Rhaponticum repens, synonyms including Acroptilon repens and Leuzea repens,[1] with the common name Russian knapweed, is a species of bushy rhizomatous perennial, up to 80 cm tall. Stems and leaves are finely arachnoid-tomentose becoming glabrous and green with age. The rosette leaves are oblanceolate, pinnately lobed to entire, 2–3 cm wide by 3–8 cm long. The lower cauline leaves are smaller, pinnately lobed; the upper leaves become much reduced, sessile, serrate to entire. The heads are numerous terminating the branches. Flowers are pink to purplish, the marginal ones not enlarged. The outer and middle involucral bracts are broad, striate, smooth with broadly rounded tips; the inner bracts are narrower with hairy tips. Pappus present with bristles 6–11 mm long. Fruit is a whitish, slightly ridged achene.
Russian knapweed is a deep-rooted long-lived perennial. Some stands have been in existence for 75 years. It forms dense colonies in cultivated fields, orchards, pastures, and roadsides.
A native to Eurasia, Russian knapweed was introduced into North America in the late 19th century. Absent only from southeastern U.S., it has become widespread in other regions, especially in the western United States.[2]
Nigropallidal encephalomalacia, also called chewing disease, a movement disorder similar to Parkinson's disease, is caused in horses ingesting Russian knapweed for prolonged periods. A sesquiterpene lactone, repin, in the plant is likely responsible for this toxicity.[3]
Taxonomyedit
The species was first described by Carl Linnaeus in 1763 as Centaurea repens.[4][5][6]Augustin Pyramus de Candolle separated it from the genus Centaurea in 1838, placing it in the genus Acroptilon.[5] The genus name derives from acro- (high, here meaning tip) and ptilo- (feather).[7] A 1995 molecular phylogenetic study, the structure of the flower, and the chromosome number support separating it from the genus Centaurea. Some sources then continue to place it as the sole member of the monotypic genus Acroptilon.[7] A phylogenetic study published in 2006 concluded that Acroptilon belongs in the genus Rhaponticum.[8]
Referencesedit
^ abc"Rhaponticum repens (L.) Hidalgo". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-11-06.
^Robles, M.; Wang, N.; Kim, R.; Choi, B.H. (1997). "Cytotoxic effects of repin, a principal sesquiterpene lactone of russian knapweed". Journal of Neuroscience Research. 47 (1): 90–7. doi:10.1002/(SICI)1097-4547(19970101)47:1<90::AID-JNR10>3.0.CO;2-E. PMID 8981242. S2CID 23156210.
^"Centaurea repens". The Plant List. Retrieved 2015-02-26.
^Carl Linnaeus (1763). "Centaurea 28 repens". Species plantarum :exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Vol. 2 (2 ed.). p. 1293.
^Hidalgo, O.; Garcia-Jacas, N; Garnatje, T; Susanna, A (2006). "Phylogeny of Rhaponticum (Asteraceae, Cardueae-Centaureinae) and Related Genera Inferred from Nuclear and Chloroplast DNA Sequence Data: Taxonomic and Biogeographic Implications". Annals of Botany. 97 (5): 705–14. doi:10.1093/aob/mcl029. PMC2803413. PMID 16495316.
External linksedit
Jepson Manual Treatment
Species Profile- Russian Knapweed (Rhaponticum repens), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Russian Knapweed.
