''Allium tuolumnense'' is a rare species of
wild onion Wild onion can refer to
* any uncultivated species in the genus '' Allium'', especially:
**'' Allium bisceptrum''
** '' Allium canadense''
** ''Allium tricoccum
''Allium tricoccum'' (commonly known as ramp, ramps, ramson, wild leek, wood leek, o ...
, known by the common name Rawhide Hill onion.
It is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
to
Tuolumne County, California
Tuolumne County (), officially the County of Tuolumne, is a county located in the U.S. state of California. As of the 2020 census, the population was 55,620. The county seat and only incorporated city is Sonora.
Tuolumne County comprises ...
, where it is known only from a small section of the
Sierra Nevada foothills at Rawhide Hill and the
Red Hills. It is a plant of
serpentine soil
Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...
s.
Description
This onion, ''Allium tuolumnense'', grows from a reddish-brown bulb one to two centimeters long, producing a slender erect stem up to tall and usually a single leaf approximately the same length.
[eFloras.org](_blank)
Accessed 2013-02-05.
The stem is topped with a hemispheric
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. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...
holding 20 to 60 flowers, each on a
pedicel one or two centimeters long. Each flower is just under a centimeter wide when fully open, with six white or pink oval-shaped
tepal
A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...
s. There are six
stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the fila ...
s and the
ovary
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...
has six pointed crests.
[Denison, S. S. & McNeal, Dale W. 1989. Madroño 36(2): 128.]
See also
*
Serpentine soils
Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...
*
Red Hills (Tuolumne County)
References
External links
*
Jepson Manual Treatment — ''Allium tuolumnense''USDA Plants ProfileFlora of North America''Allium tuolumnense'' — U.C. Photo gallery
tuolumnense
Endemic flora of California
Flora of the Sierra Nevada (United States)
Natural history of Tuolumne County, California
Onions
{{Allium-stub