Turritis glabra | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Brassicales |
Family: | Brassicaceae |
Genus: | Turritis |
Species: | T. glabra |
Binomial name | |
Turritis glabra (L.) | |
Synonyms [2] | |
List
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Turritis glabra, commonly known as tower rockcress or tower mustard, is a tall, slim, grey-green plant with small creamy flowers at the top of the stem. It usually grows on poor chalky or sandy soils, in open situations. It is native to Europe, Asia, and North Africa, and it is widespread in North America where it is also probably native. It can be found in many other parts of the world as an introduced species.
Tower mustard typically reaches 40 to 120 centimeters in height at full growth, but may be stunted to just 30 centimeters or might reach 1.5 meters in height in exceptional circumstances. It is typically a biennial herb, but may occasionally have be a short lived perennial. [3] Plants have a tap-root and fibrous side-roots. Plants usually have several erect, usually unbranched stems which are grey in the lower parts with a covering of simple hairs, but green and glabrous (hairless) above. [4]
The leaves occur in a basal rosette initially, and later grow alternately on the main stem and branches. The basal leaves are blunt and toothed or pinnatifid and up to 15 cm long, whereas the stem and branch leaves become progressively smaller, less divided and more pointed, clasping the stem. [4] The basal leaves are usually covered in hairs (pubescent) on the upper surface, but in rare cases they may be hairless. They vary in shape from spoon shape with a narrow base and wide at the end (spatulate), to being a narrow spear point with the widest point in the middle (oblanceolate), or a rounded rectangle longer than wide (oblong) with a broad point. They are typically 5 to 12 centimeters long, but may be only 4 cm or as much as 15 cm in length. The basal leaves are 1 to 3 centimeters in width. [3]
The leaves on the stems (cauline leaves) are narrowed versions of the spear head shape (blade lanceolate), a somewhat more rounded rectangle (oblong-elliptic), or fully egg shaped with a wider base than end (ovate). [3]
The inflorescence is a terminal raceme with numerous small, white flowers on small flower stems (pedicels) up to 2 centimeters long. There are four greenish sepals about 5 millimeters long; four pale yellow petals up to 1.7 cm long; 6 stamens and 1 style. The fruit is a greenish silique up to 8 cm long by 1.7 cm wide, flattened, and held vertically beside the stem. [4]
Turritis glabra was given its first scientific name by Carl Linnaeus in 1753. In 1800 it was moved from Turritis to genus Arabis by Johann Jakob Bernhardi with than name Arabis glabra. [2] Authors such as Hervé Maurice Burdet, James Cullen, and František Dvořák (1921–2016) maintained that the lack of white to purple flowers, not having seeds arranged in a single row in the pod like peas (uniserrately), and not having flattened fruits distinguishes the species in Turritis from Arabis. Botanists maintaining the contrary position such as Reed C. Rollins and Ihsan Ali Al-Shehbaz point to the ambiguous characteristics of some individuals in Turritis glabra and what they consider more critical features such as similar seed-coat anatomy and chemical similarities such as fatty-acid composition and glucosinolate content. [5] Descriptions of this and other related species in North America in the 19th century accepted the classification in Turritis, but late in the century authors such as Asa Gray were treating it as synonymous with Arabis. [6]
As of 2023 the most common classification is as Turritis glabra as listed in Plants of the World Online (POWO), [2] World Flora Online, [7] and in the Flora of North America. [3]
The genus name Turritis comes from Latin for tower as a reference to the narrow growth of the plant with the leaves and fruits upright and overlapping. [8] Many of its common names similarly reference this such as "tower rockcress", [9] "tower-mustard", and " towercress". [7]
The native distribution of tower mustard is moderately uncertain with sources having some details of its range different. POWO lists it as native to all parts of Europe with the exceptions of Ireland, Sardinia, and Corsica. [2]
They list it as growing in much of the northwest of Temperate Asia from Turkey and Iran northwards into central Asia and from Chita Oblast, Irkutsk Oblast, and Krasnoyarsk Krai westwards in Siberia. In the more southerly parts of Asia POWO lists it as native to Korea, Japan, Mongolia, Manchuria, north-central China, southeast China, Xinjiang, Nepal, and the western Himalayas. In addition they list it as introduced to Primorsky Krai, Sakhalin Island, and the Kuril Islands. [2]
In Africa POWO lists it as native to Algeria, Kenya, Morocco, Rwanda, Tanzania, Uganda, and the Democratic Republic of the Congo, with it being introduced to Lesotho and two parts of South Africa, KwaZulu-Natal, the Cape Provinces, and the Northern Provinces. [2]
In North America POWO lists it as native to all parts of Canada with the exceptions of Newfoundland and Labrador, Nova Scotia, Prince Edward Island, and Nunavut. It is also listed as native to all of the western United States, the north-central US from Missouri and Nebraska northwards, the northeastern US with the exception of Vermont, where they list it as introduced, and in the southeastern US states of Delaware, Kentucky, Maryland, North Carolina, Tennessee, and Virginia. [2] NatureServe disagrees with some of these, not listing it as present in Maryland, present but not evaluated in Vermont, additionally introduced to Kansas, not native to Montana, and also present and evaluated in Georgia. They also do not list it as present in the Northwest Territories of Canada. [1]
Finally Plants of the World Online lists it as introduced to the Australian states of New South Wales and Victoria. [2]
It is classified as an endangered species in the UK and is considered to be facing a very high risk of extinction in the wild. It is listed as a Priority Species under the UK Biodiversity Action Plan. Only 35 sites are recorded by Plantlife mostly in Norfolk, (where 100 plants were found at a new site in 1999) but includes 6 sites near Kidderminster in Worcestershire.
