AN ILLUSTRATED AND ANNOTATED KEY TO THE TaSMANIAN SPECIES OF SENECIO (ASTERACEAE) Mark Wapstra, Ian Thompson and Alex Buchanan Wapstra M., Thompson I.R., Buchanan A.M. 2008. An illustrated and annotated key to the Tasmanian species of Senecio (Asteraceae). Kanunnah 3: 49–93. ISSN 1832-536X. A key to the Tasmanian species of Senecio (Asteraceae) is presented, including all native and naturalised species, subspecies and varieties (41 taxa in total). Two species formerly placed in Senecio, Delairea odorata Lem. and Brachyglottis brunonis (Hook.f.) B.Nord., are also included. An illustrated glossary of terms is provided, together with comments on the identification and discrimination of taxa and distribution maps. Mark Wapstra, Environmental Consulting Options Tasmania 28 Suncrest Avenue, Lenah Valley, Tasmania, 7008, Australia. Email: [email protected] Ian Thompson, School of Botany, The University of Melbourne Parkville, Victoria, 3010, Australia. Email: [email protected] Alex Buchanan, Tasmanian Herbarium GPO Box 252-04, Hobart, Tasmania, 7001, Australia. Email: [email protected] KEY WORDS: Senecio, groundsel, fireweed, Asteraceae, key, Tasmania. Senecio is a large cosmopolitan genus com­ centropappus F.Muell. for which the name prising about 1250 species (Bremer 1994). Brachyglottis brunonis (Hook.f.) B.Nord. is Australia has 87 native species (Thompson current. Curtis (1963) did not recognise any 2006) and ten naturalised species, the varieties or subspecies in Senecio. latter mostly from South Africa and some Buchanan (2005) in the Census of Vas­ from Europe. Curtis (1963) in Part 2 of the cular Plants to Tasmania updated the list Student’s Flora of Tasmania recognised 22 of species of Senecio present in Tasmania, species in Senecio, four being naturalised mainly from the recent taxonomic work and eighteen native. Two have since been of Thompson (2004a–d, 2005). Excluding transferred to other genera, these being the hybrid taxa (only S. Xorarius J.M.Black introduced S. mikanioides Otto ex Harv., is currently recognised in Buchanan now known as Delairea odorata Lem., and S. (2005) but is herein not considered 49 KANUNNAH Mark Wapstra, Ian Thompson and Alex Buchanan worthy of taxonomic recognition) and S. or varieties often requires microscopic pectinatus var. major F.Muell. ex Belcher examination of capitula, stems or leaves. (now recognised by Thompson (2006) However, an annotated and illustrated as a mainland endemic), S. linearifolius glossary is provided following the key var. latifolius (that is herein recognised as to explain technical terms. Each species present) and S. georgianus (hitherto not has some accompanying notes on its recognised by Buchanan (2005)), 41 taxa recognition (in particular, confusing of Senecio are now recognised in Tasmania species or characters), distribution and (Buchanan 2005). Of the 29 native species, habitat (also following the key). one is represented by two subspecies, one Fresh or dried material may be used by one subspecies, two by one variety, one in the key below. Working with fresh by four varieties and one by five varieties. material, especially flowering material, Seven taxa are endemic to Tasmania. The is often much easier. Decisions at each four naturalised species are S. angulatus, couplet should be made after considering S. elegans, S. jacobaea and S. vulgaris. All as many of the characters mentioned as Tasmanian species, except Senecio angulatus possible. As with most complex keys, which is a climber, are herbaceous and familiarity breeds confidence. It is recom­ may be woody basally. mended that users of the key try to The almost doubling of the number identify taxa familiar to them to get used of Tasmanian Senecio taxa since Curtis to the terminology. (1963) has prompted the construction of the following key. It is mainly intended What material needs to assist field workers to identify this to be collected complex suite of species without needing Some taxa of Senecio require very little to delve into more complex taxonomic material to identify them with confidence papers. However, for recent descriptions of (e.g. some subalpine radiate species Tasmanian species, the reader is referred can be identified from basal rosettes to Thompson (2004a–d, 2005, 2006). With of leaves with no flowering material), three species listed as threatened on the although many require carefully collected Tasmanian Threatened Species Protection Act specimens that include the root system, 1995, and several others known from very representative parts of the stem, leaves few records (including several that qualify from different parts of the stem and a as ‘presumed extinct’ because they have range of flower ages (e.g. most of the non­ not been recorded for more than 50 years), radiate species, i.e. the disciform species). it is important that field workers can Several specimens collected from a site can correctly identify species of Senecio. make identification easier as the presence of characteristics such as coarse hairs on Some notes on using the key stems and