Stylidium 2740385 219633344 2008-06-16T04:33:02Z Rkitko 536375 img restored {{Taxobox | name = ''Stylidium'' | image = Stylidium graminifolium flower spike.jpg | image_caption = Flower of ''[[Stylidium graminifolium]]'' | image_width = 220px | regnum = [[Plant]]ae | divisio = [[Flowering plant|Magnoliophyta]] | classis = [[Dicotyledon|Magnoliopsida]] | ordo = [[Asterales]] | familia = [[Stylidiaceae]] | subfamilia = [[Stylidioideae]] | genus = '''''Stylidium''''' | genus_authority = [[Olof Swartz|Sw.]] ex [[Carl Ludwig Willdenow|Willd.]] | subdivision_ranks = Species | subdivision = See [[List of Stylidium species|separate list]]. }} The genus '''''Stylidium''''' (also known as '''triggerplants''' or '''trigger plants''') are a group of [[dicotyledon]]ous [[plant]]s that belong to the family [[Stylidiaceae]]. The genus name ''Stylidium'' is derived from the Greek ''στυλος'' or ''stylos'' (column or pillar), which refers to the distinctive reproductive structure that its flowers possess.<ref>Curtis's Botanical Magazine. (1832). ''Stylidium scandens'', Volume 59: Plate 3136.</ref> Pollination is achieved through the use of the sensitive "trigger", which comprises the male and female reproductive organs fused into a [[column (botany)|floral column]] that snaps forward quickly in response to touch, harmlessly covering the insect in pollen. Most of the approximately 300 [[species]] are only found in [[Australia]], making it the fifth largest genus in that country. Triggerplants are considered to be [[protocarnivorous]] or [[carnivorous plant|carnivorous]] because the glandular [[trichome]]s that cover the [[Scape (botany)|scape]] and flower can trap, kill, and digest small insects with [[protease]] enzymes produced by the plant. == Characteristics == [[Image:Stylidium turbinatum column movement.png|thumb|right|223px|''[[Stylidium turbinatum|S. turbinatum]]'' flowers untriggered (left) and after being triggered (right). The floral column will reset to the original position.]] The majority of the ''Stylidium'' species are [[perennial plant|perennial herbs]] of which some are [[geophyte]]s that utilize [[bulb]]s as their storage organ. The remaining small group of species consists of [[ephemeral plant|ephemeral]] [[annual plant|annuals]].<ref name="Good">Good, R. (1925). On the Geographical Distribution of the Stylidiaceae. ''New Phytologist'', 24(4): 225-240.</ref> Members of the genus are most easily identified by their unique [[column (botany)|floral column]], in which the [[stamen]] and [[carpel|style]] are fused. The column--also commonly called a "trigger" in this genus--typically resides beneath the plane of the flower. ''Stylidium'' flowers are [[zygomorphic]], which means they are only symmetrical in one plane.<ref name="Laurent">Laurent, N., Bremer, B., Bremer, K. (1998). Phylogeny and Generic Interrelationships of the Stylidiaceae (Asterales), with a Possible Extreme Case of Floral Paedomorphosis. ''Systematic Botany'', 23(3): 289-304.</ref> Flowers usually bloom in the late Spring in Australia.<ref name="Rica">Erickson, Rica. (1961). An introduction to triggerplants. ''Australian Plants'', 1(9): 15-17. (Available online: [http://farrer.csu.edu.au/ASGAP/APOL18/jun00-3.html HTML])</ref> === Morphology === [[Image:Stylidiumdebileanimation2.gif|thumb|223px|right|''[[Stylidium debile]]'' flower, resetting after being triggered.]] Species of the genus ''Stylidium'' represent a very diverse selection of plants. Some are only a few centimeters tall, while others can grow to be 1.8 meters tall (''[[Stylidium laricifolium|S. laricifolium]]''). One typical plant form is a dense [[Rosette (botany)|rosette]] of leaves close to the ground that gives rise to the [[inflorescence|floral]] [[raceme|spike]] in the center. Plant forms ranges from wiry, creeping mats (''[[Stylidium scandens|S. scandens]]'') to the bushy ''S. laricifolium''.<ref name="Rica" /><ref name="Darnowski">Darnowski, Douglas W. (2002). ''Triggerplants''. Australia: Rosenberg Publishing. ISBN 1-877058-03-3</ref> Flower morphology differs in details, but ascribes to a simple blueprint: four petals, zygomorphic in nature, with the trigger protruding from the "throat" of the flower and resting below the plane of the flower petals. Flower size ranges from many species that have small 0.5 cm wide flowers to the 2-3 cm wide flowers of ''[[Stylidium schoenoides|S. schoenoides]]''. Flower color can also vary from species to species, but most include some combination of white, cream, yellow, or pink. Flowers are usually arranged in a spike or dense [[raceme]], but there is at least one exception to the rule: ''[[Stylidium uniflorum|S. uniflorum]]'', as its name suggests, produces a single flower per [[inflorescence]].