Taxonomy
- Kingdom: Plantae
- Clade: Angiosperms → Monocots
- Order: Liliales
- Family: Colchicaceae
- Genus: Colchicum
- Species: C. speciosum
- Authority: (Fisch.) Spreng.
Common names
Autumn crocus, Persian crocus, ornamental crocus.
Description
Colchicum speciosum is a herbaceous, perennial geophyte that grows from a flattened corm. Mature plants reach 20–30 cm in height. The species is notable for its large, funnel‑shaped flowers that appear in autumn, typically from September to November, before the emergence of foliage. Flowers are usually deep pink to violet with a contrasting white or pale throat; the tepals are reflexed, giving the blossom a goblet‑like appearance.
After flowering, a pair of narrow, linear leaves develop in spring. The leaves are glaucous, up to 30 cm long, and bear a conspicuous central rib. The plant produces a few to several seeds per flower; each seed is a small, dark brown, globular nutlet.
Distribution and habitat
The species is native to the mountainous regions of the Caucasus, northern Iran, and eastern Turkey. It occurs in open woodlands, meadow edges, and rocky slopes at elevations ranging from 1,000 to 2,500 m.
Cultivation
Colchicum speciosum is cultivated as an ornamental for its striking autumn flowers. It prefers a well‑drained, humus‑rich soil and a sunny to part‑shaded position. The corms are hardy in USDA hardiness zones 5–8, tolerating winter freezing to about –20 °C (–4 °F).
Propagation is most commonly achieved by dividing mature corms in late summer or by sowing seeds. Seed germination may be enhanced by a period of cold stratification (4–6 °C for 8–12 weeks).
Several cultivars have been selected for variation in flower color and size, including ‘Album’ (white flowers) and ‘Violet Queen’ (deep violet blooms).
Toxicity
All parts of the plant contain colchicine, a toxic alkaloid. Ingestion can cause severe gastrointestinal distress, organ failure, and may be fatal. Handling the plant is generally safe, but care should be taken to avoid ingestion or contact with broken skin.
Conservation status
The species has not been assessed for the IUCN Red List; it is not known to be under significant threat in its native range.
References
- Flora of the Caucasus, Vol. 5, 1971.
- Royal Horticultural Society, “Colchicum speciosum” plant profile.
- USDA Plant Database, Species Fact Sheet.
Note: Information presented reflects current consensus from reputable botanical and horticultural sources.