Arabis, or rockcress, is a genus of flowering plants, within the family Brassicaceae.
Arabis hirsuta, known as hairy rock-cress, is a flowering plant of the genus Arabis in the family Brassicaceae. In previous North American works, this species has been broadly defined to include plants native to Europe, Asia, and the northern half of North America, but is now more often restricted to a narrower subgroup restricted to Europe.
Arabis aculeolata is a species of flowering plant in the mustard family known by the common name Waldo rockcress.
Boechera cobrensis is a species of flowering plant in the mustard family known by the common names Masonic rockcress and sagebrush rockcress. It is native to the western United States from eastern California to Wyoming, where it is found in sandy habitat, especially sagebrush. This is a perennial herb growing several erect, slender stems to heights near half a meter from a branching caudex. The plant forms a narrow clump with a base of narrow, linear, densely hairy leaves up to 5 centimeters long. There are also a few slightly shorter leaves clasping the stems at intervals. The top of each stem is occupied by an inflorescence of small, nodding flowers with dull yellowish sepals and white petals. The flowers give way to fruits which are narrow, straight siliques up to 4 centimeters long containing winged seeds.
Boechera stricta is a species of flowering plant in the mustard family known by the common name Drummond's rockcress. It is native to much of North America, including most of Canada, and the western and northeastern United States.
Arabis lemmonii is a species of flowering plant in the family Brassicaceae known by the common name Lemmon's rockcress. It is native to western North America from Alaska to California to Colorado, where it grows in a number of rocky habitat types.
Arabis macdonaldiana is a species of flowering plant in the mustard family known by the common name MacDonald's rockcress. It is native to northern California and Oregon, where it grows on newly exposed, barren serpentine soils in openings in temperate coniferous forest habitat. It is a rare and endangered plant known from several sites in California and approximately two occurrences in Oregon, where it is threatened mainly by mining, particularly of nickel, which is one of several metals plentiful in the serpentine. On September 29, 1978, this was the second plant to be federally listed as an endangered species.
Borodinia perstellata, commonly known as Braun's rockcress and Nevada rockcress, is a rare species of flowering plant in the mustard family. It is native to Kentucky and Tennessee, where it is known from perhaps 25 total populations. Most of the occurrences have few individuals, and all are deteriorating in quality. The plant grows in shady forest habitat on limestone substrates, usually near streams or rivers. This is a federally listed endangered species of the United States.
Borodinia serotina is a rare species of flowering plant in the mustard family known by the common name shale barren rockcress. It is native to eastern West Virginia and western Virginia in and around the Shenandoah Valley, where it is known from fewer than 60 populations. It is endemic to the shale barrens, a type of habitat characterized by steep slopes of bare shale, an exposed, rocky habitat type that is subject to very dry and hot conditions. Shale barrens host a number of endemics, such as Allium oxyphilum and Taenidia montana, and this rockcress is among the rarest. It is a federally listed endangered species.
Boechera ophira is a rare species of flowering plant in the mustard family known by the common name Ophir Pass rockcress, or Ophir rockcress. It is endemic to Nevada in the United States, where it is known from Nye and Lander Counties. It grows on the crest of the Toiyabe Range.
Pennellia tricornuta is a species of flowering plant in the mustard family known by the common names Rincon Mountain rockcress and Chiricahua rockcress. It is endemic to Arizona in the United States, where it occurs in Cochise, Pima, and Santa Cruz Counties.
Boechera fecunda is a species of flowering plant in the mustard family known by the common names Mt. Sapphire rockcress and bitterroot rockcress. It is endemic to Montana in the United States, where there are twenty known occurrences in three counties.
Turritis is a plant genus in the family Brassicaceae. It contains the following two species:
Symphyotrichum georgianum is a rare species of flowering plant in the Asteraceae, the aster family. Its common name is Georgia aster. It is native to the southeastern United States where it is known from Alabama, Florida, Georgia, North Carolina, and South Carolina. As of 2013, it may be extirpated from the state of Florida.
Nasturtium gambellii is a rare species of flowering plant in the mustard family known by the common names Gambel's yellowcress and Gambel's watercress. It is known from three or four scattered occurrences in California. It is also native to central Mexico and Guatemala. Its total U.S. population was last estimated at fewer than 300 individuals. It was federally listed in California, as an endangered species of the United States in 1993.
Lepidium coronopus,, is a species of flowering plant in the mustard family which is native to parts of Africa, western Asia and Europe, growing in shingle banks, wasteland or cultivated fields.
Symphyotrichum racemosum is a species of flowering plant native to parts of the United States and introduced in Canada. It is known as smooth white oldfield aster and small white aster. It is a perennial, herbaceous plant in the family Asteraceae. It is a late-summer and fall blooming flower.
Camelina alyssum is a species of flowering plant belonging to the family Brassicaceae. Its native range is Europe to Caucasus.
Penstemon ambiguus, commonly known as the bush penstemon, pink plains penstemon, or gilia beardtongue is a species of Penstemon that grows in the shortgrass prairies and deserts of the western United States and northern Mexico. This bush-like penstemon grows in sandy, loose, and creosote soils and is particularly known for the spectacular flowering show it produces, sometime seasons turning whole hillsides bright pink–white.
Penstemon caespitosus, commonly known as mat penstemon, is a summer blooming perennial flower in the large Penstemon genus. It is a widespread plant from near timberline to the foothills in the Southern Rocky Mountains and Colorado Plateau in North America. It is noted for its ground hugging growth habit and as a plant used in xeriscape and rock gardening.