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Magnoliopsida
Digitalis L.
EOL Text
Digitalis (/ˌdɪdʒɨˈteɪlɨs/[2] or /ˌdɪdʒɨˈtælɨs/[3]) is a genus of about 20 species of herbaceous perennials, shrubs, and biennials commonly called foxgloves. This genus was traditionally placed in the figwort family Scrophulariaceae, but recent phylogenetic research has placed it in the much enlarged family Plantaginaceae.[1] This genus is native to western and southwestern Europe,[4] western and central Asia, Australasia and northwestern Africa. The scientific name means "finger-like" and refers to the ease with which a flower of Digitalis purpurea can be fitted over a human fingertip. The flowers are produced on a tall spike, are tubular, and vary in colour with species, from purple to pink, white, and yellow. The best-known species is the common foxglove, Digitalis purpurea. This biennial plant is often grown as an ornamental plant due to its vivid flowers which range in colour from various purple tints through various shades of light gray, and to purely white. The flowers can also possess various marks and spottings.
The first year of growth of the common foxglove produces only the stem with its long, basal leaves. During the second year of the plant's life, a long, leafy stem from 50 to 255 centimeters tall grows atop the roots of healthy plants.
The larvae of the moth the "foxglove pug" consume the flowers of the common foxglove for food. Other species of Lepidoptera eat the leaves, including lesser yellow underwing.
The term digitalis is also used for drug preparations that contain cardiac glycosides, particularly one called digoxin, extracted from various plants of this genus.
Contents
Etymology[edit]
Many suggestions for the derivation of the name "foxglove" have been proffered. According to the 19th-century book, English Botany, Or, Coloured Figures of British Plants:
Dr. Prior, whose authority is great in the origin of popular names, says "It seems probably that the name was in the first place, foxes' glew, or music, in reference to the favourite instrument of an earlier time, a ring of bells hung on an arched support, the tintinnabulum"... we cannot quite agree with Dr. Prior for it seems quite probable that the shape of the flowers suggested the idea of a glove, and that associated with the name of the botanist Fuchs, who first gave it a botanical name, may have been easily corrupted into foxglove. It happens, moreover, the name foxglove is a very ancient one and exists in a list of plants as old as the time of Edward III. The "folks" of our ancestors were the fairies and nothing is more likely than that the pretty coloured bells of the plant would be designated "folksgloves," afterwards, "foxglove." In Wales it is declared to be a favourite lurking-place of the fairies, who are said to occasion a snapping sound when children, holding one end of the digitalis bell, suddenly strike the other on the hand to hear the clap of fairy thunder, with which the indignant fairy makes her escape from her injured retreat. In south of Scotland it is called "bloody fingers" more northward, "deadman's bells" whilst in Wales it is known as "fairy-folks-fingers" or "lambs-tongue-leaves".[5]
Habitat[edit]
Digitalis species thrive in acidic soils, in partial sunlight to deep shade, in a range of habitats, including open woods, woodland clearings, moorland and heath margins, sea-cliffs, rocky mountain slopes and hedge banks.[4][6] It is commonly found on sites where the ground has been disturbed, such as recently cleared woodland, or where the vegetation has been burnt.[7]
Medicinal uses[edit]
Cardiac[edit]
A group of medicines extracted from foxglove plants are called digitalin. The use of D. purpurea extract containing cardiac glycosides for the treatment of heart conditions was first described in the English-speaking medical literature by William Withering, in 1785,[8][9] which is considered the beginning of modern therapeutics.[10][11] It is used to increase cardiac contractility (it is a positive inotrope) and as an antiarrhythmic agent to control the heart rate, particularly in the irregular (and often fast) atrial fibrillation. Digitalis is hence often prescribed for patients in atrial fibrillation, especially if they have been diagnosed with congestive heart failure. Digoxin was approved for heart failure in 1998 under current regulations by the Food and Drug Administration on the basis of prospective, randomized study and clinical trials. It was also approved for the control of ventricular response rate for patients with atrial fibrillation. American College of Cardiology/American Heart Association guidelines recommend digoxin for symptomatic chronic heart failure for patients with reduced systolic function, preservation of systolic function, and/or rate control for atrial fibrillation with a rapid ventricular response. Heart Failure Society of America guidelines for heart failure provide similar recommendations. Despite its relatively recent approval by the Food and Drug Administration and the guideline recommendations, the therapeutic use of digoxin is declining in patients with heart failure—likely the result of several factors. Safety concerns regarding a proposed link between digoxin therapy and increased mortality in women may be contributing to the decline in therapeutic use of digoxin.
