the Voyage of the Beagle is thought by some to be Silybum marianum. Cultivation Milk thistle is an adaptive crop with low requirements. It is mainly cultivated as a medicinal plant but it's also mentioned as a food source. It's mainly cultivated in Europe but also in Asia and North America. Milk thistle is a biennial plant, it is normally grown as a annual plant, which simplifies cultivation. This can be achieved when the main requirements are met, then the milk thistle already blossoms in the first year. Milk thistle has low soil requirements and is drought resistant. The optimal pH ranges from 5.5 to 7.6, but a wide range is acceptable. The seeds are directly sown into the soil with a sowing depth of 1 to 1.5 cm. For germination, a minimal temperature of 2 °C is needed. Sowing can be done in Autumn or in Spring, depending on the climate conditions. Row spacing is between 40 and 75 cm with a plant space of about 25 cm in the rows. Fertilization is not necessarily needed because of the low nutrient requirements. A standard fertilization rate of 50 kg nitrogen, 30 kg phosphorus and 60 kg potassium per hectare is applied before sowing, to improve yields. Harvest normally occurs in July or August. Since the flower heads don't ripen evenly, optimal harvest time is about a fortnight after 50% of the flower heads are dry. For harvesting a common cereal combine harvester can be used. In Poland, average yields are 1230 kg per ha with an average silmarin content of 26.5 kg per ha. Chemistry Traditional milk thistle extract is made from the seeds, which contain approximately 4–6% silymarin. The extract consists of about 65–80% silymarin (a flavonolignan complex) and 20–35% fatty acids, including linoleic acid. Silymarin is a complex mixture of polyphenolic molecules, including seven closely related flavonolignans (silybin A, silybin B, isosilybin A, isosilybin B, silychristin, isosilychristin, silydianin) and one flavonoid (taxifolin). Silibinin, a semipurified fraction of silymarin, is primarily a mixture of 2 diastereoisomers, silybin A and silybin B, in a roughly 1:1 ratio. Traditional medicine and adverse effects Although milk thistle has been used in traditional medicine for centuries, there is no clinical evidence that it has any medicinal effect, and the quality of research has been poor. Silymarin is extracted from the milk thistle seeds and available as a standardized extract. In 2019, Cancer