leaves, cobwebby hairs on As with most keys, it is difficult to avoid flowerheads and hairs on achenes can the use of technical terms, especially in vary depending on the age of plants so it the case of a genus like Senecio, in which is often desirable to develop a ‘population the identification of species, subspecies picture’, rather than rely on identification 50 An Illustrated and Annotated Key to the Tasmanian Species of Senecio KANUNNAH from a single specimen. With the disciform Hybrids between disciform and radiate species, it is particularly important to species are usually identifiable by the collect mature achenes because young presence of ligules that are shorter (mostly achenes will be considerably shorter and 0.5–4 mm long), and narrower than those less hairy than their mature counterparts. seen in radiate species, and, in the field, by Collected material should be pressed the identification of populations of parent promptly, especially for taxa with larger species in the vicinity. leaves prone to curling, and for those Several hybrids between radiate and with large radiate flowerheads that wither disciform species have been recognised quickly. If prompt curation is not possible, as occurring in Tasmania. One is a hybrid notes should be made on the length and between S. pinnatifolius and S. biserratus. number of ray florets in radiate species This entity was described as S. Xorarius as this is easier to do with fresh material. (Black 1928). It occurs infrequently on the Specimens will stay fresh if carefully Victorian and South Australian coasts, wrapped in moist (but not wet) paper towel and only one Tasmanian specimen at (or moss) and kept cool for transport. Some the Tasmanian Herbarium has been fleshy leaved species will require careful determined as this entity. It does not curation to avoid development of mould. appear to form stable populations and Light pressing is recommended for all taxa plants are sterile (Lawrence 1980); thus to avoid overly deforming flowerheads (or is not considered worthy of taxonomic measuring the diameter of the flowerheads recognition. The other recognised hybrid upon collection is advised). If far enough is between S. linearifolius var. linearifolius advanced at the time of collection, achenes and S. minimus. There are a few collections may develop to maturity during pressing. of this hybrid from both Tasmania and Victoria. Hybrids between S. linearifolius Species nomenclature (unknown variety but probably var. Botanical nomenclature follows Buchanan linearifolius) and S. hispidulus have also been (2005), except where indicated in the observed recently (M. Wapstra, pers. obs.) species’ notes, and vernacular nomen­ in the north­east (Elephant Pass) and the clature follows Wapstra et al. (2005). An south­east (Surges Bay). asterisk (*) next to the botanical name in Hybrids between disciform species may the key and notes indicates that the species key with difficulty to a recognised taxon is naturalised in Tasmania. and users of the key should be cautious if a hybrid is suspected – collection of A note on hybrids additional possible parent material from Species of Senecio readily hybridise, both the vicinity may be necessary to help within and between the two morph­ confirm identification of such entities. ologically distinct groups (i.e. the radiate Hybridisation between non­radiate parents and disciform species). Hybrids are not has been recorded from mainland Aust ralia inc luded in the present key but are discussed and is a possibility in Tasmania wherever in the notes below each species in the species co­occur (up to five species of key that may be possible parent species. Senecio can co­occur together). 51 KANUNNAH Mark Wapstra, Ian Thompson and Alex Buchanan (generally difficult to access), many parts of the central, eastern and northern Midlands (mainly private property), parts of the north­east and several areas in the north­ west (notably much of the private property areas and two offshore islands). This map also shows that many areas of the state are represented by numerous collections. Of note are the coastal areas, many of the Bass Strait islands, parts of the Central Highlands and around the major population centres in the Tamar (Launceston) and Derwent (Hobart) river systems. Macquarie Island, a sub­antarctic island administered by Tasmania, is not included on the distrib­ ution maps because no species of Senecio Fig. 1. Distribution records for all Tasmanian are known from there (Buchanan 2005). species of Senecio. Conservation status Distribution maps Three species are presently listed as Maps are based on specimens held by threatened on the Tasmanian Threatened the Tasmanian Herbarium (excluding Species Protection Act 1995 (S. macrocarpus as unidentified specimens), specimens from extinct, and S. squarrosus and S. velleioides Mark Wapstra’s personal herbarium, and as rare). Several other species, most notably records of threatened taxa held by the S. campylocarpus, S. extensus, S. georgianus, Threatened Species Section of the Depart­ S.