Variations[edit]
A group of pharmacologically active compounds are extracted mostly from the leaves of the second year's growth, and in pure form are referred to by common chemical names, such as digitoxin or digoxin, or by brand names such as Crystodigin and Lanoxin, respectively. The two drugs differ in that digoxin has an additional hydroxyl group at the C-3 position on the B-ring (adjacent to the pentane). Both molecules include a lactone and a triple-repeating sugar called a glycoside.
Mechanism of action[edit]
Digitalis works by inhibiting sodium-potassium ATPase. This results in an increased intracellular concentration of sodium ions and thus a decreased concentration gradient across the cell membrane. This increase in intracellular sodium causes the Na/Ca exchanger to reverse potential, i.e., transition from pumping sodium into the cell in exchange for pumping calcium out of the cell, to pumping sodium out of the cell in exchange for pumping calcium into the cell. This leads to an increase in cytoplasmic calcium concentration, which improves cardiac contractility. Under normal physiological conditions, the cytoplasmic calcium used in cardiac contractions originates from the sarcoplasmic reticulum, an intracellular organelle that specializes in the storage of calcium. Human newborns, some animals, and patients with chronic heart failure lack well developed and fully functioning sarcoplasmic reticula and must rely on the Na/Ca exchanger to provide all or a majority of the cytoplasmic calcium required for cardiac contraction. For this to occur, cytoplasmic sodium must exceed its typical concentration to favor a reversal in potential, which naturally occurs in human newborns and some animals primarily through an elevated heart rate; in patients with chronic heart failure it occurs through the administration of digitalis. As a result of increased contractility, stroke volume is increased. Ultimately, digitalis increases cardiac output (Cardiac Output=Stroke Volume x Heart Rate). This is the mechanism that makes this drug a popular treatment for congestive heart failure, which is characterized by low cardiac output. Digitalis also has a vagal effect on the parasympathetic nervous system, and as such is used in re-entrant cardiac arrhythmias and to slow the ventricular rate during atrial fibrillation. The dependence on the vagal effect means digitalis is not effective when a patient has a high sympathetic nervous system drive, which is the case with acutely ill persons, and also during exercise.
Toxicity[edit]
Digitalis toxicity (Digitalis intoxication) results from an overdose of digitalis and causes nausea, vomiting and diarrhoea, as well as sometimes resulting in xanthopsia (jaundiced or yellow vision) and the appearance of blurred outlines (halos), drooling, abnormal heart rate, cardiac arrhythmias, weakness, collapse, dilated pupils, tremors, seizures, and even death. Bradycardia also occurs. Because a frequent side effect of digitalis is reduction of appetite, some individuals have used the drug as a weight-loss aid.
Digitalis is an example of a drug derived from a plant that was formerly used by folklorists and herbalists; herbalists have largely abandoned its use because of its narrow therapeutic index and the difficulty of determining the amount of active drug in herbal preparations. Once the usefulness of digitalis in regulating the human pulse was understood, it was employed for a variety of purposes, including the treatment of epilepsy and other seizure disorders, which are now considered to be inappropriate treatments.
Depending on the species, the digitalis plant may contain several deadly physiological and chemically related cardiac and steroidal glycosides. Thus, the digitalis plants have earned several, more sinister, names: dead man’s bells and witch's gloves.
