Ruellia pedunculata Torr. - Wild Petunia

Ruellia pedunculata plant

Family - Acanthaceae

Stems - To +/-50cm tall, erect, branching, somewhat angled or ribbed, with vertical striations, from a rhizome, retrorse pubescent with longer cilia at the nodes, often purplish, herbaceous.

Ruellia pedunculata stem

Leaves - Opposite, short-petiolate (petioles to +/-10mm long), mostly decussate, ovate-lanceolate, acute, deep green above, light green below, pubescent above and below. Margins entire or slightly crisped, ciliate. Blades to +/-7cm long, +/-3.5cm broad.

Ruellia pedunculata leavesPressed leaves.

Inflorescence - Single axillary flowers on bracteate peduncles. Peduncles to +/-3cm long, with a pair of foliaceous bracts subtending the calyx. Peduncles pubescent as the stem.

Flowers - Corolla +/-4cm long, contracted portion to 2cm long, tan, pubescent externally, glabrous internally. Expanded portion of corolla tube +/-2cm long, purple to white, 5-lobed. Lobes rounded, to 1cm long. Stamens 4, didynamous, adnate near the apex of the expanded portion of the corolla tube. Filaments white, mostly glabrous but with a few sparse hairs near base, to 1cm long. Anthers lilac to purplish, to 4mm long. Ovary green, superior, cylindric, 4mm long, villosulous, 2-locular. Placentation axile. Style villosulous, white, +2.6cm long. Stigma flattened, to 2mm long. Fruits villosulous, few-seeded. Calyx accrescent. Tube to -2mm long, 5-lobed, puberulent. Lobes linear-attenuate, to 2cm long in flower.

Ruellia pedunculata flower

Ruellia pedunculata calyxCalyx.

Flowering - May - September.

Habitat - Dry rocky woods, ravines, lowlands, glades, slopes.

Origin - Native to U.S.

Other info. - This species can be found in the southeastern 1/3 of Missouri. This plant can be easily identified in the field by its long, thin calyx lobes and the fact that its flowers are on peduncles. It is a striking plant and would do well in cultivation with little care.

Photographs taken in Minimum, MO., 5-31-03.


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