Protection Quarterly Vol.19(2) 2004 59 • needlegrass (N. leucotricha Trin. & Rupr.) The distribution, impacts and identifi cation of exotic • Lobed needlegrass (N. charruana Are- stipoid grasses in Australia chav.) • Short-spined needlegrass (N. megapota-

A,D B C mia Spreng. ex Trin.) David A. McLaren , Val Stajsic and Linda Iaconis • Uruguayan ricegrass (Piptochaetium A Primary Industries Research Victoria (PIRVic), Department of Primary montevidense (Spreng.) Parodi) Industries, Frankston Centre, PO Box 48, Frankston, Victoria 3199, Australia. • Broad-kernel espartillo (Achnatherum B National Herbarium of Victoria, Royal Botanic Gardens, Birdwood Avenue, caudatum Trin.) South Yarra, Victoria 3141, Australia. • Narrow-kernel espartillo (A. brachycha- C Catchment and Agriculture Services, Department of Primary Industries, etum (Godr.) Barkworth) and Frankston Centre, PO Box 48, Frankston, Victoria 3199, Australia. • Plumerillo (Jarava plumosa (Spreng.) D CRC for Australian Weed Management. S.W.L.Jacobs & J.Everett). All of these species are proclaimed in South Australia, under the Animal and Plant Control (Agricultural Protection and Other Purposes) Act, 1986. Abstract For each species, a summary has been Exotic stipoid grasses are one of the structures at the base of a spikelet) which produced of its: most signifi cant issues affecting grazing are often purplish in colour, and one fl oret • Distribution – known overseas distri- industries and threatening nationally im- (in which the seed is formed). The fl oret butions, current Australian distribu- portant remnant grasslands in Australia. consists of the lemma and palea. The lem- tion and potential distribution in Aus- This paper documents their distribution, ma is usually terete (i.e. circular in cross tralia (based on its current distribution impacts and identifi cation. It also dis- section) or gibbous (i.e. asymmetric) and in Australia). cusses how these grasses are coming into fi rmly membranous. The palea is enfolded • Impacts – agricultural and environ- Australia and makes recommendations and concealed by the lemma. Seed may be mental. on how this could be addressed. tipped by a callus of hairs (see Figure 1), • Identifi cation – vegetative and fl oral and has an awn (a curved, bristle-like tail) characteristics that help differentiate Introduction at the opposite end. the species. South-eastern Australian indigenous The exotic stipoid grasses are one of grasslands are now regarded as one of the most signifi cant threats facing graz- Serrated tussock, Australia’s most threatened ecosystems. ing industries and indigenous grasslands trichotoma Only half of one percent (10 000 hectares) in south-eastern Australia (McLaren et al. Distribution of the original two million hectares of low- 1998). Eleven exotic stipoid grass species (syn. trichotoma) land grasslands now remain in near natu- have naturalized in Australia (McLaren is a perennial, drought resistant species ral condition, and they contain the greatest et al. 1998), whilst white tussock (Nassella that is native to the pampas grasslands number of species facing extinction (Mar- tenuissima (Trin.) Barkworth) has been sold of Argentina, Uruguay, Chile and Peru riott and Marriott 1998). Since European in Australia through the nursery trade (Parodi 1930, Rosengurtt et al. 1970) and settlement, native grasslands have been (McLaren et al. 1999). The stipoid grasses it has been reported from Bolivia (Walsh rapidly transformed due to land clear- come from the Family that com- and Entwisle 1994). It has also natural- ance, urbanization, grazing by introduced prises approximately 9500 species and 650 ized in Australia, New Zealand and South ungulates (e.g., sheep, cattle, horses) genera worldwide (Walsh and Entwisle Africa, whilst small infestations also occur and large scale agricultural production 1994). The Stipeae is a cosmopolitan tribe in England, France, Italy, Scotland (Camp- (cropping and grazing using introduced of approximately 450 species in 14 genera bell 1982, Stace 1997) and the United States grasses and wide-scale addition of su- (Barkworth 1993, Reyna and Barkworth (Westbrooks 1991, Westbrooks and Cross perphosphate). Introduced pests such as 1994, Jacobs and Everett 1996). There are 1993). rabbits and weeds have added additional six stipoid genera in Australia, of which Nassella trichotoma was probably intro- pressures to these remnant grasslands. At fi ve are of exotic origin. Austrostipa is the duced into Australia in the early 1900s but the same time, sheep and beef production only indigenous Australian genus. The was not recorded in Australia until 1935 have become some of Australia’s most im- exotic genera include Achnatherum, Jarava, when a collection was made at Yass, 55 portant rural industries. For many years Nassella, Piptochaetium and Piptatherum. km north-east of Canberra (Campbell and Australia’s economy was said to ‘live off As rice millet (Piptatherum miliaceum (L.) Vere 1995). In 1977 it occupied 680 000 the sheep’s back’. This paper examines the Coss.) appears to be confi ned to urban hectares (Campbell 1977) and now occu- impacts caused by exotic stipoid grasses to settlements, in Victoria at least (Walsh and pies more than 870 000 hectares in New agriculture and the environment and how Entwisle 1994), it will not be considered in South Wales with an estimated 2 000 000 we can recognize these serious weeds. this paper. Species of the other genera are a hectares at risk of infestation (McGowan The Stipeae are strongly tussock cause for serious alarm from both an envi- personal communication). In Victoria N. forming, mostly