lobelia

lobelia, any plant of the genus Lobelia, annual and perennial herbs of tropical and temperate woodlands and moist places. Most lobelias have blue or purple flowers on a long (1-4 ft/30-122 cm), leafy stem. Native North American species, often cultivated as ornamentals, include the only red lobelia, the cardinal flower (L. cardinalis), which is becoming rare; the blue lobelia (L. syphilitica), used by Native Americans for the treatment of syphilis; and Indian tobacco (L. inflata), named for its odor. The dried leaves and stems of Indian tobacco and sometimes of other species furnish medicinal lobelia, the source of lobeline, which is used as a respiratory stimulant but is poisonous in overdose as are the roots. L. erinus, introduced from S Africa, is a common border plant. Most botanists include Lobelia and related genera in the family Campanulaceae (bluebell family); others consider them a separate family, the Lobeliaceae. Lobelia is classified in the division Magnoliophyta, class Magnoliopsida, order Campanulales, family Campanulaceae.

Lobelia is a genus of flowering plant comprising 360–400 species, with a subcosmopolitan distribution primarily in tropical to warm temperate regions of the world, a few species extending into cooler temperate regions. English names include Lobelia, Asthma Weed, Indian Tobacco, Pukeweed, and Vomitwort.

Some botanists place the genus and its relatives in the separate family Lobeliaceae, others as a subfamily Lobelioideae within the Campanulaceae. The Angiosperm Phylogeny Group did not make a firm decision in this, listing the genus under both families.

Lobelia is probably the base form from which many other lobelioid genera are derived; it is therefore highly paraphyletic and not a good genus. For example, the Hawaiian species are part of a group including other genera that appear very different (see Hawaiian lobelioids). However, the group has not yet been studied adequately to rearrange the classification.

Lobelia species are used as food plants by the larvae of some Lepidoptera species including the Setaceous Hebrew Character.

The genus is named after the Belgian botanist Matthias de Lobel (1538–1616).

Selected species

Lobelia aberdarica Lobelia anatina – Southwestern Blue Lobelia Lobelia anceps Lobelia appendiculata Lobelia assurgens Lobelia berlandieri Lobelia boykinii Lobelia canbyi Lobelia cardinalis (syn. L. fulgens) – Cardinal flower Lobelia chinensis Lobelia comosa Lobelia coronopifolia Lobelia deckenii Lobelia dortmanna Lobelia erinus – Edging Lobelia Lobelia flaccidifolia Lobelia flaccida Lobelia gaudichaudii Lobelia gerardii Lobelia gibberoa Lobelia ilicifolia (syn. L. purpurascens) – Purple Lobelia Lobelia inflata – Indian Tobacco Lobelia kalmii

Lobelia keniensis Lobelia laxiflora – Sierra Madre Lobelia Lobelia leschenaultiana Lobelia monostachya Lobelia nicotianifolia Lobelia niihauensis Lobelia oahuensis Lobelia persicifolia Lobelia pinifolia Lobelia puberula Lobelia pyramidalis Lobelia rhombifolia Lobelia rosea Lobelia sessilifolia Lobelia siphilitica Lobelia spicata Lobelia telekii Lobelia tenuior Lobelia thapsoidea Lobelia tupa Lobelia urens Lobelia valida Lobelia zeylanica

Cultivation and uses

Several species are cultivated as ornamental plants in gardens. These include Lobelia cardinalis (Cardinal Flower or Indian Pink), Lobelia siphilitica (Blue Lobelia), Lobelia fulgens and Lobelia erinus, as well as some hybrids.

Lobelia erinus, a South African annual plant that includes many cultivated selections in a wide variety of colours. They are grown in beds, large pots, window boxes and in hanging baskets. The plants are most often grown away from sunny hot southern exposures (northern exposure's in the southern hemisphere) in soils that are moisture retentive.

In the Victorian language of flowers, the lobelia symbolizes malevolence and ill will.

Medicinal use

Native Americans used lobelia to treat respiratory and muscle disorders, and as a purgative. Today it is used to treat asthma and food poisoning, and is often used as part of smoking cessation programs. It is a physical relaxant, and can serve as a nerve depressant, easing tension and panic. The species used most commonly in modern herbalism is Lobelia inflata (Indian Tobacco).

Extracts of Lobelia inflata contain lobeline, which showed positive effects in the treatment of multidrug-resistant tumor cells. Furthermore, lobeline can be modified to lobelane which decreased methamphetamine self-administration in rats. It therefore opens a perspective in methamphetamine dependency treatment.

As used in North America, lobelia's medicinal properties include the following: emetic (induces vomiting), stimulant, antispasmodic, expectorant, diaphoretic, relaxant, nauseant, sedative, diuretic, and nervine.

Because of its similarity to nicotine, the internal use of lobelia may be dangerous to susceptible populations, including children, pregnant women, and individuals with cardiac disease. Excessive use will cause nausea and vomiting. It is not recommended for use by pregnant women and is best administered by a practitioner qualified in its use.

Two species, Lobelia siphilitica and Lobelia cardinalis, were considered a cure for syphilis.

Herbalist Samuel Thompson popularized medicinal use of lobelia in the United States in the early 19th century, as well as other medicinal plants like goldenseal.

One species, L. chinensis (called bàn biān lián, 半边莲 in Chinese), is used as one of the fifty fundamental herbs in traditional Chinese medicine.

References

Further reading

Everitt, J.H.; Lonard, R.L., Little, C.R. (2007). Weeds in South Texas and Northern Mexico. Lubbock: Texas Tech University Press. ISBN 0-89672-614-2