Crocus (English plural: crocuses or croci) is a genus of flowering plants in the iris family comprising 90 species of perennials growing from corms. Many are cultivated for their flowers appearing in autumn, winter, or spring. The spice saffron is obtained from the stigmas of Crocus sativus, an autumn-blooming species. Crocuses are native to woodland, scrub, and meadows from sea level to alpine tundra in central and southern Europe, North Africa and the Middle East, on the islands of the Aegean, and across Central Asia to Xinjiang Province in western China.
The name of the genus is derived from the Greek κρόκος (krokos). This, in turn, is probably a loan word from a Semitic language, related to Hebrew כרכום karkōm, Aramaic ܟܟܘܪܟܟܡܡܐ kurkama, and Arabic كركم kurkum, which mean "saffron" (Crocus sativus), "saffron yellow" or turmeric (see Curcuma). The word ultimately traces back to the Sanskrit kunkumam (कुङ्कुमं) for "saffron". The English name is a learned 16th-century adoption from the Latin, but Old English already had croh "saffron".
Cultivation and harvesting of Crocus sativus for saffron was first documented in the Mediterranean, notably on the island of Crete. Frescos showing them are found at the Knossos site on Crete, as well as from the comparably aged Akrotiri site on Santorini.
The first crocus seen in the Netherlands, where crocus species are not native, were from corms brought back in the 1560s from Constantinople by the Holy Roman Emperor's ambassador to the Sublime Porte, Ogier Ghiselin de Busbecq. A few corms were forwarded to Carolus Clusius at the botanical garden in Leiden. By 1620, the approximate date of Ambrosius Bosschaert's painting (illustration, below), new garden varieties had been developed, such as the cream-colored crocus feathered with bronze at the base of the bouquet, similar to varieties still on the market. Bosschaert, working from a preparatory drawing to paint his composed piece spanning the whole of spring, exaggerated the crocus so that it passes for a tulip, but its narrow, grass-like leaves give it away.
The cup-shaped, solitary, salverform flower tapers off into a narrow tube. Their colors vary enormously, although lilac, mauve, yellow, and white are predominant. The grass-like, ensiform leaf shows generally a white central stripe along the leaf axis. The leaf margin is entire.
A crocus has three stamens, while a similar-looking toxic plant, colchicum, sometimes popularly referred to as "autumn crocus", has six stamens. In addition, crocus have one style, while colchicum have three.
Crocuses are distributed across central and southern Europe, North Africa, Middle East, and Central Asia to western China.
Distribution map of 16 species of genus Crocus in Europe and Asia
Crocus tommasinianus (Section Crocus, Series Verni)
Crocus ligusticus (Section Crocus, Series Longiflori)
Crocus ochroleucus (Section Crocus, Series Kotschyani)
Crocus sativus (Section Crocus, Series Crocus)
Crocus mathewii (Section Crocus, Series Crocus)
Crocus sieberi subsp. sublimis 'Tricolor' (Section Nudiscapus, Series Reticulati)
Crocus speciosus (Section Nudiscapus, Series Speciosi)
The taxonomic classification proposed by Brian Mathew in 1982 was based mainly on three character states:
- the presence or absence of a prophyll (a basal spathe);
- the aspect of the style;
- the corm tunic.
The seven species discovered since then have been integrated into this classification.
Molecular analysis carried out at the University of Copenhagen suggests this classification should be reviewed. In particular, the DNA data suggest there are no grounds for isolating C. banaticus in its own subgenus Crociris, though it is a unique species in the genus. Because it has a prophyll at the base of the pedicel, it therefore would fall within section Crocus, although its exact relationship to the rest of the subgenus remains unclear.
Another anomalous species, C. baytopiorum, should now be placed in a series of its own, series Baytopi. C. gargaricus subsp. herbertii has been raised to species status, as C. herbertii. Perhaps most surprisingly, autumn-flowering C. longiflorus, the type species of series Longiflori (long regarded by Mathew as "a disparate assemblage"), now seems to lie within series Verni. In addition, the position of C. malyi is currently unclear.
DNA analysis and morphological studies suggest further that series Reticulati, Biflori and Speciosi are "probably inseparable". C. adanensis and C. caspius should probably be removed from Biflori; C. adanensis falls in a clade with C. paschei as a sister group to the species of series Flavi; C. caspius appears to be sister to the species of series Orientales.