perennial grasses that ronmental and agricultural perspective. trichotoma was fi rst collected in 1954 at generally have narrow, inrolled leaves. Eleven exotic stipoid grass species are Broadmeadows where infestations were The ligule (a small fl ap at the junction described in this paper, in the following then estimated at four hectares (Lane of the leaf blade and leaf sheath) is often order: personal communication). By 1979 it had short, membranous and fringed. Au- • Serrated tussock (Nassella trichotoma spread to occupy approximately 30 000 ricles (paired projections either side of (Nees) Hack. ex Arechav.) hectares (Lane et al. 1980) and by 1995 the ligule) are glabrous or fringed. The • White tussock (N. tenuissima (Trin.) it occupied in excess of 130 000 hectares infl orescence (fl owering stem) is a panicle Barkworth) (Pest Management Information System, which is rarely branched at the base or • Chilean needlegrass (N. neesiana Trin. & Department of Primary Industries (DPI) occasionally reduced to a few spikelets. Rupr.) Frankston). The Victorian Government Each spikelet has two glumes (leaf-like • Cane needlegrass (N. hyalina Nees) has recently increased N. trichotoma 60 Plant Protection Quarterly Vol.19(2) 2004 control operations that have been fa- Identifi cation White tussock, Nassella tenuissima cilitated by the Victorian Serrated Tussock Vegetative characters Nassella trichotoma Distribution Working Party. It has been estimated that forms a very dense tussock, to 50 cm high Nassella tenuissima (syn. Stipa tenuissima) in excess of 70 000 hectares of serrated tus- and 60 cm across, composed of numerous is native to Argentina, Chile, New Mexico sock infestations have now been treated in fi ne leaves. Leaves are tightly rolled and and Texas (Jacobs et al. 1998). In 1996, Victoria (Boyle personal communication). appear cylindrical when cut in cross sec- N. tenuissima was found being sold at a N. trichotoma now occupies 82 000 hectares tion. Unlike Australian native grasses, N. nursery in Melbourne. Its potential dis- in Victoria, which is a 37% reduction from trichotoma leaves, when rolled between tribution in Australia, predicted from its the 1995 infestation (Boyle 2003). N. tri- the index fi nger and thumb, roll smoothly countries of origin, has been estimated at chotoma is also found in Tasmania where – like a needle. N. trichotoma leaves are 14.2 million hectares (McLaren et al. 1999). it was fi rst recorded in 1956 (Parsons and rough to touch due to small serrations N. tenuissima can potentially occupy six Cuthbertson 1992) and is currently spread on their surfaces and these are easily felt times the area predicted for N. trichotoma in scattered populations over an area of when drawn between the fi ngers. Mature in Australia. The availability of N. ten- approximately 1000 hectares (Goninon plants have drooping leaves. Flower- uissima via the internet and other plant personal communication). Its potential ing stems emerge in spring and grow to purchasing situations makes its entry and distribution in Australia, predicted from a length of 95 cm, twice as long as the naturalization in Australia almost inevita- its current distribution in Australia, has leaves. They are initially erect but droop ble (McLaren et al. 1999). been estimated at 32 million hectares at maturity. They are much branched and (McLaren et al. 1998). usually break off at the base after seed set. Impacts The ligule is about 1 mm long, rounded, In Argentina N. tenuissima is regarded as Impacts membranous and glabrous. an unpalatable grass (Moretto and Distel Nassella trichotoma probably accounts for 1998). It has been classifi ed as a non-pre- a greater reduction in pasture carrying Floral characters The general floral ferred species that can become dominant capacity than any other weed in Australia characteristics of the Genus Nassella under continual heavy grazing pressure (Parsons and Cuthbertson 1992). Its high are: Lemma – strongly convolute (i.e. with a low frequency of high intensity fibre content and low protein content inrolled margins, as in Austrostipa). Co- fi re (Distel and Boo 1995). Similarly, it is make it indigestible and stock will only rona – present (sometimes evident only regarded as a species that is rarely eaten by attempt to eat it if nothing else is avail- on dissection.). Palea – reduced, usually deer in Texas (Simons 1996). N. tenuissima able. Heavily infested paddocks in NSW glabrous (i.e. hairless), unveined. For all is less palatable than serrated tussock in carry only 0.5 dry sheep equivalent (dse) the exotic stipoid grasses, the easiest time Argentina (Distel personal communica- per hectare compared to 7 to 15 dse on for identifi cation is at fl owering during tion). N. tenuissima is climatically very improved pasture without the weed (Par- spring and summer. well matched to Australian conditions sons and Cuthbertson 1992). In 1988, N. In N. trichotoma the infl orescence is an and its taxonomic similarity to N. tri- trichotoma was estimated to be costing the open branched panicle up to 35 cm long. chotoma makes this species a potential Australian Wool Industry approximately Major branches are in pairs that break into disaster for the Australian environment $12.9 million annually (Sloane Cook and numerous branchlets where the florets (McLaren et al. 1999). An economic as- King Pty Ltd 1988). Aberdeen (1995) stated develop. The panicle readily detaches at sessment estimated that preventing N. that Victoria could save approximately $35 maturity. Glumes are strongly purplish. tenuissima naturalizing in Australia would million per year if it restricted