Cirsium horridulum var. megacanthum

Species:Cirsium horridulum Michaux var. megacanthum (Nuttall) Keil, in ed.
Common Name:Big Spine Thistle
Associated Ecological Communities:**
Growth Habit:**
USDA Symbol:**
Plant Notes:Big Spine Thistle is a native herbaceous biennial in the Sunflower family (Asteraceae). It found in near-coastal areas of Alabama. Big Spine Thistle grows in wet, open areas such as marshes, roadside ditches, bogs, and seeps. It is a biennial with a stout taproot. Fleshy lateral roots often give rise to new plants. During the first year of growth the plant forms a basal rosette of leaves. During the second spring, an erect flowering stalk 3-8 feet in height emerges. The stem is hollow, usually unbranched, glabrous to sparsely pubescent, with alternate leaves. Stem leaves are sessile to auriculate clasping, linear to elliptic in outline, subglabrous, with spiny dentate margins. The spines are up to 1 inch in length. Basal leaves are similar but larger and with spiny winged petioles. Leaves are 5-18 inches in length. Flowers are produced in heads. The heads are solitary or in corymbs. Each head is subtended by an involucre-like ring of glabrous, spiny-margined bracts. Corollas are white to pale pink or lavender in color. The fruit is an achene with a crown of plumose bristles. Botanist Thomas Nuttall described this species as "one of the most terribly armed plants in the genus."—A. Diamond
Taxonomic Notes:**
Status:Native, G5 (Global Rank)
Specimen: View specimen details in the Alabama Herbarium Consortium Specimen Database

** Not applicable or data not available.


FamilyASTERACEAE - Aster family
Genus Cirsium
Species Cirsium horridulum Michaux var. megacanthum (Nuttall) Keil, in ed. - Big Spine Thistle


Citation **
Basionym: **
Type: **

** Not applicable or data not available.


No synonyms exist for this species.

Specimens and Distribution

This species has been reported in the following counties by the herbaria listed. An overview of the individual specimens are provided in the table that follows. Click on the accession number to view details; click on column headers to sort; choose a county or herbaria to filter the specimen data.

Counties included on distribution map: Baldwin, Mobile

Counties represented by specimen data listed below:

Herbaria represented by specimen data listed below: TROY, UNA

Range of years during which specimens were collected: 1965 - 1965

Barcode / Accession No. County Coll. Date Collector &
Collection No.
Herbarium &
Herbarium Name Used
UNA00027041 Mobile 27 Mar 1965 Deramus, Rebecca
D 306
Cirsium horridulum Michx. var. megacanthum (Nutt.) Keil
TROY000052068 Mobile 08 Apr 2021 Diamond, Alvin R.
Cirsium horridulum Michaux var. megacanthum (Nuttall) Keil
UNA00027068 Mobile _ Apr 1896 Mohr, Charles
Cirsium horridulum Michx. var. megacanthum (Nutt.) Keil
TROY000052064 Baldwin 08 Apr 2021 Diamond, Alvin R.
Cirsium horridulum Michaux var. megacanthum (Nuttall) Keil
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