Buddleja
Buddleja (; Buddleia; also historically given as Buddlea) is a genus comprising over 140 species of flowering plants endemic to Asia, Africa, and the Americas. The generic name bestowed by Linnaeus posthumously honoured the Reverend Adam Buddle (1662–1715), an English botanist and rector, at the suggestion of Dr. William Houstoun. Houstoun sent the first plants to become known to science as buddleja ("B. americana") to England from the Caribbean about 15 years after Buddle's death. Nomenclature. The botanic name has been the source of some confusion. By modern practice of botanical Latin, the spelling of a generic name made  from 'Buddle' would be "Buddleia", but Linnaeus in his "Species Plantarum" of 1753 and 1754 spelled it "Buddleja", with the long i between two vowels, common in early modern orthography. The pronunciation of the long i in "Buddleja" as "j" is a common modern error. The International Code of Botanical Nomenclature has gradually changed to incorporate stricter rules about orthographic variants and as of the 2006 edition requires (article 60, particularly 60.5) that Linnaeus' spelling should be followed in this case. Classification. The genus "Buddleja" is now included in Scrophulariaceae, having earlier been classified under Buddlejaceae (synonym: Oftiaceae) and Loganiaceae  Description. Of the approximately 140 species, nearly all are shrubs less than tall, but a few qualify as trees, the largest reaching . Both evergreen and deciduous species occur, in tropical and temperate regions respectively. The leaves are lanceolate in most species, and arranged in opposite pairs on the stems (alternate in one species, "B. alternifolia"); they range from long. The flowers of the Asiatic species are mostly produced in terminal panicles long; the American species more commonly as cymes forming small, globose heads. Each individual flower is tubular and divided into four spreading lobes (petals) about across, the corolla length  ranging from around 10 mm in the Asiatics to 3–30 mm in the American species, the wider variation in the latter because some South American species have evolved long red flowers to attract hummingbirds, rather than insects, as exclusive pollinators. The colour of the flowers varies widely, from mostly pastel pinks and blues in Asia, to vibrant yellows and reds in the New World, while many cultivars have deeper tones. The flowers are generally rich in nectar and often strongly honey-scented. The fruit is a small capsule about long and diameter, containing numerous small seeds; in a few species  (previously classified in the separate genus "Nicodemia") the capsule is soft and fleshy, forming a berry. Distribution. The genus is found in four continents. Over 60 species are native through the New World from the southern United States south to Chile, while many other species are found in the Old World, in Africa, and parts of Asia, but all are absent as natives from Europe and Australasia. The species are divided into three groups based on their floral type: those in the New World are mostly dioecious (occasionally hermaphrodite or trioecious), while those in the Old World are exclusively hermaphrodite  with perfect flowers. Cultivation and uses. As garden shrubs buddlejas are essentially 20th-century plants, with the exception of "B. globosa" which was introduced to Britain from southern Chile in 1774 and disseminated from the nursery of Lee and Kennedy, Hammersmith. Several species are popular garden plants, the species are commonly known as 'butterfly bushes' owing to their attractiveness to butterflies, and have become staples of the modern butterfly garden; they are also attractive to bees and moths. The most popular cultivated species is "Buddleja davidii" from central China, named for the French Basque missionary and naturalist Père Armand David . Other common garden species include the aforementioned "B. globosa", grown for its strongly honey-scented orange globular inflorescences, and the weeping "Buddleja alternifolia". Several interspecific hybrids have been made, notably "B." 'Lochinch' ("B. davidii" × "B. fallowiana") and "B. × weyeriana" ("B. globosa" × "B. davidii"), the latter a cross between a South American and an Asiatic species. Some species commonly escape from the garden. "B. davidii" in particular is an extensive coloniser of dry open ground; in urban areas in the United Kingdom, it often self-sows on waste ground or old masonry, where it grows into a dense  thicket. A number of agricultural organizations and governing authorities throughout the world have designated the plant as an invasive species or a "noxious weed". It is frequently seen in the United Kingdom beside railway lines, on the sites of derelict factories and other buildings and, in the aftermath of World War II, on urban bomb sites. This has earned it the popular nickname of "the bomb site plant". Popular garden cultivars include 'Royal Red' (reddish-purple flowers), 'Black Knight' (very dark purple), 'Sungold' (golden yellow), and 'Pink Delight' (pure pink). In recent years, much breeding work has been undertaken to  create seed sterile cultivars (see Non-invasive Buddleja cultivars). This is a particularly important consideration in the United States, where several states have banned "B. davidii" and its fertile cultivars because of their invasiveness. Unlike native "B. davidii", some of these non-invasive cultivars are small and compact, such as 'Blue Chip', which only reaches a height of and a width of . Buddleja collections. In Britain, there are four National Council for the Conservation of Plants and Gardens collections, held by: List of Buddleja species and naturally occurring hybrids. The many species of "Buddleja" have been the subject of much  taxonomic contention. The listing below includes the names, still prevalent in horticulture, of many former Asiatic species sunk by the late Toon Leeuwenberg as "Buddleja crispa" and adopted as such in the definitive "Flora of China". RHS Award of Garden Merit. The following Buddleja species and cultivars are (2017) holders of the Royal Horticultural Society's Award of Garden Merit: