Draba verna

Last updated

Draba verna
MDF Draba verna 01.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Brassicales
Family: Brassicaceae
Genus: Draba
Species:
D. verna
Binomial name
Draba verna
L.

Draba verna (syn. Erophila verna), common whitlowgrass, is a species of plant in the cabbage family. It is a small spring-flowering annual which is widely dispersed around the world, and which is found on walls, pavements and patches of bare ground. It has a complex taxonomy which is not yet fully elucidated.

Contents

Description

Common whitlowgrass is a spring-flowering annual, typically up to 10 cm (4 in) tall (sometimes as much as 25 cm (10 in)) with a basal rosette and one or more leafless flowering stems. It is variably hairy, sometimes almost completely glabrous (hairless), especially on the stems. The elliptical leaves are up to 20 mm (1 in) long (exceptionally up to 35 mm (1.4 in)) and 8 mm (0.3 in) wide and are often entire, but sometimes with a single tooth on one or both sides, and they taper gradually into a more-or-less distinct petiole. The surfaces and margins usually have a scattering of hairs that are forked, or Y-shaped, at the tips. The central vein is faintly visible on the top side of the leaf but easily distinguishable on the underside. Mature leaves can turn a reddish colour. [1] [2]

Flowers of common whitlowgrass Draba verna flower.jpg
Flowers of common whitlowgrass
The leaves are often covered with forked hairs Draba verna leaves.jpg
The leaves are often covered with forked hairs

Flowering occurs in early spring, March–May in northern latitudes. Each stem (of which there can be several) bears a lax raceme of about 10 long-stalked flowers with 4 white petals, about 3 mm (0.1 in) long, which are so deeply divided (bifid) that it can appear that there are 8 petals. The flowers have 6 stamens with yellow anthers, and one style. The sepals are about 2 mm (0.1 in) long, green, hairy and often have a purplish margin. The fruit (called a silique), forms immediately after flowering while the petals are still present, due to self-pollination. It is oval to elliptical, flattened and up to 9 mm (0.4 in) long by 3 mm (0.1 in) wide with a persistent style at the tip Each silique contains a dozen or so round seeds in two "valves", which split open to leave just the transparent membrane between them, which looks like a tiny version of an honesty seedpod. [3] [4] [1]

The seedpods split open to leave just the translucent membrane that separates the valves. DrabaV4.jpg
The seedpods split open to leave just the translucent membrane that separates the valves.

In the summer months the seeds remain dormant, and they need about 3 months to after-ripen before they can germinate successfully, [5] during which time they need 5–7 weeks of sunlight or they will not germinate well in the autumn. [6] In experiments, they were found to germinate most successfully at 50% to 60% relative humidity. [7]

Some leaves have a single tooth on one side of the leaf blade, resembling a whitlow. Erophila verna plant (12).jpg
Some leaves have a single tooth on one side of the leaf blade, resembling a whitlow.

Taxonomy

The taxonomy of the genus Draba is extraordinarily complex, particularly for Draba verna, which is sometimes treated as a whole genus (ErophilaDC.) in its own right, with a number of different species and varieties listed under various treatments. The reason for this is that D. verna reproduces almost entirely by inbreeding (the flowers pollinating themselves immediately on opening), so a large number of genetically similar lines can be recognised. These lines can even have different chromosome numbers (or ploidy levels), making them less compatible with other plants even when cross-pollination does occur. A full list of synonyms, subspecies and varieties is given in the Brassicaceae Species Checklist. The account here is for Draba vernaL. in its original, aggregate, sense, although D. praecox and D. majuscula can be viewed as separate species. [8] [9] [1] [4]

The chromosome number of Draba verna (as the segregate Erophila verna(L.) DC.) is 2n = 30-46. If it is treated as the aggregate, then D. majuscula has 2n = 14, and D. praecox has 2n = 48-56. [4] [10]

The common name "whitlowgrass" refers to an old meaning of the word, which Aulus Cornelius Celsus described as "a small piece of flesh [which] sometimes grows out from the nail, causing great pain; the Greeks call it pterygium." [11] The leaves of whitlowgrass sometimes have a single forward-pointing tooth on one side, thus resembling this condition. The "grass" part of the name simply means "plant" and does not imply that it is in the botanical grasses family. Other common names for it include "spring draba", "shadflower", "nailwort", "vernal whitlow grass" and "early whitlow grass".

