Lobelia inflata L.

Lobelia inflata plant

Family - Campanulaceae

Stems - To .75m tall, from fibrous roots, herbaceous, erect, typically branching, sparse hirsute, winged(wings to -1mm broad), with milky sap.

Lobelia inflata stem

Leaves - Alternate, sessile or with short winged petioles, spatulate below, becoming lanceolate to oblong above, pubescent, irregularly crenate-serrate, typically acute, to 7cm long, -3cm broad, reduced above in inflorescence. Teeth of margin typically with minute whitish apices.

Lobelia inflata leaves

Inflorescence - Terminal and axillary racemose arrangement of single axillary flowers. Pedicels to 3mm long, puberulent, elongating in fruit to 6mm.

Flowers - Resupinate. Corolla whitish to tinged with blue, to 7mm long, 5-lobed, glabrous. "Upper" three lobes acute, to 3.2mm long, 1.5mm broad. "Lower" two lobes deflexed, acute, to 2.5mm long. Stamens 5, adnate at base of corolla tube. Anthers purple, -2mm long, connate around stigma, visible between lower two corolla lobes. Style 3.5mm long, greenish, glabrous. Ovary 2-locular. Placentation axile. Calyx tube to 2.1mm long(in flower), green, glabrous, 10-nerved, 5-lobed. Lobes spreading to recurved, attenuate, 4-4.5mm long, .7mm broad at base. Fruit an inflated capsule to 8mm long, 5-6mm in diameter. Seeds many, tan.

Lobelia inflata flower

Lobelia inflata flower

Lobelia inflata fruitFruit.

Flowering - June - October.

Habitat - Moist ground, open woods, thickets.

Origin - Native to U.S.

Other info. - The species designation obviously comes from the inflated fruits. The plant can be toxic if a significant quantity is eaten. This species is somewhat similar to L. spicata Lam. but the latter has much more elongate spikiform racemes. Because the flowers are twisted on their pedicels (resupinate), what looks like the top of the flower is actually the bottom and vice versa.

Photographs taken in Brown Summit, NC., 7-15-02.


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