Combination of Sanger and target-enrichment markers supports revised generic delimitation in the problematic 'Urera clade' of the nettle family (Urticaceae).

Urera Gaudich, s.l. is a pantropical genus comprising c. 35 species of trees, shrubs, and vines. It has a long history of taxonomic uncertainty, and is repeatedly recovered as polyphyletic within a poorly resolved complex of genera in the Urticeae tribe of the nettle family (Urticaceae). To provide generic delimitations concordant with evolutionary history, we use increased taxonomic and genomic sampling to investigate phylogenetic relationships among Urera and associated genera. A cost-effective two-tier genome-sampling approach provides good phylogenetic resolution by using (i) a taxon-dense sample of Sanger sequence data from two barcoding regions to recover clades of putative generic rank, and (ii) a genome-dense sample of target-enrichment data for a subset of representative species from each well-supported clade to resolve relationships among them. The results confirm the polyphyly of Urera s.l. with respect to the morphologically distinct genera Obetia, Poikilospermum and Touchardia. Afrotropic members of Urera s.l. are recovered in a clade sister to the xerophytic African shrubs Obetia; and Hawaiian ones with Touchardia, also from Hawaii. Combined with distinctive morphological differences between Neotropical and African members of Urera s.l., these results lead us to resurrect the previously synonymised name Scepocarpus Wedd. for the latter. The new species epiphet Touchardia oahuensis T.Wells & A.K. Monro is offered as a replacement name for Touchardia glabra non H.St.John, and subgenera are created within Urera s.s. to account for the two morphologically distinct Neotropical clades. This new classification minimises taxonomic and nomenclatural disruption, while more accurately reflecting evolutionary relationships within the group.

Molecular phylogeny and morphology of Elatostema s.l. (Urticaceae): Implications for inter- and infrageneric classifications.

Elatostema s.s. (Urticaceae) comprises approximately 500 species of herbs and subshrubs distributed in tropical and subtropical Asia, Australasia, and Africa. The delimitation of Elatostema s.s. and the closely related genera Elatostematoides, Pellionia, and Procris has long been problematic because of the large number of taxa and presumed homoplasy among diagnostic morphological characters. In the present study, we refer to these four genera together as Elatostema s.l. To evaluate the circumscription of Elatostema s.l. and its generic and subgeneric classification, we conducted phylogenetic analyses of DNA sequence data from the internal transcribed spacer of the nuclear genome (nrITS) and two markers from the plastid genome (psbA-trnH and psbM-trnD) for 126 taxa, representing 88 species of Elatostema s.s., four of Elatostematoides, nine of Pellionia, and five of Procris. Ten selected morphological characters were investigated using ancestral state reconstructions. Our results show that Elatostema s.l. can be divided into three well-supported and morphologically distinct genera: Procris, Elatostematoides, and Elatostema sensu auct. The results of our molecular phylogeny suggest four strongly supported clades within this newly defined Elatostema s.a.: core Elatostema, Pellionia, Weddellia, and an as yet undescribed clade African Elatostema. Homoplasy among the morphological characters used in this study makes it impossible to circumscribe genera using synapomorphies, but combined suites of characters do enable the morphological diagnosis of Elatostema s.a., Elatostematoides, and Procris.

Anatomy solves the puzzle of explosive pollen release in wind-pollinated urticalean rosids.

PREMISE OF THE STUDY: This study details the unusual synorganization of the staminate flower in wind-pollinated urticalean rosids to add the missing pieces that complete the puzzle of the explosive mechanism of pollen release in this group. METHODS: Flower buds and flowers were analyzed using light and scanning electron microscopy. KEY RESULTS: The pistillode, stamens, and sepals form a floral apparatus that explosively releases pollen to be carried by the wind. The anthers dehisce when the stamens are still inflexed on the floral bud and are enveloped by the sepals and supported by an inflated pistillode. The distension of the filaments presses the pistillode, which decreases the pressure exerted on the anthers by releasing the air accumulated internally through its apical orifice. The extended filaments and the dehiscent free anthers move rapidly outward from the center of the flower. This movement of the filaments is then blocked by the robust basally united sepals, which causes a rapid inversion of the anther position, thus hurling the pollen grains far from the flower. The pollen grains are released grouped by the mucilage produced in high quantity in the cells found in all floral organs. CONCLUSIONS: The anatomical structure of the pistillode and the finding of mucilaginous cells are the main features that help in the understanding the explosive mechanism of pollen release in urticalean rosids. The pistillode can be considered an exaptation because it was evolved later to provide a new role in the plant, optimizing male fitness.

Pulling the sting out of nettle systematics - A comprehensive phylogeny of the genus Urtica L. (Urticaceae).

The genus Urtica L. is subcosmopolitan, found on all continents (except Antarctica) and most extratropical islands and ranges from Alaska to Patagonia, Spitzbergen to the Cape and Camtschatka to the subantarctic islands. However, throughout its geographical range morphologically nearly indistinguishable species are found alongside morphologically quite disparate species, with the overall diversity of morphological characters extremely limited. The systematics of Urtica have puzzled scientists for the past 200years and no single comprehensive attempt at understanding infrageneric relationships has been published in the past, nor are species delimitations unequivocally established. We here provide the first comprehensive phylogeny of the genus including 61 of the 63 species recognized, represented by 144 ingroup accessions and 14 outgroup taxa. The markers ITS1-5.8S-ITS2, psbA-trnH intergenic spacer, trnL-trnF and trnS-trnG are used. The phylogeny is well resolved. The eastern Asian Zhengyia shennongensis T. Deng, D.G. Zhang & H. Sun is retrieved as sister to Urtica. Within Urtica, a clade comprising the western Eurasian species U. pilulifera L. and U. neubaueri Chrtek is sister to all other species of the genus. The phylogenetic analyses retrieve numerous well-supported clades, suggesting previously unsuspected relationships and implying that classically used taxonomic characters such as leaf morphology and growth habit are highly homoplasious. Species delimitation is problematical, and several accessions assigned to Urtica dioica L. (as subspecies) are retrieved in widely different places in the phylogeny. The genus seems to have undergone numerous dispersal-establishment events both between continents and onto different islands. Three recent species radiations are inferred, one in America centered in the Andes, one in New Zealand, and one in northern Eurasia which includes Urtica dioica s.str. sensu Henning et al. (2014). The present study provides the basis of a critical re-examination of species limits and taxonomy, but also of the dispersal ecology of this widespread plant group and an in-depth study of the three clades with recent radiations.

[Macroscopic and microscopic identification of Memorialis hirta].

OBJECTIVE: To provide the scientific basis for identification and utilization of Memorialis hirta ( BL) Wedd. METHODS: Macroscopical identification and microscopic identification. RESULTS: To make system pharmacognostical studies on stalk and fine powder of Memorialis hirta (BL) Wedd. CONCLUSION: These characteristic can provide the scientific basis for identification of Memorialis hirta (BL) Wedd.