The study shows "no support for a system of sections as currently defined", although, despite the many inconsistencies between Mathew's 1982 classification and the current hypothesis, "the main assignment of species to the sections and series of that system is actually supported". The authors state, "further studies are required before any firm decisions about a hierarchical system of classification can be considered" and conclude "future re-classification is likely to involve all infrageneric levels, subgenera, sections and series".
Below is the classification proposed by Brian Mathew in 1982, adapted in accordance with the above findings:
- A. Section Crocus : species with a basal prophyll
- Series Verni: corms with reticulated fibers, spring-flowering (apart from Crocus longiflorus), flowers for the most part without conspicuous outer striping, bracts absent
- Crocus etruscus Parl.
- Crocus ilvensis Peruzzi & Carta
- Crocus kosaninii Pulevic
- Crocus longiflorus Raf. – Italian crocus (formerly in Series Longiflori)
- Crocus tommasinianus Herb. – Woodland crocus, Tommasini's crocus
- Crocus vernus (L.) Hill – Spring crocus, Dutch crocus
- Crocus vernus subsp. albiflorus (Kit. ex Schult.) Asch. & Graebn.
- Crocus vernus subsp. vernus
- Series Baytopi (new Series): corms with strongly reticulated fibers; leaves numerous, narrowly linear; spring-flowering, bracts absent; anthers extrorsely dehiscent
- Crocus baytopiorum Mathew (formerly in Series Verni)
- Series Scardici: spring-flowering, leaves have no pale stripe on the upper surface
- Crocus pelistericus Pulevic
- Crocus scardicus Kos.
- Series Versicolores: spring-flowering, corms with tunics, which for the most part have parallel fibers, flowers with conspicuous exterior striping
- Series Longiflori: autumn-flowering, yellow anthers, styles much divided
- Series Kotschyani: autumn-flowering, anthers white, styles for the most part three-forked
- Crocus autranii Albov.
- Crocus gilanicus B. Matthew (discovered in 1973 and named after Gilan province in Iran where it was first found)
- Crocus karduchorum Kotschy ex Maw
- Crocus kotschyanus K. Koch – Kotschy's crocus (syn. C. zonatus)
- Crocus kotschyanus subsp. cappadocicus B.Mathew
- Crocus kotschyanus subsp. hakkariensis B.Mathew
- Crocus kotschyanus subsp. kotschyanus
- Crocus kotschyanus subsp. suworowianus (K.Koch) B.Mathew
- Crocus ochroleucus Boiss. & Gaill.
- Crocus scharojanii Ruprecht
- Crocus scharojanii subsp. scharojanii
- Crocus scharojanii subsp. lazicus (Boiss.) B.Mathew
- Crocus vallicola Herb.
- Series Crocus: autumn-flowering, anthers yellow, style distinctly three-branched
- Crocus asumaniae B. Mathew & T. Baytop
- Crocus cartwrightianus Herb.
- Crocus hadriaticus Herb.
- Crocus hadriaticus subsp. hadriaticus
- Crocus hadriaticus subsp. parnassicus (B.Mathew) B.Mathew
- Crocus hadriaticus subsp. parnonicus B.Mathew
- Crocus moabiticus Bornm. & Dinsmore ex Bornm.
- Crocus mathewii H. Kemdorff & E. Pasche (1994)
- Crocus naqabensis Al-Eisawi (2001)
- Crocus oreocreticus B.L. Burtt
- Crocus pallasii Goldb.
- Crocus pallasii subsp. dispathaceus (Bowles) B.Mathew
- Crocus pallasii subsp. haussknechtii (Boiss. & Reut. ex Maw) B.Mathew
- Crocus pallasii subsp. pallasii
- Crocus pallasii subsp. turcicus B.Mathew
- Crocus thomasii Ten.
- Position unclear
- B. Section Nudiscapus: species without a basal prophyll
- Series Reticulati: corm tunic for the most part decidedly covered with reticulated fibers, flower produced in winter or spring, style three-forked or much divided
- Crocus abantensis T.Baytop & B.Mathew
- Crocus ancyrensis (Herb.) Maw – Ankara crocus
- Crocus angustifolius Weston – cloth-of-gold crocus
- Crocus cancellatus Herb.
