Description:
This herbaceous perennial plant forms loose tufts of large basal leaves
that are 8–24" across and 8–20" long on petioles up to 12" long; the
blades of these basal leaves are usually held parallel in relation to
the ground. The basal leaves are reniform-orbicular in shape with
margins that are coarsely crenate or crenate-dentate, slightly
undulate, and sometimes
shallowly lobed. Stems with alternate leaves are often produced that
terminate in ;inflorescences; these hairless stems are 3¼–9' tall,
light green or light yellowish green or purplish green, and terete with
rounded
longitudinal ridges and narrow furrows. The stems are normally erect or
ascending, but they sometimes topple over. Alternate leaves occur along
the entire length of each stem, becoming gradually smaller in size as
they ascend and with shorter petioles; they are up to 12" across and
10" long. The alternate leaves are mostly reniform-orbicular to
orbicular in shape, although the uppermost alternate leaves are often
oval-ovate or oval-obovate. The margins of the alternate leaves are
coarsely
crenate, coarsely dentate, slightly undulate, and sometimes shallowly
lobed. The upper surface of both the basal and alternate leaves is
grayish green to dark green and hairless, while the lower surface of
these leaves is light grayish green, sparsely short-hairy along the
veins, and either hairless to finely short-pubescent between the veins.
The bases of both the basal and alternate leaves are truncate-cordate,
except for the uppermost alternate leaves, which are often rounded or
broadly wedge-shaped (cuneate). The relatively stout petioles of both
the basal and alternate leaves are light green to light yellowish
green, sometimes with purplish upper edges; they are convex below,
deeply concave above, and hairless.
Each central stem terminates in a
flat-headed panicle of flowerheads about 3–10" across. Individual
flowerheads are about 8–11 mm. long, 3–5 mm. across, and lanceoloid in
shape, consisting of 5 light green floral bracts (phyllaries) that are
appressed together and 5 perfect disk florets with white or
cream-colored corollas. Individual floral bracts are narrowly
oblong-lanceolate in shape, bluntly keeled, and hairless. Individual
corollas have narrowly tubular bases with 5 rather long recurved lobes.
Peduncle and primary lateral branches of the panicle are light green
with yellowish, whitish, or purplish tints; they are angular or terete
with longitudinal furrows, and largely hairless. The lateral branches
of the inflorescence are ascending-straight or ascending-incurved. The
petioles are usually shorter than the flowerheads, forming somewhat
divergent clusters of flowerheads within the inflorescence; they are
similar to the branches of the inflorescence, except they tend to be
more whitish. Sometimes there are 1 or 2 minute bractlets along the
length of each pedicel. The blooming period occurs during the summer,
lasting about 3 weeks for a colony of plants. The flowerheads are
fragrant. Afterwards, the florets
are replaced by achenes with white tufts of hair. The dark-colored
achenes are about 4–5 mm. long and narrowly ellipsoid-oblongoid in
shape with 5 inconspicuous narrow ridges; they are distributed by the
wind. The root system has fleshy fibrous roots. This plant reproduces
by reseeding itself; it sometimes forms small colonies.
Cultivation:
The preference is partial sun to medium shade, moist to mesic
conditions, and loamy or silty soil with decaying organic matter. After
it has germinated from seed, this plant will not flower until the
second or third year. It can become quite large in size.
Range
&
Habitat: The native Great Indian Plantain (Arnoglossum
reniforme) is
uncommon in southern and central Illinois, while in the northern
section of the state it is rare (see
Distribution
Map).
This herbaceous
plant occurs in the central and northern Mississippi River valley, the
Ohio River Valley, the Appalachian mountains, and areas in between in
the United States. Habitats include bottomland woodlands, wooded areas
along streams, open woodlands, wooded bluffs, lower slopes of
wooded bluffs, and areas at the bottom of wooded bluffs. Great Indian
Plantain is normally found in high quality wooded habitats.
Faunal
Associations: The nectar and pollen of the flowerheads
attract
primarily bees, wasps, and flies, including little carpenter bees
(Ceratina spp.), Halictid bees (Halictus spp., Lasioglossum spp.),
masked bees (Hylaeus spp.), Sphecid wasps (Cerceris spp., Ammophila
spp.), Eumenine wasps (Ancistrocerus spp., Parancistrocerus spp.,
Stenodynerus spp.), Syrphid flies (Eristalis spp., Toxomerus spp.),
soldier flies (Stratiomyidae), Tachinid flies, and Muscid flies
(Robertson, 1929; Graenicher, 1909). The larvae of a Gracillariid moth,
Phyllocnistis insignis,
are serpentine leaf-miners of Great Indian Plantain (Arnoglossum
reniforme) and other
Arnoglossum
spp. (Indian Plantain). The stems of
these plants are bored by the larvae of the Maritime Sunflower Borer
Moth (Papaipema maritima) and the larvae of a lizard beetle,
Languria
bicolor (Natural History Museum website, 2010; Panzer,
2006; Vestal, 1913).
Photographic
Location:
A wooded area near a river in Fox Ridge State Park in Coles
County, Illinois.
Comments:
The large basal leaves of Great Indian Plantain (Arnoglossum reniforme)
often persist through the summer. They are reasonably attractive. The
flowerheads are less showy, but still reasonably attractive during the
relatively short period when they are in bloom. Unfortunately, this
plant is rarely available through nurseries, even though it could be
cultivated in shaded areas if there is sufficient space for it. Great
Indian Plantain can be confused with the similar Pale Indian Plantain
(Arnoglossum atriplicifolium), which tends to occur in more upland
areas and tolerates more sunlight. Both the basal and alternate leaves
of Great Indian Plantain tend to be less lobed and less sharply toothed
than those of Pale Indian Plantain, and the former plant tends to have
more abundant blunt teeth along the margins of its leaves. The leaf
undersides of Great Indian Plantain are not glaucous and conspicuously
whitened, unlike the leaf undersides of Great Indian Plantain. There
are also minor differences in the structural shapes of the flowerheads
of these two plants: the floral bracts (phyllaries) of Great Indian
Plantain are more lanceolate in shape and keeled, while those of Pale
Indian Plantain are more oblong in shape and flat. In addition, the
lobes of the corollas of Great Indian Plantain are longer than those of
Pale Indian Plantain. Another scientific name of Great Indian Plantain
is
Cacalia muhlenbergii,
which is considered obsolete.