The entire plant is toxic (including the roots and seeds). Mortality is rare, but case reports do exist. Most plant exposures occur in children younger than six years and are usually unintentional and without associated significant toxicity. More serious toxicity occurs with intentional ingestions by adolescents and adults.[12] Early symptoms of ingestion include nausea, vomiting, diarrhoea, abdominal pain, wild hallucinations, delirium, and severe headache. Depending on the severity of the toxicosis, the victim may later suffer irregular and slow pulse, tremors, various cerebral disturbances, especially of a visual nature (unusual colour visions (see xanthopsia) with objects appearing yellowish to green, and blue halos around lights), convulsions, and deadly disturbances of the heart. For a case description, see the paper by Lacassie.[13]Vincent van Gogh's "Yellow Period" may have been influenced by digitalis therapy which, at the time, was thought to control seizures. As noted above, other oculotoxic effects of digitalis include generalized blurry vision, as well as seeing a "halo" around each point of light.[14]
In some instances, people have confused digitalis with the relatively harmless comfrey (Symphytum) plant, which is often brewed into a tea, with fatal consequences. Other fatal accidents involve children drinking the water in a vase containing digitalis plants.[15] Drying does not reduce the toxicity of the plant. The plant is toxic to animals, including all classes of livestock and poultry, as well as felines and canines.
Digitalis poisoning can cause heart block and either bradycardia (decreased heart rate) or tachycardia (increased heart rate), depending on the dose and the condition of one's heart. Notably, the electric cardioversion (to "shock" the heart) is generally not indicated in ventricular fibrillation in digitalis toxicity, as it can increase the dysrhythmia.[citation needed] Also, the classic drug of choice for ventricular fibrillation in emergency setting,[16]amiodarone, can worsen the dysrhythmia caused by digitalis, therefore, the second-choice drug lidocaine is more commonly used.[citation needed]
Digoxigenin[edit]
Digoxigenin (DIG) is a steroid found exclusively in the flowers and leaves of the plants D. purpurea and D. lanata. It is used as a molecular probe to detect DNA or RNA. It can easily be attached to nucleotides by chemical modifications. DIG molecules are often linked to uridine nucleotides; DIG-labelled uridine (DIG-U) can then be incorporated into RNA probes via in vitro transcription. Once hybridisation occurs in situ, RNA probes with the incorporated DIG-U can be detected with anti-DIG antibodies that are conjugated to alkaline phosphatase. To reveal the hybridised transcripts, alkaline phosphatase can be reacted with a chromogen to produce a coloured precipitate.
See also[edit]
Footnotes[edit]
- ^ a b Olmstead, R. G., dePamphilis, C. W., Wolfe, A. D., Young, N. D., Elisons, W. J. & Reeves P. A. (2001). "Disintegration of the Scrophulariaceae". American Journal of Botany (American Journal of Botany, Vol. 88, No. 2) 88 (2): 348–361. doi:10.2307/2657024. JSTOR 2657024. PMID 11222255.
- ^ OED: "Digitalis"
- ^ Digitalis at Dictionary.com]
- ^ a b Anon. "Foxglove (Digitalis purpurea)". Arkive: images of life on Earth. Wildscreen. Retrieved 6 May 2010.
- ^ Lankester, Mrs. (1866). Boswell J.T., ed. English Botany, Or, Coloured Figures of British Plants (full text). VI campanulacae to verbanacea. Sowerby J, Smith C, Johnson J.E, Salter J.W. (III ed.). London: Edward Hardwicke. p. 128.
- ^ Anon. "Foxglove: Digitalis purpurea (Scrophulariaceae)". Wildflowers in Bloom. Wildseed farms. Retrieved 7 May 2010.
- ^ Klein, Carol (18 May 2002). "How to grow: Foxgloves". The Telegraph (London, UK: Telegraph Media Group Limited). Retrieved 6 May 2010.
- ^ William Withering, An Account of the Foxglove and some of its Medical Uses (Birmingham, England: M. Swinney, 1785).
- ^ Goldthorp WO (2009). "Medical Classics: An Account of the Foxglove and Some of its Medicinal Uses by William Withering, published 1785". Brit Med J 338: b2189.