- Crocus cancellatus subsp. cancellatus
- Crocus cancellatus subsp. damascenus (Herb.) B.Mathew
- Crocus cancellatus subsp. lycius B.Mathew
- Crocus cancellatus subsp. mazziaricus (Herb.) B.Mathew
- Crocus cancellatus subsp. pamphylicus B.Mathew
- Crocus cvijicii Kos.
- Crocus dalmaticus Vis.
- Crocus gargaricus Herb.
- Crocus herbertii B. Mathew (became a "true" species)
- Crocus hermoneus Kotschy ex Maw
- Crocus jablanicensis N. Randj. & V. Randj.
- Crocus reticulatus Steven ex Adams
- Crocus reticulatus subsp. hittiticus (T.Baytop & B.Mathew) B.Mathew
- Crocus reticulatus subsp. reticulatus
- Crocus robertianus C.D. Brickell
- Crocus rujanensis Randjel. & D.A. Hill (1990)
- Crocus sieberi J. Gay – Sieber's crocus, Cretan crocus
- Crocus sieberi subsp. atticus (Boiss. & Orph.) B.Mathew
- Crocus sieberi subsp. nivalis (Bory & Chaub.) B.Mathew
- Crocus sieberi subsp. sieberi
- Crocus sieberi subsp. sublimis (Herb.) B.Mathew
- Crocus sieheanus Barr ex B.L. Burtt
- Crocus veluchensis Herb.
- Series Biflori: tunics of corms split into rings at the base, either entire or with toothlike projections, leathery in texture, spring- or late-winter flowering, style three-forked
- Crocus aerius Herb.
- Crocus almehensis C.D. Brickell & B. Mathew
- Crocus biflorus Mill. – silvery crocus, Scotch crocus
- Crocus biflorus subsp. biflorus
- Crocus biflorus subsp. adamii (J.Gay) K.Richt.
- Crocus biflorus subsp. alexandri (Nicic ex Velen.) B. Mathew
- Crocus biflorus subsp. artvinensis (J.Philippow) B. Mathew
- Crocus biflorus subsp. atrospermus Kernd. & Pasche
- Crocus biflorus subsp. caelestis Kernd. & Pasche
- Crocus biflorus subsp. caricus Kernd. & Pasche
- Crocus biflorus subsp. crewei (Hook.f.) B. Mathew
- Crocus biflorus subsp. fibroannulatus Kernd. & Pasche
- Crocus biflorus subsp. ionopharynx Kernd. & Pasche
- Crocus biflorus subsp. isauricus (Siehe ex Bowles) B.Mathew
- Crocus biflorus subsp. leucostylosus Kernd. & Pasche
- Crocus biflorus subsp. melantherus B. Mathew
- Crocus biflorus subsp. nubigena (Herb.) B. Mathew
- Crocus biflorus subsp. pseudonubigena B. Mathew
- Crocus biflorus subsp. pulchricolor (Herb.) B. Mathew
- Crocus biflorus subsp. punctatus B.Mathew
- Crocus biflorus subsp. stridii (Papan. & Zacharof) B.Mathew
- Crocus biflorus subsp. tauri (Maw) B. Mathew
- Crocus biflorus subsp. weldenii (Hoppe & Fuernr.) B. Mathew
- Crocus biflorus subsp. yataganensis Kernd. & Pasche
- Crocus chrysanthus Herb. – Golden crocus, Snow crocus
- Crocus chrysanthus subsp. chrysanthus
- Crocus chrysanthus subsp. multifolius Papan. & Zacharof
- Crocus cyprius Boiss. & Kotschy
- Crocus danfordiae Maw
- Crocus danfordiae subsp. danfordiae
- Crocus danfordiae subsp. kurdistanicus Maroofi & Assadi
- Crocus hartmannianus Holmboe
- Crocus kerndorffiorum Pasche (1993)
- Crocus leichtlinii (Dewar) Bowles
- Crocus nerimaniae Yüzbasioglu & Varol (2004)
- Crocus pestalozzae Boiss.
- Crocus wattiorum (B. Mathew, 1995) B. Mathew (2000)
- Crocus demirizianus O.Erol & L.Can (2012)
- Crocus yakarianus Yıldırım & O.Erol (2013)
- Series Speciosi: corm tunic splits into rings at the base, leathery or membranous, foliage after the flowers, autumn-flowering, style much divided
- Crocus pulchellus Herb. – hairy crocus
- Crocus speciosus M. Bieb. – Bieberstein's crocus, large purple crocus
- Crocus speciosus subsp. ilgazensis B.Mathew
- Crocus speciosus subsp. speciosus
- Crocus speciosus subsp. xantholaimos B.Mathew
- Series Orientales: corm with parallel fibers or lightly reticulated, numerous leaves, spring-flowering, style three-forked
- Crocus alatavicus Semenova & Reg.