December 15, 2023
rhaponticum, repens, synonyms, including, acroptilon, repens, leuzea, repens, with, common, name, russian, knapweed, species, bushy, rhizomatous, perennial, tall, stems, leaves, finely, arachnoid, tomentose, becoming, glabrous, green, with, rosette, leaves, ob. Rhaponticum repens synonyms including Acroptilon repens and Leuzea repens 1 with the common name Russian knapweed is a species of bushy rhizomatous perennial up to 80 cm tall Stems and leaves are finely arachnoid tomentose becoming glabrous and green with age The rosette leaves are oblanceolate pinnately lobed to entire 2 3 cm wide by 3 8 cm long The lower cauline leaves are smaller pinnately lobed the upper leaves become much reduced sessile serrate to entire The heads are numerous terminating the branches Flowers are pink to purplish the marginal ones not enlarged The outer and middle involucral bracts are broad striate smooth with broadly rounded tips the inner bracts are narrower with hairy tips Pappus present with bristles 6 11 mm long Fruit is a whitish slightly ridged achene Russian knapweedScientific classificationKingdom PlantaeClade TracheophytesClade AngiospermsClade EudicotsClade AsteridsOrder AsteralesFamily AsteraceaeTribe CardueaeGenus RhaponticumSpecies R repensBinomial nameRhaponticum repens L Hidalgo 1 Synonyms 1 Acroptilon angustifolium Cass Acroptilon australe IljinAcroptilon obtusifolium Cass Acroptilon picris Pall ex Willd C A Mey Acroptilon repens L DC Acroptilon repens subsp australe Iljin Rech f Acroptilon serratum Cass Acroptilon subdentatum Cass Carduus picris Pall ex Willd SweetCentaurea picris Pall ex Willd Centaurea repens L Leuzea repens L D J N HindSerratula amara Pall Serratula picris Pall ex Willd M Bieb Russian knapweed is a deep rooted long lived perennial Some stands have been in existence for 75 years It forms dense colonies in cultivated fields orchards pastures and roadsides A native to Eurasia Russian knapweed was introduced into North America in the late 19th century Absent only from southeastern U S it has become widespread in other regions especially in the western United States 2 Nigropallidal encephalomalacia also called chewing disease a movement disorder similar to Parkinson s disease is caused in horses ingesting Russian knapweed for prolonged periods A sesquiterpene lactone repin in the plant is likely responsible for this toxicity 3 Taxonomy editThe species was first described by Carl Linnaeus in 1763 as Centaurea repens 4 5 6 Augustin Pyramus de Candolle separated it from the genus Centaurea in 1838 placing it in the genus Acroptilon 5 The genus name derives from acro high here meaning tip and ptilo feather 7 A 1995 molecular phylogenetic study the structure of the flower and the chromosome number support separating it from the genus Centaurea Some sources then continue to place it as the sole member of the monotypic genus Acroptilon 7 A phylogenetic study published in 2006 concluded that Acroptilon belongs in the genus Rhaponticum 8 References edit a b c Rhaponticum repens L Hidalgo Plants of the World Online Royal Botanic Gardens Kew Retrieved 2023 11 06 Acroptilon repens Flora of North America Robles M Wang N Kim R Choi B H 1997 Cytotoxic effects of repin a principal sesquiterpene lactone of russian knapweed Journal of Neuroscience Research 47 1 90 7 doi 10 1002 SICI 1097 4547 19970101 47 1 lt 90 AID JNR10 gt 3 0 CO 2 E PMID 8981242 S2CID 23156210 Centaurea repens The Plant List Retrieved 2015 02 26 a b IPNI Plant Name Query Results for Centaurea repens The International Plant Names Index Retrieved 2015 02 26 Carl Linnaeus 1763 Centaurea 28 repens Species plantarum exhibentes plantas rite cognitas ad genera relatas cum differentiis specificis nominibus trivialibus synonymis selectis locis natalibus secundum systema sexuale digestas Vol 2 2 ed p 1293 a b Acroptilon Flora of North America Hidalgo O Garcia Jacas N Garnatje T Susanna A 2006 Phylogeny of Rhaponticum Asteraceae Cardueae Centaureinae and Related Genera Inferred from Nuclear and Chloroplast DNA Sequence Data Taxonomic and Biogeographic Implications Annals of Botany 97 5 705 14 doi 10 1093 aob mcl029 PMC 2803413 PMID 16495316 External links editJepson Manual Treatment Species Profile Russian Knapweed Rhaponticum repens National Invasive Species Information Center United States National Agricultural Library Lists general information and resources for Russian Knapweed Retrieved from https en wikipedia org w index php title Rhaponticum repens amp oldid 1183847577, wikipedia, wiki, book, books, library,
