Magnolia tripetala, commonly called umbrella magnolia or simply umbrella-tree, is a deciduous tree native to the eastern United States in the Appalachian Mountains, the Ozarks, and the Ouachita Mountains. The name "umbrella tree" derives from the fact that the large leaves are clustered at the tips of the branches forming an umbrella-shaped structure.

Description

Umbrella magnolias have large shiny leaves 30–50 cm long, spreading from stout stems. In a natural setting the umbrella magnolia can grow 15 m tall. The flowers are large, appear in the spring, malodorous, These trees are naturally in rich and moist woods, along slopes, streams and ravines. The bark is thin and gray, mostly smooth and can have raised lenticels. Trees typically grow from single stems, though multiple stems are not uncommon. The flowers on M. tripetala have been described to have unpleasant smells but are not toxic to organisms. These trees grow at a moderate rate during the spring season.

Taxonomy

The name M. tripetala was originally described by Linnaeus in his Systema Naturae in 1759. It is most commonly known as the umbrella magnolia or the umbrella tree. Tripetala comes from Latin and means "three petals". This naming convention was used for the three petal-like sepals of the tree's flowers. Synonyms for M. tripetala include Kobus tripetala, Magnolia frondosa, Magnolia umbrella, Magnolia virginiana var. tripetala, and Magnolia umbrella var. tripetala.

Distribution and habitat

Umbrella magnolias have a native range from New York state to southern Florida. This range also expands as far west as Arkansas and parts of Oklahoma. It is located in deciduous forests of the Appalachian Mountains. Research has shown the species to be non-native to northern states such as Pennsylvania, and only being a recent arrival. Magnolia tripetala has been observed in forests outside its native range in multiple instances. Single individuals and small populations have been observed near areas where M. tripetala is in cultivation. Magnolia tripetala has been given the FACU wetland status, tending to prefer average to dry soil.

Notable trees

The largest known Magnolia tripetala is 15.2 m in height with a trunk diameter of 87 cm in Bucks County, Pennsylvania.

Uses

Magnolia tripetala contains a substance called ethyl acetate in its branches, and this substance displays nematicidal activity. This activity allows it to specifically resist Bursaphelenchus xylophilus, Panagrellus redivivus, and Caenorhabditis elegans. The hybrid has resulted in multiple hybrid variants, including the named 'Silk Road' and 'Silver Parasol' cultivars. The variants are described to be deciduous, medium trees with elliptic to ovate leaves. The leaves are 20-45cm by 10-22cm and the flowers are white, 16-25cm across at the end of branches. The cultivars have fruits with features such as number of follicles or stamen scars that are intermediate between the parent species.

<gallery mode="nolines" widths="200" heights="200">

File:Magnolia Tripetala Seedling.webp|Seedling

File:Magnolia Tripetala fruit1.jpg|Immature fruit and leaf details

File:Tree of Magnolia tripetala.jpg|Tree

File:Magnolia Tripetala fruit.jpg|Immature fruit

File:Magnolia tripetala fruit 2.jpg|Nearly mature fruit

File:Magnolia tripetala fruit.jpg|Mature fruit with seeds

</gallery>

Diseases

Umbrella magnolias are victim to pests such as magnolia scales or yellow poplar weevils. Magnolia scales infest and slowly kill branches of many trees, including species of magnolias. Yellow poplar weevils infest the leaves of magnolias and can cause mortality.

Conservation

Magnolia tripetala has a secure conservation status across multiple states in most of its native range. However there are multiple states where the tree is considered critically imperiled or exotic. Many states within the native range of M. tripetala have not assessed its endangerment status. States where there is no status ranking (SNR/SU/SNA) for M. tripetala include Missouri, Arkansas, Tennessee, Alabama, Georgia, South Carolina, Massachusetts, and Connecticut. States where the tree is considered secure (S5) include North Carolina, Virginia, West Virginia, and Kentucky. Magnolia tripetala is critically imperiled (S1) in Oklahoma, Mississippi, Florida, and Indiana. Global status for M. tripetala is secure (G5) as of 1991. Global status is in need of review.

Ecology

Magnolia tripetala most commonly lives in slope forests on north-facing slopes. Beetles enter buds of the flowers to feed on pollen and move this pollen from male parts of the flower to female parts. The male reproductive parts of the flower mature first.