- Hymenoxys odorata
Taxobox
name = "Hymenoxys odorata"
image_width = 250px
regnum =Plant ae
divisio = Magnoliophyta
classis =Magnoliopsida
ordo =Asterales
familia =Asteraceae
genus = "Hymenoxys "
species = "H. odorata"
binomial = "Hymenoxys odorata"
binomial_authority = DC."Hymenoxys odorata" is a species of flowering plant in the daisy family known by the common names bitter rubberweed and western bitterweed. It is native to the southwestern United States from
California toTexas and northern Mexico, where it grows in dry regions. This is an annual herb producing a branching stem to a maximum height near 60 centimeters. The stems are covered in a foliage of short leaves which are divided into narrow, pointed lobes. The plentiful flower heads contain bright yellow disc florets and about eight short yellow ray florets.This plant is poisonous to livestock; it is mostly a problem of the
sheep industry. The toxic compounds aresesquiterpene lactone s calledhymenovin [ [http://www.merckvetmanual.com/mvm/htm/bc/ttox04.htm Poisonous Range Plants of Temperate North America] Merck Veterinary Manual] andhymenoxon [Pfeiffer, F. A. and M. C. Calhoun. (1987). Effects of environmental, site and phenological factors on hymenoxon content of bitterweed ("Hymenoxys odorata"). "J Anim Sci" 65 1553-62.] . When ingested by sheep the plant producesinflammation of thestomach , renalnecrosis , and toxichepatitis [Witzel, D. A., L. P. Jones, and G. W. Ivie. (1977). Pathology of subacute bitterweed ("Hymenoxys odorata") poisoning in sheep. "Vet Path" 14(1) 73-8.] , as well as inhibition of clotting factors [Steel, E. G., D. A. Witzel, and A. Blanks. (1976). Acquired coagulation factor X activity deficiency connected with "Hymenoxys odorata" DC (Compositae), bitterweed poisoning in sheep. "Am J Vet Res" 37(12) 1383-6.] . An ill sheep may be bloated, anorexic, weak, drooling, andvomit ing. [http://www.ars.usda.gov/Services/docs.htm?docid=9858 Bitter Rubberweed ("Hymenoxys odorata")] USDA Poisonous Plants Research] Acute and chronic, cumulative poisoning is often fatal. Sheep tend to avoid the plant because they find it distasteful but they will eat it in the absence of other forage.References
External links
* [http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?609,1441,1445 Jepson Manual Treatment]
* [http://www.plants.usda.gov/java/profile?symbol=HYOD USDA Plants Profile]
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