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NOTE FROM EDITORS: THIS IS A TEST ARTICLE UNDER DEVELOPMENT (Sept. 2019)
Taxonomic note Two geographic variants, var. ozarkensis and var. ludoviciana [AUTHORITIES NEEDED], named on account of their glabrous leaves or large flowers and tomentose leaves, have been sunk under the species name. Charles Sargent described var. ludoviciana from plants collected in West Feliciana, Louisiana, during 1914/15. The flowers were up to 10 cm long
Magnolia acuminata is a large, elegant, fast-growing deciduous tree which is widely distributed in eastern North America from Lake Erie in Canada to northern Florida [distribution details should be in the botanical description]. Its introduction to the British Isles is well documented. Peter Collinson, a Quaker linen draper from Peckham in London, was a garden enthusiast to whom like-minded people in America sent seeds and plants. One of these was John Bartram, a Quaker farmer, amateur physician, and self-taught botanist from Pennsylvania, who in July 1743 set out on a long journey from Pennsylvania to Lake Ontario. He kept a journal of this journey, three copies of which were sent to Collinson. Two never reached him, being taken by French privateers. The third, which was published by Collinson in 1751 under the title Observations … made on his travels from Pensilvania to the Lake Ontario, documents the discovery of M. acuminata. Its seeds were included in a selection of 100 species of seeds (mainly trees) that Bartram sent in a number of boxes to Collinson, who then distributed them to his patrons, including the dukes of Richmond, Bedford, and Norfolk and Lord Bute, who supplied the Dowager Princess of Wales with plants for Kew. Each box was initially priced at 5 guineas, which soon increased to 10. M. acuminata duly flowered for Collinson at Mill Hill on 20 May 1762.
In cultivation it develops into a large tree of upright pyramidal outline which broadens with age. In the British Isles it grows to nearly 30 m [TROBI records needed here] but it reaches its greatest height in the southern Appalachian Mountains. The largest specimen on record is 38 m in height with a spread of 18 m; it was found in the Great Smoky Mountains National Park in Tennessee. In the wild the plants show considerable variation in habit, from majestic straight stemmed columnar trees to multistemmed large shrubs or small trees. As a consequence, they vary in growth rate from 30 cm to 75 cm a year. The bark is a light brown to grey which often exfoliates. The plant gets its specific name from the shape of the large leaves, which taper to a point at the apex in the form termed ‘acuminate’. In autumn the autumn foliage varies considerably, depending on clones, from a dull dark brown to a bright butter yellow.
The rather small and insignificant flowers occur on leafy shoots from late May to July (from early April in its habitat). In colour they are a mixture of glaucous green and yellow, but colour forms can be found varying from a blue through to a yellow. A distinctly yellow-flowered form, M. acuminata var. aurea AUTH, has been collected from the Carolinas, Tennessee, Georgia, and possibly Alabama. This yellow coloration of the flower was perceived to be a potential gene source to raise a yellow-flowered hybrid on leafless stems. In 1977, the Brooklyn Botanic Garden patented ‘Elizabeth’, a hybrid between M. acuminata and M. denudata. For further information on M. ‘Elizabeth’ and other M. acuminata hybrids, please refer to M. acuminata hybrids, which include Brooklyn Botanic Garden and Phil Savage hybrids.
The popular name, Cucumber Tree, refers to the shape and colour of the fruits when they are young. These turn from bright green to red in autumn, but are not produced in sufficient quantity or size (7.5 cm) to rank as an ornamental feature.It is also known as Indian Bitter, described originally by François Michaux because a fusion of whisky with half ripe seed cones produced an extremely bitter liquid which was taken as a ‘preservative against autumnal fevers’.
It is probably the hardiest Magnolia species, being quoted as hardiness zone 4 in North America; the hardiest forms of all probably come from those plants found in New York State. In North America it is widely planted because of its ability to grow in a wide range of its soils, including alkaline ones, but it is not tolerant of drought. In its native environment it grows in deep, rich, moist soils with other deciduous trees such as Acer saccharum (the Sugar Maple) and Quercus alba (the White Oak). The timber is light and durable, close-grained, and of a light yellow-brown colour. It was formerly used by the North American Indians to make canoes and wooden bowls and is now used for flooring and cabinet work.
Magnolia acuminata is often used as an understock for grafting selected species or cultivars onto. This is common in the United States, where grafting magnolias is practised. However, in Scandinavia, where a number of magnolias are grown on their extreme limits of hardiness, M. acuminata is used as it is thought that it improves the scion’s cold hardiness ability.
There are several clones of M. acuminata in cultivation, and they are grown for their habit, hardiness, leaf and flower colour and shape.
A tree from Urbana, Illinois, with spreading branches and very good autumn leaf colour. Selected by Professor Joe McDaniel of Urbana.
An exceptionally ‘fecund’ seedling found in Northern Ohio by Phil Savage of Michigan. Used extensively in breeding programmes. Dr. August Kehr of Hendersonville, North Carolina, has named colchicine treated ‘Fertile Myrtle’ seedlings ‘Laser’ and ‘Patriot’ as both being more vigorous than the parent. ‘Laser’, with 16 sets of chromosomes, and ‘Patriot’ with 8 are being used for breeding programmes and not in their own right.