Description:
This perennial herbaceous plant forms a rosette of basal
leaves spanning ¾-2½' across. The basal leaves are ascending to widely
spreading (usually the latter). Individually, these leaves are 4-18"
long, ½-2¼" across, and sessile; they are oblong-lanceolate,
oblong-oblanceolate, or oblong-elliptic in shape and their margins are
finely dentate (denticulate) and, to a lesser extent, smooth
(entire). The basal leaves are often folded upward along their
margins, otherwise they are flat. The leaf surfaces are pale green,
glabrous, and occasionally glaucous; sometimes they are speckled
purple. The texture of these leaves is slightly succulent and stiff. At
maturity, an erect flowering stalk (2-6' in length) develops from the
rosette of basal leaves. This stalk is pale to medium green, terete,
glabrous,
and often glaucous. Along its length underneath the inflorescence,
there are widely separated leafy bracts about ½-4" long that become
smaller as they ascend the stalk. These bracts are linear-lanceolate,
ascending to erect, and pale green. Toward the upper end of this stalk,
there is a
spike of 10-60 flowers about ½-2' long.
Each flower is ¾-1¼" long,
approximately tubular in shape, whitish green or yellowish green, and
ascending to erect. Each flower has a tubular corolla with 6 convex
ridges, 6 narrowly triangular lobes that are held erect, 6 strongly
exerted stamens, and an inferior ovary with exerted style. The tubular
body of the corolla is about 2-3 times as long as its lobes; they are
both pale green and glabrous. The filaments of the stamens are golden
yellow; the long slender anthers are white, becoming brown and
deciduous with age. The style is also golden yellow, except for its
3-lobed stigma, which is white. At the base of each flower, there is a
membranous-leafy bract up to ½" long. The flowers are mostly sessile,
although a few lower flowers may have very short pedicels. The blooming
period occurs from early- to mid-summer. The flowers have a slight to
moderate
fragrance that is sweet and fruity. Afterwards, the flowers are
replaced by 3-celled seed capsules that become about ½" long at
maturity. These capsules are globoid-ovoid in shape and angular. Within
each cell of a capsule, there are 2 rows of flattened seeds. Mature
seeds are black and half-orbicular in shape; they can be blown about by
the wind. The root system consists of a bulbous caudex with fibrous
roots below.
Cultivation:
The preference is partial to full sun, dry-mesic to dry
conditions, and either thin rocky soil or sandy soil where there is
reduced competition from other ground vegetation. Eastern Agave
(
Manfreda virginica)
can be cultivated as an ornamental plant in the
back of a rock garden. While the flowers are not particularly showy,
the basal leaves are attractive. Because Eastern Agave has a Crassula
acid metabolism (CAM), like cacti and other desert plants, it is very
drought tolerant.
Range
& Habitat: The native Eastern Agave (
Manfreda virginica)
is occasional in southern Illinois, while in the rest of the state it
is absent. Illinois lies along the northern
range-limit of this species. Habitats include rocky openings in upland
woodlands, rocky ledges and cliffs along rivers or streams, thinly
wooded rocky slopes, upland savannas, and rocky glades (including
chert, sandstone, and limestone). Outside of Illinois, this species has
also been found in sandy habitats. It occurs in higher quality
natural areas.
Faunal
Associations: The flowers are cross-pollinated by Sphinx
moths,
Noctuid moths, and bumblebees (Groman & Pellmyr, 1999).
Generally, the moths have been found to be more important pollinators
than the bumblebees. These visitors suck nectar from the flowers; some
of the bumblebees also collect pollen for their larvae. Aside from its
pollination ecology, little is known about the floral-faunal
relationships for this species.
Photographic
Location: A thinly wooded rocky slope in southern Illinois.
Comments: This is the only member of the Agave family that
is native
to, or has naturalized in, Illinois. The distinctive Agave-like leaves
and the tall spike of greenish flowers makes this species easy to
identify when it is encountered in the wild. Unlike true Agaves (
Agave
spp.), the Eastern Agave (
Manfreda virginica)
can bloom multiple times
during its lifespan. In contrast, the true Agaves bloom only once at
the end of their lifespans after a period of several years (or even
decades). The latter can be found in the desert SW and Florida of the
United States, in Mexico, and other countries further to the south.
Other scientific names of Eastern Agave are
Polianthes virginica
and
Agave virginica.
Other common names for this species are Virginia Agave and False Aloe.
Sometimes Eastern Agave is assigned to the Lily family (Liliaceae) when
the Agave family (Agavaceae) is reclassified as a subfamily of the
former family.