Common
Name: Aster, Starwort,
Michaelmas daisy (U.K.), l’oeil de Christ
- eye of Christ (France) – The appearance of the flower with its yellow
center and circumferential rays are reminiscent of a star, which is aster in Greek. There are many varieties. The one depicted
above is the New England Aster.
Scientific
Name: Aster was the original genus
name. Recent DNA testing has separated
the North American flowers in ten new genera (discussed below). The New England aster depicted above is in
the genus Symphyotrichum with a specific name novae angliae – a direct Latin translation of New England.
The Asteraceae or Aster family is one of the largest
taxonomic groupings of vascular plants with over 20,000 thousand species in
over 1600 genera worldwide. Many, but by
no means most of the species are North American; the USDA Plants database lists
4846 taxa in 477 genera (taxa is the plural of taxon, an element of a
classification structure). In the 19th
Century, all aster-like florae were grouped into the genus Aster by the taxonomists George Bentham and Joseph Hooker with the
publication of the seminal three volume reference Genera plantarum ad exemplaria imprimis in herbariis kewensibus servata
definita between 1862 and 1883. This arrangement persisted until the advent
of recombinant DNA analysis to determine the phylogeny, or evolutionary
history, of the species. The DNA
sequencing of 80 species of aster revealed that North American asters are on a
separate evolutionary line from Old World asters. Based on this analysis, there are now ten
genera of North American asters: Symphyotrichum
(90 species) is the most common; flowers in the original genus Aster are mostly Eurasian. It should be
noted that most field guides, including the National Audobon Society Field
Guide to North American Wildflowers and Newcomb’s Wildflower Guide
continue to list all asters in the genus
Aster.
The family Asteraceae is also known as Compositae,
or the composite family. All of the flora in the family, which includes
daisies, sunflowers, goldenrods and fleabanes in addition to asters, have a composite structure. The term composite implies a
structure composed of individual assembled parts. A composite flower isn’t a
flower, but a combination of many individual flowers. The central disc or capitulum is comprised of
many individual disc flowers called florets. The surrounding “petals” are
actually individual ray flowers that have involuted to the extent that the
corolla is on only one side and is shaped like a strap. The (mostly) sterile
ray flowers are imbricated so that the effect is one of overlapping petals
around the central disk. The evolutionary success of the composite family is
evidence of the success of the arrangement. The disc flowers are tubular with
the stamens (pollen producing male structure) forming a cylinder around the
stigma (top of female pistil that encloses the ovules). Insect pollinators are
guided by the surrounding contrasting ray flowers where they are attracted to
the olfactory disc flowers that sequentially bloom, producing the quintessential
nectar that is their quest. The frequent arthropod visits to the tubular
pollen-lined florets almost guarantee cross pollination and fertilization
resulting in the eventual production of myriad achenes, which are commonly
called seeds, to propagate the species.
The
diversification and global range of the asters has inspired some scientific
speculation as to the underlying reason. In addition to the prodigious seed
production machinery of the capitulum, asters store carbohydrates in the form
of short chain fructose molecules called fructans that are sustaining in the
dry conditions that is a characteristic of their habitat preference. In
addition, they produce a diverse set of compounds called metabolites during the
cell growth and reproduction process (metabolism). It is hypothesized that
aster diversification began in the Eocene Epoch about 50 million years ago in
South America and extended to Africa and Eurasia in the Oligocene Epoch 20
million years later. It is doubtless
true that whatever the mechanism, asters adapt and evolve to the extent that
botanists are driven to extremes in establishing species distinctions,
resulting in a ubiquity of names that range from Arrow-leaved Aster to White
Wood Aster. Pictured is the Heart-leaved Aster.
Asters have long been well-known to the Eurasian and
Native American peoples. The noted Roman poet Virgil wrote of the starwort or
aster in his four volume book of poems Georgics, which preceded the Aeneid:
There is a meadow-flower by country
folk
Hight star-wort; ‘tis a plant not
far to seek;
For from one sod an ample growth it
rears,
Itself all golden, but girt with
plenteous leaves,
Where glory of purple shines through
the violet gloom
It is evident from this that the aster was recognizable
and “not far to seek” indicating that they were easy to find. However, there is no evidence that asters
played a significant role in Eurasian culture. There are a few tangential references
to medicinal applications but no established pharmacopoeia; the English herbalist
Thomas Culpepper recommended asters in the treatment of asthma and the Romans
or Greeks used them in the treatment of snakebite, to frighten serpents – or
perhaps both, the lack of clarity evidence of dubious etiology. The various allusions
to the mythological provenance of asters are almost certainly fabrications. The
most common stories are that asters resulted either when the goddess Virgo
scattered stardust over the earth or when the goddess Astrea wept at being
distraught by the wars of men. Virgo is the goddess of the autumn, evident in
the zodiacal constellation’s rise in late August which would coincide with the
florescence of asters – it would therefore be a logical assignment of the aster
to the realm of the constellation Virgo. The association with Astrea, the ‘star-maiden’
is almost certainly due to an alliterative association with the root word for
star. Asters were purportedly used in
Chinese medicine for everything from hangover to hemorrhage.
From the North American perspective, asters played a
much greater ethnobotanical role, likely a result of the ubiquity of asters and
the herbal skills of the autochthonous peoples. Perhaps the most novel of these was as a lure
to attract game; the Ojibwa or Chippewa, third largest tribe in North America
with a Great Lakes nexus, employed the smoke from a variety of asters as a
means of drawing deer close enough for a bow and arrow – the scent presumably a
pheromone. The Meskwaki or Fox tribe of the upper Mississippi Valley used
asters in an Inipi, or sweat lodge to drive away the bad spirits of illness,
particularly those associated with mental disorders. The New England Aster
stands apart as a medicinal that was not only widely used by Native Americans
but also adopted by the early colonists. The primary Indian uses were as a
febrifuge when made into a tea and as a salve against skin rashes when decocted
or boiled. The colonists extended its
use in employing vaporous steam inhalation as an aromatic nervine to reduce
nervous anxiety. C. S. Rafinesque’s 1830 Medical Flora extolled the
virtues of aster as a palliative for skin rashes caused by poison sumac and as a
treatment to alleviate nervous disorders, “in many cases preferable to
Valerian,” - valerian is a traditional herbal sedative dating to Ancient
Greece. It has been generally reported that chewing aster flowers results in a
peaceful state of mind that promotes calming.