Cirsium engelmannii

Rydberg

Fl. Rocky Mts., 1069. 1917.

Common names: Blackland or Engelmann’s thistle
Endemic
Basionym: Cirsium virginianum var. filipendulum A. Gray Manual ed. 2, 233. 1856,
Synonyms: Cirsium terrae-nigrae Shinners
Treatment appears in FNA Volume 19. Treatment on page 117. Mentioned on page 99.

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. Heads 1–10+, borne at tips of main-stem and branches. 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. 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. 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. Cypselae brown, 5–6 mm, apical collars yellow, ca. 1 mm; pappi 25–30 mm. 2n = 18 (as C. terrae-nigrae), 20 + 1B.


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

Discussion

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

Selected References

None.

Lower Taxa

None.

"fine" is not a number."broad" is not a number.

... more about "Cirsium engelmannii"
white-tomentose +
glabrate +  and villous +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
scarious +
1 cm10 mm <br />0.01 m <br /> (?) +
corymbiform +, paniculiform +, subcapitate +, spiciform +  and racemiform +
indeterminate +  and determinate +
David J. Keil +
Rydberg +
winged-petiolate +
narrowed +  and tapered +
Cirsium virginianum var. filipendulum +
compound +  and simple +
5 cm50 mm <br />0.05 m <br /> (20 cm200 mm <br />0.2 m <br />) +
pinnatifid;ovate;elliptic +
1cm;10cm +
10-nerved or 20-nerved +  and rugose +
reduced +
tawny +  and white +
? (?) +  and ? (?) +
Blackland or Engelmann’s thistle +
actinomorphic +
pink +  and purple +
3.2 cm32 mm <br />0.032 m <br /> (3.8 cm38 mm <br />0.038 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
La. +, Okla. +  and Tex. +
50–200 m +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Tallgrass prairies, old fields, roadsides, oak savannas, forest edges, in calcareous clay or rarely sandy soils +
indeterminate +
each +  and sessile +
2.5 cm25 mm <br />0.025 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
ovoid;broadly cylindric or campanulate +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
triangular +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
spinulose to remotely few-toothed or sharply lobed +  and entire +
usually lobed +  and dissected +
2-carpellate +
persistent +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
2 cm20 mm <br />0.02 m <br /> (20 cm200 mm <br />0.2 m <br />) +
Flowering spring–summer (May–Jul). +
middle +  and outer +
weakly to strongly +
papillate +  and smooth +
Fl. Rocky Mts., +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
abruptly spreading +  and deflexed +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Cirsium terrae-nigrae +
Cirsium engelmannii +
species +
cylindric +
expanded +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
bristly-dentate to coarsely +
slender +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
perennial +  and biennial +
40 cm400 mm <br />0.4 m <br /> (200 cm2,000 mm <br />2 m <br />) +
tree +, vine +, shrub +  and subshrub +