowers or fruit that feature generic diagnostic characters. Previously its relationship to <i>Geniostoma</i> has been considered and its affinities to <i>Orianthera</i> are unknown. <i>Orianthera</i> has been recently recognised as a segregate of <i>Logania</i>. Using leaf material from a small fragment of <i>L. depressa</i> held in Allan Herbarium (CHR) we recovered 9,368 bp of plastid sequence data that mapped to <i>Mitreola yangchuensis</i>, with <i>Mitreola</i> being the closest generic relative of <i>Logania</i> for which whole genome data was available. Available genetic data for Loganiaceae is limited to several chloroplast markers, including the <i>rps</i>16 intron, <i>pet</i>D intron, and <i>pet</i>D–<i>pet</i>B intergenic spacer. From the novel plastid sequence data for <i>Logania depressa</i>, 48 bp of the <i>rps</i>16 intron, 45 bp of the <i>pet</i>D intron and 49 bp of the <i>pet</i>D–<i>pet</i>B intergenic spacer could be recovered to compare with available Loganiaceae sequences. Phylogenetic analysis of these sequences confirmed <i>L. depressa</i> as the only New Zealand member of <i>Logania</i> sens. str., but its relationships to Australian species are unresolved.