the distribu- The lemma is obovoid and truncate at potentially save Australia $39 million over tion of N. trichotoma to 200 000 hectares. A its apex, measuring 1.5–3 mm long. The the next 60 years (Centre for International conservative fi gure for the cost of N. tri- corona is only evident on dissection and Economics 2001). chotoma in Victoria is $5 million per year is very small (ca. 0.1 mm long). The awn is A national campaign to stop this weed (Nicholson et al. 1997) and for New South 25–35 mm long, attaching obliquely to the has resulted in it being declared noxious Wales $40 million per year (Jones and Vere lemma (Figure 1). N. trichotoma can be eas- in most States in Australia. The CRC for 1998). ily mistaken for N. tenuissima. Distinguish- Australian Weed Management offered Carr et al. (1992) classifi ed N. trichotoma ing features are a shorter awn (25–35 mm a reward of $100 to people returning N. as a very serious environmental weed that compared to 50–90 mm for N. tenuissima) tenuissima plants sold through the nursery invades dry coastal vegetation, lowland and the oblique attachment of the awn to trade. A number of plants were returned grassland, grassy woodland, sclerophyll the lemma. but many more have not. N. tenuissima forest and woodland and rocky outcrop is on the ‘Weed Alert List’ of the Com- vegetation. In Victoria, N. trichotoma is ei- monwealth Department of Environment ther actively invading or has the potential and Heritage. Its potential as an agricul- to invade some of Australia’s most endan- tural and environmental weed has seen gered native grassland remnants. hairs ➔ it declared a State Prohibited Weed in N. trichotoma is also a signifi cant fi re Victoria. risk. Its high fi bre content makes it highly combustible and has reportedly extended Identifi cation ➔ the fire season by two months in the callus ➔ Vegetative characters Nassella tenuissima Geelong region of Victoria (Churnside forms a very densely tufted tussock to 70

➔ base of personal communication). lemma awn cm high and 60–100 cm across, composed N. trichotoma has been declared a Weed of numerous fi ne leaves. Culms (stems) of National Significance in Australia grow to 70 cm high with 2–3 unthickened (Thorp and Lynch 2000, Agriculture and Figure 1. Nassella trichotoma seed. nodes. Culms are smooth, hairless and Resource Management Council of Aus- round in cross section between nodes. tralia and New Zealand et al. 2001a). The fl ower-bearing section of the culm is 15–25 cm long and green or purplish in appearance. The lower section is Plant Protection Quarterly Vol.19(2) 2004 61 enclosed in a leaf-like sheath and, unlike 1934. It was later identifi ed in NSW (Glen Identifi cation N. trichotoma, the mature seed head does Innes on the New England Tablelands) in Vegetative characters When grazed N. not always fully project and spread from 1944 and is also naturalized in South Aus- neesiana will tiller profusely, producing this sheath. Ligules are membranous and tralia (Lucindale) (McLaren et al. 1998). A many shoots from the base that develop glabrous. In general, N. tenuissima is very survey conducted in Victoria and NSW into a wide, untidy tussock 30–60 cm similar to, but grows more upright than, during 2002 estimated that N. neesiana across. However, the growth form is rather N. trichotoma. was dispersed over an area of more than more like that of rye grass (Lolium spp.) 4 million hectares (McLaren et al. 2002). Its or cocksfoot (Dactylis glomerata L.) than Floral characters Nassella tenuissima potential distribution, predicted from its the very pronounced tussock growth of has a single bisexual fl oret per spikelet, current distribution in Australia, has been plants such as N. trichotoma and the com- surrounded by two persistent bracts estimated at 42 million hectares (McLaren mon native tussock grass (Poa labillardierei (glumes). Seed has an awn 50–90 mm et al. 1998). Steud.). The leaves are fl at or somewhat long and it is not readily detached from inrolled, to 30 cm long and 5 mm wide, the seed. The lemma is 2–3 mm long and Impacts and harsh to touch due to their strong ribs its awn attaches centrally (Figure 2). Nassella neesiana tolerates drought, heavy and short marginal hairs. The leaf surface grazing and sites that are subject to sea- is mostly glabrous and often bright green sonal waterlogging (McLaren et al. 1998). in colour. At the base of each leaf is a 3

➤ Its competitive ability and effi cient re- mm long, glabrous, membranous ligule, productive mechanisms has enabled N. which extends across the leaf base and is neesiana to dominate large areas of highly bordered by two small tufts of erect hairs ➤ 2–3 mm productive pastures on the Northern either side (which are easily seen when the Tablelands of New South Wales and the leaf is pulled away from the stem). ➤ Volcanic Plains of Victoria (Gardener 1998). During warmer months it produces Floral characters Nassella neesiana fl ow- large numbers of unpalatable fl ower stalks ers from spring to early summer but and very little leaf material, resulting in a occasional plants can be found in fl ower severe reduction in summer stock car- until April. It produces both panicle seeds rying capacity. Conversely, a reasonable (cross-pollinating) and cleistogamous quantity of good feed is produced during seeds (selfi ng, stem seeds). The panicles the winter months on the New England are loose, sometimes interrupted and up awn Tablelands (Gardener 1998). N. neesiana to 40 cm long. The glumes are 16–20 mm 50–90 mm seeds have very sharp points that report- long and have a distinctive purplish col- edly penetrate and damage