Ionactis
Encyclopedia
Ionactis, or the Stiff-leaved Asters, is small genus
of five species, belonging to the sunflower
family (Asteraceae
)
The generic name, Ionactis, is derived from two Greek words meaning "violet rays."
This aster-like plants are endemic
in North America
. Four species occur on dry clearings or rocky slopes at mid to high elevations in the Rocky Mountains
and the Cascade Mountains. One species, Ionactis linariifolia
, occurs in most of eastern North America.
Ionactis was classified as a separate genus by Edward Lee Greene in 1897 with the species Ionactis linariifolia, which had been classified by Carolus Linnaeus
as Aster linariifolius. Three other species were formerly classified under Aster, Chaetopappa
or Ionactis. The species of Aster (in a strict sense) are now restricted to Eurasia
.
The Stiff-leaved Asters are perennial
herbs with numerous green stems
, about 2,5 cm long (rarely 10 cm), usually in a tussock. The spatulate leaves
are small, stiff, sharply ascending and thick about the stem. The upper leaves are much smaller than the lower. Yellow-orange resin
droplets form on the leaves of the Red Rock Canyon Aster (Ionactis caelestis).
The involucral phyllaries (bract
s under the flower head) are narrow and overlapping. They have, along the midrib, a narrow zone containing chlorophyll
. The silky-hairy, fusiform achene
s form a crown with a double pappus in two series, the inner one with long, barbellate bristles, the outher one with short bristles or minute scales.
The small flower
heads grow solitary or sometimes in a cluster at the end of the stems. The 10–24 fertile ray florets are nearly white, blue to pink, lavender, purple or blue violet. The sterile disc florets are yellowish. The peduncle
s are nearly naked.
They have a chromosome
base number of x = 9.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of five species, belonging to the sunflower
Sunflower
Sunflower is an annual plant native to the Americas. It possesses a large inflorescence . The sunflower got its name from its huge, fiery blooms, whose shape and image is often used to depict the sun. The sunflower has a rough, hairy stem, broad, coarsely toothed, rough leaves and circular heads...
family (Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
)
The generic name, Ionactis, is derived from two Greek words meaning "violet rays."
This aster-like plants are endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. Four species occur on dry clearings or rocky slopes at mid to high elevations in the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
and the Cascade Mountains. One species, Ionactis linariifolia
Ionactis linariifolia
Ionactis linariifolia also known as the flax-leaf ankle-aster, flaxleaf whitetop or aster was previously classified by Carolus Linnaeus as Aster linariifolius, known as the stiff-leafed aster.Ionactis was classified as a separate genus by Edward Lee Greene in 1897. It occurs in most of eastern...
, occurs in most of eastern North America.
Ionactis was classified as a separate genus by Edward Lee Greene in 1897 with the species Ionactis linariifolia, which had been classified by Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
as Aster linariifolius. Three other species were formerly classified under Aster, Chaetopappa
Chaetopappa
Chaetopappa is a genus of plants in the daisy family which are known generally as leastdaisies. These wildflowers are native to western and central North America...
or Ionactis. The species of Aster (in a strict sense) are now restricted to Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
.
The Stiff-leaved Asters are perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
herbs with numerous green stems
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
, about 2,5 cm long (rarely 10 cm), usually in a tussock. The spatulate leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are small, stiff, sharply ascending and thick about the stem. The upper leaves are much smaller than the lower. Yellow-orange resin
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
droplets form on the leaves of the Red Rock Canyon Aster (Ionactis caelestis).
The involucral phyllaries (bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s under the flower head) are narrow and overlapping. They have, along the midrib, a narrow zone containing chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
. The silky-hairy, fusiform achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
s form a crown with a double pappus in two series, the inner one with long, barbellate bristles, the outher one with short bristles or minute scales.
The small flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
heads grow solitary or sometimes in a cluster at the end of the stems. The 10–24 fertile ray florets are nearly white, blue to pink, lavender, purple or blue violet. The sterile disc florets are yellowish. The peduncle
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
s are nearly naked.
They have a chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
base number of x = 9.
Species
- Ionactis alpinaIonactis alpinaIonactis alpina is a species of aster known by the common name lava aster. It is native to western North America from California to Montana, where it grows in dry areas.-Description:...
: Lava Aster, Alpine Ionactis. - Ionactis caelestis : Red Rock Canyon Aster, described in 1992 by P. J. Leary and Guy L. Nesom.
- Ionactis elegans : Sierra Blanca Cliff Daisy.
- Ionactis linariifoliaIonactis linariifoliaIonactis linariifolia also known as the flax-leaf ankle-aster, flaxleaf whitetop or aster was previously classified by Carolus Linnaeus as Aster linariifolius, known as the stiff-leafed aster.Ionactis was classified as a separate genus by Edward Lee Greene in 1897. It occurs in most of eastern...
: Flaxleaf Whitetop Aster, Grass-leaf Aster, Narrow-leaved White-topped Aster. - Ionactis stenomeres : Rocky Mountain Aster.