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