The autumn crocus, or Colchicum autumnale, is a type of flower that resembles a true crocus — which generally flowers in the spring — but instead blooms in the autumn. It is a tough plant that can bloom even during or after a snowfall, and it is alternately known as "naked lady" since the bloom can happen long after the leaves have died. The autumn crocus contains chemicals used for medicinal purposes; these chemicals are also toxic.
A regular crocus falls into the iris family, and is a perennial flower, which means it blooms over the course of two or more years without having to be replanted. The autumn crocus, however, is part of the Colchicaceae family but is similarly a hardy plant. It grows in a variety of conditions, from woodlands to meadows, and is a hardy flower that can live and bloom through adverse conditions. While crocuses are more commonly seen blooming in the spring — they are a popular choice of gardeners because they are hardy enough to bloom early — they can also bloom in the autumn, making the distinction between a regular crocus and a true autumn crocus difficult to identify.
The autumn crocus grows from a corm, which is an underground bulb that acts as a base for the plant. The corm is essentially a storage unit for the plant that allows the plant to survive in harsh conditions, and it differs from a true bulb in both texture and function. When the plant flowers from this base, the petals are usually a shade of pink or white.
Chemicals within the plant have been used for centuries to treat certain medical conditions. The autumn crocus contains colchicine, which can relieve symptoms of gout and arthritis. The chemical affects cell division, and it has been tested for use in treating forms of cancer; doctors found it was too toxic in the doses necessary to effectively treat the disease. Colchicine is a powerful anti-inflammatory, and while it can be useful for some purposes, it can be extremely harmful to others, especially young children. The compound can cause defects in fetuses, as well, and can have severe side effects on adults.
Ingesting the autumn crocus can be toxic. Since it looks very similar to a regular crocus, accidental ingestion can happen; the corm can also resemble a wild onion, further causing confusion. The plant is extremely toxic, however, and if ingested, it can cause kidney failure within hours. It is important to distinguish between the safe crocus and the harmful autumn crocus before using for cooking or ingestion.