the fleece, our. The lemma is 8–10 mm long, with a skins and eyes of livestock (Bourdot and 1 mm long, terminal corona with slightly Ryde 1986). divergent apical spines 0.2–0.5 mm in On average, N. neesiana costs from length. The callus is 2–4 mm long and the $64.50 to $118.75 per hectare to control on awn is 60–90 mm long (Figure 3). When grazing lands, depending on whether the seeding, the awns of several seeds can infestation is scattered or dense (McLaren become twisted together forming a tan- et al. 2002). An economic assessment of N. gled seed mass. N. neesiana also produces neesiana in Victoria shows that without cleistogamous (stem) seeds within stems. government investment in its coordinated Cleistogenes allow the plant to reproduce ➤ treatment, under the worst-case scenario even if fl owering has been inhibited. of weed spread rate, N. neesiana is likely to cost the Victorian community approxi- Figure 2. Nassella tenuissima seed. mately $464 million in 30 years. Govern- ment investment in N. neesiana control corona

under the base-case ‘high’ rate of spread resembling a scenario was assessed to deliver to Victo- ➔ crown Chilean needlegrass, Nassella ria a net present value (NPV) of about $82 neesiana million in terms of saving potential pro- ➤ Distribution duction losses and avoiding future control Nassella neesiana (syn. Stipa neesiana ) is a costs (Morfe et al. 2003). tufted perennial grass that is indigenous Nassella neesiana has been described to Argentina, Bolivia, Chile, Ecuador, as potentially the worst environmental southern Brazil and Uruguay (Rosengurtt weed of indigenous grasslands in Victoria 8–10 mm et al. 1970). This species is a serious weed (McLaren et al. 1998 ). Carr et al. (1992) in Australia (McLaren et al. 1998) and New classifi ed N. neesiana as a very serious en- Zealand (Bourdot and Hurrell 1992). It has vironmental weed that invades lowland also been recorded in south-east England grassland, grassy woodland and rocky (Stace 1997) and has been found in the outcrop vegetation. N. neesiana has been USA on ballast dumps such as in Mobile, declared a Weed of National Signifi cance Alabama (US Department of Agriculture in Australia (Thorp and Lynch 2000, ➤ 1953), but there have been no recent Agriculture and Resource Management records according to Barkworth (1993). Council of Australia and New Zealand et The first record of N. neesiana from al. 2001b). Figure 3. Nassella neesiana seed. Australia was in Victoria (Northcote) in 62 Plant Protection Quarterly Vol.19(2) 2004 Cane needlegrass, Nassella hyalina Floral characters The panicle of N. hy- Distribution alina is contracted, to 25 cm long. Glumes hairs on corona

Nassella hyalina is a tufted, perennial grass are 6–12 mm long (6–8 mm in Caro 1966). 0.6–1.5 mm indigenous to Argentina, southern Brazil The lemma is 3.5–4.5 mm long (Figure 4). ➔ and Uruguay (Caro 1966, Rosengurtt et al. The corona is 0.5–1 mm long with apical 1970). It was fi rst recorded in Australia in hairs or slender spines 0.6–1.5 mm long. central New South Wales (between Glen The callus is 1–3 mm long and awn 35–40 Innes and Inverell) in 1951 and was later mm long. When fl owering the seed heads ➤ recorded in Victoria (Woodstock) in 1964. are erect and contracted (like a cane). N. Signifi cant infestations are centered on the hyalina also produces cleistogamous seeds outer western suburbs of Melbourne and within the basal crown and within the 6–10 mm central Victoria (McLaren et al. 1998). Its stems. potential distribution, predicted from its current distribution in Australia, has been Texas needlegrass, Nassella leucotricha estimated at 0.9 million hectares (McLaren Distribution et al. 1998). Nassella leucotricha (syn. Stipa leucotricha) is a tufted perennial grass indigenous Impacts to Oklahoma, Texas and central Mexico In Argentina, N. hyalina is reportedly pal- (Leithead et al. 1971, Reyna and Barkworth ➤ atable to stock (Rosengurtt et al. 1970) and 1994). It was fi rst found in Victoria (North- is regarded as producing reasonable fod- cote) in 1934 and has since spread through der. Carr et al. (1992) considered N. hyalina the northern and western suburbs of Mel- a serious risk as an environmental weed. bourne and into central Victoria (McLaren Figure 5. Nassella leucotricha seed. It is primarily a weed of indigenous grass- et al. 1998). It is also naturalized in South lands but has also been observed growing Australia. The potential distribution of N. in areas subject to seasonal waterlogging leucotricha, predicted from its current Aus- and riparian vegetation (McLaren et al. tralian distribution, has been estimated at Lobed needlegrass, Nassella 1998). N. hyalina is on the ‘Weed Alert List’ 4.8 million hectares (McLaren et al. 1998). charruana of the Commonwealth Department of En- Distribution vironment and Heritage. Impacts Nassella charruana (syn. Stipa charruana) is a In North America, the species is known ei- perennial tussock grass that is indigenous Identifi cation ther as Texas needlegrass or Texas winter- to Uruguay, Argentina and south-east Nassella hyalina can be confused with N. grass. It is readily grazed by livestock and Brazil (Rosengurtt et al. 1970). It is becom- leucotricha. This confusion could be due apparently of signifi cant value for early ing a serious weed in Australia (McLaren to intraspecific variation of N. hyalina spring or winter grazing (Leithead et al. et al. 1998). To date it has only naturalized and/or N. leucotricha. Alternatively, what 1971, Gould 1978). In its indigenous habi- in Victoria and was fi rst collected in 1995 is currently called N. hyalina in Australia