A revision of infrageneric classification in Astelia Banks & Sol. ex R.Br. (Asteliaceae)

Abstract Systematic investigations and phylogenetic analyses have indicated that Astelia, as currently circumscribed, is paraphyletic, with Collospermum nested within it. Further, Astelia subgenus Astelia is polyphyletic, and Astelia subgenera Asteliopsis and Tricella are paraphyletic, as currently circumscribed. Revision of the subgeneric classification of Astelia is warranted to ensure classification accurately reflects the evolutionary history of these taxa. Collospermum is relegated to synonymy within Astelia. Astelia is dioecious or polygamodioecious, with a superior ovary, anthers dorsi- or basifixed, pistillodes or pistils that have a single short or poorly defined style, a 3 lobed stigma, and fleshy uni- or trilocular fruit with funicular hairs that are poorly to well developed. Astelia subgenus Collospermum (Skottsb.) Birch is described. A key to Astelia sections is provided. Astelia hastata Colenso, Astelia montana Seem., and Astelia microsperma Colenso pro parte are resurrected and the new combination Astelia samoense (Skottsb.) Birch, comb. nov. is made.


Introduction
Astelia Banks & Sol. ex R.Br. is the largest genus in Asteliaceae Dumort., containing twenty-six species and three non-nominotypical varieties with an Austral-Pacifi c distribution. Astelia species exhibit a range of growth forms including low, cushion-forming and tall, clustered habits. Astelia species grow in a diverse range of habitats including Within these subgenera, he recognized seven sections (A. sect. Astelia Skottsb., A. sect. Desmoneuron Skottsb., A. sect. Isoneuron Skottsb., A. sect. Micrastelia Skottsb., A. sect. Palaeastelia Skottsb., A. sect. Periastelia Skottsb., and A. sect. Tricella Skottsb.) based on leaf venation, pistillode size, seed surface features, and extent of funicle development. In phylogenetic analyses (Birch unpublished PhD thesis 2011, Birch et al. 2012, each of Skottsberg's (1934) sections, except A. sect. Tricella, were monophyletic, A. subg. Astelia and A. subg. Asteliopsis were polyphyletic, and A. subg. Tricella was paraphyletic. A revised circumscription of Astelia subgenera is proposed that accurately refl ects the evolutionary relationships within the genus. Collospermum is relegated to synonomy under Astelia. Skottsberg's sections are retained as they are monophyletic and accurately capture the extensive morphological diversity that is present within the subgenera.
A revision based on recognition of monophyletic taxa is proposed here. Multiple characters support the proposed circumscription of Astelia. All taxa are dioecious or polygamodioecious, with a superior ovary, dorsi-or basifi xed anthers, pistillodes or pistils that have a single short or poorly defi ned style, a 3 lobed stigma, and fl eshy unior trilocular fruit with funicular hairs that are poorly to well developed.

Taxonomic sampling
All Astelia taxa, (twenty-six species and three non-nominotypical varieties) and all Collospermum (four species) were included in this study. Herbarium specimens were examined from the following herbaria: Auckland War Memorial Museum (AK), Herbarium Pacifi cum (BISH), Allan Herbarium (CHR), Harvard University (GH), Kew Royal Botanic Gardens (K), National Herbarium of Victoria (MEL), Missouri Botanical Garden (MO), Herbier National de Paris (P), National Tropical Botanical Garden (PTBG), United States National Herbarium (US), and Museum of New Zealand Te Papa Tongarewa (WELT). Type specimens were examined from AK, BISH, MEL, P, WELT and digital images of type specimens were examined from CHR and K (Herbarium abbreviations follow Index Herbariorum (Th iers continuously updated).

