Liatris aspera Michx.

Liatris aspera plant

Family - Asteraceae

Stems - To +1m tall, herbaceous, erect, simple. terete, single or double from a large corm, antrorse strigose, glabrescent at the base, typically about 3-4mm in diameter, ribbed.

Liatris aspera stem

Leaves - Alternate, petiolate below, sessile above. Basal leaves long-petiolate. Petioles to 10cm long, mostly glabrous, with a square adaxial groove near the base of the leaf blade. Leaf blades linear-elliptic, to +15cm long, 2-3cm broad, entire, sparse pubescent, with many minute punctations, acute, tapering at the base down the petiole. Cauline leaves greatly reduced towards the apex of the plant, linear, entire, pubescent, 2-6mm broad, 2-9cm long. All leaves with a single midrib.

Liatris aspera leaves

Liatris aspera baseLeaves near the base of the plant.

Inflorescence - Determinate terminal spike to +35cm long. Flower heads sessile, each head typically subtended by one reduced leaf (bract).

Involucre - To 1.5cm long (tall), +1cm in diameter, cylindrical. Phyllaries with scarious margins and a green middle portion, glabrous internally and externally, punctate in the green portion externally, 6-10mm long, to 5mm broad, broadest above the middle, spreading in the apical 1/2 or 2/3, becoming purple in strong sun. The scarious margins deflexed, erose.

Liatris aspera involucreInvolucre of shade.

Liatris aspera involucreInvolucre of sun.

Ray flowers - Absent.

Disk flowers - Flowers +/-30 per head. Corolla tube 5-7mm long, glabrous externally, pubescent at the base internally, whitish at the base, pinkish near the apex, expanding toward the apex, 5-lobed. Lobes purplish-pink, acute, spreading, 2-2.5mm long, 1mm broad. Stamens 5, adnate near the basal 1/3 of the corolla tube. Filaments white, pubescent, 1-1.4mm long, compressed. Anthers brownish, connate around the style, 3-4mm long, partially exserted. Style white in lower 1/3, purple in apical 2/3, glabrous, divided for the apical 2/3, to 1.3cm long. Stigmas spreading. Achenes white in flower, 3mm long, densely antrorse pubescent. Pappus of many capillary bristles. Bristles barbellate, 6-8mm long, white with purple apices.

Liatris aspera flowers

Flowering - August to November.

Habitat - Dry areas of prairies, glades, meadows, open woods, roadsides, railroads. Also cultivated.

Origin - Native to U.S.

Other info. - This is a very popular species of Liatris. The plant is frequent in the habitats mentioned above and is becoming quite popular in cultivation. This is also an easy species to identify in the field because of its distinct phyllaries. No other species in Missouri has the spreading, scarious-margined phyllaries of L. aspera.
Steyermark lists two forms for the species. Form aspera, shown above, has pink to rose disk flowers. Form benkei has white disk flowers and is much less common.
A synonym for the plant is L. scariosa Willd. - Gates

Photographs taken off Hwy 60 and off Hwy C, Carter County, MO., 8-28-03.


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