Identification

The combination of bifid petals (sometimes giving the impression of having flowers with 8 petals) and leafless stems makes this species very easy to identify. Separating it from the critical segregates D. majuscula and D. praecox, if you choose to accept them, is much more difficult. The depth of division of the petals, the hairiness of the leaves and stems, and the length of the petiole are all useful field characters. [1] [12]

Whitlowgrasses can look as if they have 8 petals Draba verna whole.jpg
Whitlowgrasses can look as if they have 8 petals

Distribution and status

Common whitlowgrass is native to Europe, western Asia and parts of North Africa southwards to Ethiopia. [13] It is also widely established in the temperate regions of the Americas, Australia, New Zealand and Japan. [14] [15] It has been postulated that it was brought to North America when the European colonizers came to the New World. [16]

Whitlowgrass grows on bare soils, with the minimum of competition Draba verna sward.jpg
Whitlowgrass grows on bare soils, with the minimum of competition

It is sometimes listed as an invasive species in places where it is introduced, such as the United States, but there is no suggestion that it causes any harm. [17] Its global status has not been assessed, [18] but in countries where it is native it is generally listed as "Least Concern." [19] [20]

Habitat and ecology

Typical places for common whitlowgrass to grow include almost any place where there is bare soil, including limestone pavements, sand dunes, field margins, urban pavements and quarry waste. [21]

Its Ellenberg values in Britain are L = 3, F = 3, R = 6, N = 3, and S = 0, [22] which shows that it favours relatively dry, neutral soils and low levels of fertility.

The UK's database of Insects and their Food Plants lists just 4 species that feed on common whitlowgrass. Three of these are weevils: the cabbage leaf weevil, Ceutorhynchus contractus, the cabbage stem weevil, C. quadridens, and C. hirtulus. The other is a butterfly, the orange tip, which is a common species whose larvae feed on the flowers of plants in the cabbage family.

Two species of downy mildew infect common whitlowgrass, particularly when it is suffering from water stress: Hyaloperonospora erophilae coats the leaves and turns them chlorotic, whereas H. praecox has more localised and less obvious symptoms. They can be identified by the differences in their haustoria. [23]

Uses

There appear to be no recorded uses for whitlowgrass. [24] In the 1600s Culpeper described it as "exceedingly good for those imposthumes in the joints, and under the nails, which they call Whitlows, Felons, Andicorns and Nail-wheals", [25] but Vickery [26] explains that it was never really used in folk medicine either in Britain or Ireland. Neither is it mentioned in American herbals. [27] Presumably Culpeper ascribed to it this property according to the doctrine of signatures, owing to the unusual shape of the leaves.

Related Research Articles

<span class="mw-page-title-main">Brassicaceae</span> Family of flowering plants

Brassicaceae or Cruciferae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The leaves are simple, lack stipules, and appear alternately on stems or in rosettes. The inflorescences are terminal and lack bracts. The flowers have four free sepals, four free alternating petals, two shorter free stamens and four longer free stamens. The fruit has seeds in rows, divided by a thin wall.

<i>Barbarea verna</i> Species of plant in the family Brassicaceae

Barbarea verna is a biennial herb in the family Brassicaceae. Common names include land cress, American cress, bank cress, black wood cress, Belle Isle cress, Bermuda cress, poor man's cabbage, early yellowrocket, early wintercress, scurvy cress, creasy greens, and upland cress. It is native to southern Europe and western Asia, and naturalized elsewhere It has been cultivated as a leaf vegetable in England since the 17th century. As it requires less water than watercress, it is easier to cultivate.

<i>Raphanus raphanistrum</i> Species of flowering plant

Raphanus raphanistrum, also known as wild radish, white charlock or jointed charlock, is a flowering plant in the family Brassicaceae. One of its subspecies, Raphanus raphanistrum subsp. sativus, includes a diverse variety of cultivated radishes. The species is native to western Asia, Europe and parts of Northern Africa. It has been introduced into most parts of the world and is regarded as a habitat threatening invasive species in many areas, for example, Australia. It spreads rapidly and is often found growing on roadsides or in other places where the ground has been disturbed.

<i>Draba aizoides</i> Species of flowering plant

Draba aizoides is a species of flowering plant in the family Brassicaceae, known as yellow whitlow-grass. It is native to Europe where it is found on limestone rocks and walls. In the British Isles it is found only on the Gower Peninsula in Wales.

