Liatris squarrosa (L.) Michx.


Liatris squarrosa plant

Family - Asteraceae

Stems - To +60cm tall, erect, simple, single or multiple from a corm, herbaceous, glabrous to pilose (the hairs multicellular), terete, typically light green with darker vertical lines.

Liatris squarrosa stem

Leaves - Alternate, sessile, linear and grasslike, scabrous or not, glabrous to strigose hairy, entire, reduced upward, to +20cm long, 4-12mm broad. Veins of the leaves appearing parallel. Hairs multicellular as on the stem.

Liatris squarrosa leaves

Inflorescence - Single, sessile flowerheads in the leaf axils.

Involucre - To +/-1.8cm long (tall), +/-7mm in diameter, cylindric or slightly wider near the base. Phyllaries imbricate, the longest to -1.5cm long, 2-4mm broad, glabrous to pubescent externally, glabrous internally, with ciliate margins apically, abruptly short acuminate to acuminate at the apex, often dark purple at the apex in strong sun. The apices of the phyllaries somewhat to greatly spreading (depending on the variety).

Liatris squarrosa involucreInvolucre.

Ray flowers - Absent.

Disk flowers - 10-60 per flowerhead. Corolla green basally, purplish in the apical half, 5-lobed, to 1.4cm long (including the lobes), glabrous externally, pubescent internally. Lobes to +/-4mm long, -1mm broad, acute, linear, with punctate glands externally (use a lens to see). Stamens 5, adnate at the middle of the corolla tube. Filaments white, glabrous, -2mm long. Anthers brown, connate around the style, 3mm long, mostly included. Style white basally, purple in the apical half, glabrous, +/-2cm long total, divided in the apical half, well exserted beyond the corolla. Pappus of purplish plumose bristles to +/-9mm long, uniseriate. The shaft of the bristle is purple the plumose hairs are white. Achene in flower ribbed, +/-5mm long, +/-1.2mm broad, antrorse pubescent.

Liatris squarrosa flowers

Flowering - June - September.

Habitat - Rocky and dry open woods, glades, rocky prairies, bluff ledges.

Origin - Native to U.S.

Other info. - This striking species can be found in much of Missouri but is apparently absent from the bootheel portion of the state as well as the loess-rich northwest corner of the state.
L. squarrosa is easily recognized in the field by its grass-like leaves, squarrose phyllaries, and habitat. The pubescence of the stem, leaves, and involucre is variable in this species and different varieties exist. I won't go the varieties here but to see what typical plants look like in the southeastern U.S., click here.

Photographs taken at the Sunklands Conservation Area, Shannon County, MO., 7-26-04.