Magnolia macrophylla
Magnolia macrophylla, the bigleaf magnolia, is a deciduous magnolia native to the southeastern United States. This species boasts the largest simple leaf and single flower of any native woody plant in North America.
Classification
Magnolia macrophylla is currently considered monotypic, with no subspecies or varieties. In the past, it was often treated as having two subspecies, subsp. ashei and subsp. dealbata, but these are now treated as separate species, Magnolia ashei in Florida, and Magnolia dealbata in eastern Mexico.Description
The bigleaf magnolia is a medium-sized understory tree tall, though some individuals over 27 m tall have been documented by the . This species is distinguished from other magnolias by the large leaf size, long and broad, with a stout petiole. The tree's branches often bend under the weight of this heavy foliage. The flowers typically have nine tepals, with three whorls of three tepals each, the larger ones with a purple spot at the base. The tepals are typically about long and wide. It is, like all Magnolias, beetle pollinated. The fruit is a cone-like cluster of achenes long. The mature seeds, each covered with an orange aril, hang down from the cone on silk-like threads, making themselves readily available to passing birds.Bee mortality
At the Arnold Arboretum, dead bees have been observed inside bigleaf magnolia flowers. However the bees in cited article are honeybees which are not native to North America.Distribution and habitat
Bigleaf magnolia is found in rich mesic woods; any disturbance that lets more light reach the ground is beneficial to the establishment of bigleaf magnolia, but despite its relatively fast growth-rate when stimulated by more light, other understory and canopy trees/seedlings are usually able to outgrow and out-compete it. This suits the plant just fine as it is tolerant of low light levels; it does not need full sun to survive once established. Natural regeneration is quite limited due to the scarcity of mature, seed-bearing plants and the fact that this tree's population mostly consists of widely scattered individuals. In addition, this species is plagued by poor seed set and low seed viability, a trait shared by its cousin and frequent associate in the wild in Appalachia, the Fraser magnolia.In the southeastern United States, especially Alabama and surrounding areas, Magnolia macrophylla is sometimes called the "cowcumber magnolia", in contrast with the much smaller-leaved cucumber-tree magnolia, M. acuminata.