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Lobelia
inflata L.
Standardized Common
Name: Lobelia
Other Common Names: Asthma Weed, Indian
Tobacco, Pukeweed, Wild Tobacco
Family: Campanulaceae
Taxonomy: Lobelia
includes about 300 species, which occur almost worldwide and are quite diverse.
The temperate North American species are mostly small, attractive herbs; in
Africa, some species are large shrubs or trees.
Description: Annual herb with
milky latex. Stem erect, usually branching, 0.15–0.5(–1) m high, pubescent with
soft hairs especially near base. Leaves alternate, sessile or nearly so,
obovate to oblong or ovate, 2.5–5(–9) cm long; base rounded, often
asymmetrical; margins dentate to serrate; lower surface usually pubescent with
stiff hairs. Inflorescence racemose, terminal, to 30 cm long, bracteate, loose;
flowers pedicellate. Calyx campanulate, 5-lobed; in fruit, calyx inflated and
broadly ovoid to spherical. Corolla 7–10 mm long, pale violet to whitish or
pinkish, with a straight tube; upper lip of 2 erect narrow lobes, deeply cleft;
lower lip of 3 spreading lobes, pubescent at the base with straight stiff
hairs. Stamens 5; filaments fused; 2 smaller anthers pubescent above. Fruit a
capsule, contained within the inflated calyx, 5–8 mm long, 2-locular, opening
at the top, many-seeded.
Parts
in Commerce:
Leaves and tops, collected after some fruits have begun to mature
Identification:
Stem
- Stem slender in
tops, coarsely angled
- Usually
branching freely
- Often purplish
- Pubescent at
least on basal part of stem, with long white hairs
Leaves
- Leaves ovate to
oval, 2.5–5(–9) cm long
- Base rounded,
with little or no petiole, often slightly asymmetrical
- Apex acute to
obtuse
- Margins with
very short irregular teeth, with pale glands at tooth apices
- Lower surface
often pubescent, especially along veins
- Color yellowish
green
- Odor unpleasant
but weak
- Taste similar to
tobacco, acrid and burning, causing salivation
Flowers
- 7–10 mm long
- Calyx in flower
has short tube and long narrow teeth
- Corolla
2-lipped, with upper lip of 2 deeply divided narrow lobes, lower lip of 3
shorter and broader spreading lobes
- Corolla lilac to
pale blue, pink or white, with hairy patch at base of lower lip
- Stamens fused
into a tube
Fruits
- Tube of calyx in
fruit swollen, containing capsule, with long calyx teeth still present at
apex of fruit
- Ovoid to
spherical, 5–8 mm long, 10-ribbed
- 2-loculed,
containing numerous tiny seeds
- Seeds brown,
elliptical, with reticulated ridges on surface
Adulterants: Adulteration with
other species is not reported; most species of Lobelia have larger and
showier flowers, and would not be mistaken for L. inflata. However, some
wild-harvested material has been reported to be of poor quality. It should not
contain many large stems (Youngken recommends that no more than 10% of the
stems should be over 2 mm in diameter), nor should it contain roots.
References:
Fernald ML. Gray’s Manual of Botany, 8th ed. New York: American Book
Company; 1950:1354–1357.
McVaugh
R. Studies in the taxonomy and distribution of the eastern North American
species of Lobelia. Rhodora. 1936;38:241–263, 276–298, 305–329,
346–362.
van
der Meijden R, Vermeulen JJ. Over Lobelia inflata L. en Lobelia urens
L. (Campanulaceae). Gorteria. 1994;20:105–108.
Youngken HW. Text-Book of Pharmacognosy, 5th ed. Philadelphia, PA: The
Blakiston Company; 1943:863–866.
Figure 40: a–d, Lobelia inflata habit, leaf close-up,
flower and fruit.
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