Crocus

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Crocus
Crocus longiflorus
Crocus longiflorus
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Asparagales
Family: Iridaceae
Genus: Crocus
L.

Species
See text.
Wild crocus growing in the foothills of the Eiger in the European Alps.

Crocus (plural: crocus, crocuses or croci) is a genus of perennial flowering plants, native to a large area from coastal and subalpine areas of central and southern Europe (including the islands of the Aegean), North Africa and the Middle East, across Central Asia to western China.

The genus Crocus is placed botanically in the iris family (Iridaceae). The plants grow from corms and are mainly hardy perennials, and are found a wide range of habitats, including woodland, scrub and meadows.

There are about eighty species of crocus, of which approximately 30 are commonly cultivated. Their flowers are cup-shaped, solitary, salverform, tapering off into a narrow tube; they vary enormously in colour, though lilac, mauve, yellow and white are predominant. The grass-like, ensiform leaf generally shows a white central stripe along the leaf axis. The leaf margin is entire. All crocuses typically have three stamens.

The name of the genus is derived from the Latin adjective crocatus, meaning saffron yellow. The spice saffron is obtained from the stigmas of Crocus sativus, an autumn/fall-blooming species.

True autumn crocuses

Most true autumn crocus flower in September to November in the northern hemisphere. Some flower before their leaves appear. Autumn/fall flowering species include: Crocus banaticus (syn. C. iridiflorus), C.cancellatus, C. goulimyi, C. hadriaticus, C. kotschyanus (syn. C. zonatus), C. laevigatus, C. medius, C. niveus, C. nudiflorus, C. ochroleucus, C. pulchellus, C. sativus (saffron crocus), C. serotinus, C. speciosus, C. tournefortii. Crocus laevigatus has a long flowering-period which starts in late autumn or early winter and may continue into February.

In cultivation

As one of the first flowers to bloom in spring, the large selected hybrid Dutch crocus are popular with gardeners. However, in areas where snow and frost occasionally occur in the early spring it is not uncommon for early-flowering crocuses to suddenly wither and die from a unseasonable frost or snowfall.

Most crocus species and hybrids should be planted in a sunny position, in gritty, 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 3–4 cm deep; in heavy soils a quantity of sharp grit should be dug 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.

History

The first crocus seen in the Netherlands, where Crocus species are not native, were corms brought back from the Holy Roman Emperor's ambassador to the Sublime Porte, A. Ghislain de Busbeq, in the 1560s. 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, left), 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 in the market. Bosschaert, working from a preparatory drawing to paint his composed piece, which spans the whole of Spring, exaggerated the crocus so that it passes for a tulip, but its narrow, grasslike leaves give it away.

Species

Cloth of gold (Crocus angustifolius)
from Curtis's Botanical Magazine 1803

The taxonomic characteristics are based mainly on the presence or absence of a prophyll (a basal spathe) and the aspect of the style and the corm tunic.

1 Subgenus Crocus

A. Section Crocus
Series Kotschyani
Series Longiflori
Crocus serotinus subsp. clusii
Series Scardici
Series Verni
Crocus vernus subsp. vernus
Crocus vernus subsp. albiflorus
Series Versicolores
Series Crocus
B. Section Nudiscapus
Series Aleppici
Series Biflori
Series Carpetani
Series Flavi
Series Intertexti
Series Laevigatae
Series Orientales
Series Reticulati
Series Speciosi

2. Subgenus Crociris

Misuses of the name crocus

Though some true crocus bloom with the fall (autumn) rains, after summer's heat and drought, the name "autumn crocus" is often misused as a common name for Colchicum, which is in the lily family (Liliaceae), and which has six stamens; it is also (confusingly and incorrectly) known as "meadow saffron". The so-called "prairie crocus" (formerly Anemone patens, now Pulsatilla patens or P. ludoviciana) belongs to the buttercup family (Ranunculaceae).

References

  • 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

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