<i>Barbarea vulgaris</i> Species of flowering plant

Barbarea vulgaris, also called wintercress, or alternatively winter rocket, rocketcress, yellow rocketcress, yellow rocket, wound rocket, herb barbara, creases, or creasy greens, is a biennial herb of the genus Barbarea, belonging to the family Brassicaceae.

<i>Lepidium draba</i> Species of flowering plant

Lepidium draba, also known as whitetop, hoary cress, or Thanet cress, is a rhizomatous perennial flowering plant in the family Brassicaceae. It is native to western Asia and southeastern Europe and has been widely introduced elsewhere.

<i>Sisymbrium irio</i> Species of flowering plant

Sisymbrium irio, London rocket, is a flowering plant in the cabbage family which is native to the Middle East, north Africa and southern Europe, and which has spread widely around the world as an invasive plant of dry, disturbed land in towns, deserts and farmland. It has traditionally been used as a medicinal herb for a variety of ailments. Its English common name originated when it flourished after the Great Fire of London in 1666, although it is not native to Britain and it does not tend to persist there.

<i>Cochlearia officinalis</i> Species of flowering plant in the cabbage family Brassicaceae

Cochlearia officinalis, common scurvygrass, scurvy-grass, or spoonwort, is a species of flowering plant in the family Brassicaceae. The plant acquired its common name from the observation that it cured scurvy, and it was taken on board ships in dried bundles or distilled extracts. Its very bitter taste was usually disguised with herbs and spices; however, this did not prevent scurvygrass drinks and sandwiches becoming a popular fad in the UK until the middle of the nineteenth century, when citrus fruits became more readily available.

<i>Diplotaxis tenuifolia</i> Species of flowering plant

Diplotaxis tenuifolia is a species of flowering plant in the mustard family known by the common name perennial wall-rocket. It is native to Europe and western Asia, where it grows on disturbed ground and roadsides, and it can now be found throughout much of the temperate world where it has naturalized. In recent years it has increasingly been cultivated to produce salad leaves, which are marketed as wild rocket in Britain or arugula in the US. It is easily confused with garden rocket, which has similar uses.

<i>Draba aureola</i> Species of flowering plant

Draba aureola is a species of flowering plant in the family Brassicaceae known as the Mt. Lassen draba or Mt. Lassen whitlow-grass. This plant is native to the Cascade Range of western North America, where it grows at elevations above 2000 meters. This is usually a perennial plant found growing in rocky areas such as volcanic cliffs and scree. It has one or more short, stout stems which are covered in stiff hairs. The leaves grow in a dense basal clump at the ground. They are fat and fleshy and covered in a carpetlike coat of stiff, light-colored, branching hairs. The stem may be erect above the clump of leaves or its inflorescence may rest directly upon them. The spherical or club-shaped inflorescence may have up to 80 small, yellow flowers packed densely in it, each petal about 5 millimeters wide. The fruit is a wavy-edged, hairy silique about a centimeter long and half a centimeter wide.

<i>Draba cuneifolia</i> Species of flowering plant

Draba cuneifolia is a species of flowering plant in the family Brassicaceae known as the wedgeleaf draba or wedgeleaf whitlow-grass. This annual plant is native to the southern half of North America where it grows in open, rocky fields and other disturbed areas. The plant forms a basal cluster of leaves, which are thick, widely toothed, and coated in stiff hairs. It bolts one or more erect stems which may approach 40 centimeters in maximum height. Each hairy stem bears an inflorescence of up to 75 small white flowers that continue at intervals down the stem as the stem grows in height. This family and its plants are easy to identify with its 4 petals and 4 sepals arranged like a "cross", either in an "X" or "H" shape, thus the name "Cruciferae". Mustards have 6 stamens usually 4 are taller and 2 are shorter. Fruits are either a long thin silique or short often rounded silicle.

<i>Draba densifolia</i> Species of flowering plant

Draba densifolia is a species of flowering plant in the family Brassicaceae known by the common names Alpine Whitlow-Grass and denseleaf draba. This small perennial is native to western North America, where it is found in mountain environments above 2000 meters from California to Alaska to Wyoming. The plant forms cushion-like mats of small fleshy, hairy, pointed leaves in rocky crevices and on slopes. If it bolts a stem it is no taller than 15 centimeters. The flowers open in an obvious inflorescence of a few tiny blooms at times, but often appear as a layer on the surface of the mat of tiny leaves. The flowers are bright yellow with petals just a few millimeters wide. The fruit is a flat podlike silique less than a centimeter long. Grows in alpine rocky slopes, barren outcrops.

