Italian thistle

Names and Synonyms

Common Names

• Plymouth Thistle
• Italian thistle
• sheep thistle
• shore thistle
• slender thistle
• slender winged thistle
• slender-flower thistle
• winged slender thistle
• woolly thistle

Scientific Names

Accepted name

Synonyms

• Onopyxus pycnocephalus
• Carduus tenuiflorus var. pycnocephalus
• Cnicus pycnocephalus

Regional and Traditional Names

Sources: Wikidata, Catalogue of Life

Taxonomical Classification

This plant belongs to the kingdom Plantae and the phylum Streptophyta, situated within the class Equisetopsida and subclass Magnoliidae. It is further classified under the order Asterales and the family Asteraceae. Finally, its taxonomic identity is defined by the genus Carduus.

Sources: The World Checklist of Vascular Plants (WCVP)

Distribution

This plant exhibits a broad presence across several regions of the European continent. In Northern Europe, its range extends through Denmark, Great Britain, and Sweden. Moving toward Middle Europe, the species can also be found growing in Belgium. Additionally, the plant is documented to inhabit parts of Austria. Together, these locations highlight a distribution that spans both northern and central territories.

Sources: The World Checklist of Vascular Plants (WCVP)

Botanical Identification

Ecology

The ecology of Carduus pycnocephalus is characterized by its adaptability to a broad vertical gradient, spanning an elevational range from sea level (0 m AMSL) up to a maximum of 1600 m AMSL. Primarily distributed within lowland habitats, this species is well-suited to lower-altitude environments where its growth patterns are established. To survive within these ecosystems and mitigate herbivory, the plant employs active defense mechanisms, making it a resilient component of its native landscape.

Defense :

yes

Elevational range max:

1600 m AMSL

Elevational range min:

0 m AMSL

Habitat :

Lowland

Genetics

The genetics of Carduus pycnocephalus are characterized by significant karyotypic complexity and a high degree of chromosomal variability, which is indicative of a polyploid nature. The plant exhibits a wide range of chromosome numbers, specifically documented as 18, 32, 54, 60, 62, 64, and 80. This diversity in chromosome counts suggests a history of genome duplication events and varying ploidy levels within different populations, contributing to the genetic plasticity and evolutionary adaptability of the species.

Chromosome number :

18, 32, 54, 60, 62, 64, 80

Life history

The life history of Carduus pycnocephalus is characterized by an annual lifecycle, meaning the plant completes its entire developmental process from germination to seed production within a single growing season. As a therophyte, it survives unfavorable environmental periods primarily through the production of seeds, which remain dormant until conditions are optimal for growth. Its structural life form is classified as a hemicryptophyte, indicating that its perennating buds are located at or just below the soil surface, protected by leaf litter or soil cover. Additionally, the plant exhibits deciduousness, shedding its foliage as it completes its seasonal cycle.

Deciduousness :

deciduous

Life form :

hemicryptophyte

Life form :

therophyte

Lifecycle :

annual

Morphology

The morphology of Carduus pycnocephalus is characterized by its growth form as a non-woody herb and forb. This terrestrial plant is self-supporting, neither functioning as a climber nor as an epiphyte or parasite, maintaining an independent lifestyle. The shoots exhibit an erect orientation, rising from the ground to reach varying heights; specifically, the plant height typically ranges from a minimum of 0.2 m to a maximum of 1.5 m, with an average height of approximately 0.8 m.

Aquatic :

terrestrial

Climber :

self-supporting

Epiphyte :

terrestrial

Growth form :

herb

Growth form :

forb

Parasite :

independent

Plant height max:

1.5 m

Plant height mean:

0.8 m

Plant height min:

0.2 m

Shoot orientation :

erect

Woodiness :

non-woody

Physiology

The physiological characteristics of Carduus pycnocephalus are largely defined by its vegetative architecture and nutritional requirements. The plant exhibits an alternate leaf arrangement, with individual leaves displaying a pinnatifid form. These leaves vary significantly in size, with lengths ranging from a minimum of 5 cm to a maximum of 25 cm, while the width fluctuates between 2 cm and 8 cm, maintaining a mean width of approximately 10 cm. From a metabolic standpoint, the species does not function as a nitrogen fixer, meaning it relies on the availability of nitrogen within the soil rather than through symbiotic nitrogen-fixing processes.

Leaf arrangement :

alternate

Leaf form :

pinnatifid

Leaf length max:

25 cm

Leaf length min:

5 cm

Leaf width max:

8 cm

Leaf width mean:

10 cm

Leaf width min:

2 cm

Nitrogen fixer :

no

Reproduction

The reproduction of Carduus pycnocephalus is characterized by a sexual reproductive cycle, as asexual reproduction is notably absent. The flowering period typically commences in March and concludes in July. During this stage, the plant produces red flowers that vary in size, with flower lengths ranging from 0.55 cm to 0.8 cm and flower widths ranging from 0.65 cm to 0.9 cm. Following pollination, the plant develops fruits categorized as achenes, which are indehiscent in nature. These fruits maintain a mean length of 0.4 cm (ranging from 0.4 cm to a maximum of 0.5 cm) and a mean width of 0.2 cm. The seeds contained within these fruits are highly consistent in dimension, featuring a mean length and width of 3.75 mm, with a seed mass that averages approximately 0.0039455 g (ranging from a minimum of 0.005467 g to a maximum of 0.00621 g). Dispersal of the seeds is facilitated through an anemochorous syndrome, meaning they are primarily dispersed by the wind.

Dehiscence :

indehiscent

Dispersal syndrome :

anemochorous

Flower colour :

red

Flower length max:

0.8 cm

Flower length min:

0.55 cm

Flower width max:

0.9 cm

Flower width min:

0.65 cm

Flowering time :

Mar

Flowering time :

Jul

Fruit length max:

0.5 cm

Fruit length mean:

0.4 cm

Fruit type :

achene

Fruit width mean:

0.2 cm

Reproduction asexual :

absent

Seed length mean:

3.75 mm

Seed mass max:

0.00621 g

Seed mass mean:

0.0039455 g

Seed mass min:

0.005467 g

Seed width mean:

1.75 mm

Sources: Global Inventory of Floras and Traits (GIFT)

Chemicals

Carduus pycnocephalus has 1 reported phytochemicals identified across 0 scientific publications and several other databases. The most consistently reported chemicals include Flavonoids.

Flavonoids

1. Food research international (Ottawa, Ont.)