tat, N. leucotricha thrives under conditions at Thomastown, just north of Melbourne may in fact be another species (i.e. N. for- of moderate disturbance and is frequently (McLaren et al. 1998). The potential dis- micarum). abundant on roadsides, in open grassland tribution of N. charruana, predicted from sites and heavily grazed pastures (Leit- its Australian distribution, has been esti- Vegetative characters Nassella hyalina head et al. 1971). To date no information is mated at 0.6 million hectares (McLaren et forms a loosely tufted, sparse tussock of available about its fodder value in Austral- al. 1998). less than 30 cm across. ia. In Victoria, N. leucotricha invades native pasture and native grasslands. Seeds be- Impacts come readily attached to the hair and wool A personal observation by Mark Gardner of grazing animals and can cause injury to in Argentina showed that N. charruana stock (Leithead et al. 1971). was regarded as very poor fodder and, unlike N. trichotoma and N. neesiana, it hairs on corona Identifi cation was considered an extremely damaging

0.6–1.5 mm Vegetative characters Stems of N. leu- noxious weed due to its invasiveness, ➔ cotricha are erect, to 1–1.5 m high, un- competitiveness, unpalatability and very branched and mostly hairless. Leaves are sharp and clinging seeds (McLaren et al. approximately 30 cm long and 5 cm wide. 1998). In contrast, Rosengurtt et al. (1970) ➤ The blades are fl at or slightly inrolled. The says it provides productive winter fodder ligule is 0.5–1 mm long and hairless. (Pen- but its seeds can penetrate the fur and skin nhall et al. 2000) of stock. The potential of N. charruana as an agricultural and environmental weed 3.5–4.5 mm Floral characters The panicle of N. leu- has seen it declared a State Prohibited cotricha is contracted or more or less loose Weed in Victoria. The Victorian Depart- to 25 cm long. Glumes are 11–15 mm long ment of Primary Industries has recently (12–21 mm long in Barkworth 1993). The commenced an eradication program. N.

➤ lemma is 6–10 mm long. The corona is ca.1 charruana is on the ‘Weed Alert List’ of the mm long, with erect, apical hairs or slen- Commonwealth Department of Environ- der spines 0.6–1.5 mm long. The callus is ment and Heritage. Figure 4. Nassella hyalina seed. 1–3 mm long (Figure 5). The awn is bent twice and is 35–60 mm long, with 10–20 Identifi cation mm to the fi rst bend (Pennhall et al.2000). Vegetative characters Nassella charruana forms large, densely tufted tussocks with Plant Protection Quarterly Vol.19(2) 2004 63 Impacts diameter and are almost the same length In its country of origin, N. megapotamia as the stems, which are jointed. Leaf

➤ inhabits undisturbed areas and is rarely blades are hairless but are covered with found on grazed land. It is considered fi ne projections, whilst the leaf sheath may rare, palatable and of low to medium have scattered hairs. The ligule is 1–2 mm corona productive potential. The seeds of N. in length and hairless. 7 mm megapotamia are considered innocuous (Rosengurtt et al. 1970). The environmental Floral characters Piptochaetium monte- weed status of this species is unknown in vidense has dense, branched panicles to ➤ Australia. However, N. megapotamia could 10 cm long. The seed is about 2 mm long, ➤ be considered a potential environmental whilst the awn is about 10 mm long. The weed (M. Lazarides personal communica- glumes are up to 3.5 mm long and are pur- tion). plish in colour when young.

lemma Identifi cation Broad-kernel espartillo, 8 mm Vegetative characters Ligules of N. Achnatherum caudatum megapotamia are membranous, glabrous Distribution and truncate, to 0.7 mm long. Auricles Achnatherum caudatum (syn. Stipa caudata) have hair tufts. is a perennial, densely tufted grass indig-

➤ enous to Chile and Argentina (Rosengurtt Floral characters The panicle of N. mega- 1970, Caro and Sanchez 1971). The earliest potamia is contracted and 25–35 cm long. known collection in Australia was made Figure 6. Nassella charruana seed. Glumes are 8–10 mm long. The lemma in the Cootamundra district of New South is 5.5–6 mm long, with lobes 0.1–0.2 mm Wales in 1959 and it has since spread to long. The corona is 0.5–0.8 mm long with the Deniliquin area in New South Wales spines on its upper margin. The callus is (Parsons and Cuthbertson 1992). In Vic- mature plants being greater than 30 cm in 2–2.5 mm long and the awn ca. 50 mm toria it was fi rst observed near Dunnolly diameter and 0.5–1.0 m high. Leaves have long. in 1984. It has also been collected from a tough, leathery feel and grow up to 50 Cambells Creek near Castlemaine and cm long. They are narrow, rolled inwards Uruguayan ricegrass, Piptochaetium found invading riparian vegetation along and have a short, membranous, glabrous montevidense Edgars Creek, Coburg. According to ligule. Auricles have short hair tufts. Distribution McPhee and May (1992), A. caudatum was Piptochaetium montevidense is indigenous fi rst introduced to Clunes in gravel, pos- Floral Characters Nassella charruana has to Argentina, Bolivia, southern Brazil, sibly during the 1970s. It was recorded on a very distinctive seed with large, apical Paraguay, Uruguay and Chile (Roig 1978). Flinders Island in 1979 (Parsons and Cuth- lemma lobes (Rosengurtt et al. 1970). The It was fi rst recorded in 1988 from Cherry bertson 1992) and on mainland Tasmania panicle is contracted. Glumes are purplish, Lake, Altona, Victoria (Carr personal com- at Bridgewater and is declared a noxious, shiny and longer than the fl oret (excluding munication). Its potential distribution in prohibited species in that state. Its poten- the