- Crocus caspius Fischer & Meyer (formerly in Series Biflori)
- Crocus korolkowii Regel ex Maw – celandine crocus
- Crocus michelsonii B. Fedtsch.
- Series Flavi: tunics of the corms membranous, split into parallel fibers, spring-flowering, styles much divided
- Crocus adanensis T. Baytop & B. Mathew (formerly in Series Biflori)
- Crocus antalyensis Mathew
- Crocus antalyensis subsp. antalyensis
- Crocus antalyensis subsp. striatus O.Erol & M.Koçyiğit (2010)
- Crocus antalyensis subsp. gemicii L.Sik & O.Erol (2011)
- Crocus candidus E.D. Clarke
- Crocus flavus Weston – Yellow crocus
- Crocus flavus subsp. flavus
- Crocus flavus subsp. dissectus T.Baytop & B.Mathew
- Crocus flavus subsp. sarichinarensis Rukšans
- Crocus graveolens Boiss. &Reut.
- Crocus hyemalis Boiss.
- Crocus olivieri Gray
- Crocus olivieri subsp. olivieri – Balkan and Turkey
- Crocus olivieri subsp. balansae (J.Gay ex Baker) B. Mathew – endemic round İzmir, West-Turkey
- Crocus olivieri subsp. istanbulensis B. Mathew, Istanbul, Turkey.
- Crocus paschei H. Kerndorff
- Crocus vitellinus Wahl.
- Series Aleppici: tunics of the corms membranous, with split, parallel fibers, foliage produced at the same time as the flowers, fall- or winter-flowering
- Series Carpetani: undersurface of the leaves rounded with grooves, upper surface channeled, spring-flowering, style whitish, obscurely divided
- Crocus carpetanus Boiss. & Reut.
- Crocus nevadensis Amo & Campo
- Series Intertexti: corm tunic fibrous with fibers interwoven, spring-flowering
- Series Laevigatae: corm tunic membranous or splitting into parallel fibers, sometimes leathery, foliage produced at the same time as flowers, autumn-flowering, anthers white, style much divided
Crocus cartwrightianus 'Albus'
Crocus etruscus 'Zwanenburg'
Crocus imperati 'De Jager'
Crocus laevigatus 'Fontenayi'
Crocus serotinus subsp. clusii
Crocus serotinus subsp. salzmannii
Some species, known as "autumn crocus", flower in late summer and autumn, often before their leaves appear. They should not be confused with a different genus of autumn-flowering plants, Colchicum. Autumn-flowering species of crocus include:
- C. banaticus (syn. C. iridiflorus)
- C. cancellatus
- C. goulimyi
- C. hadriaticus
- C. kotschyanus (syn. C. zonatus)
- C. laevigatus
- C. ligusticus (syn. C. medius )
- C. niveus
- C. nudiflorus
- C. ochroleucus
- C. pulchellus
- C. sativus (saffron crocus)
- C. serotinus
- C. speciosus
- C. tournefortii
C. laevigatus has a long flowering period which starts in late autumn or early winter and may continue into February.
About 30 of the species are cultivated, including Crocus sativus for saffron production. The varieties cultivated for decoration mainly represent five species: C. vernus, C. chrysanthus, C. flavus, C. sieberi, and C. tommasinianus. Among the first flowers to bloom in spring, crocuses are popular with gardeners. Their flowering time varies from the late winter C. tommasinianus to the later large hybridized and selected Giant "Dutch crocuses" (C. vernus). Crocus flowers and leaves are protected from frost by a waxy cuticle; in areas where snow and frost occasionally occur in the early spring, it is not uncommon to see early flowering crocuses blooming through a light late snowfall.
field of flowering purple crocuses
Crocus 'E.A. Bowles',
a C. chrysanthus hybrid
C. sieberi corms, showing the net-like papery outer covering
Purple crocuses with closed flowers
Crocuses appearing through the snow
Most crocus species and hybrids should be planted in a sunny position, in gritty (sandy), well-drained soil, although a few prefer shadier sites in moist soil. Some are suitable for naturalising in grass. The corms should be planted about 3 to 4 cm deep; in heavy soils, a quantity of sharp grit should be worked in to improve drainage.
