- Acorus, the Latin form of the Greek 'akoron
(akoron), presumably an ancient plant name for the Sweet Flag
or the Yellow Flag Iris (Iris pseudacorus)
- americanus, from the Latin, "of America", to distinguish
the native species from the virtually identical Eurasion Acorus
calamus (calamus, from the Greek, kalamos
- Sweet Flag, from the sweet fragrance of the bruised leaves, and their
similarity to the leaves of iris, also known as flag (eg, Blue Flag,
- Other common names include: Calamus, Flagroot, Myrtle Flag, Sweet
Sedge, belle-angelique (Qué), shih-ch'ang pu
(Chi), Kalmus (Dan, Ger, Swe), Groene Kalmoes (NL),
Kalmojuuri (Fin), Bachh (Hindi), Calamo Aromatico
(It), Kalmusrot (Nor), Racha (Vedic)
- Kingdom Plantae, the Plants
- Division Magnoliophyta, the Angiosperms (flowering plants)
- Class Liliopsida, the Monocotyledons
- Subclass Arecidae
- Order Arales
- Family Acoraceae, the Sweet Flags (sometimes
- Genus Acorus, the Sweet Flags
- Taxonomic Serial Number: 42523
- Also known as Acorus aromaticus, Acorus calamus,
Acorus calamus var. americanus
- Some measure of confusion exists over the taxonomic the status of
Acorus in North America. Whether native or introduced, whether
one or more species, have been among the questions. Recent studies of
morphology, essential oil chemistry, cytology, isozymes, and ethnobotany
suggest the existence of two species in North America -- Acorus
calamus, an introduced Eurasian species and Acorus americanus,
the native Sweet Flag. The Integrated
Taxonomic Information System (ITIS) lists the accepted name of North
American Sweet Flag as Acorus americanus (TSN182561). Because
all Sweet Flag in North American has long been lumped together as Acorus
calamus, especially in the popular, non-professional realm, expect
the confusion to continue.
- Although historically considered an aberrant genus within the family
Araceae, recent evidence based on DNA sequences fails to show
any close relationships between Acorus and other genera, and
instead supports Acorus as the oldest surviving line of monocots.
So despite its sparse fossil record, the group has great importance
for paleontologists, providing one picture of what early monocots may
have looked like.
- A hardy perennial swamp or bog plant with sweet, spicy-scented leaves.
- Leaves sword-shaped, erect in clumps, usually about
2' tall but twice that in rich soil. Bright yellow-green for most of
their length; white with pink or red at the base. Leaf shows 2-6 major
veins, more-or-less equally raised above the leaf surface. Leaf cross-section
thickened in center, tapering to sometimes crinkled edges. Crushed leaves
exude distinct tangerine odor.
- Rootstalk creeping, with brownish-red bark and a
white, fleshy interior. Usually 1"-2" thick, it can spread several feet
in mature plant.
a cylindrical spike (spadix),
2"-4" long and studded with tiny greenish-yellow blossoms; angles
out near the base of the leaf.
- Sepals 6, papery
- Stamens 6
- Fruit a berry, dry outside and jelly-like inside,
containing 1 to 3 seeds.
- Seed tan, narrowly oblong to obovate, 3mm-4mm
- A waterside plant with iris-like leaves.
- Distinguished from the Blue Flag Iris (Iris
versicolor) with which it is often found by its decidedly unflower-like
flower, and its brighter, yellow green color.
- Distinguished from the introduced Eurasian Acorus calamus
by having the midvein, plus 1 to 5 additional veins, more-or-less equally
raised above leaf surface. (In Acorus calamus, only the midvein
is prominently raised above leaf surface, the other veins scarcely raised
if at all.)
- Although leaf and spadix size of the two species overlap, those measurements
differ significantly, with the Eurasian Acorus calamus tending
to have longer and wider leaves and longer spadices.
- Labrador and Quebec to Alaska, south to Virginia, Ohio, Iowa, Nebraska,
Montana, northern Idaho, and Washington.
- Specimens from central Siberia with similar leaf venation have been
examined, and the species is perhaps holarctic in distribution.
- In North America, Native Americans probably played a significant role
in the present-day distribution of Acorus americanus because
Sweet Flag rhizomes and plants were valued by many groups and were objects
of trade. Disjunct populations occur in localities that are often near
old Native American village sites or camping areas.
- Edges of ponds and moist soils, marshes, shallow waters
- Aromatic roots used medicinally and ritually by Algonquins, Cree and
other NE tribes.
- Acorus calamus, a sterile triploid, was introduced to North
America by early European settlers, who grew it for medicinal uses.
Rhizomes propagate easily, and the species has spread throughout northeast
and central United States. Scattered populations occur elsewhere.
- Long known for its medicinal value, and cultivated in Asia for this
reason. Spicy-scented leaves and fragrant (but rather bitter-tasting)
root often are used for sachets, medicines, and candy. Calamus root
long was used in a home remedy for colic.
- Oleum calami distilled from the rhizomes for use in perfumery
- Active ingredients: Asarone and beta-Asarone
- The rhizomes, harvested in autumn or spring, are edible and can be
used as a substitute for ginger, cinnamon or nutmeg; in the past were
candied and used as a sweetmeat. The inner portion of young stems can
be eaten raw and young leaves can be eaten cooked. Other virtues of
this plant include its mature leaves, which are insect repellant, the
lower stem and rhizome, which can be dried and used to scent clothes,
cupboards etc, and an essential oil which can be extracted from the
- The rhizomes are considered to possess anti-spasmodic, carminative
and anthelmintic properties and also used for the treatment of epilepsy,
mental ailments, chronic diarrhoea, dysentery, bronchial catarrh, intermittent
fevers and glandular and abdominal tumours. They are also employed for
kidney and liver troubles, rheumatism, sinusitis, and eczema. It is
also used as antibiotic and insecticide. (Whew!)
- Leaves can be used as a substitute for vanilla pods. They can also
be cut up and stored in dry foods to prevent infestation by weevils.
Leaves and rhizomes are a nice addition to potpourri.
- The rhizomes of Acorus calamus contain an aromatic oil that
has been used medicinally since ancient times and has been harvested
commercially. Native Americans exploited Acorus as a medicine
and for ceremonial uses. Although this plant is cited in the ethnographic
and ethnobotanical literature as Acorus calamus, the distribution
of the tribes reported to use Acorus corresponds to the range
of the native species.
- Sexually by seed
- Flowers June/July
- Assexually by rhizome
- Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
- Cultural Requirements
- Full Sun
- Permanently wet soil
- Good for bogs and water gardens.
- Available by mail order from specialty suppliers or occasionally at
local nurseries. The related Asian species is available in a variegated
- An unusual but appealing plant. A personal favorite.
Last updated on
14 April, 2004