awn). The lemma is unmistakable with Australia, predicted from its current dis- tial distribution in Australia, predicted long corona lobes. The lemma is at least 8 tribution in Australia, has been estimated from its current distribution in Australia, mm long and relatively slender (Figure 6). at 0.6 million hectares (McLaren et al. has been estimated at 12.9 million hectares The corona is approximately 7 mm long 1998). However, several recent visits to its (McLaren et al. 1998). with lobes forming a collar of fi rm tissue recorded location have failed to locate any surrounding the base of the awn. The co- remaining specimens. It appears that since Impacts rona is divided at its end into 0.5–1.9 mm 1988, the Altona site has been covered by Achnatherum caudatum and the closely re- long ‘fi ngers’, in turn divided into fi ne 0.5 approximately 5 metres of soil/land- lated species A. brachychaetum have been mm long hairs. The awn is 45–85 mm long fi ll. identifi ed as problem weeds in lucerne and is not readily detached from the seed crops in both Argentina and California (Faithful 1999). Impacts (Parsons and Cuthbertson 1992). In Chile This grass is uncommon in Argentina and and Argentina A. caudatum and A. brachy- Short-spined needlegrass, Nassella is a small perennial that produces many chaetum are considered to have little to no megapotamia seeds. Its stock food value is unknown, its fodder value but their seeds are not harm- Distribution seeds cause no problems to stock and have ful to stock. They inhabit fertile areas and Nassella megapotamia (syn. Stipa megapota- low weed potential (Gardener personal are considered aggressive plants on fallow mia) is indigenous to Argentina and south- communication). P. montevidense has been lands of calcareous soils (Rosengurtt et al. ern Brazil (Rosengurtt et al. 1970). The fi rst observed as a component of an overgrazed 1970). collection in Australia was made in 1961 at cattle pasture on the pampas in Argentina In New South Wales, A. caudatum is be- the CSIRO site at Black Mountain, Canber- where unpalatable grasses dominated coming a serious weed invading pasture, ra and it appears to be confi ned entirely to (McLaren personal observation). Its im- particularly after cultivation. It invades this area. No collections have been lodged pact as an agricultural or environmental re-sown pasture and becomes prominent at the New South Wales and Canberra weed is unknown. P. montevidense is on by the third year. In native pasture it is herbaria since the 1960s but it was still the ‘Weed Alert List’ of the Common- limited to areas of disturbance and along thought to be surviving at Black Mountain wealth Department of Environment and fence lines. A. caudatum poses a serious during the 1980s (S. Jacobs personal com- Heritage. threat to grazing production near Clunes munication). It was apparently an escapee in Victoria. It is a poor fodder plant but from the CSIRO plant introduction plots Identifi cation starving stock will feed on young plants (Pullen personal communication). Vegetative characters Piptochaetium mon- that are still vigorous under heavy graz- tevidense forms dense tussocks to about 0.5 ing pressure (McPhee and May 1992). m high. Leaf blades are about 0.5 mm in At Maryborough, Victoria, cattle were 64 Plant Protection Quarterly Vol.19(2) 2004 feeding on A. caudatum where little or no ballast near Portland, Oregon and occurs across Australia (Department of Environ- other pasture species remained (V. Stajsic, in California (USA Department of Agricul- ment and Heritage 2004). E. Bruzzese personal observation). ture 1953, Barkworth 1993). The exotic stipoid grasses are having a Achnatherum caudatum is reportedly signifi cant impact on grazing industries in spread by water, particularly after fl ooding Identifi cation Australia. N. trichotoma has been described and by stock along stock routes (J. Cherry Same as A. caudatum, except the seed ker- as causing a greater reduction in pasture personal communication, McPhee and nel is narrower. carrying capacity than any other weed May 1992). It is also spread by slashing, in Australia (Parsons and Cuthbertson mowing and soil disturbance by machin- Plumerillo, Jarava plumosa 1992). None of the exotic stipoid grasses ery along roadsides in the Maryborough, Distribution are wholly useful pasture species. Some, Talbot and Clunes areas (V. Stajsic person- Jarava plumosa (syn. Stipa papposa) is in- such as N. neesiana, may be palatable at al observation, McPhee and May 1992). digenous to southern Brazil, Uruguay, certain times of the year (Gardener 1998), A. caudatum has been observed invading Argentina and Chile (Roig 1978). This but farmers would overwhelmingly pre- riparian vegetation in central Victoria and species has been recorded in Catalonia in fer to be rid of this species (McLaren et al. in Melbourne (McLaren et al. 1998). Spain (Casasayas et al. 1985) and was also 2002). In particular, these grasses threaten found at Berkley, California in 1983 but the wool industry through contamination Identifi cation has not persisted (Barkworth 1993). Its po- of wool, reductions in animal condition Vegetative characters Achnatherum cau- tential distribution in Australia, predicted and physical damage from their sharp- datum forms large, dense tussocks to 1.5 from its current distribution in Australia, pointed seeds penetrating the fl eece, skins m high and 1 m across. The erect stems has been estimated at 1.8 million hectares and eyes of livestock. of mature plants can stand 60–100 cm tall (McLaren et al. 1998). J. plumosa was fi rst Impacts by exotic stipoid grasses on with 2–4 