Solidago altissima L.

Tall Goldenrod

Solidago altissima plant

Family - Asteraceae

Stems - To +2m tall, erect, stout, terete, puberulent, to +/-1cm in diameter at the base, from slender rhizomes, typically branching in the apical 1/2, herbaceous.

Solidago altissima stem

Leaves - Alternate, sessile or on petioles to +/-2mm long, many on the stem, widest in the middle portion of the stem. Basal leaves absent at anthesis. Blades to 15cm long, +2cm broad, shallow serrate, pubescent abaxially, scabrous adaxially from antrorse strigillose hairs or glabrous, green above, lighter below, linear-lanceolate.

Solidago altissima leaves

Inflorescence - Terminal pyramidal paniculate inflorescence of many branches and flower heads. Inflorescence to +15cm broad , +20cm tall. Flower heads secund in few to many-flowered axillary panicles on the inflorescence branches. Each small group subtended by a linear bract. Each flower head subtended by a minute subulate bract. Bracts, peduncles, and branches of the inflorescence pubescent. Peduncles of each flower head to 1mm long.

Solidago altissima inflorescenceBranch of inflorescence.

Involucre - To 3-5mm tall, 1-1.5mm broad, light-green, pale yellow, or whitish. Phyllaries imbricate, linear, glabrous, 1-2mm long, .5mm broad.

Ray flowers - +/-5 per head, yellow, pistillate. Ligule yellow, glabrous, to 2mm long, .5mm broad, notched at the apex. Corolla tube to 3mm long, translucent-yellow, with a few translucent hairs at the apex. Style yellowish, bifurcate for +/-1mm, +3mm long, glabrous. Pappus white, uniseriate, of capillary bristles, antrorse barbellate, +/-3mm long. Achenes (in flower) retrorse pubescent. Mature achenes not seen.

Disk flowers - Flowers 1-3 per head, yellow, 5-lobed. Lobes spreading, linear-ovate to subulate, +/-1mm long, glabrous, yellow. Corolla tube +2mm long, glabrous externally and internally, pale yellow to whitish. Style 1, yellow, glabrous, exserted, to +/-3mm long, mostly undivided. Stamens 5. Anthers small, included, reddish, -1mm long, -.3mm broad. Filaments translucent, glabrous, -2mm long, adnate at the base of the corolla tube. Pappus as in the ray flowers.

Solidago altissima flowers

Flowering - August - November.

Habitat - Fallow fields, prairies, bottoms, rocky outcrops, open woods, thickets, waste ground, roadsides, railroads.

Origin - Native to U.S.

Other info. - This is one the most common species of goldenrod in Missouri. The plant grows quite large ("altissima" means "tall") and can be seen along nearly every roadside of the state in the fall.
This species is in the group of tall Goldenrods which includes other similar species like S. gigantea Ait. and S. canadensis L.. These species have no basal rosettes at anthesis and have leaves which are largest in the central portion of the stem but are typically all similar in size. The best way to differentiate these species is vegetatively and Justin Thomas has written an excellent key to the Solidago species based on vegetative characters only. You can acquire a copy of this key in the 2003 issue of Missouriensis, a publication of the Missouri Native Plant Society.
S. altissima can be identified by its pubescent stems, three-nerved leaves, pyramid-shaped inflorescences, and small flowerheads, which are only about 3-5mm tall.

Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 8-16-03.