The Genus Aster
Remark
The words or terms in red
(actually dark orange) in the text are defined in a
glossary.
In Greek αστηρ (aster)
means star, and the name refers then to the shape of the flower head.
Asters are usually characterized by leafy stems, and
opposite,
often spear-shaped (lanceolate) leaves,
ranging from one to three inches in length.
The small flowers are daisy-like, with yellow or orange centers
that turn reddish-brown after they are fertilized and fine,
often thickly growing petals.
The stems are frequently much branched near the top,
producing large clusters of flowers which individually range
from less than one inch, to two inches across.
The colors range from deep purple through lavender, blue, pink and rose
to white.
Most species
species bloom in the late summer and fall when many other plants have
finished blooming.
With 150 species in North America, 55 of which grow in the northeast,
the Aster genus
is arguably the largest on the continent.
To further confuse botanists, asters easily
hybridize.
Small, white asters are especially confusing.
Traditional treatments place most asters in the genus Aster Linnaeus.
However, during the last decade analyses of
morphology,
chloroplast DNA
restriction fragment length
polymorphisms and ITS sequence data,
and on going
karyotype
studies have all demonstrated that asters
are polyphyletic
and members of a number of very distinct phylads
within the tribe.
Asters can be divided into two categories
following the general
phylogeny
of the entire tribe:
- (I) 'asters' related to genera native to South America,
Africa and Asian.
- (II) 'asters' of the North American
clade of the tribe.
The genus Aster is then now generally restricted
to the Old World species,
with Aster amellus being the type species of the genus
(and of the family Asteraceae).
The other species have now been reclassified in the genera
Almutaster, Canadanthus, Doellingeria, Eucephalus, Eurybia, Ionactis,
Oclemena, Oligoneuron, Oreostemma, Sericocarpus and Symphyotrichum.
In what follows, we will then use in the list below the new
taxonomy,
with the old in parenthesis.
According to the Flore Laurentienne by Frère Marie-Victorin,
the following species can be found in Québec:
-
Oclemena acuminata (Aster acuminatus)
[on Tuesday the 11th of October 2005, there were about 853 results on
Google for Aster acuminatus and about 204 for
Oclemena acuminata].
- Aster adscendens
- Aster anticostensis
- Aster brachyactis
- Aster calderi
- Aster ciliolatus (Symphyotrichum ciliolatum)
-
Symphyotrichum cordifolium (Aster cordifolius)
[on Tuesday the 11th of October 2005, there were about 15 000 results on
Google for Aster cordifolius and 36 for
Symphyotrichum cordifolium].
- Aster crenifolius
- Aster ericoides
- Aster foliaceus
- Aster gaspensis
- Aster johannensis
- Aster junciformis
- Aster lateriflorus
- Aster laurentianus
- Aster linariifolius
- Aster longifolius (Symphyotrichum novi-belgii var.
villicaule)
- Aster lowrieanus
- Aster lucidulus
-
Eurybia macrophylla (Aster macrophyllus)
[on Thursday the 13th of October 2005, there were about 15 300 results
on Google for Aster macrophyllus and about 428 for
Eurybia macrophylla].
-
Oclemena nemoralis (Aster nemoralis)
[on Sunday the 16th of October 2005, there were about 474 results
on Google for Aster nemoralis and about 348 for
Oclemena nemoralis].
-
Symphyotrichum novae-angliae (Aster novae-angliae)
[on Monday the 17th of October 2005, there were about 48 900 results
on Google for Aster novae-angliae and about 1040 for
Symphyotrichum novae-angliae].
- Aster novi-belgii
- Aster ontarionis (Symphyotrichum ontarionis)
-
Symphyotrichum pilosum (Aster pilosus)
[on Saturday the 29th of August 2009, there were about 48 500 results
on Google for Aster pilosus and about 5200 for
Symphyotrichum pilosum].
- Aster praealtus
- Aster ptarmicoides
- Aster puniceus
-
Symphyotrichum puniceum (Aster puniceus)
[on Tuesday the 18th of October 2005, there were about 11 800 results on
Google for Aster puniceus and about 273 for
Symphyotrichum puniceum].
- Aster radula (Eyrybia radula)
- Aster simplex
- Aster tardiflorus
- Aster tradescanti
- Aster umbellatus
-
Doellingeria umbellata (Aster umbellatus)
(picture above)
[on Friday the 21th of October 2005, there were about 9230 results on
Google for Aster umbellatus and about 374 for
Doellingeria umbellata].
- Aster undulatus
- Aster vaurealis
- Aster vimineus
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