Budawangia* an E-Newsletter for All Those Interested in the Native Plants of the Nsw South Coast
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BUDAWANGIA* AN E-NEWSLETTER FOR ALL THOSE INTERESTED IN THE NATIVE PLANTS OF THE NSW SOUTH COAST Contact: Dr Kevin Mills – [email protected] No. 28 - July 2014 Aims: To connect those interested in the native flora of the NSW South Coast, to share up to date information on the flora of the region and to broaden the appreciation of the region’s native plants. Editorial July, the middle of winter, is perhaps not the most inviting time to get out into the bush, windy and cold weather discouraging excursions too far from home. There is however much to see in the bush at this time of year. Many rainforest plants have fruit, the foggy highlands provide good opportunities for early morning photographs, while the winter-flowering Banksias are putting on a show on the foreshores and in the woodlands. This edition contains an article on mistletoes, those plants that parasitise other plants. These shrubs play an important role in the ecology of forests and woodlands and recent research has identified them as critical to the well being of many animal species. The purpose of „plant of the month‟ is to discuss some of the more uncommon species in our region. This month we have Acacia hispidula, an uncommon wattle of the sandstone country. As usual, another mystery weed is presented, along with an article about two noxious weeds in the genus Xanthium and another article in the series on wetland plants. I am glad readers are finding the newsletter enjoyable and informative; comments such as the following encourage me to keep it going: Les from Kangaroo Valley - “Thanks for a very interesting issue.” Diane from Nowra - “Thanks Kevin. Really interesting as always.” Mike from Cudmirrah – “Another interesting edition.” Jane from Bowral – “Thanks Kevin, I am enjoying your Budawangia very much.” Janet from Foxground says – “I do read Budawangia and have learned a lot from that.” Finally from Bob, an enthusiastic reader from Jamberoo - “I am excited when it arrives as it contains such wonderful information.” Thanks to all who have encouraged me over the past two and a half years; especially to those who have taken the time to share their passion and expertise by sending in articles and photographs. I would be pleased to receive appropriate articles, however small, on interesting observations, new discoveries, plant name changes, etc., up to two A4 pages, including some photographs. Kevin Mills, Jamberoo, NSW. Tel. 02 4236 0620 All photographs ©Kevin Mills 2014, unless otherwise stated. * Budawangia is a monotypic, endemic genus restricted to the Budawang Range on the western edge of the South Coast region. The genus was named by Telford in 1992; the species Budawangia gnidioides (Ericaceae) was previously Rupicola gnidioides. Page | 1 Mistletoes Mistletoes are parasitic plants, mostly shrubs, that grow on other plants, usually trees. These plants attach themselves to other woody plants, penetrate their stems and take nutrients and water from the host plant. There are reported to be 89 species of mistletoe in 14 genera and two families in Australia. The family Loranthaceae is cosmopolitan and contains at least 900 species, while Viscaceae in mainly tropical to sub- tropical in occurrence and contains at least 400 species. The name mistletoe comes from an Old English word for the mistletoe of Britain, namely Viscum album. In New South Wales, two mistletoe families contain a total of 11 species; Loranthaceae contains nine species and Viscaceae two species. Most mistletoes have leaves that resemble the host plant. For example, Amyema cambagei grows on She-oaks Casuarina species, and produces leaves that look like the branchlets of the casuarina. Amyema gaudichaudii on the other hand produces leaves that look like some of the paperbarks Melaleuca species upon which it grows. Evolution has also produced a species of mistletoe that parasitises other mistletoe plants! The Golden Mistletoe Notothixos subaureus (Viscaceae) is found growing on other species of mistletoe in the family Loranthaceae. The Jointed Mistletoe Korthalsella rubra ssp. rubra (Viscaceae), which appeared in newsletter No 16, mainly grows on the rainforest tree Sassafras Doryphora sassafras in this region. Amyema gaudichaudii produces foliage similar Amyema cambagei, showing the casuarina look- to some species of Melaleuca, upon which it alike foliage. grows. Amyema congener, commonly found growing on species of Acacia. Golden Mistletoe Notothixos subureus¸ a species that parasitises other mistletoes. Page | 2 Mystery Weed Another mystery weed for your consideration. This is one of the most common weeds of roadsides and disturbed land. Bathurst Burr or Noogoora Burr? Xanthium (Asteraceae) are annual herbs. Up to six species are introduced to Australia, depending upon the treatment of the taxa. Xanthium comes from the Greek meaning yellow. The two taxa dealt with here are declared noxious weeds due to their impact on agricultural activities. These species are primarily plants of the tablelands, although they occur here and there on the coast, where seeds have probably been brought in by vehicles, soil or perhaps manure used as fertiliser. Noodoora Burr Xanthium occidentale produces largish leaves and prickly „burrs‟ about the size of a grape. The burrs are a problem to sheep graziers as they get caught in the wool. The species name occidentale means western, presumably referring to the distribution in its native North America. Taxonomy is problematic, with this taxon often included in the X. strumarium species complex. Bathurst Burr Xanthium spinosum is readily differentiated from the previous species by the spines on the stems, as suggested by the species name. This species of probable South American origin is known elsewhere as Cocklebur. Photographs. Above left: Xanthium occidentale; above right Xanthium spinosum. The Earliest wood In a paper published in 2011, Canadian and French scientists reported their discovery of what is thought to be the oldest example of a plant that produces wood. The following is the abstract from the paper. The advent of wood (secondary xylem) is a major event of the Paleozoic Era, facilitating the evolution of large perennial plants. The first steps of wood evolution are unknown. We describe two small Early Devonian (407 to 397 million years ago) plants with secondary xylem including simple rays. Their wood currently represents the earliest evidence of secondary growth in plants. The small size of the plants and the presence of thick-walled cortical cells confirm that wood early evolution was driven by hydraulic constraints rather than by the necessity of mechanical support for increasing height. The plants described here are most probably precursors of lignophytes. Gerrienne, P. et al. (2011). A Simple Type of Wood in Two Early Devonian Plants, Science 333 (6044): 837. Page | 3 Wetland Plants No. 4 – Common Reed The Common Reed Phragmites australis (Poacaee) is a large grass that may grow to at least 2.5 metres tall. It was first described and named Arundo australis by Spaniard Cavanilles in 1799 based on a specimen obtained between Port Jackson and Botany Bay; in 1841 the current name was applied to the species. The species is common in the upper saltmarsh of coastal lakes and rivers and is found in inland freshwater swamps. The plants produce a strong rhizome that promotes the spread of the plant. The species flowers in winter and dies back to regrow new shoots from the rhizomes in spring/summer. Plants mainly spread through this mechanism rather than from seed. Right. Early summer photograph of Phragmites australis, showing new growth after late winter die-back. Below. The flowering head of P. australis. Plant of the Month – Acacia hispidula Rough-leaved Wattle Acacia hispidula (Fabaceae) is a small shrub that grows in the sandstone country and occurs as far south as the northern Shoalhaven area. It often grows amongst rocks. The species name derives from hispid, which means rough and refers to the roughness exhibited by the leaves of this species. Above. The reddish stems, leaves and flower heads of Acacia hispidula. Right. The rough leaves of A. hispidula. Photographs taken near Flat Rock Dam, west of Nowra. Page | 4 .