Morphological data and analyses
Morphological data were obtained for 410 herbarium specimens (Appendix 1). Data were obtained for ten specimens per species, including fi ve staminate and fi ve pistillate specimens for species with unisexual fl owers. Measurements and scores were averaged across all specimens to give a mean value for each taxon. Flower and fruit color data were obtained from multiple sources including fi eld observations, specimen label data, and taxon descriptions in national fl oras (Drake del Castillo 1893, L. B. Moore and Edgar 1976, Coode 1978, D. M. Moore 1983, Williams 1987, Wagner et al. 1999 Morphological characters that varied at or below the genus rank were measured or scored for all Astelia and Collospermum taxa in the fi eld and/or herbarium. Herbarium specimens were studied under a dissecting microscope and measurements obtained using digital calipers. Pollen and seed characters were examined directly from material obtained from herbarium specimens after coating with gold-palladium using a Hitachi S-4800 fi eld emission scanning electron microscope (SEM) at the Biological Electron Microscope Facility, Pacifi c Biosciences Research Center of the University of Hawai'i at Mānoa. Images were digitally processed and the fi nal plates were prepared in Photoshop 10.0. Note. Herbaceous perennials, terrestrial or epiphytic, often growing in clusters with three ramets in trigonal arrangement, some species turf-forming, rhizomatous, dioecious or polygamodioecious. Leaves: 3-ranked, linear, ensiform, or subulate; leaves usually keeled, margins erect or revolute; leaf sheath closed, with surface obscured by dense long white hairs; parallel venation, variously incrassate; tomentum composed of scales and lanate wool at base of scale stalk, scales with basal stalk or peltate. Infl orescence: a terminal panicle, sometimes reduced to a few fl owers; lateral branches racemes or sub-panicles, subtended by foliaceous or membranous, linear or lanceolate spathes; peduncle tomentum composed of distinct, narrow scales with dense basal wool. Flowers: pedicillate; bracts membranous, linear or spathulate; perianth membranous or fl eshy, 6 tepals in 2 series; connate at base into tube of variable length; outer tepals triangular to lanceolate, with three veins, scales present over entire surface; inner tepals linear with one midvein, scales present along midvein only. Staminate fl owers: lobes recurved; stamens 6; fi laments fi lamentous, adnate to tepals at base of tepal lobes; anthers elliptic or linear-hastate, dorsifi xed and versatile or basifi xed and immobile, latrorse; pistillode present, style undiff erentiated or distinct; stigma not formed. Pistillate fl owers: 6 reduced staminodes present, adnate to base of tepal lobes, fi lament fi lamentous, anthers fl attened, sterile; ovary superior, uni-or trilocular, placentation parietal from three placentas or axile, with subapical placentas, ovules few to many; style distinct or undiff erentiated, stigmas 3. Fruit: berry, stigma typically persistent. Seeds: black, obovoid, ellipsoid, fusiform, or polygonal; testa smooth or sculptured; funicle with mucilaginous funicular hairs poorly or well developed, funicle hairs surrounding the seeds and either adhering to the testa or not. Remarks. Astelia microsperma was described by Colenso based on a specimen at Kew that contained material from two species (Skottsberg 1934). Th e species description "referred to both, but mainly to the pistillate raceme in the envelope" (Skottsberg 1934, 82 Remarks. Seemann stated in the preface of Flora Vitiensis (1965, iv) that "the fi rst set of specimens collected by me were deposited at the Royal Herbarium, Kew and from these the plates accompanying this work have chiefl y been taken". Th e type material of A. montana, which was eff ectively published in Flora Vitiensis, can reasonably be expected to have been accessioned at Kew. Two sheets containing Astelia montana specimens collected by Seemann are accessioned at K. One sheet (K000524875) includes a vegetative plant collected at Mt. Mbuke Levu and a second sheet (K000524876) includes a leaf fragment annotated as collected at "Vuna, June 1860" and a pistillate infl orescence labeled as collected by Seemann (n. 641) in 1860. Sheet K000524876 includes the illustrations of the pistillate fl ower, staminode, berry and seed that appear in the plate that accompanies the protologue of A. montana (Seemann 1965).

Taxonomic treatment
Th e pistillate infl orescence labeled as Seemann's collection n. 641 on sheet K000524876 represents the holotype. According to Seemann's (1962Seemann's ( , 1965 accounts of his fi eld collections, he successfully ascended Mt. Mbuke Levu only once, on 6 September 1860. Th e vegetative specimen on sheet K000524875 was also collected by Seemann on "Buke Levu" [sic]. A type specimen can be mounted on multiple sheets "as long as the parts are clearly labeled as being part of that same specimen" (International Botanical Congress and JH Wiersema 2015); Article 8.3). Although it is likely that sheets K000524875 and K00524876 represent a single specimen that was mounted on separate sheets (Birch pers. comm., Smith 1979), they were not clearly labeled as such. Th erefore, K000524875 is considered a duplicate. Th e leaf fragment on sheet K000524876 annotated as collected in "Vuna June 1860" may represent a fragment of an earlier collection from Vuna on the island of Taveuni (Smith 1979) where Seemann spent time during June 1860 (Seemann 1962 (Birch unpublished PhD thesis 2011, Birch et al. 2012. Astelia sect. Periastelia is monophyletic; however A. sect. Tricella is present as a grade and relationships within each of these sections remain equivocal.
Remarks. Th e relationships of A. sect. Micrastelia are poorly resolved, with alternate relationships with A. subg. Asteliopsis and the clade containing A. subg. Tricella and Collospermum (Birch unpublished PhD thesis 2011, Birch et al. 2012. Astelia sect. Microastelia contains a single species, Astelia pumila, which is a compact, turf-forming plant and dominant component of Astelia moorland in Chile, the Falkland Islands, and Tierra del Fuego. As a cushion-forming species, it diff ers morphologically from A. subg. Asteliopsis, which contains species with open, spreading growth form that are epiphytic or terrestrial and primarily found of the understory in lowland to montane forests. Astelia pumila does share morphological features with A. subg. Asteliopsis (e.g. short pistillode or pistil) and, alternatively, with A. subg. Collospermum and A. subg. Tricella (e.g. seeds with a short, truncate funicle). Th e subgeneric placement of A. sect. Micrastelia remains equivocal and the section is unplaced (incertae sedis).