Liatris pycnostachya Michx.

Liatris pycnostachya plants

Family - Asteraceae

Stems - To -2m tall, glabrous to hirsute (at least above), erect, typically simple, striate to carinate, from thick roots herbaceous.

Liatris pycnostachya stemGlabrous stem.

Leaves - Alternate, dense, linear, entire, punctate, +/-5mm wide, to +20cm long, reduced upward, sessile, glabrous to pubescent or slightly scabrous, very numerous. Basal leaves to -40cm long.

Inflorescence - Dense terminal spike to 40cm tall. Flower heads sessile, usually subtended by single foliaceous bract. Axis pubescent to hirsute.

Involucre - To 1cm long(tall), 4-5mm in diameter, cylindric. Phyllaries to 7mm long, +/-2.5mm broad, green below fading to red above, mostly glabrous, punctate, with ciliate margins, tips recurved, acuminate. Flower heads with +/-7 flowers.

Liatris pycnostachya involucreInvolucre.

Ray flowers - Absent.

Disk flowers - Corolla tube pink, 5-6mm long, glabrous, 5-lobed. Lobes acute, erect to spreading, 2mm long, glabrous. Stamens 5, adnate about 1/3 to 1/2 way up tube, exserted. Anthers connate around style, 3mm long, brownish-purple. Style exserted, bifurcate. Stigma deep pink. Achenes dense pubescent, 3-sided, 3mm long in flower. Pappus of barbed capillary bristles to 5mm long.

Liatris pycnostachya flowers

Flowering - July - October.

Habitat - Prairies, meadows, open ground, glades, railroads, roadsides.

Origin - Native to U.S.

Other info. - This species is commonly seen in prairie habitats and along roadsides in the Ozarks. The dense linear leaves and densely flowered spikes are good characteristics for identifying the species.
The form shown above is form pycnostachya. Steyermark lists a second form of the species, form hubrighti, which has white disk flowers. This form is much less common.
All the plants in this genus are gaining popularity in cultivation due to the increased interest in butterfly and native landscape gardening.

Photographs taken at Taum Sauk Mountain, MO., 7-28-03.


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