Symphyotrichum drummondii (Lindl.) Nesom - Drummond's Aster

Aster drummondii plant

Family - Asteraceae

Stems - From a short rhizome, erect, herbaceous, to +60cm tall, typically densely puberulent (more so above), terete, 2-4mm in diameter, branching near the apex (in the inflorescence), green.

Aster drummondii stem

Leaves - Alternate, petiolate. Petioles of the early-season basal rosette to +6cm long, pubescent abaxially, scabrous adaxially, the narrow wings forming an adaxial groove. Petioles of the upper leaves reduced in length but with much more broad wings. Blades cordate, ovate, serrate, to +6cm long, +3.5cm broad, green above, lighter below, scabrous above, soft pubescent below. Veins expressed below.

Aster drummondii leaves

Inflorescence - Open, paniculate inflorescence at the apex of the plant. Leaves reduced to small bracts in the inflorescence. Branches densely puberulent. Heads on minutely branched peduncles to +/-1cm long. Bracts of the peduncles subulate, pubescent, +/-3mm long, 1mm broad, acute.

Aster drummondii inflorescence

Involucre - +/-5mm long (tall), +/-2mm broad (in diameter). Phyllaries imbricate, glabrous, 2-3.5mm long, -1mm broad, acute, whitish-translucent below, with elongate diamond-shaped green tips. Margins sometimes ciliate at the tips and sometimes with a minute red apex.

Aster drummondii involucre

Ray flowers - +/-12 per head, fertile, pistillate. Ligules blue to white, +/-6mm long, to 1.5mm broad, glabrous. Corolla tube 2mm long, glabrous, whitish. Style partially to fully exserted about 1mm beyond corolla, bifurcate. Stigmas yellow, .5-.8mm long, erect to spreading, glabrous. Pappus white, of capillary bristles, to +/-3mm long. Achenes (in flower) glabrous, 2mm long, oblong.

Aster drummondii flowers

Disk flowers - Disk 2-3mm broad, with +/-10 flowers. Corolla tube +/-3.5mm long, glabrous, whitish to pale yellow when fresh, contracted in the basal 1/2, expanded in the apical 1/2, 5-lobed. Lobes erect, acute, .5-.8mm long, .5mm broad at the base, glabrous. Stamens 5, adnate at the base of the expanded portion of the corolla tube. Filaments translucent, 1mm long, glabrous. Anthers yellow, connate around the style, 1-1.5mm long, partially to fully exserted. Style barely exserted beyond the anthers, bifurcate, translucent, glabrous. Stigmas +/-1mm long, erect, whitish. Pappus white, of capillary bristles, to +/-3mm long. Receptacle flat, without chaff. Matyre achenes not seen. Disk flowers quickly becoming purplish with age.

Aster drummondii diskDisk close-up.

Flowering - August - October.

Habitat - Rocky or dry open woods, thickets, rocky prairies.

Origin - Native to U.S.

Other info. - This attractive species can be found throughout most of Missouri but is apparently uncommon to absent in many counties from the central Ozark region. The plant is similar to other blue-flowered asters but can be identified by its pubescent stems, winged leaf petioles, scabrous adaxial leaf surfaces, and bluish ray flowers. The phyllaries of the involucre have green apices which are an elongate diamond shape.

Photographs taken at Tall Grass Prairie National Preserve, KS., 9-29-06.


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