Anchusa is a genus of roughly 35 species of annual, biennial, and perennial herbaceous flowering plants in the borage family (Boraginaceae), order Boraginales. The genus is native to Europe, North Africa, South Africa, and western Asia, and has been introduced in North America.
Plants in the genus share the typical characteristics of Boraginaceae: simple or undulate leaves densely clothed in stiff bristly hairs, and small radially symmetrical flowers arranged in axillary cymes that are simple or branched. The flowers are usually a vivid sapphire blue and hold their colour well; each bloom has five sepals fused at the base and five petals that form a slender upward-facing tube. The flowers are strongly attractive to bees and other pollinators. A few species produce pale yellow flowers, notably Anchusa ochroleuca (yellow alkanet).
Anchusa roots contain anchusin (also called alkanet-red), a red-brown resinoid pigment also present in the related genera Alkanna and Lithospermum. The pigment is insoluble in water but dissolves readily in alcohol, chloroform, and ether, and has historically been used as a dye and colouring agent.
The genus is divided into four subgenera — Anchusa, Buglossum, Buglossoides, and Buglossellum — which form two main subclades in molecular phylogenies. Anchusa sensu lato has been treated as also encompassing the subgenus Limbata, which differs markedly in floral morphology. Taxonomic revision is ongoing, with three of the four subgenera considered candidates for recognition as independent genera.
In horticulture, bugloss species are widely grown in trough and rock gardens, valued for their long-lasting blue flowers. The larvae of some Lepidoptera, including Coleophora pennella, feed on Anchusa species.
Etymology
The common name bugloss applied to several Anchusa species derives from the Greek bouglossos ("ox-tongue"), a reference to the rough, tongue-shaped leaves characteristic of the genus. The genus name Anchusa itself is from the Greek anchousa (ἄγχουσα), referring to the red cosmetic dye obtained from the plant's roots — the same word that gives rise to "alkanet".
Distribution
Anchusa is native across Europe, North Africa, South Africa, and western Asia, with approximately 35 accepted species distributed across these regions. Several species, including A. arvensis and A. officinalis, have been introduced and naturalised in North America.
Ecology
The tubular flowers of Anchusa are particularly attractive to bees, which are their primary pollinators. Several Lepidoptera larvae use Anchusa species as food plants, including Coleophora pennella.
Cultivation
Anchusa species are commonly cultivated in trough and rock gardens, where they are valued for their intense, long-lasting blue flowers. The perennial Anchusa azurea (Italian bugloss) is the most widely grown ornamental species.
Cultural Uses
The roots of Anchusa contain anchusin (alkanet-red), a red-brown resinoid dye that is insoluble in water but soluble in alcohol, chloroform, and ether. This pigment, shared with the related genera Alkanna and Lithospermum, has historically been used as a colouring agent for cosmetics, foodstuffs, and textiles.
