flowering and seed release, the stem and fruits usually persist in winter, drying into dark brown, stiff structures of densely packed, ovoid-shaped, and dry seed capsules. The dried stems may persist into the following spring or even the next summer. The plant produces a shallow taproot. Flowers are pentamerous with (usually) five stamen, a five-lobed calyx tube, and a five-petalled corolla, the latter bright yellow and an wide. The flowers are almost sessile, with very short pedicels (2 mm, 0.08 in). The five stamens are of two types, with the three upper stamens being shorter, their filaments covered by yellow or whitish hairs, and having smaller anthers, while the lower two stamens have glabrous filaments and larger anthers. The plant produces small, ovoid (6 mm, 0.24 in) capsules that split open by way of two valves, each capsule containing large numbers of minute, brown seeds less than 1 mm (0.04 in) in size, marked with longitudinal ridges. A white-flowered form, V. thapsus f. candicans, is known to occur. Flowering lasts up to three months from early to late summer (June to August in northern Europe), with flowering starting at the bottom of the spike and progressing irregularly upward; each flower opens for part of a day and only a few open at the same time around the stem. Taxonomy For the purpose of botanical nomenclature, Verbascum thapsus was first described by Carl Linnaeus in his 1753 . The specific epithet thapsus had been first used by Theophrastus (as , ) for an unspecified herb from the Ancient Greek settlement of Thapsos, near modern Syracuse, Sicily, though it is often assimilated to the ancient Tunisian city of Thapsus. At the time, no type specimen was specified, as the practice only arose later, in the 19th century. When a lectotype (type selected amongst original material) was designated, it was assigned to specimen 242.1 of Linnaeus' herbarium, the only V. thapsus specimen. The species had previously been designated as type species for Verbascum. European plants exhibit considerable phenotypical variation, which has led to the plant acquiring many synonyms over the years. Introduced American populations show much less variation. The taxonomy of Verbascum has not undergone any significant revision since Svanve Mürbeck's monographs in the 1930s, with the exception of the work of Arthur Huber-Morath, who used informal grouping in organizing the genus for the florae of Iran and Turkey to account for many