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yellow tuft (Alyssum murale, A. corsicum)
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ODA rating: A and T

 
USDA Symbol: ALMU & ALCO
Oregon yellow tuft distribution
 
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Images courtesy of Ken French, Oregon Dept. of Agriculture

 
If images are downloaded and used from the ODA web site please be sure to credit the photographer.
 
Description
Plants are fast growing perennials, reaching reproductive maturity within one or two years, and are fairly long-lived. The gray-green oval or spatula-shaped (wide at the top and narrower at the bottom) leaves of A. murale are 0.5-1.0 cm long and are covered with tiny stellate hairs. A. corsicum is very similar, although the leaves of this species are more oval in shape and have a dense covering of silvery hairs, giving them a pale gray or white appearance. Plants of both species produce hundreds of small, bright yellow flowers on branched umbels (corymbs) in early summer. Because most leaves are shed prior to the initiation of flowering, the two species look almost identical when in flower. Both species produce the papery, circular to oval flattened fruits (silicles), each with a single flattened seed, that are typical Alyssum murale is a widespread species found on serpentine soils throughout central and southern Europe (Dudley 1965).
 
Impacts
The Illinois Valley contains the greatest concentration of serpentine soils in Oregon, and supports a diverse and unique flora. Fifteen plant taxa with conservation status (listed as rare, threatened or endangered by Oregon Department of Agriculture, U.S. Fish and Wildlife Service or Oregon Natural Heritage Information Center) occur in this area, including two species federally listed as endangered. Yellowtuft threatens to overtake the Illinois Valley's unique native plant communities.
 
Known hazards
Hyperaccumulators are highly toxic, containing concentrations of their target metals far in excess of levels considered toxic to cattle, sheep, swine and chickens, often by orders of magnitude (Angle and Linacre 2005). Although no data on the palatability of Alyssum species to livestock or wildlife is available, the high alkaloid and metal content characteristic of hyperaccumulators probably limits the attractiveness of these species as forage. However, the ingestion of even moderate amounts of Alyssum, as might occur in cattle confined in an infested field, would probably result in livestock poisoning. Wildlife might also resort to using Alyssum as forage under some conditions, and small herbivores might ingest seeds or flowers.
 
Introduction
Alyssum murale is a widespread species found on serpentine soils throughout central and southern Europe (Dudley 1965). It is a well-represented component of the serpentine flora in this area, and is frequently documented from "waste areas," indicating its tolerance of harsh conditions. This species is very variable, exhibiting high levels of genetic variation (Mengoni et al. 2003), as well as subspecific morphological variation recognized by traditional taxonomy (Duldley 1965).  A. corsicum has a more restricted range, occurring only in Turkey and Corsica, with the Corsican population theorized to have been transported from Turkey by humans (Mengoni et al. 2003). Breeding agricultural cultivars of these two species has been a priority for development of Alyssum species for phytomining (2003). Promoted as an environmentally conscious method for cleaning up contaminated mining sites, phytoremediation consists of planting hyperaccumulators (plants with the ability to extract metals from the soil and concentrate them in stems, shoots and leaves) on mine wastes. Once plants are mature, they are harvested and burned. The metallic ash is processed to produce usable metals, and the concentrations of toxic elements in the contaminated soils eventually decrease.   
 
Distribution in Oregon
A record of collection of A. murale was made in 1963 from a garden in Benton County and is stored in the OSU Herbarium. More recently plants of Alyssum murale occuring outside of cultivated fields were first discovered in Oregon in 2006 on U.S. Forest Service land by botanical technicians working for Wild Rivers Ranger District on the Rogue River-Siskiyou National Forest.


Biological controls
Biological control agents are not used on "A" listed weeds in Oregon. This weed is being managed for eradication.
 
Informational links
Yellow tuft printable trifold(pdf)