OF THE WEEK
Dr. T. Ombrello - UCC Biology Department
Flowering Maple, Parlor Maple, Indian Mallow
Scientific name: Abutilon striatum
of scientific name:
- a name of Arabic origin applied to this genus of plants
- striated, striped, in reference to the handsomely veined petals of this
While commonly called
the Flowering Maple, Abutilon
is not at all closely related to the Maple trees most of us are familiar with.
The common name, however, reflects the similarity of this species’ leaf
shape to the true Maples. The
Flowering Maple belongs to the Mallow family of plants
(Malvaceae) and includes
among its close relatives the Mallows, Hollyhocks, Cotton, Hibiscus, Okra, and
Rose of Sharon. Naturalized and
commonly found throughout South and Central America, the Flowering Maple is
native to Brazil.
Now considered an
old-fashioned houseplant, Abutilon
was brought to Europe and North America early in the 19th
century where it proved to be an attractive indoor flowering plant in temperate
regions, and a small flowering shrub in tropical habitats.
When planted outdoors as annuals in our area, Flowering Maples look
spectacular and last well into autumn, tolerating light frosts without damage.
The old common name of Parlor Maple reflects its extensive use for
interior decorating in past years. Today
it is much less commonly seen as a houseplant, neglected in favor of the more
exotic species available to the plant enthusiast.
Flowering Maples tend to get tall and lanky with age, but their
interesting foliage and bell-like flowers that come in shades of white, yellow,
salmon or red, make them quite desirable.
The Flowering Maples
that were first introduced into Europe had solid green colored leaves.
In 1868, however, one seedling in a shipment of Abutilons
imported into England from the West Indies had leaves that showed bright yellow
mottling on the green blades. This
plant was propagated vegetatively and soon replaced the solid-green leaved types
as the favored ornamental of this species.
Apparently no one gave much thought to the origin of this unusual form at
Early in the development
of the science of Virology (the study of viruses), 1904, the mottled leaves of
Flowering Maples were studied in an attempt to determine if some virus parasite
was responsible for the condition. The
virus hypothesis was rejected since mottle-leaved and green-leaved Abutilons
could grow side by side in European greenhouses without any evidence of
transmission. In 1933, however, it
was discovered that the condition could be transmitted by the seeds of the
Today we know that
indeed a virus is responsible for the mottled leaves of Flowering Maples.
Commonly called Abutilon Mosaic Virus or AMV, this virus goes by the
scientific designation of Marmor abutilon.
With a worldwide distribution, AMV can be transmitted from one Abutilon
to another by grafting, occasionally by seed, and in Brazil by the whitefly
insect Bemisia tabaci.
Since the common greenhouse whitefly of Europe and North America, Trialeurodes
vaporariorum, does not transmit the virus and the Brazilian whitefly is not
found in Europe, early European virologists did not recognize the transmission
possibilities of this virus.
abutilon a mosaic virus has a very specific meaning.
Upon close observation, the leaves’ normal green and discolored areas
are usually sharply bordered at small veins.
The non-green regions are made up of infected cells while the green
regions or “islands” contain no appreciable amounts of the virus.
The infection of the leaf cells occurs while the leaves develop, with
mosaic symptoms visible as soon as the leaves appear.
The expression of the
mosaic symptoms tends to disappear in subdued light.
If grown under very low light conditions, newly developing leaves will be
completely green despite being virus infected.
Even under bright light conditions, Flowering Maples may recover from the
virus infection and produce completely green leaves if the mosaic leaves are
although infected, do not seem to suffer in regard to vigor and flowering.
In fact, the virus is responsible for most of the species’ ornamental
Thus, the question arises – Is AMV a disease?
According to Webster’s definition of a disease as “an
impairment of the normal state of the living animal or plant body that affects
the performance of the vital functions”, one could argue that it
Looking beyond the Flowering Maple, there are numerous cases of plants being more useful when virus infected. The best, and probably the oldest, example is the striped tulip flower. Today, striped tulips are commercially bred for their unusual color patterns on the petals, but the original striped tulips were solid flower colored plants infected by a virus. In the 1600’s the condition called “Tulip-break” was first described in Holland. The multicolored flowers instantly became very popular, and vast fortunes were paid for bulbs with “Tulip-break”. Wild speculation followed by a loss of interest and subsequent value of the infected bulbs almost caused the collapse of Holland’s economy. Tulipomania, as the episode came to be known, remains today as an interesting example of silly horticultural fads. After all, today we know that people were simply buying “diseased” bulbs.