Cirsium horridulum var. megacanthum

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Distribution Map: Based on vouchered plant specimens only. View county names by placing the mouse cursor over a particular county.

Species Distribution Map
Family:ASTERACEAE
Species:Cirsium horridulum Michx. var. megacanthum (Nutt.) D.J. Keil
Common Name:Big Spine Thistle
Habitat:**
Associated Ecological Communities:**
Growth Habit:Herb
Duration:Biennial
Category:Vascular
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)
References:**

** Not applicable or data not available.

Classification

FamilyASTERACEAE - Aster family
Genus Cirsium
Species Cirsium horridulum Michx. var. megacanthum (Nutt.) D.J. Keil - Big Spine Thistle

Citation

Citation Cirsium horridulum Michaux var. megacanthum (Nuttall) D.J. Keil, Sida 21(1): 214. 2004.
Basionym: Cirsium megacanthum Nutt. 1841.
Type: USA: LOUISIANA: Banks of the Mississippi near New Orleans, s.d., Little s.n. (lectotype: PH). Lectotypified by D. J. Keil, Sida 21: 214. 2004.

** Not applicable or data not available.

Synonyms

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: ALNHS, 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		 Image
TROY000052068 Mobile 08 Apr 2021 Diamond, Alvin R.
29571		 TROY
Cirsium horridulum Michaux var. megacanthum (Nuttall) Keil
TROY000052064 Baldwin 08 Apr 2021 Diamond, Alvin R.
29570		 TROY
Cirsium horridulum Michaux var. megacanthum (Nuttall) Keil
ALNHS00007507 Mobile 04 MAY 2022 Barger, T. Wayne
SP#5707		 ALNHS
Cirsium horridulum Michx. var. megacanthum (Nutt.) Keil
UNA00027068 Mobile _ Apr 1896 Mohr, Charles
s.n.		 UNA
Cirsium horridulum Michx. var. megacanthum (Nutt.) Keil
UNA00027041 Mobile 27 Mar 1965 Deramus, Rebecca
D 306		 UNA
Cirsium horridulum Michx. var. megacanthum (Nutt.) Keil
ALNHS00007506 Mobile 04 MAY 2022 Barger, T. Wayne
SP#5707		 ALNHS
Cirsium horridulum Michx. var. megacanthum (Nutt.) Keil
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