- ^ In contemporary medicine, a purer form of digitalis (usually digoxin) is obtained from D. lanata.
- ^ Digoxin comes from Digitalis lanata. Hollman A. BMJ 1996;312:912. online version accessed 18 October 2006 [1]
- ^ "Cardiac Glycoside Plant Poisoning: Medscape reference". Retrieved 3 July 2012.
- ^ A non-fatal case of intoxication with foxglove, documented by means of liquid chromatography-electrospray-mass spectrometry. Lacassie E et al., J Forensic Sci. 2000 Sep;45(5):1154–8. Abstract accessed online 19 September 2006. [2]
- ^ Goldfrank LW (2006). Goldfrank's Toxicologic Emergencies (8th ed.). New York: McGraw-Hill.
- ^ Anon. "Notes on poisoning:Digitalis purpura". Canadian poisonous plants information system. Canadian Biodiversity Information Facility. Retrieved 9 March 2013.
- ^ "European Resuscitation Council". [verification needed]
References[edit]
- Richard B. Silverman, The Organic Chemistry of Drug Design and Drug Action.
- Flora of Turkey. Edinburgh University Press.
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Biennial or perennial herbs. Leaves alternate. Flowers nodding, borne in terminal 1-sided racemes. Calyx deeply 5-lobed. Corolla with a long tube, shortly 5-lobed, the two upper lobes forming an obscurely lobed upper lip, the lowest usually longer and more prominent. Stamens 4. Capsule dehiscing septicidally. Seeds numerous, small.
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Rights holder/Author | Mark Hyde, Bart Wursten, Petra Ballings, Flora of Zimbabwe |
Source | http://www.zimbabweflora.co.zw/speciesdata/genus.php?genus_id=1287 |
The preference is full or partial sun, mesic to dry-mesic conditions, and loamy soil, although other kinds of soil are readily tolerated. The size of flowering plants can vary considerably depending on soil fertility and the availability of moisture.
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Rights holder/Author | Copyright © 2002-2014 by Dr. John Hilty |
Source | http://www.illinoiswildflowers.info/weeds/plants/gr_foxglove.html |
Foodplant / sap sucker
Aulacorthum solani sucks sap of live, slightly distorted and discoloured leaf (young) of Digitalis
Foodplant / saprobe
fruitbody of Lachnella villosa is saprobic on dead, decayed stem of Digitalis
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Rights holder/Author | BioImages, BioImages - the Virtual Fieldguide (UK) |
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Digitalis lanata (often called the Woolly Foxglove or Grecian Foxglove) is a species of foxglove. It gets its name due to the texture of the leaves. Digitalis lanata, like some other foxglove species, is highly toxic in all parts of the plant. Even the ingestion of small amounts by humans can be fatal particularly for children[clarification needed][1] . Symptoms of digitalis poisoning include nausea, vomiting, severe headache, dilated pupils, problems with eyesight, and convulsions at the worst level of toxicity. The plant is also harmful to other animals. In some cases it is considered invasive or a noxious weed. Minnesota is one of the few places that consider it invasive as noted by the Western Weed Society. It is in leaf all year, in flower in June and July, and the seeds ripen in early-mid September. The flowers are hermaphroditic (having both male and female organs). Bees pollinate the flowers.[citation needed]
Contents
Description[edit]
The plant commonly grows from 0.3 to 0.6 meters in height, or about 13 to 26 inches. The plant prefers part shade and humus rich soil. The plant also prefers sandy, loamy, and clay soils. It can grow under dry or moist conditions. Seeds develop in pods that have small hooks, enabling the pods to be transported by animal fur or clothing. The elongated leaves are mid–green, wooly, veined, and covered with white hairs on the underside. They also have a very bitter taste. There is a tidy rosette before the spike goes up, and it is neatly arranged around the purple-tinged stems. The flowers are tubular and bell shaped with a creamy-white color and purplish-brown netting as well as a long broad lip. The flowers usually bloom in the second year. Both flowers and stems are also woolly or hairy as well as pretty.