<i>Draba breweri</i> Species of flowering plant

Draba breweri is a species of flowering plant in the family Brassicaceae known by the common names cushion draba, Lanceleaf Draba, Brewer's draba, and Brewer's Whitlow grass. With Draba cana now considered a variety of this species, it is distributed throughout parts of northern and western North America, including much of Canada and the western United States. The less widespread var. breweri is limited to mountainous California and western Nevada.

<i>Draba fladnizensis</i> Species of flowering plant

Draba fladnizensis is a species of plant in the family Brassicaceae known by the common names arctic draba, Austrian draba, and white arctic whitlow-grass. It has a circumpolar distribution, occurring throughout the northern latitudes of the Northern Hemisphere. It is present in Europe, Asia, and North America from Alaska across northern Canada to Greenland. Its distribution extends south through the higher elevations in the Rocky Mountains to Colorado and Utah. It is common and widespread in the Canadian Arctic Archipelago, occurring on several Arctic islands including Baffin, Devon, and Ellesmere Islands. It is named after the Austrian village of Flattnitz, in the Gurktaler Alpen.

Draba burkei is a species of flowering plant in the family Brassicaceae known by the common names snowbasin draba and Burke's draba. It is endemic to Utah in the United States, where it is known from Box Elder, Cache, Morgan, and Weber Counties. This plant was considered a variety of Draba maguirei until 2004, when it was elevated to species status.

<i>Paysonia stonensis</i> Species of flowering plant

Paysonia stonensis is a species of flowering plant in the family Brassicaceae, known by the common name Stones River bladderpod. It is endemic to Tennessee in the United States, where it is limited to Rutherford County. It grows only in the floodplains of the Stones River, and certain tributaries.

Draba exunguiculata is a species of flowering plant in the family Brassicaceae known by the common names clawless draba and Grays Peak draba. It is endemic to Colorado in the United States.

<i>Draba weberi</i> Species of flowering plant

Draba weberi is a species of flowering plant in the family Brassicaceae known by the common names Weber's whitlow-grass and Weber's draba. It is narrowly endemic to Summit and Park Counties, Colorado, where several populations were estimated to total to approximately 300 individuals as of 2012. D. weberi is principally threatened by alterations to its hydrologic environment, owing to its preference for wet, rocky streamside crevices.

<i>Draba norvegica</i> Species of flowering plant

Draba norvegica is a species of flowering plant in the mustard family (Brassicaceae) know by the common names Norwegian draba and Norwegian whitlow grass.

<i>Iberis amara</i> Species of plant in the family Brassicaceae

Iberis amara, called wild candytuft, rocket candytuft and bitter candytuft, is a species of flowering plant in the family Brassicaceae, native to Belgium, France, Germany, Great Britain, Italy, Spain, and Switzerland. It has been introduced to numerous locations including Algeria, Sweden, Eastern Europe, the Caucasus, Iraq, Kazakhstan, the Indian Subcontinent, Korea, Far Eastern Russia, New Zealand, Argentina, Ecuador, Hispaniola, the United States, and Canada. It prefers to grow in warm and sunny conditions, in high-calcium soil.

