Solidago rigida L.

Solidago rigida plant

Family - Asteraceae

Stems - To 1m tall, erect, herbaceous, fro a vertical caudex and slightly thickened roots, terete, glabrescent basally, hispidulous with multicellular hairs in the apical 1/2.

Solidago rigida stem

Leaves - Alternate, the basal and lower-most petiolate, sessile above. Petioles of the basal leaves to +20cm long, with a very narrow adaxial groove, mostly glabrous but with some hairs in the groove. Blades to +/-20cm long, +/-8cm broad, scabrous above and below, greyish because of dense hairs below, elliptic-lanceolate, shallow serrate, acute, tapering slightly at the base. Cauline leaves sessile, quickly reduced upward, shallow crenate-serrate, densely pubescent (with a greyish cast), scabrous, those in the middle of the stem oblanceolate. Leaves in the apical 1/3 of the stem reduced to bracts, ovate to orbicular.

Solidago rigida leaves

Inflorescence - Terminal corymbiform arrangement of flowerheads. Peduncles densely hispidulous. Each division of the inflorescence subtended by a small foliaceous bract.

Solidago rigida inflorescence

Involucre - To +8mm long (tall), 5mm in diameter, cylindric. Phyllaries imbricate, appressed, unequal, the longest to 6mm long, 2mm broad, rounded at the apex, greenish (mostly at the apex), scarious below, with a green midrib, glabrous internally and externally, with ciliolate margins, oblong.

Solidago rigida involucreInvolucre.

Ray flowers - Flowers 8-10 per flowerhead, fertile, pistillate. Corolla tube 4mm long, glabrous, yellowish. Ligule 4mm long, 2mm broad, yellow, glabrous or with a few sparse hairs, rounded at the apex. Style purplish, glabrous, thin, 5mm long, bifurcate. Stigmas 1mm long. Pappus of capillary bristles, white, 5mm long. Bristles antrorse barbellate. Achene green in flower, 2.2mm long, ribbed, glabrous.

Disk flowers - Disk corollas yellow, contracted and thin in the basal 2/3, expanded in the upper 1/3, 5mm long, 5-lobed, glabrous or with a few small hairs. Lobes acute, spreading, 1.1mm long. Stamens 5, adnate in the basal 1/3 of the corolla tube. Filaments glabrous, compressed, thin, glabrous, yellowish. Anthers yellow, 2.5mm long, connate around the style, partially to wholly exserted, acute at the apices. Style exserted, purplish, bifurcate for about 1mm. Stigmas erect (mostly). Pappus and achenes as the ray flowers.

Solidago rigida flowers

Flowering - August - October.

Habitat - Prairies, glades, rocky open ground, thickets, borders of wet meadows.

Origin - Native to U.S.

Other info. - This showy species can be found throughout most of Missouri but is apparently absent in the southeast corner of the state. The plant is easy to identify in the field because of its big basal leaves and large, showy flowerheads. It has larger flowerheads than any other Solidago species in Missouri. This is a characteristic plant of prairies and is certainly worthy of cultivation as it is drought tolerant and requires little care.

Photographs taken in Eminence, MO., 9-21-03.


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