Oligoneuron houghtonii
Encyclopedia
Oligoneuron houghtonii is a rare species of flowering plant in the aster family
known by the common name Houghton's goldenrod. It is native to southern Ontario
in Canada and northern Michigan
in the United States. It is threatened by the loss and degradation of its habitat. It is a federally listed threatened species of the United States and it is designated a species of special concern by Canada's COSEWIC.
This plant is a perennial herb producing one or more erect stems up to 60 centimeters tall or more from a branching caudex
covered with the remains of previous seasons' leaves. The leaves near the base of the plant are oval in shape and those higher on the stem are linear or lance-shaped and up to 17 or 18 centimeters in length. The inflorescence
is an array of many flower heads
each up to a centimeter long. The head contains 6 to 12 yellow ray florets and several disc florets. The fruit is about half a centimeter long including the pappus
of bristles at the tip. Blooming occurs in August.
This plant grows on the shores of the Great Lakes
, mainly Lake Huron
and Lake Michigan
, at the Michigan-Ontario border. Reported occurrences from New York
were misidentified and belong to different species. It grows in sandy lakeshore habitat types as well as moist limestone
alvar
s. The habitat is sometimes submerged but the plants return when water levels drop. It also occurs in bog
habitat.
The species is threatened by the loss, degradation and fragmentation
of its habitat during development and construction. Any disturbance of the dune
s among which the plant grows can be harmful. The use of off-road vehicle
s in the habitat is detrimental, and the installation of walls, roads, and other structures affects the dunes. Maintenance activities such as herbicide
application, mowing, and road salting are threats, as is beach recreation.
Since 1975 about 20% of the populations of this plant have been eliminated.
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 the common name Houghton's goldenrod. It is native to southern Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
in Canada and northern 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"....
in the United States. It is threatened by the loss and degradation of its habitat. It is a federally listed threatened species of the United States and it is designated a species of special concern by Canada's COSEWIC.
This plant is a perennial herb producing one or more erect stems up to 60 centimeters tall or more from a branching caudex
Caudex
A caudex is a form of stem morphology appearing as a thickened, short, perennial stem that is either underground or near ground level . It may be swollen for the purpose of water storage, especially in xerophytes...
covered with the remains of previous seasons' leaves. The leaves near the base of the plant are oval in shape and those higher on the stem are linear or lance-shaped and up to 17 or 18 centimeters in length. 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 an array of many flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
each up to a centimeter long. The head contains 6 to 12 yellow ray florets and several disc florets. The fruit is about half a centimeter long including the pappus
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
of bristles at the tip. Blooming occurs in August.
This plant grows on the shores of the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
, mainly Lake Huron
Lake Huron
Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...
and Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
, at the Michigan-Ontario border. Reported occurrences from New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
were misidentified and belong to different species. It grows in sandy lakeshore habitat types as well as moist limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
alvar
Alvar
An alvar is a biological environment based on a limestone plain with thin or no soil and, as a result, sparse vegetation. It is also known as a pavement barren although this term is also used for similar landforms based on sandstone. In the United Kingdom the exposed landform is called a limestone...
s. The habitat is sometimes submerged but the plants return when water levels drop. It also occurs in bog
Bog
A bog, quagmire or mire is a wetland that accumulates acidic peat, a deposit of dead plant material—often mosses or, in Arctic climates, lichens....
habitat.
The species is threatened by the loss, degradation and fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
of its habitat during development and construction. Any disturbance of the dune
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
s among which the plant grows can be harmful. The use of off-road vehicle
Off-road vehicle
An off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with deep, open treads, a flexible suspension, or even caterpillar tracks...
s in the habitat is detrimental, and the installation of walls, roads, and other structures affects the dunes. Maintenance activities such as herbicide
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
application, mowing, and road salting are threats, as is beach recreation.
Since 1975 about 20% of the populations of this plant have been eliminated.