<ref name="Darnowski" /> Leaf morphology is also very diverse in this large genus. Some leaves are very thin, almost needle-like (''[[Stylidium affine|S. affine]]''), while others are short, stubby, and arranged in rosettes (''[[Stylidium pulviniforme|S. pulviniforme]]''). Another group of species, such as ''S. scandens'' (climbing triggerplant) form scrambling, tangled mats typically propped up on [[aerial root]]s.<ref name="Darnowski" /> === Pollination mechanism === [[Image:StylidiumFlora5.jpg|thumb|right|223px|''[[Stylidium turbinatum]]'' flower, showing the reproductive column.]] The column typical of the genus ''Stylidium'' is sensitive and responds to touch. The change in pressure when a pollinating insect lands on a ''Stylidium'' flower causes a physiological change in the column [[turgor pressure]] by way of an [[action potential]], sending the column quickly flying toward the insect.<ref name="Findlay">Findlay, G.P. and Pallaghy, C.K. (1978). Potassium chloride in the motor tissue of ''Stylidium''. ''Australian Journal of Plant Physiology'', 5(2): 219 - 229. (Abstract available online: [http://www.publish.csiro.au/paper/PP9780219.htm HTML])</ref> Upon impact, the insect will be covered in pollen and stunned, but not harmed. Because the column comprises the fused male and female reproductive organs of the flower, the stamen and [[carpel|stigma]] take turns in dominating the function of the column--the [[anther]]s develop first and then are pushed aside by the developing stigma. This delayed development of the stigma prevents [[self-pollination]] and ensures that cross pollination will occur between individuals of a population. Different species have evolved the trigger mechanism in different locations, with some attacking the pollinating insect from above and others from below (a "punch in the gut" to the insect).<ref name="Rica" /><ref name="Armbruster">Armbruster, W.S., Edwards, M.E., Debevec, E.M. (1994). Floral Character Displacement Generates Assemblage Structure of Western Australian Triggerplants (Stylidium). ''Ecology'', 75(2): 315-329.</ref> The response to touch is very quick in ''Stylidium'' species. The column can complete its "attack" on the insect in as little as 15 milliseconds. After firing, the column resets to its original position in anywhere from a few minutes to a half hour, depending on temperature and species-specific qualities. The column is able to fire many times before it no longer responds to stimuli. The response time is highly dependent upon ambient temperature, with lower temperatures relating to slower movement.<ref name="Findlay2">Findlay, G.P. (1978) Movement of the Column of ''Stylidium crassifolium'' as a Function of Temperature. ''Australian Journal of Plant Physiology'', 5(4): 477-484.</ref> === Carnivory === [[Image:Stylidium bud and scape.jpg|thumb|right|223px|Bud and scape of ''[[Stylidium fimbriatum|S. fimbriatum]]'' displaying the [[trichome]]s that can trap and kill insects.]] Members of the genus have been considered to be [[protocarnivorous]] (or subcarnivorous) in the past. They have glandular trichomes projecting from [[sepal]]s, leaves, flower parts, and the [[scape]]. The tip of the trichome produces a sticky [[mucilage]]—a mixture of sugar polymers and water—that is capable of attracting and suffocating small insects.<ref name="Darnowski" /> Recent research has revealed that these trichomes produce digestive enzymes, specifically [[protease]]s, like other [[carnivorous plant]]s. The plants are also able to absorb the nutrients created by the protease activity on the captured insects, making them [[carnivorous plant]]s in the opinion of some researchers. Adding species of ''Stylidium'' to the list of plants that engage in carnivory would significantly increase the total number of known carnivorous plants.<ref>Darnowski, D.W., Carroll, D.M., Płachno, B., Kabanoff, E., and Cinnamon, E. (2006). Evidence of protocarnivory in triggerplants (''Stylidium'' spp.; Stylidiaceae). ''Plant Biology'', 8(6): 805-812. (Abstract online: [http://www.thieme-connect.com/ejournals/abstract/plantbiology/doi/10.1055/s-2006-924472 HTML])</ref><ref name="Darnowski 2007">Darnowski, D., Moberly, S., and Plachno, B. 2007. [http://www.2007.botanyconference.org/engine/search/index.php?func=detail&aid=18 Triggerplants (''Stylidium'' spp.; Stylidiaceae): A Previously Unrecognized Genus of Carnivorous Plants]. ''Proceedings of the 2007 Botany and Plant Biology Joint Congress'', ''Botanical Society of America''. Abstract accessed online: 21 March 2007.