nodes. The sheath-like leaves are introduced as a potential pasture plant by threatened species within endangered tightly adpressed to the stems, and loosen the Waite Agricultural Research Institute, grasslands are now becoming particu- as they grow upwards. The stiff leaf blades Adelaide, South Australia, probably in larly serious. In Victoria, there is now are strongly ribbed on both sides and may the early 1940s and the fi rst herbarium less than half of one percent of relatively be fl attened or rolled (Parsons and Cuth- record came from a cultivated glasshouse ‘pristine’ grasslands remaining with six bertson 1992). The leaf blades are tightly specimen in 1941 (Gardner et al. 1996). It nationally recognized, critically-endan- whorled to give stiff spikelet tips and, to has since been found naturalized in the gered grassland remnants being listed in the open hand of an observer, the plant vicinity of the Waite Institute but popula- Victoria alone (Craigie 1999). Within these feels spiny. It has been suggested that this tions are grubbed out on an ongoing basis remnants, fl ora such as the Sunshine spi- is a mechanism to protect the basal leaf (Gardner et al. 1996). der orchid (Diuris fragrantissima) and the sheaths of the plant that harbour seeds plains rice fl ower (Pimelea spinescens) and (Bonnici 2000). Impacts fauna such as the grassland earless dragon Jarava plumosa is reportedly of little value (Tympanocryptis pinguicolla), the grassland Floral characters Terminal panicle stems for fodder and its seed is irritable to stock growling frog (Litoria raniformis) and the of A. caudatum are 15–35 cm in length and (Rosengurtt et al. 1970). plains-wanderer (Pedionomus torquatus) much branched. The lemma (5-6 mm in are critically endangered. N. neesiana in length) has a short coma 0.2–1 mm long Identifi cation particular, is invading these remnants and and is membranous to papery (not thick- Vegetative characters Jarava plumosa is rapidly degrading their integrity. ened or leathery as in Austrostipa). The a tufted perennial, 25–80 cm high and is Efforts to manage these exotic stipoid seed does not have a corona or callus. The sometimes branched at lower nodes. Its grasses are resulting in increased herbicide awn is 10–15 mm long. The species pro- growth form resembles Austrodanthonia. use, rock clearing, cultivation, soil fertility duces abundant, hard, awnless, ‘nut-like’ and replacement of native pastures with cleistogenes at the base of the leaf sheaths Floral characters The seed of J. plumosa exotic pastures. In addition, afforestation and within the stems. The tussocks are has an apical pappus and is the only ex- is being increasingly used in grasslands spiny at the crown that may serve to otic stipoid species in Australia that has for management of grass weeds such as protect the basal sheaths containing the seed adapted for wind dispersal (Jacobs N. trichotoma (Campbell and Vere 1995). cleistogenes (McPhee and May 1992). and Everett 1996). The glumes are usu- The exotic stipoid grasses are causing ally shorter than the lemma. The lemma wholesale changes in land management Narrow-kernel espartillo, is 6–7.5 mm long, with no coma or corona. from grazing to cropping and from sheep Achnatherum brachychaetum The callus is 1–1.5 mm long. The palea is to beef, resulting in signifi cant impacts Distribution ca. 20% the length of lemma and hyaline. to both land managers and the environ- Achnatherum brachychaetum (syn. Stipa The awn is 15–30 mm long, with basal, ment. These exotic grasses are also af- brachychaeta) is native to Uruguay, Chile pappus-like hairs 4–8 mm long. fecting fi re frequency and intensity with and central Argentina (Rosengurtt et al. unknown consequences. All these factors 1970). The earliest Australian record comes Discussion combined are placing severe pressures on from Merriwa, New South Wales in 1955. The combined effects of introduced exotic native grasslands to the point where our It has been diffi cult to obtain reliable data stipoid grasses on grazing industries and capacity to harvest seed of native species on this species in New South Wales due its native grasslands in Australia are consid- such as kangaroo grass (Themeda triandra close resemblance to A. caudatum. Its po- erable. Their signifi cance as weeds can be Forssk.) for rehabilitation purposes is di- tential distribution in Australia, predicted seen by the fact that two exotic stipoids minishing. from its current distribution in Australia, (N. trichotoma and N. neesiana) are Weeds Another critically important issue is has been estimated at 0.6 million hectares of National Signifi cance (Thorp and Lynch how these grasses are being introduced (McLaren et al. 1998). 2000). Similarly, four exotic stipoids (N. into Australia. The northern suburbs of tenuissima, N. charruana, N. hyalina and Melbourne appear to be the epicentre Impacts P. montevidense) have been identifi ed as of stipoid introductions into Australia. Achnatherum brachychaetum is listed by the a priority weeds for control on the ‘Na- Our only hint on how this may have oc- Federal Government of the United States tional Environmental Weed Alert List’ out curred is that N. leucotricha was locally as a noxious weed. It was collected from of twenty-eight weed species nominated called Tatlow grass, after a local trotting Plant Protection Quarterly Vol.19(2) 2004 65 identity called Edgar Tatlow. The grass whether any illegal importations have of Agriculture NSW Technical Bulletin 18, was thought to have originated from taken place. 