Lobelia cardinalis L.

Cardinal Flower

Lobelia cardinalis plant

Family - Campanulaceae

Stems - To 1.2m tall, simple to branching above, glabrous to puberulent or retrorse strigose, carinate above, angled, purplish-green, herbaceous, with milky sap.

Lobelia cardinalis stem

Leaves - Alternate, sessile above, petiolate below, reduced upward and at base.  Petioles to +1cm long. Blades lanceolate to oblanceolate, typically glabrous to sparse hirsute or strigose, serrulate to denticulate, to 20cm long, 5cm wide, acute to acuminate. Margins often sinuous.

Lobelia cardinalis leaves

Inflorescence - A terminal raceme to 70cm long(tall). Each flower subtended by single foliaceous bract (reduced leaf). Pedicels to 5mm, puberulent to strigose.

Flowers - Corolla deep red (scarlet, crimson, vermilion), to +4cm long, resupinate, tubular, 5-lobed, fenestrate, glabrous to puberulent externally and internally. Stamens 5. Filaments red, united into a tube to +3cm long and surrounding style. Stigma 2-lobed. Calyx campanulate, small at anthesis but quickly enlarging to 1.5cm long, 5-lobed, 10-ribbed, greenish-purple, puberulent to strigose. Lobes up to 2.5cm long, +/-2mm broad, linear-attenuate.

Lobelia cardinalis flowersFlowers.

Lobelia cardinalis calyxCalyx.

Flowering - July - October.

Habitat - Wet ground, lake margins, streambanks, ditches.

Origin - Native to U.S.

Other info. - This is one of the most striking species of the genus Lobelia. The deep red flowers are easily noticed near bodies of water and in wet areas.
Steyermark lists three forms of the plant based on flower color. Form cardinalis (shown above) has deep red flowers and is the most common. Form alba has white flowers. Lastly, form rosea has rose or pinkish flowers.

Photographs taken in Brown Summit, NC., 7-31-02 and along the shores of the Current River, Shannon County, MO., 8-15-03.