Centaurea solstitialis
Yellow Starthistle
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Asterales Family: Asteraceae Genus: Centaurea Species: C. solstitialis
Binomial name
Centaurea solstitialis L.

The yellow starthistle (Centaurea solstitialis) is native to the Mediterranean region, but since its introduction to North America in the mid-nineteenth century it has become a large-scale noxious weed there. It is extremely invasive and has now dominated over 18 million acres in the United States alone. Download high resolution version (640x975, 162 KB)Yellow star thistle from http://www. ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms or Magnoliophyta) are one of the major groups of modern plants, comprising those that produce seeds in specialized reproductive organs called flowers, where the ovulary or carpel is enclosed. ... Orders see text Dicotyledons or dicots are flowering plants whose seed contains two embryonic leaves or cotyledons. ... Families See text The Asterales are an order of dicotyledonous flowering plants which include the composite family Asteraceae (sunflowers and daisies) and its related families. ... Genera many, see list The aster or sunflower family (Family Asteraceae or, alternatively Family Compositae) is a taxon of dicotyledonous flowering plants. ... Species Around 350-500 species; see text Centaurea is a genus of about 350-500 species of herbaceous thistles and thistle-like flowering plants in the family Asteraceae, mostly native to the Old World. ... In biology, binomial nomenclature is a standard convention used for naming species. ... Satellite image Map of the Mediterranean Sea The Mediterranean Sea is a part of the Atlantic Ocean almost completely enclosed by land, on the north by Europe, on the south by Africa, and on the east by Asia. ... World map showing location of North America A satellite composite image of North America North America is a continent in the northern hemisphere, bounded on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the south by the Caribbean Sea, and on the west... Purple flowers of the highly invasive Pattersons Curse infest the Warrumbungle National Park in New South Wales, Australia. ...

Yellow starthistle is a thorny winter annual in the knapweed genus. It is a grayish-green plant with multiple rigid stems that extend in all directions from the base, forming a bushy-looking cluster that can reach two meters in height and more than that in diameter. It produces bright yellow flowers ringed with long, sharp spines. The plant grows quickly and is very competitive. It bears a taproot that can reach a meter deep into the soil, allowing it to thrive during dry, hot summers. It is versatile in its growth patterns, and can adapt to drought or low soil moisture content by producing smaller plants with fewer seeds during dry years. An annual is a plant that usually germinates, flowers and dies in one year. ... Species Around 350-500 species; see text Centaurea is a genus of about 350-500 species of herbaceous thistles and thistle-like flowering plants in the family Asteraceae, mostly native to the Old World. ... A plants taproot is a straight tapering root that grows vertically down. ...

Yellow Starthistle as an Invasive Species

The plant grows as a normal part of the ecology in Eurasia, where it is kept in check by an assortment of natural enemies and other plants that have co-evolved with it in its native habitat. It was imported to the United States in the mid-1800s as a contaminant in a batch of alfalfa seed. It was dispersed into agricultural fields in California, and immediately took hold in this new environment with its own ideal Mediterranean-type climate. Human factors such as mowing, domestic animal grazing, and cultivation of wildlands contributed to the success and spread of the plant. It is now a very common sight in pastures, fields, and vacant lots, and along roadsides. Most of the western United States has yellow starthistle infestations, with California and the Pacific Northwest being the most heavily affected areas. Species Medicago arabica Medicago heldreichii Medicago hybrida Medicago laciniata Medicago littoralis Medicago lupulina Medicago minima Medicago monantha Medicago monspeliaca Medicago orbicularis Medicago polymorpha Medicago praecox Medicago rigidula Medicago rugosa Medicago ruthenica Medicago sativa Medicago scutellata Medicago secundiflora Medicago truncatula Medicago turbinata Ref: ITIS 183622 as of 2002-07-31 Alfalfa... State nickname: The Golden State Other U.S. States Capital Sacramento Largest city Los Angeles Governor Arnold Schwarzenegger (R) Official languages English Area 410,000 km² (3rd)  - Land 404,298 km²  - Water 20,047 km² (4. ... A Mediterranean climate is one that resembles those of the lands bordering the Mediterranean Sea. ... Darker red states are always part of the Pacific Northwest. ...

The yellow starthistle plant has the ability to create monotypic stands in fields that prevent other species from growing there. Whole fields of solid yellow starthistle are not uncommon. Its growth plasticity, competitiveness, preference for the Mediterranean climate, and lack of natural enemies and co-evolved species make it a very successful invader. The plant is a pest in field crops, prevents domestic animals' grazing in rangelands, acts as a physical barrier to wild animal movement in wildlands, and is toxic to horses.

Biological Control

Yellow starthistle is sometimes resistant to removal methods such as mowing, because of its long root system, and burning, due to the seeds' ability to withstand fire. The plant has been the target of biological pest control programs with positive results. Six types of seed-feeding insect have been found to be effective against the plant. Biological control of pests and diseases // Overview A key belief of the organic gardener is that diversity furthers health. ... Classes & Orders Subclass: Apterygota Orders Archaeognatha (Bristletails) Thysanura (Silverfish) Monura - extinct Subclass: Pterygota Orders Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Infraclass: Neoptera Orders Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, etc) Phasmatodea (walking sticks) Embioptera (webspinners) Zoraptera...

• Three species of weevil in the beetle subfamily Cleoninae effectively reduce seed production in the yellow starthistle.
  • Yellow starthistle bud weevil (Bangasternus orientalis) is a fuzzy brown weevil that lays its eggs in the flowers, and when its larvae hatch, they feed on the developing seed.
  • Yellow starthistle hairy weevil (Eustenopus villosus) is a long-snouted, hairy-looking weevil that lays a single egg inside each flower bud. The larva then consumes the seeds within.
  • Yellow starthistle flower weevil (Larinus curtus) is a brownish weevil that lays eggs in the flowers as it feeds on the pollen. The larvae then eat the seeds when they hatch.
• Three species of tephritid fruit fly also attack the seedheads of yellow starthistle.
  • Yellow starthistle peacock fly and false peacock fly (Chaetorellia australis and C. succinea, respectively) are small nectar-feeding flies that deposit eggs into the seedheads, where their larvae consume the seeds and flower ovaries.
  • Banded yellow starthistle gall fly (Urophora sirunaseva) produces larvae that pupate within a woody gall within the flower and disrupt seed production.

Additionally, a variety of the rust fungus Puccinia jaceae has shown promise as an agent against yellow starthistle. The rust causes widespread pathology in the leaves of the plant and slow its dispersal. Families Nemonychidae Anthribidae Belidae Attelabidae Brentidae Caridae Ithyceridae Curculionidae A weevil is a beetle from the Curculionoidea superfamily. ... Genera 500 genera & about 5,000 species Tephritidae is a family of insects that includes fruit flies. ... Kalanchoë infected with crown-gall using Agrobacterium tumefaciens. ... This article is about the fungus. ...

External Links

Comprehensive Yellow Starthistle Info Site
Long List of YST Info Sources
Rust Article