Distribution[edit]
It is found mostly in Eastern Europe. One of the biggest populations can be found near Bácsalmás in Hungary. Even though it is native to Europe, the plant can now be found throughout the world, growing in woodland areas, on roadsides, and in mountainous regions. In North America, it can be found mostly in the Northeast and Southwest regions. It is cultivated mainly in New York, Washington, Utah, and Colorado.
Taxonomy[edit]
The Plantaginaceae family, also known as the plantain family, is a family of flowering plants included in the order Lamiales. The Plantaginaceae family was not originally placed in the order Lamiales, but in the order Plantaginales. However, in recent years phylogenetic studies conducted by the Angiosperm Phylogeny Group have indicated that it should be included in the order Lamiales. The original family name was Veronicaceae until 1789 when the family name became Plantaginaceae. This is the conserved name under the International Code of Botanical Nomenclature (ICBN). ICBN does not consider family names before 1789 for conservation, as a result Veronicaceae is not eligible for conservation. Digitalis lanata has several other common names such as Grecian Foxglove and Woolly Foxglove. The name Digitalis comes from the Latin word digitus, which means finger. Digitalis was first recorded in the English language in 1664 in a published work. This genus name was chosen because the German name for foxglove is Fingerhut, which means finger hat (thimble). The glove portion of the name originates from the similarity of the foxglove blossoms to the fingers of a glove.
Physiology[edit]
The species is adapted to sunny and warm sites on dry, mostly on sandy and stony loamy soil. During the first vegetation period, only the leaf rosette is developed, flowering follows during the second vegetation period. Therefore, especially during the first year, a high resistance against water stress (drought stress) has to be expected. Indeed, the leaves remain turgescent even under very low leaf water potential, due to osmotic adaptation by synthesis of non ionic substances in the leaves. The drought induced diminishing of photosynthesis is reversible after a few hours following watering of the plants.[2] Drought stress also reduces the quantum yield of photosystem 2.[3] More than 70 bitter glycosides with cardiac activity, with 5 different aglyconees Digitoxigenin, Gitoxigenin, Digoxigenin, Diginatigenin and Gitaloxigenin in the leaves act as a protection against herbivores.[4] Yield and concentration of these cardiac glycosides can be enhanced by greenhouse cultivation by enhanced temperature and enhanced carbon dioxide concentration.[5]
Medical uses[edit]
Digitalis lanata contains a powerful cardiac glycoside that may be used by patients with heart conditions. Digoxin (Digitalin) is a drug that is extracted from Digitalis lanata. It is used to treat some heart conditions such as atrial fibrillation. It slows atrioventricular conduction so that the heartbeat slows down and very slightly increases contraction power (positive inotropic effect). Because of the improved circulation in congestive heart failure caused by fast atrial fibrillation, the kidneys can function better, which stimulates the flow of urine, which lowers the volume of the blood and lessens the load on the heart. This is the effect that was first described when the plant was discovered as a medicine (Withering 1785). Digitalin was not discovered until the mid-19th century by two French scientists Homolle Ouevenne and Theodore Ouevenne. It wasn’t until 1875 that Oscar Schmiedberg identified digoxin in the plant.[6] It was first isolated in the 1930s in Britain by Dr. Sydney Smith.[7][8] Back then it was used to treat ulcers in the lower abdomen, boils, headaches, abscesses, and paralysis, and externally healing wounds. Today it is still extracted from the plant because synthetis is quite expensive and difficult. However, it is becoming less frequently used due to the narrow therapeutic margin and high potential for severe side effects. Digoxin is being replaced by newer drugs including beta blockers, angiotensin-converting enzyme inhibitors, and the calcium channel blocking agents. As new pharmacotherapeutic agents arise, the use of digitalis preparations will continue to decline. There are also other commercial uses for Digitalis lanata other than heart conditions. For example, in South America the powdered leaves are used to relieve asthma, as sedatives, and as diuretics. In India it is used as an ointment that contains digitalis glycosides used to treat wounds and burns.
