Botanical Field Reference — Italy
A structured reference for Cirsium, Carduus, and Onopordum genera found across Italian grasslands, roadsides, and montane meadows. Identification keys, phenology data, pollinator records, and conservation assessments compiled from field surveys and herbarium specimens.
Latest Field Notes
Morphological keys, habitat preferences, and distribution notes for the fourteen Cirsium taxa documented in Italian grassland ecosystems — from lowland plains to alpine meadows above 2,000 m.
Documented interactions between native Apidae, Syrphidae, and Lepidoptera and their thistle host plants. Includes seasonal activity windows and floral resource data from transect surveys across five Italian regions.
Assessment of Cirsium, Carduus, and Onopordum taxa listed under Italian regional red lists and the IUCN framework — with habitat pressure analysis and notes on protected area coverage.
Species Index
Cirsium vulgare
Spear Thistle
The most widespread Cirsium in Italy. Erect biennial to 1.5 m, with deeply lobed leaves bearing stiff yellow-tipped spines. Flower heads 3–5 cm, purple-red, solitary or clustered at stem apex. Blooms June–September across all altitudinal zones.
LC — Least Concern
Cirsium eriophorum
Woolly Thistle
Robust biennial to 2 m, identifiable by its densely white-woolly involucral bracts and large solitary flower heads (4–7 cm). Typical of calcareous grasslands and rocky slopes in the Pre-Alps and Apennines, 400–1,800 m.
LC — Least Concern
Cirsium italicum
Italian Thistle
An endemic of the central and southern Apennines and some Adriatic coastal areas. Perennial with white-cottony stem wings and pale pink to lilac flower heads 2–3.5 cm. Restricted to mesic meadows and forest margins below 1,200 m.
NT — Near Threatened
Carduus nutans
Musk Thistle / Nodding Thistle
Recognised by its characteristic drooping (nodding) flower head, 3–6 cm wide, strongly fragrant. Biennial to 1.2 m. Frequent along road verges, dry grasslands, and disturbed ground throughout peninsular Italy and the large islands.
LC — Least Concern
Carduus acanthoides
Welted Thistle
Erect annual or biennial to 1.4 m with continuous spiny stem wings extending to the flower head base. Small pink-purple heads (1–2 cm), often clustered. Common from sea level to 1,500 m across northern and central Italy.
LC — Least Concern
Onopordum acanthium
Cotton Thistle / Scotch Thistle
A striking biennial reaching 2.5 m, with broadly winged, white-felted stems and large purple flower heads 3–5 cm. Found on dry rocky slopes, ruderal ground, and overgrazed pastures across the Po Valley and central Italy.
LC — Least ConcernPhenology Overview
Thistle phenology in Italy spans from late April in lowland Sardinia and Sicily to September in the high Alpine meadows of Val d'Aosta and Trentino. The table below summarises approximate peak flowering months for the six most documented species, derived from herbarium records and the GBIF occurrence database.
Full Identification Keys| Species | Peak Bloom | J F M A M J J A S O N D |
|---|---|---|
| C. vulgare | Jul–Aug | |
| C. eriophorum | Aug–Sep | |
| C. italicum | Jun–Aug | |
| Carduus nutans | Jun–Sep | |
| C. acanthoides | Jun–Aug | |
| O. acanthium | Jul–Sep |
Genus Focus
Over 30 Cirsium species are recorded from the Italian flora, ranging from common weedy biennials to narrow Apennine endemics found in fewer than ten known localities. The genus accounts for the majority of Italy's thistle conservation concerns, with at least four species listed as Vulnerable or Endangered under national criteria.
Cirsium Identification KeysEcology
Italian thistle species collectively support over 80 documented invertebrate visitors, including specialist solitary bees in the genus Andrena and Halictus, multiple bumblebee species (Bombus terrestris, B. pascuorum), and several priority butterfly taxa. Floral resource data from transect surveys in Lombardy and Emilia-Romagna indicate that Carduus and Cirsium heads rank among the highest-density nectar sources in semi-natural grasslands during July and August.
Pollinator DataEnquiries
This reference is maintained by a small editorial group based in Milan with field contributors from across Italy. For corrections, additions, or specimen records, write to the address below.