Some crocuses, especially C. tommasinianus and its selected forms and hybrids (such as 'Whitewell Purple' and 'Ruby Giant'), seed prolifically and are ideal for naturalising. They can, however, become weeds in rock gardens, where they will often appear in the middle of choice, mat-forming alpine plants, and can be difficult to remove.
Though some true crocuses bloom with the fall (autumnal) rains, after summer's heat and drought, the name autumn crocus is often used as a common name for Colchicum, which is in its own family (Colchicaceae) in the lily order Liliales, and which has six stamens; it is also known as meadow saffron, though unlike true saffron, the plant is toxic.
The prairie crocus or pasque flower (Pulsatilla patens) belongs to the buttercup family (Ranunculaceae).
The financial community sometimes refers to companies or economic sectors that rise early after an economic downturn as "crocuses" in reference to the flower's ability to thrive in the late winter or early spring.
Crocus or Krokus (Greek: Κρόκος) was a mortal youth who, because he was unhappy with his love affair with Smilax, was turned by the gods into a plant bearing his name, the crocus.
- ^ a b c Kew World Checklist of Selected Plant Families
- ^ a b Altervista Flora Italiana, genere Crocus includes photos plus European distribution maps
- ^ a b Innes, C. (1985). The World of Iridaceae: 1–407. Holly Gare International Ltd., Ashington
- ^ κρόκος, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
- ^ OED; Babiniotis dictionary
- ^ Tawney, C. H. (1924). The Ocean of Story, chapter 104. p. 13.
- ^ "crocus (n.)". etymonline.com.
- ^ C. Michael Hogan, "Knossos fieldnotes", Modern Antiquarian (2007)
- ^ Ensiform: Having sharp edges and tapering to a slender point, like a sword blade.
- ^ A Handbook of Crocus and Colchicum for Gardeners, p. 154, etc.
- ^ Gitte Petersen, Ole Seberg, Sarah Thorsøe, Tina Jørgensen & Brian Mathew: "A phylogeny of the genus Crocus (Iridaceae) based on sequence data from five plastid regions." Taxon, 57(2), 2008, pp. 487–499. JSTOR 25066017.
- ^ a b c d e f Brian Mathew, Gitte Petersen & Ole Seberg, A reassessment of Crocus based on molecular analysis, The Plantsman (N.S.) Vol 8, Part 1, pp. 50–57, March 2009
- ^ Peruzzi Lorenzo, Carta Angelino. 2011 "Crocus ilvensis sp. nov. (sect. Crocus, Iridaceae), endemic to Elba Island (Tuscan Archipelago, Italy)", Nordic Journal of Botany, 29(1): 6–13. doi:10.1111/j.1756-1051.2010.01023.x
- ^ Example of Metaphorical Use
- E.A. Bowles, A Handbook of Crocus and Colchicum for Gardeners, Martin Hopkinson 1924
- Brian Mathew, Christopher Grey-Wilson, Bulbs, (ill. Marjorie Blamey), Collins, 1981
- Brian Mathew, Crocus: A Revision of the Genus Crocus, Timber Press, 1983. ISBN 0-917304-23-3
- Brian Mathew, Flowering Bulbs for the Garden, Collingridge/Royal Botanic Gardens, Kew, 1987. ISBN 0-600-35175-0
- Novica Randjelovic, David A. Hill, Vladimir Randjelovic, 'The Genus Crocus L. in Serbia'. Serbian Academy of Sciences and Arts, Belgrade, 1990 (in English)
- Maw, George. A Monograph of the Genus Crocus. London, Dulau and Co., 1886
- Rix, Alison. "George Maw, Joseph Hooker and the genus Crocus", Curtis's Botanical Magazine, Volume 25 Issue 2, Pages 176–187, 2008 doi:10.1111/j.1467-8748.2008.00616.x
- The Pleasures of Crocus, Royal New Zealand Institute of Horticulture 1996
- Walters, S. M., et al., editor, The European Garden Flora: A Manual for the Identification of Plants Cultivated in Europe, both Out-of-Doors and Under Glass, Volume 1, Cambridge University Press, 1984
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