Pictures[edit]
References[edit]
[9][10][11][12][13][14][15][16][17][18][19][20][21]
- ^ http://www.drugs.com/npp/digitalis.html
- ^ Thomas Stuhlfauth, Dieter F. Sültemeyer, Stefanie Weinz and Heinrich P. Fock, Fluorescence quenching and gas exchange in a water stressed C3 Plant, Digitalis lanata, Plant Physiol. (1988) 86, 0246-0250 [1]
- ^ H.P. Fock, K. Biehler and T. Stuhlfauth, Use and degradation of light energy in water-stressed Digitalis lanata, Photosynthetica 27(4):571-577, 1992
- ^ Hildebert Wagner, Pharmazeutische Biologie, 2. Drogen und ihre Inhaltsstoffe, Gustav Fischer Verlag, Stuttgart 1980
- ^ T. Stuhlfauth and H. P. Fock, effect of whole season CO2 enrichment on the cultivation of a medicinal plant, Digitalis lanata, J. Agronomy & Crop Science,, 164, 168-173, 1990 [2]
- ^ G. Dragendorff (1884). Plant Analysis Qualitative & Quantitative. London: Bailliere, Tindall and Cox. p. 142.
- ^ George Edward Trease (1961). A text book of Pharmacognosy. London: Bailliere, Tindall and Cox. p. 513.
- ^ Sydney Smith III (1931). "Digitalis glucosides". Journal of the Chemical Society 23 (3).
- ^ Niazi, Sarfaraz. Handbook of Pharmaceutical Manufacturing Formulations: Compressed Solid Products. Boca Raton: CRC, 2004.
- ^ http://www.robsplants.com/plants/DigitLanat.phpl
- ^ http://onlinedictionary.datasegment.com/word/digitalis+lanata
- ^ http://www.bmj.com/cgi/content/full/312/7035/912
- ^ http://plants.usda.gov/java/profile?symbol=DILA3
- ^ http://www.drugs.com/npp/digitalis.html
- ^ http://www.pfaf.org/database/plants.php?Digitalis+lanata
- ^ http://www.piam.com/mms_garden/plants.html
- ^ http://www.ksda.gov/plant_protection/content/355/cid/679
- ^ http://www.ksda.gov/includes/document_center/plant_protection/Miscellaneous_Plans_Reports_and_Guidelines/gfox.pdf
- ^ http://www.innvista.com/health/herbs/foxglove.htm
- ^ http://www.discoveriesinmedicine.com/Com-En/Digitalis.html
- ^ http://data.gbif.org/datasets/resource/1905
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Barcode of Life Data Systems (BOLD) Stats
Specimen Records:30
Specimens with Sequences:48
Specimens with Barcodes:36
Species:6
Species With Barcodes:6
Public Records:12
Public Species:5
Public BINs:0
Digitalis x fulva, Lindl. 1821, common name Strawberry foxglove, is a hybrid between D. grandiflora and D. purpurea (Hybrid formula: Digitalis grandiflora Mill. × Digitalis purpurea L.). This hybrid is considered fertile.
Description[edit]
This perennial herbaceous plant reaches on average a height of 60–90 centimetres (24–35 in). The erect stems rise from a basal rosette of soft leaves. It has typical tall spikes of large tubular flowers. The color ranges from strawberry pink (hence the common name) to mauve. The flowering period extends from late Spring to early Summer. It prefers neutral or mildly acidic substrate and rich, moist and regularly watered soil, in full sun or in partial shade.
This plant has gained the Royal Horticultural Society's Award of Garden Merit.[1]
Gallery[edit]
Synonyms[edit]
- Digitalis fuscescens Kirschl., Prodr. Fl. Alsace 103. 1836, nom. illeg. non Waldst. & Kit. (1812).
- Digitalis kotukovii Ivanina, Trudy Bot. Inst. Akad. Nauk S.S.S.R., Ser. 1, Fl. Sist. Vyssh. Rast. 11: 225. 1955, sine descr. lat.
