Oligoneuron
Encyclopedia
Oligoneuron is a small genus of flowering plant
s in the sunflower family (Asteraceae
).
This genus was previously treated as a section in the genus Solidago or belonged to the genus Aster. The genus Oligoneuron is considered phylogenetically a basal or near-basal member of the subtribe Astereae. A 2006 taxonomy by Semple and Cook treats it as part of Solidago.
These are herbaceous, perennial
North American plants, growing on wet prairies, open fields, ditches and dry woods, roadsides, and on dry, calcareous cliffs and ledges.
The leafy stem
grows 50-100 cm tall and is unbranched, except near the inflorescence. The stem is covered with fine white hairs, and grows from deep fibrous roots.
The light green, simple leaves
are linear-lanceolate, with smooth or slightly serrated margins. The basal leaves are longer (about 25 cm long) and may be oblong and longitudinally folded. Some may persist through the winter. The smaller leaves alternate upwards and are stalkless They become stiffer and rough textured later in the year.
The broad, flat-topped inflorescence
is a dense, apical corymb of 20-30 bright yellow flower
heads (5-15 cm across), more or less bunched together. The 7-9 ray florets are very small (0.6-1.2 cm across). These flowers have a mild fragrance.
The fruit is an achene
with small tufts of white or light brown hair. They are distributed by the wind.
Most are hard and bitter species, but Stiff Goldenrod is more palatable for grazing livestock.
Most species are very common but some are threatened such as O. houghtonii
.
One hypothesis about the origin of the garden plant x Solidaster is that it was an intergeneric hybrid between Oligoneuron album and Euthamia graminifolia
. However, molecular evidence points to Oligoneuron album being more accurately placed in Solidago (as Solidago ptarmicoides), and the other parent as being Solidago canadensis
.
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s in the sunflower 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...
).
This genus was previously treated as a section in the genus Solidago or belonged to the genus Aster. The genus Oligoneuron is considered phylogenetically a basal or near-basal member of the subtribe Astereae. A 2006 taxonomy by Semple and Cook treats it as part of Solidago.
These are herbaceous, 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...
North American plants, growing on wet prairies, open fields, ditches and dry woods, roadsides, and on dry, calcareous cliffs and ledges.
The leafy stem
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...
grows 50-100 cm tall and is unbranched, except near the inflorescence. The stem is covered with fine white hairs, and grows from deep fibrous roots.
The light green, simple 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 linear-lanceolate, with smooth or slightly serrated margins. The basal leaves are longer (about 25 cm long) and may be oblong and longitudinally folded. Some may persist through the winter. The smaller leaves alternate upwards and are stalkless They become stiffer and rough textured later in the year.
The broad, flat-topped 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 a dense, apical corymb of 20-30 bright yellow 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 (5-15 cm across), more or less bunched together. The 7-9 ray florets are very small (0.6-1.2 cm across). These flowers have a mild fragrance.
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...
with small tufts of white or light brown hair. They are distributed by the wind.
Most are hard and bitter species, but Stiff Goldenrod is more palatable for grazing livestock.
Most species are very common but some are threatened such as O. houghtonii
Oligoneuron houghtonii
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...
.
Species
- Oligoneuron album (Nutt.) Nesom. : White Upland Goldenrod, Prairie Goldenrod. (Solidago ptarmicoides)
- Oligoneuron houghtoniiOligoneuron houghtoniiOligoneuron 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...
: Houghton’s Goldenrod - Oligoneuron nitidum (Torr. & A. Gray) Small : Shiny Goldenrod
- Oligoneuron ohioense (Frank ex Riddell) G.N. Jones : Ohio Goldenrod
- Oligoneuron riddellii Frank ex Riddell) Rydb. : Riddell’s Goldenrod
- Oligoneuron rigidum (L.)Small Stiff Goldenrod
- Oligoneuron rigidum var. glabratum
- Oligoneuron rigidum var. humilis
- Oligoneuron rigidum var. rigidum
Natural hybrids
- Oligoneuron × bernardii
- Oligoneuron × krotkovii
- Oligoneuron × lutescens
- Oligoneuron × maheuxii
One hypothesis about the origin of the garden plant x Solidaster is that it was an intergeneric hybrid between Oligoneuron album and Euthamia graminifolia
Euthamia graminifolia
Euthamia graminifolia is a plant in the daisy family, Asteraceae.It is native to much of North America, and also has introduced populations in Europe and Asia.-Description:...
. However, molecular evidence points to Oligoneuron album being more accurately placed in Solidago (as Solidago ptarmicoides), and the other parent as being Solidago canadensis
Solidago canadensis
Solidago canadensis is an herbaceous perennial plant of the family Asteraceae native to North America. It is often grown as a wildflower....
.