Symphyotrichum sericeum
Encyclopedia
Symphyotrichum sericeum is a species of flowering plant in the aster family
known by several common names, including western silver aster and silky aster. It is native to the central plains of North America.
s, wood glades, and gravel hill prairies. It ranges from the eastern tall grass prairies and west in the short grass Great Plains
to the foothills of the Rocky Mountains
of the from Texas
and New Mexico
into the central grassland
s in Canada. Its occurrence is rare in the northeast part of its range. It is seldom found outside its preferred habitat.
s. The stem is erect, sometimes branching. It is sericeous (silky) throughout, giving the stem a silvery-grey appearance. Basal leaves are oblanceolate in shape and have petioles
. Cauline leaves, those growing along the stem, are ovate to ovate-lanceolate in shape, with alternate attachment to stem, sessile, acuminate at the base, acute at the tip. Leaf margins are entire, or smooth and lacking teeth or serration. Leaf texture is sericeous adaxally (above) and abaxally (below), giving the leaves a silvery-grey appearance.
Compared to other American asters, the flowers appear disproportionately large for the plant's size. The inflorescence
is terminal, occurring at the top of the stem, and consists of a single head
. The involucre is ovate to lanceolate in shape and sericeous. Ray flowers are blue and fertile. Disc flowers are white, with stamen
s yellow to brown. The fruit is an achene
.
in Indiana
, and as a threatened species
in Michigan
.
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...
known by several common names, including western silver aster and silky aster. It is native to the central plains of North America.
Distribution
Symphyotrichum sericeum is an aster of rocky prairiePrairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
s, wood glades, and gravel hill prairies. It ranges from the eastern tall grass prairies and west in the short grass Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
to the foothills of 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...
of the from Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
and New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
into the central grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s in Canada. Its occurrence is rare in the northeast part of its range. It is seldom found outside its preferred habitat.
Description
The Symphyotrichum sericeum plant is distinctive in the wild due to the silky texture; no other American aster is sericeous throughout. This is a perennial herb growing from rhizomeRhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s. The stem is erect, sometimes branching. It is sericeous (silky) throughout, giving the stem a silvery-grey appearance. Basal leaves are oblanceolate in shape and have petioles
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
. Cauline leaves, those growing along the stem, are ovate to ovate-lanceolate in shape, with alternate attachment to stem, sessile, acuminate at the base, acute at the tip. Leaf margins are entire, or smooth and lacking teeth or serration. Leaf texture is sericeous adaxally (above) and abaxally (below), giving the leaves a silvery-grey appearance.
Compared to other American asters, the flowers appear disproportionately large for the plant's size. The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is terminal, occurring at the top of the stem, and consists of a single head
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
. The involucre is ovate to lanceolate in shape and sericeous. Ray flowers are blue and fertile. Disc flowers are white, with stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s yellow to brown. The fruit is an achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
.
Conservation
Symphyotrichum sericeum is listed as a rare speciesRare species
A rare species is a group of organisms that are very uncommon or scarce. This designation may be applied to either a plant or animal taxon, and may be distinct from the term "endangered" or "threatened species" but not "extinct"....
in Indiana
Indiana
Indiana is a US state, admitted to the United States as the 19th on December 11, 1816. It is located in the Midwestern United States and Great Lakes Region. With 6,483,802 residents, the state is ranked 15th in population and 16th in population density. Indiana is ranked 38th in land area and is...
, and as a threatened species
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
in Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
.