Helianthus mollis Lam.

Helianthus mollis plant

Family - Asteraceae

Stems - To +1.2m tall, erect to reclining, herbaceous, from rhizomes, single or multiple from base, simple to branching above, hirsute to canescent.

Helianthus mollis stem

Leaves - Opposite, decussate, sessile, clasping, cordate, ovate, acute to acuminate, serrate, canescent, +12cm long, +8cm broad, quickly turning black when bruised or dried.

Helianthus mollis leavesThis is not a black and white picture.

Inflorescence - Single flower heads terminating stems.

Involucre - To 1.3cm tall, 2cm in diameter. Phyllaries imbricate, acuminate, pubescent to canescent, not tightly appressed, with loose but erect apices. Innermost phyllaries to +1.6cm long, 4-5mm broad at base. Phyllaries sometimes viscid.

Helianthus mollis involucreInvolucre.

Ray flowers - Sterile. Ligules yellow, 2.5-3cm long, -1cm broad, typically 2-notched at apex, pubescent and viscid below, less so above. Achenes 3-angled, 4mm long, glabrous, whitish (in flower). Pappus of 3 scalelike awns to 3mm long.

Disk flowers - Disk to 2.5cm in diameter, basically yellow. Corolla tubes to 6mm long, glabrous or with few sparse strigose hairs, 5-lobed. Lobes acute, pubescent, 1.1mm long. Stamens 5, adnate at base of corolla tube. Filaments whitish, glabrous. Anthers dark brown-purple, connate around style, 4mm long. Style slightly exserted beyond anthers, bifurcate. Stigmas pubescent. Achenes to 4mm long, 3-sided, pubescent on angles and at apex. Pappus of 2 scalelike awns to 4mm long. Receptacle slightly convex. Chaff to +1.1cm long, glandular to pubescent at apex, mostly glabrous near base, folded.

Helianthus mollis flower

Flowering - July - October.

Habitat - Prairies, glades, fields, thickets, roadsides, railroads.

Origin - Native to U.S.

Other info. - This sunflower is very easy to ID in the field. The densely grey-pubescent stems and ovate opposite leaves are good characteristics to look for. The stems typically recline when mature, especially in times of drought. The plants can form large colonies with their spreading rhizomes.
Oddly enough, I have noticed that the flowers of this plant sometimes face AWAY from the sun. I do not know why. Most sunflowers exhibit heliotropism.

Photographs taken off Hwy 19, Ripley County, MO., 7-26-03.


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