''Echium pininana'', commonly known as the tree echium, pine echium, giant viper's-bugloss, or tower of jewels, is a species of flowering plant in the borage family Boraginaceae. It is endemic to the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

, where it is restricted to the island of La Palma.Manuel Arechavaleta, S. Rodríguez, Nieves Zurita, A. García (Hrsg.):
Lista de especies silvestres de Canarias. Hongos, plantas y animales terrestres
' (''List of Forest Species of the Canary Islands''). 2009. Gobierno de Canarias, p. 151 ''Echium pininana'' is an

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

, and is listed in Appendix I to, and is therefore protected under, the Convention on the Conservation of European Wildlife and Natural Habitats. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''pininana'' is Latin for "small pine", though ''E. pininana'' is neither closely related to the pine, nor does it resemble that plant.

Description

Lifecycle

''Echium pininana'' is biennial or triennial, meaning each plant lives for only two or three years respectively. It is a monocarpic species; each plant flowers only once before dying.

Morphology

In their first year, plants produce a rosette of lanceolate leaves approximately in length, with silver hairs. Plants also produce a

trunk Trunk may refer to: Biology * Trunk (anatomy), synonym for torso * Trunk (botany), a tree's central superstructure * Trunk of corpus callosum, in neuroanatomy * Elephant trunk, the proboscis of an elephant Computing * Trunk (software), in rev ...

tall in their first year, which is covered with many lanceolate leaves. In their second (or third) year, plants produce a cone-like inflorescence up to high with a dense mass of leaves and small blue flowers. Between April and June, the flower spike can grow per day. Flowers are funnel-shaped, and each produce up to 1.4 μL of

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

, which is approximately 26%

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...

. Flowers at the bottom of the flower spike are first to open, with those at the top opening last. Pollinators such as

bees Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...

butterflies Butterflies are insects in the macrolepidopteran clade Rhopalocera from the Order (biology), order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The ...

, and

moths Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

are attracted to the flowers. Following pollination, each flower produces four nutlets. Each plant can produce over 200,000

seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...

, which are

disbursed A disbursement is a form of payment from a public or dedicated fund. Alternatively, it means a payment made on behalf of a client to a third party for which reimbursement is subsequently sought from the client. It is a term most commonly used by s ...

short distances by the wind.

Phytochemistry

Various pyrrolizidine alkaloids, a class of toxic organic compounds that may cause liver damage, have been isolated from ''Echium pininana.'' The plant is toxic to

horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...

Phylogeny

''Echium pininana'', '' E. simplex'', and '' E. wildpretii'' comprise a monophyletic clade. All three of these ''Echium'' species are monocarpic, have a similar habit, similar floral morphology, and produce a dimethylated

flavone Flavone is an organic compound with the formula . A white solid, flavone is a derivative of chromone with a phenyl (Ph) substituent adjacent to the ether group. The compound is of little direct practical importance, but susbstituted derivatives, t ...

not detected in other ''Echium'' species.

Distribution and habitat

''Echium pininana'' is endemic to the island of La Palma in the Canary Islands, where it grows in

laurel forest Laurel forest, also called laurisilva or laurissilva, is a type of subtropical forest found in areas with high humidity and relatively stable, mild temperatures. The forest is characterized by broadleaf tree species with evergreen, glossy and elo ...

s. It is endangered due to habitat loss caused by agriculture. Outside La Palma, ''Echium pininana'' has been introduced to France, Great Britain, Ireland, New Zealand (both North and

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

), and the United States (north and central coast of California). It is also in ''ex situ'' conservation; in fact, the ''ex situ'' conservation population is greater than the wild population. It is conserved in botanical gardens such as Kew Gardens in London, where it has

naturalised Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the in ...

Cultivation

''Echium pininana'' is cultivated as a garden ornamental, and has gained the Royal Horticultural Society's

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

. It is used as a bedding plant or planted in borders, and grows best in full sun. It is recommended for the southern maritime counties of England, the Channel Islands and the Scilly Isles. There are, however, reports of successful cultivation in the English Midlands and Yorkshire, albeit in favourable locations. Specimens are also grown in Dublin gardens at Howth and in the Irish National Botanic Gardens at Glasnevin. The plant also grows readily in North Wales where it seeds very widely. Although ''E. pininana'' is

half-hardy Hardiness of plants describes their ability to survive adverse growing conditions. It is usually limited to discussions of climatic adversity. Thus a plant's ability to tolerate cold, heat, drought, flooding, or wind are typically considered meas ...

in Britain and Ireland, it will self-seed to form clusters of plants, and it is suggested that by natural selection a hardier variety will emerge. The plant is most vulnerable to frosts in its first year. Because of its large leaves when partly grown, it is also very susceptible to wind damage. Hence a sheltered garden position is essential. ''Echium pininana'' 'Alba' is a cultivar with white flowers.

Notes

References

External links

Garden plant information
{{Taxonbar, from=Q164211 pininana Flora of La Palma Endemic flora of the Canary Islands Garden plants of Africa Plants described in 1844