References

  1. 1 2 3 4 Rich, T.C.G. (1991). Crucifers of Great Britain and Ireland. London: Botanical Society of the British Isles. ISBN   0901158208.
  2. ↑ Sutton, David (1988). Field Guide to Wildflowers of Britain and Northern Europe. Kingfisher Books. ISBN   1-85813-215-0.
  3. ↑ Rose, Francis (2006). The Wild Flower Key. London: Frederick Warne. ISBN   978-0-7232-5175-0.
  4. 1 2 3 Stace, C.A. (2019). New Flora of the British Isles. Suffolk. ISBN   978-1-5272-2630-2.{{cite book}}: CS1 maint: location missing publisher (link)
  5. ↑ Baskin, J.M.; Baskin, C.C. (1970). "Germination eco-physiology of Draba verna". Bulletin of the Torrey Botanical Club. 97 (1): 209. doi:10.2307/2483459. JSTOR   2483459.
  6. ↑ Baskin, J.M.; Baskin, C.C. (1972). "The Light Factor in the Germination Ecology of Draba verna". American Journal of Botany. 57 (7): 756. doi:10.2307/2441148. JSTOR   2441148.
  7. ↑ Baskin, J.M.; Baskin, C.C. (1979). "Effect of Relative Humidity on Afterripening and Viability in Seeds of the Winter Annual Draba verna". Botanical Gazette. 140 (3): 284–287. doi:10.1086/337087. S2CID   85002496.
  8. ↑ Jordan-Thaden, I.; Hase, I; Al-Shehbaz, I; Koch, M (2002). "Molecular data indicate complex intra- and intercontinental differentiation of American Draba (Brassicaceae)". Annals of the Missouri Botanical Garden. 89 (1): 88–109. doi:10.2307/3298659. JSTOR   3298659.
  9. ↑ Jordan-Thaden, I. E.; Al-Shehbaz, I.A.; Koch, M.A. (2013). "Species richness of the globally distributed, arctic–alpine genus Draba L. (Brassicaceae)". Alpine Botany. 123 (2): 97–107. doi:10.1007/s00035-013-0120-9. S2CID   16878175.
  10. ↑ Jordan-Thaden, I.; Koch, M.A. (2008). "Species richness and polyploid patterns in the genus Draba (Brassicaceae): a first global perspective". Plant Ecology & Diversity. 1 (2): 255–263. doi:10.1080/17550870802349112. S2CID   83865900.
  11. ↑ Celsus, Aurus Cornelius. De Medicina . Retrieved 22 March 2023.
  12. ↑ Rich, T.C.G.; Jermy, A.C. (1998). Plant Crib 1998. London: Botanical Society of the British Isles. ISBN   0-901-158-28-3.
  13. ↑ Jonsell, B. (2000). "A new subspecific combination in Erophila (Brassicaceae) from Ethiopia". Nordic Journal of Botany. 20 (2): 201. doi: 10.1111/j.1756-1051.2000.tb01569.x .
  14. ↑ Global Biodiversity Information Facility. "Draba verna L." Retrieved 19 March 2023.
  15. ↑ Plants of the World Online. "Draba verna L." Retrieved 19 March 2023.
  16. ↑ Ugarte, E.; Lira, F.; Fuentes, N; Klotz, S (2011). "Vascular alien flora, Chile". Check List. 7 (3): 365. doi: 10.15560/7.3.365 .
  17. ↑ Invasive Plant Atlas of the United States. "Spring whitlowgrass, Draba verna" . Retrieved 19 March 2023.
  18. ↑ European Environment Agency. "Erophila verna subsp. verna" . Retrieved 19 March 2023.
  19. ↑ Cheffings, C.M.; Farrell, L. (2005). The Vascular Plant Red Data List for Great Britain. Peterborough: Joint Nature Conservation Committee.
  20. ↑ Inventaire National du Patrimoine Naturel. "Draba verna L." Retrieved 20 March 2023.
  21. ↑ Preston, C.D.; Pearman, D.A.; Dines, T.D. (2002). New Atlas of the British and Irish Flora. Oxford: Oxford University Press.
  22. ↑ Hill, M.O.; Mountford, J.O.; Roy, D.B.; Bunce, R.G.H. (1999). Ellenberg's indicator values for British plants. ECOFACT Volume 2. Technical Annex (PDF). Institute of Terrestrial Ecology. ISBN   1870393481 . Retrieved 29 May 2017.
  23. ↑ Voglmayr, Hermann; Göker, Markus (2011). "Morphology and phylogeny of Hyaloperonospora erophilae and H. praecox sp. nov., two downy mildew species co-occurring on Draba verna sensu lato". Mycol. Progress. 10 (3): 283–292. doi:10.1007/s11557-010-0699-9. S2CID   31301203.
  24. ↑ Allen, D.E.; Hatfield, Gabrielle (2004). Medicinal plants in folk tradition: an ethnobotany of Britain and Ireland (PDF). Portland, Oregon: Timber Press. ISBN   0-88192-638-8.
  25. ↑ Culpeper, Nicholas (1850). The Complete Herbal. London: Thomas Kelly.
  26. ↑ Vickery, Roy (2019). Vickery's Folk Flora. London: Weidenfeld & Nicolson. ISBN   978-1-4746-0462-8.
  27. ↑ Grieve, Maud (1931). A Modern Herbal. New York: Dover Publications Inc. ISBN   0-486-22798-7.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.