</ref> The insects captured by the glandular trichomes are much too small to serve any role in pollination. It is unclear, however, whether these plants evolved the ability to trap and kill insects as an adaptation to low environmental nutrient availability or simply a defensive mechanism against insects damaging flower parts.<ref name="Darnowski" /> There is also a correlation between location of ''Stylidium'' species and proximity of known carnivorous species, like [[sundew]]s (''Drosera''), [[bladderwort]]s (''Utricularia''), the [[Cephalotus|Albany pitcher plant]] (''Cephalotus follicularis''), and the [[Byblis (plant)|rainbow plant]] (''Byblis''). While this alone does not prove that ''Stylidium'' species are themselves carnivorous, the hypothesis is that the association arose because ''Stylidium'' species and the known carnivorous plants obtain scarce nutrients using the same source, namely captured insects. Preliminary proof is given that the trapping mechanisms of two associated plants are the same (the [[tentacle]]s of ''Byblis'' and ''Drosera''), though this may be only a coincidence and further research must be done.<ref name="Darnowski" /> As of 2007, Darnowski and his research team have published an abstract of a paper to be presented at the 2007 Botany and Plant Biology Joint Congress in Chicago. The presentation will explain their research into the carnivory of ''Stylidium'' including its ability to digest prey and absorb the resulting nutrients, two of the main criteria to be considered a carnivorous plant.<ref name="Darnowski 2007" /> === Distribution and habitat === Most ''Stylidium'' species are [[endemic (ecology)|endemic]] to Australia. In [[Western Australia]] alone, there are more than 150 species, at least 50 of which are in the area immediately around [[Perth, Western Australia|Perth]]. There are at least four species of ''Stylidium'' that are not confined to the Australian continent: ''[[Stylidium tenellum|S. tenellum]]'' is found in [[Myanmar]], [[Melaka]], and [[Tonkin]]; ''[[Stylidium kunthii|S. kunthii]]'' in [[Bengal]] and Myanmar; ''[[Stylidium uliginosum|S. uliginosum]]'' in [[Queensland]], [[Sri Lanka]], and the south coast of [[China]]; and ''[[Stylidium alsinoides|S. alsinoides]]'' in Northeast Australia, Queensland, and the [[Philippines]]. The cladistic group ''Stylidium'' contains more than 230 individual species (more than 300 species exist, but many specimens have not yet been formally described),<ref name="Talking Plants">[http://www.rbgsyd.nsw.gov.au/information_about_plants/talking_plants/talking_plants_archive/talking_plants_events_calendar/event_view?SQ_CALENDAR_VIEW=event&SQ_CALENDAR_EVENT_ID=72326 Information from a October 26, 2004 edition of "Talking Plants"], a program of the Botanic Gardens Trust, a division of the [[New South Wales]] Department of Environment and Conservation</ref> making it the fifth largest genus in Australia.<ref name="Good" /> ''Stylidium'' habitat includes grassy plains, open [[Heath (habitat)|heaths]], rocky slopes, sandplains, forests, and the margins of creeks and water holes.<ref name="Rica" /> Somes species, such as ''[[Stylidium eglandulosum|S. eglandulosum]]'', can even be found in disturbed areas like near roads and under powerlines. Others (i.e. ''[[Stylidium coroniforme|S. coronmiforme]]'') are sensitive to disturbance and are considered rare because of their extremely specific habitat.<ref name="Darnowski" /> == Botanical history == [[Image:Stylidiumviolaceum print.jpg|thumb|right|223px|''[[Stylidium violaceum|S. violaceum]]'' from [[Ferdinand Bauer]]'s 1813 ''[[Illustrationes Florae Novae Hollandiae]]''.]] [[Image:StylidiumHabitus.jpg|thumb|right|223px|''[[Stylidium turbinatum|S. turbinatum]]'' in cultivation.]] Discovery and description of new ''Stylidium'' species has been occurring since the late 18th century, the first of which was discovered in [[Botany Bay]] in 1770 by [[Joseph Banks]] and [[Daniel Solander]] during their travels in the Pacific with [[James Cook]] aboard the ''[[HM Bark Endeavour|Endeavour]]''.<ref name="Talking Plants" /> The five species collected by Banks and Solander were sketched by [[Sydney Parkinson]] on board the Endeavour and were later engraved in preparation for publication in [[Banks' Florilegium]]. Later, in the early 19th century, the French [[botanist]] [[Charles François Antoine Morren]] wrote one of the first descriptions of the triggerplant anatomy, illustrated by many botanical artists including [[Ferdinand Bauer]]. Around the same time, British botanist [[Robert Brown (botanist)|Robert Brown]] described (or "authored") several ''Stylidium'' species, including ''[[Stylidium adnatum|S. adnatum]]'' and ''[[Stylidium repens|S. repens]]''. More species began to be described as more botanists explored Australia more thoroughly. In 1958, [[Rica Erickson]] wrote ''Triggerplants'', describing