1-23. Edgar Tatlow’s trotting stables in Epping, 4. That governments and industry sup- Campbell, M.H. (1982). The biology of east of Darebin creek (Haberfi eld personal port biological control of exotic stipoid Australian weeds 9. Nassella trichotoma communication). Perhaps horses and hay species that are beyond expiration. (Nees) Arech. Journal of Australian came in from South America from where 5. That efforts to eradicate or suppress N. Institute of Agricultural Science 48, these weeds have spread. tenuissima, N. charruana, N. megapota- 76-84. Plant ‘hunters’ have been roaming the mia, P. montevidense, J. plumosa, A. cau- Campbell, M.H. and Vere, D.T. (1995). Nas- planet for centuries, transporting plants datum and A. brachychaetum continue. sella trichotoma (Nees) Arech. In ‘The Bi- for ornamental and commercial uses to ology of Australian Weeds Vol. 1’, eds. new countries. This practice continues to- Acknowledgments R.H. Groves, R.C.H. Shepherd and R.G. day and new material is continually enter- The authors would like to thank Jim Back- Richardson, pp. 189-202. (R.G. and F.J. ing Australia. Fads and fashion drive the holer and Linda Merrin for help with geo- Richardson, Melbourne). nursery trade with customers demanding graphic information system assessments. Caro, J.A. (1966). Las especies de Stipa new and exciting plants, resulting in a They would also like to thank Vannessa (Gramineae) de la region central Ar- great deal of pressure on nurseries and Craigie and Fiona Ferwerda for informa- gentina. Kurtziana 3, 7-119. garden centres to seasonally provide tion on grassland threatened species. Seed Caro J.A. and Sanchez, E. (1971). La new lines of plants. Novel plants are usu- drawings were done by Enid Mayfi eld. identidad de Stipa brachychaeta Godron, ally fi rst obtained legally but sometimes S. caudata Trinius y S. bertrandii Philippi. plant collectors, gardeners and some References Darwiniana 16, 637-53. smaller nursery operators have brought Aberdeen, I. (1995). Strategy for the man- Carr, G.W., Yugovic, J.V. and Robinson, in material without approval from the agement of serrated tussock in Victoria. K.E. (1992). ‘Environmental weed in- Australian Quarantine Inspection Service Inland Agriculture. vasions in Victoria’. (Department of (AQIS). Agriculture and Resource Management Conservation and Environment and During the past decade, native grasses Council of Australia and New Zealand, Ecological Horticulture Pty. Ltd.). have become very popular as ornamental Australia and New Zealand Environ- Casasayas, I., Fornell, T., Farras, I. and plantings in Australia. In many capital ment and Conservation Council and de Blas, A. (1985). Stipa papposa Nees, and regional cities, native grasses such as Forestry Ministers. (2001a). Weeds of Eragrostis curvula (Schrad.) Nees i tussock grass (Poa labillardierei Steud.) are National Signifi cance serrated tussock Chenopodium pumilio R.Br.: tres especies being used extensively as a low mainte- (Nassella trichotoma) Strategic Plan. exotiques noves per a Catalunya. Col- nance, attractive groundcover along road (National Weeds Strategy Executive lect. Bot. 16, 161-4. and freeway verges. The popularity of Committee, Launceston). Centre for International Economics (2001). grasses in urban areas has resulted in rare Agriculture and Resource Management The CRC for Australian Weed Manage- plant nurseries taking an increased inter- Council of Australia and New Zealand, ment Systems: an impact assessment. est in importing new, attractive, hardy, Australia and New Zealand Environ- CRC for Australian Weed Manage- easily grown species. The resemblance of ment and Conservation Council and ment Systems Technical Series No. 6, these exotic stipoid species to indigenous Forestry Ministers. (2001b). Weeds of pp. 22-6. Austrostipa species has meant that they are National Signifi cance Chilean needle- Craigie, V. (1999). Status of grassy eco- easily overlooked as weeds, increasing the grass (Nassella neesiana) Strategic Plan. systems in Victoria; and the Grassy likelihood that they will successfully natu- (National Weeds Strategy Executive Ecosystems Reference Group. Proceed- ralize. Many gardening books and maga- Committee, Launceston). ings of a conference on management zines are advertising these exotic grasses, Barkworth, M.E. (1993). North Ameri- of grassy ecosystems. ‘Down to grass creating a demand. can Stipeae (Gramineae): Taxonomic roots,’ eds V. Craigie, and C. Hocking The increased use of the internet for changes and other comments. Phytolo- 9–10 July 1998. Victoria University, St global trading has made plants more ac- gia 74, 1-25. Albans, pp. 1-6. cessible to a much wider range of custom- Bonnici, T.H. (2000). Efficacy of herbi- Department of Environment and Heritage ers and has undoubtedly increased the cides against broad-kernel espartillo (2004). Weed Alert List. Available at: rate of illegal plant introductions coming (Achnatherum caudatum) in a pot trial. http://www.deh.gov.au/biodiversity/ into Australia. N. tenuissima has been sold Honours thesis, Department of Applied invasive/weeds/alert-list.html. through nurseries in Victoria and NSW Chemistry, RMIT University, Victoria. Distel, R.A. and Boo, R.M. (1995). Vegeta- (McLaren et al. 1999) but to date it has not Bourdot, G.W. and Hurrell, G.A. (1992). tion states and transitions in temperate naturalized in Australia. It has now been Aspects of the ecology of Stipa neesiana semiarid rangelands of Argentina. Fifth declared a State Prohibited weed in Victo- Trin & Rupr. Seeds. New Zealand Journal International Rangelands Congress, ria that should end any future trade with of Agricultural Research 35, 101-8. 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