Agnorhiza reticulata
Encyclopedia
Agnorhiza reticulata is a rare species of flowering plant known by the common name El Dorado County mule's ears. It is endemic to El Dorado County, California
, where it is known from fewer than 30 occurrences in the woods and chaparral
of the Sierra Nevada foothills. The genetic diversity
of the populations is probably low because they are often clonal
, spreading via vegetative reproduction
with rhizome
s rather than sexual reproduction
by seed. Some populations are also threatened by development of their habitat. This is a perennial herb producing a hairy, glandular, sticky-textured stem growing 40 to 70 centimeters tall, at times reaching one meter. The leaves have triangular or lance-shaped blades up to 15 centimeters long. The inflorescence
is a usually solitary sunflowerlike flower head
with up to 21 yellow ray florets measuring up to 2.5 centimeters long. At the center are yellow disc florets. The flowers are pollinated
by native bee
s. The fruit is an achene
a few millimeters long which usually lacks a pappus
.
El Dorado County, California
El Dorado County is a county located in the historic Gold Country in the Sierra Nevada Mountains and foothills of the U.S. state of California. The 2010 population was 181,058. The El Dorado county seat is in Placerville....
, where it is known from fewer than 30 occurrences in the woods and chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
of the Sierra Nevada foothills. The genetic diversity
Genetic diversity
Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary....
of the populations is probably low because they are often clonal
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
, spreading via vegetative reproduction
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
with rhizome
Rhizome
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 rather than sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
by seed. Some populations are also threatened by development of their habitat. This is a perennial herb producing a hairy, glandular, sticky-textured stem growing 40 to 70 centimeters tall, at times reaching one meter. The leaves have triangular or lance-shaped blades up to 15 centimeters long. 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 a usually solitary sunflowerlike flower head
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
with up to 21 yellow ray florets measuring up to 2.5 centimeters long. At the center are yellow disc florets. The flowers are pollinated
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
by native bee
Bee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s. 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...
a few millimeters long which usually lacks a 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...
.