habitat, distribution, and plant forms ([[ephemeral]], creeping, leafy-stemmed, [[rosette (botany)|rosette]], tufted, scale-leaved, and tropical). It was Erickson that began placing certain species into these [[morphology (biology)|morphologically]]-based groups, which may or may not resemble true [[plant taxonomy|taxonomic]] divergences. It was not until the 1970s and 1980s that research of the trigger [[plant physiology|physiology]] was begun in the lab of Dr. Findlay of [[Flinders University]]. Douglas Darnowski added to the growing library of knowledge on ''Stylidium'' when he published his book ''Triggerplants'' in 2002, describing an overview of habitat, plant morphology, carnivory, and research done to date. Following its publication, he attempted to assist in the organization of the [http://web.archive.org/web/20020930085051/http://www.triggerplants.org/ International Triggerplant Society], which has not been formally created yet.<ref name="ITS">Darnowski, Douglas W. (2002). The history of triggerplants. International Triggerplant Society. (Archived, available online: [http://web.archive.org/web/20030713182018/www.triggerplants.org/history.html HTML])</ref> As of 2002, only 221 ''Stylidium'' species were known.<ref name="Wagstaff">Wagstaff, S.J. and Wege, J. (2002). Patterns of diversification in New Zealand Stylidiaceae. ''[[American Journal of Botany]]'', 89(5): 865-874. (Available online: [http://www.amjbot.org/cgi/content/full/89/5/865 HTML] or [http://www.amjbot.org/cgi/reprint/89/5/865 PDF] versions)</ref> There are now [[List of Stylidium species|over 300 species]], many of which are awaiting formal description. == Cultivation == [[Image:Stylidium graminifolium cultivation.jpg|thumb|right|223px|''[[Stylidium graminifolium]]'' is available in cultivation with two [[cultivar]]s: 'Tiny Trina' and 'Little Sapphire'.]] Most ''Stylidium'' species tend to be hardy species and can be easily cultivated in greenhouses or gardens. They are drought resistant, hardy to cold weather, and the species diversity in this genus gives gardeners a wide variety of choices. Most species that are native to Western Australia will be cold hardy to at least -1 to -2°C. The few that can be found all over Australia, like ''[[Stylidium graminifolium|S. graminifolium]]'', will tolerate a wider range of habitat since their native ranges includes a great diversity of [[ecoregion]]s. Some species of triggerplants are suitable for cultivation outdoors outside of the Australian continent including most of the [[United Kingdom]] and as far north as [[New York City]] or [[Seattle]] in the [[United States]].<ref name="Darnowski" /> Cultivation from seed may be difficult or easy, depending on the species. The more difficult species to grow include the ones that require a period of dormancy or smoke treatment to simulate a [[bushfire]]. ''Stylidium'' specimens should be grown in a medium that is kept moist and has a relatively low concentration of nutrients. It should also be noted that they appear to be sensitive to disturbance of their root systems. Minimization of such disturbance will likely result in healthier plants.<ref name="Darnowski" /> == References == {{Reflist}} == External links == {{Wikisource|Edwards's Botanical Register/Appendix to the First Twenty-three Volumes/A Sketch of the Vegetation of the Swan River Colony/Stylidiaceae|A Sketch of the Vegetation of the Swan River Colony/&#8203;Stylidiaceae}} {{Wikisource|Iconography of Candolleaceous Plants}} {{Commons-inline|Stylidium|''Stylidium''}} * [http://www.deh.gov.au/biodiversity/threatened/publications/recovery/s-coroniforme/index.html Australian Department of the Environment and Heritage] document on the "Wongan Hills Triggerplant (''Stylidium coroniforme'') Interim Recovery Plan 2003-2008". ([http://www.deh.gov.au/biodiversity/threatened/publications/recovery/s-coroniforme/pubs/s-coroniforme.pdf PDF version]) * [http://florabase.calm.wa.gov.au/browse/flora?f=343&level=g&id=1495 FloraBase] (Western Australia's flora database) entry on ''Stylidium''. * Association of Societies for Growing Australian Plants (ASGAP) information on ''[http://farrer.riv.csu.edu.au/ASGAP/s-lar.html Stylidium laricifolium]'' and ''[http://farrer.riv.csu.edu.au/ASGAP/s-gra.html Stylidium graminifolium]''. * [[IPNI|International Plant Names Index]] (IPNI) [http://132.236.163.181/cgi-bin/dol/dol_terminal.pl?taxon_name=Stylidium&rank=genus list of published ''Stylidium'' species names]. * [http://www.gdaywa.com/wildflowers/triggerplants.php Photos and animations] of triggerplants, featuring several species. {{CarnivorousPlants}} [[Category:Pollination]] [[Category:Stylidium]] [[de:Schusspflanzen]] [[es:Stylidium]] [[it:Stylidium]]