FNA: Cirsium engelmannii

	Cirsium engelmannii
	blackland thistle, Engelmann's thistle
Habit	Biennials or monocarpic perennials, 40–200 cm; taproots and clusters of coarse fibrous roots that often have tuberlike thickenings.
Stems	single, erect, often branched above middle, thinly arachnoid-tomentose, ± glabrate; branches few, ascending.
Leaves	blades elliptic or ovate, 5–20 × 1–10 cm, usually deeply pinnatifid, lobes narrowly to broadly triangular, sinuses broad, rounded (basal and distal cauline sometimes less divided, lobes linear-lanceolate), margins revolute, spreading, entire or spinulose to remotely few-toothed or sharply lobed, main spines slender, 1–5 mm, abaxial faces white-tomentose, adaxial green, villous with septate trichomes or glabrate; basal usually absent at flowering, winged-petiolate, bases tapered; principal cauline well distributed, gradually reduced, bases narrowed, sometimes weakly clasping; distal reduced, widely separated, distalmost bractlike.
Peduncles	2–20+ cm, essentially naked with much reduced bracts.
Involucres	ovoid to broadly cylindric or campanulate, 2.5–3.5 × 2–3 cm, thinly arachnoid.
Corollas	pink to purple (white), 32–38 mm, tubes 15–20 mm, throats 6–9 mm, lobes 8–11 mm; style tips 5–6 mm.
Phyllaries	in 10–12 series, strongly imbricate, greenish with subapical darker central zone, ovate (outer) to lanceolate (inner), abaxial faces with narrow glutinous ridge; outer and middle entire, bodies appressed, spines abruptly spreading to deflexed, slender, 2–4 mm; apices of inner phyllaries narrow, flexuous, flattened, entire or finely erose.
Heads	1–10+, borne at tips of main stem and branches.
Cypselae	brown, 5–6 mm, apical collars yellow, ca. 1 mm; pappi 25–30 mm.
2n	= 18 (as C. terrae-nigrae), 20 + 1B.

	Cirsium engelmannii
Phenology	Flowering spring–summer (May–Jul).
Habitat	Tallgrass prairies, old fields, roadsides, oak savannas, forest edges, in calcareous clay or rarely sandy soils
Elevation	50–200 m (200–700 ft)
Distribution	LA; OK; TX [BONAP county map]
Discussion	Cirsium engelmannii occurs mostly in the blackland prairies of eastern Texas. It ranges northward into southeastern Oklahoma and eastward to northwestern Arkansas. (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 19, p. 117.
Parent taxa	Asteraceae > tribe Cardueae > Cirsium
Sibling taxa	C. altissimum, C. andersonii, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. nuttallii, C. occidentale, C. ochrocentrum, C. ownbeyi, C. palustre, C. parryi, C. perplexans, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
Synonyms	C. virginianum var. filipendulum, C. terrae-nigrae
Name authority	Rydberg: Fl. Rocky Mts., 1069. (1917)
Web links	Local Web sites: LA Plants WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Cirsium engelmannii

blackland thistle, Engelmann's thistle

Habit

Biennials or monocarpic perennials, 40–200 cm; taproots and clusters of coarse fibrous roots that often have tuberlike thickenings.

Stems

single, erect, often branched above middle, thinly arachnoid-tomentose, ± glabrate;

branches few, ascending.

Leaves

blades elliptic or ovate, 5–20 × 1–10 cm, usually deeply pinnatifid, lobes narrowly to broadly triangular, sinuses broad, rounded (basal and distal cauline sometimes less divided, lobes linear-lanceolate), margins revolute, spreading, entire or spinulose to remotely few-toothed or sharply lobed, main spines slender, 1–5 mm, abaxial faces white-tomentose, adaxial green, villous with septate trichomes or glabrate;

basal usually absent at flowering, winged-petiolate, bases tapered;

principal cauline well distributed, gradually reduced, bases narrowed, sometimes weakly clasping;

distal reduced, widely separated, distalmost bractlike.

Peduncles

2–20+ cm, essentially naked with much reduced bracts.

Involucres

ovoid to broadly cylindric or campanulate, 2.5–3.5 × 2–3 cm, thinly arachnoid.

Corollas

pink to purple (white), 32–38 mm, tubes 15–20 mm, throats 6–9 mm, lobes 8–11 mm;

style tips 5–6 mm.

Phyllaries

in 10–12 series, strongly imbricate, greenish with subapical darker central zone, ovate (outer) to lanceolate (inner), abaxial faces with narrow glutinous ridge;

outer and middle entire, bodies appressed, spines abruptly spreading to deflexed, slender, 2–4 mm;

apices of inner phyllaries narrow, flexuous, flattened, entire or finely erose.

Heads

1–10+, borne at tips of main stem and branches.

Cypselae

brown, 5–6 mm, apical collars yellow, ca. 1 mm;

pappi 25–30 mm.

= 18 (as C. terrae-nigrae), 20 + 1B.

Cirsium engelmannii

Phenology

Flowering spring–summer (May–Jul).

Habitat

Tallgrass prairies, old fields, roadsides, oak savannas, forest edges, in calcareous clay or rarely sandy soils

Elevation

50–200 m (200–700 ft)

Distribution

LA; OK; TX

[BONAP county map]

Discussion

Cirsium engelmannii occurs mostly in the blackland prairies of eastern Texas. It ranges northward into southeastern Oklahoma and eastward to northwestern Arkansas.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source

FNA vol. 19, p. 117.

Parent taxa

Asteraceae > tribe Cardueae > Cirsium

Sibling taxa

C. altissimum, C. andersonii, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. nuttallii, C. occidentale, C. ochrocentrum, C. ownbeyi, C. palustre, C. parryi, C. perplexans, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii

Synonyms

C. virginianum var. filipendulum, C. terrae-nigrae

Name authority

Rydberg: Fl. Rocky Mts., 1069. (1917)

Web links

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America

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Cirsium engelmannii

Cirsium engelmannii