- Digitalis mertonensis B.H.Buxton & C.D.Darl., Nature 127: 94. 1931.
- Digitalis obtusa Moench, Methodus (Moench) 443. 1794.
- Digitalis purpureoides H.Lév., Bull. Géogr. Bot., sér. 4, 25 : 65, nom. illeg.
References[edit]
Wikimedia Commons has media related to Digitalis x fulva. |
Wikispecies has information related to: Digitalis x fulva |
- ^ "RHS Plant Selector Digitalis × mertonensis AGM / RHS Gardening". Apps.rhs.org.uk. Retrieved 2012-07-23.
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Grecian Foxglove has large striking flowers that are oddly colored (by North American standards). In the past, it has been an important source of digoxin and other cardiac glycosides that are used in modern medicine to treat patients with various heart conditions. It is a dangerously toxic plant, however, and should not be used as a home remedy. Today, the cardiac glycosides of Grecian Foxglove and closely related species are used less often in modern medicine than they have in the past now that less risky medications have become available. Two other European species, Digitalis purpurea (Purple Foxglove) and Digitalis lutea (Yellow Foxglove), uncommonly naturalize in the Midwest and northeastern United States. They are readily distinguished by the appearance of their flowers
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Source | http://www.illinoiswildflowers.info/weeds/plants/gr_foxglove.html |
This perennial wildflower is a biennial or short-lived perennial. During the first year, it forms a low rosette of basal leaves. The basal leaves are up to 6" long and 2" across; they are lanceolate, oblanceolate, or elliptic in shape and usually smooth (entire) along their margins. Both the lower and upper surfaces of these leaves are dull green and glabrous. During the second year and thereafter, an erect flowering stalk develops that is 2-4' tall and unbranched. The lower half of the stalk is light green, yellowish green, or purple, terete, and glabrous; sometimes their are purple or brown dots on light-colored stalks. Spreading to slightly drooping alternate leaves occur along the lower stalk that are up to 8" long and 1½" across. The alternate leaves are lanceolate-oblong in shape, smooth along their margins, and sessile or nearly so. The lower and upper surfaces of these leaves are dull green and glabrous. The primary veins of both basal and alternate leaves are parallel. The stalk terminates in a spike-like raceme of flowers about 1-2' tall. The flowers are densely arranged along the raceme and they are oriented in all directions. The upper half of the stalk (or axis of the raceme) is light green, yellowish green, or purple, terete, and more or less glandular-hairy. Individual flowers are about 1¼-2" long. Each flowers consists of a broad tubular corolla with 5 lobes, a calyx with 5 sepals, 4 stamens, and a pistil with a long style. The corolla tube is pale cream to yellowish green with an intricate network of brown or purple veins; its exterior is finely pubescent. The two upper lobes and two lateral lobes along the outer rime of the corolla are small in size and curve backward. The lower lobe is much larger in size (about ½-¾" long) than the other lobes; it is bright white and curves downward. The stamens and style are located along the upper surface of the corolla's interior. The sepals are light green, linear-lanceolate, hairy, and ciliate along their margins; they are about ½" long. The short pedicels are green and hairy. Underneath the flowers, are individual leafy bracts that are longer toward the bottom of the raceme than toward the top; they are highly variable in length (from ¼" long above to 6" long below). The leafy bracts are green, usually lanceolate-oblong in shape, variably hairy, and sessile; their margins are smooth and often ciliate. The blooming period occurs from late spring to mid-summer, lasting about 1 month. Afterwards, the flowers are replaced by ovoid seed capsules about ½" long that are green and hairy. At the apex of each seed capsule, the persistent style of the flower becomes stiff and hooked toward its tip. Each capsule contains numerous seeds. The root system consists of a taproot. If a plant lives longer than 2 years, it will die down to a rosette of basal leaves that persists during the winter. It will develop another flowering stalk when warm weather returns.
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Source | http://www.illinoiswildflowers.info/weeds/plants/gr_foxglove.html |