University of Tennessee
Forest Resources AgResearch and Education Center
Plants P and Q

Pawpaw (Asimina triloba)

Pawpaw blossom Attracting Beetle A planting of Pawpaws below the Program shelter began blooming in early April. Colonies of Pawpaw are also found along several trails, but these rarely bloom. Pawpaw is the northernmost member of the subtropical and tropical plant family Annonaceae. The bell-shaped flowers have six brown to purple petals. The stamens and pistils are borne on a raised receptacle. The flowers have a fetid smell that attracts beetles and flies as pollinators.

Pawpaw fruit The large, fleshy, edible fruit (up to 16 cm long) matures in September and October and has been described as having a taste similar to a mixture of banana, mango and pineapple. Pawpaws are eaten raw or processed into deserts such as pies and ice cream, though they may cause stomach trouble for some people. They are eaten by a variety of wildlife. Recent research indicates Pawpaw has potential as an anti-cancer drug and as a pesticide. It is found throughout the Eastern U.S., except in New England, and as far west as Nebraska.

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Persimmon (Diospyros virginiana)

Persimmon Fruit Persimmon is a moderately sized tree growing to 60 feet tall and 2 feet in diameter. It is the most northern member of the Ebony family - other members of the family are tropical or subtropical. A Persimmon tree found just above the end of the Tulip Poplar Trail is currently loaded with orange fruit that will become deep purple as they mature during the next few weeks.

Persimmons are dioecious - meaning that male and female flowers are found on separate trees. The leaves and fruits of the tree are astringent, and have been described as puckery. However, when mature, the fruits lose their astringent tannins and become sweet and delicious. The genus name Diospyros can be translated from the Greek as "food for the gods."

Persimmon is native to the Eastern U.S. - New England to Florida, west to Texas, Iowa, and Kansas. The bark is dark brown to black and is deeply divided into small blocks. The dense wood has been used for such purposes as golf club heads and billiard cues.

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Pink Lady's Slipper (Cypripedium acaule)

Pink Lady's Slipper Pink Lady's Slippers (also known as Moccasin Flowers) begin blooming at the Arboretum in late April and early May. These beautiful orchids, which are usually found in pine forests in our area, are gradually disapearing from the Arboretum as deciduous forests replace the pines.

The common names "Slipper" and "Moccasin" refer to the conspicuous pink pouch of the flower (the labellum). The flower attracts bees, which enter a slit down the front of the pouch; once inside, a bee must exit through the rear of the flower, thus ensuring pollination.

Over the years, Lady's Slipper populations on the White Pine Trail have been removed by vandals and have not become reestablished. Look for Lady's Slippers on the upper forested slope as you walk along the Marsh Road. If you are fortunate enough to see one of these plants, please stay on the road to avoid disturbing the plant or its habitat.

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Pipsissewa (Chimaphila maculata)

Pipsissewa Pipsissewa, also known as Striped or Spotted Wintergreen, is a small evergreen plant with whorls of 2-3 dark green leaves having light colored mid-veins borne mainly near the base of the stem. It bears 2-5 nodding white to pink, waxy flowers in June that mature into dry brown capsules later in the year. It is in bloom along the Oak-Hickory and Lost Chestnut trails beginning in early June. The evergreen leaves can be found on the forest floor throughout the year. This species is widely distributed from the north central and eastern U.S. and adjacent Canada south to Florida and Mississippi. A closely related species, Chimaphila umbellata (also known as Pipsissewa), does not have a light colored mid-vein and has a more northern and western distribution.

Pipsisewa The common name Pipsissewa is derived from the use of this herb by Native Americans and early settlers to treat kidney stones. It is touted by herbalists to have a variety of medicinal uses and has been used as flavoring for rootbeer and candy. Hunters have also found Pipsissewa as stomach contents in grouse during winter months, and it may be used as food by other birds and wildlife.

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Pitch Pine (Pinus rigida)

Pitch Pine The main distribution of Pitch Pine is in the Northeastern U.S., but it extends south along the Appalachians and adjacent Valley and Ridge physiographic province. Although it is not common in our area, several individuals, planted in 1965, can be seen near the Arboretum's Program Shelter.

Pitch Pine is most abundant on unfavorable sites having poor soils such as the Pine Barrens in New Jersey and low swampy areas on the Atlantic Coastal Plain. In East Tennessee, the species is found primarily on dry, rocky ridges.

Historically, Pitch Pine provided a source of pitch and timber for ship building. The high resin content of the wood makes it resistant to rot and suitable for use as mine timbers and railroad ties. Pitch Pine is now most commonly used for rough construction, pallets, crates, and fuel.

Pitch Pine Bark Pitch Pine Needles and Cones The needles of Pitch Pine are 2.5 to 5 in. long, borne in fascicles of 3. The cones are broad, up to 3.5 in. long and wide and have prickles on the thick cone scales.

Pitch Pine exhibits several adaptations to fire. Its thick bark can protect the tree from damage from light fires. Some of its cones are serotinous, an adaptation in which the cones do not open until subjected to heat from fires. Another interesting adaptation is its ability to regenerate vegetatively after disturbances such as fire from basal sprouting and epicormic branching (development of needles and short branches directly from dormant buds on the trunk or branches).

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Spruce Pine (Pinus glabra)

Spruce Pine A native of the Southeast Coastal Plain, Spruce Pine is found on moderately to poorly drained sandy soils in southern South Carolina, northern Florida, and along the Gulf Coast to Mississippi and Louisiana. A well-developed Spruce Pine specimen planted in 1965 can be seen near the Central China Collection.

Unlike many other pines, Spruce Pine is shade tolerant and may regenerate beneath a forest canopy. It can be used for pulp and rough lumber, but the wood is brittle and not particularly suitable for commercial use. It also is used as a landscape tree.

Spruce Pine Cones Black Alder Male Catkins Spruce Pine can grow to heights of 80-100 ft. The straight or slightly twisted, dark green needles are 2-3 in. long and borne in fascicles of 2. The bark of young trees is smooth and gray, but develops shallow ridges and fissures on older trees. The common name reflects the resemblance of the branching pattern and bark to spruce. The cones are about 2.5 inches in diameter and have small or no prickles at the tips of the scales. The seed cones develop over a 2-year period and may remain on the tree for 3-4 years.

Post Oak (Quercus stellata)

Post Oak Branch Post Oak, a small to medium sized tree, is mostly found along forest edges at the Arboretum. The heavy wood is resistant to decay and has a variety of uses such as railroad ties, mine timbers, and fence posts. Post Oak ranges from southern New England south to Florida and west to Kansas, Oklahoma, and Texas. It is tolerant of drought and is found on dry, sandy to rocky sites but also occurs on moister floodplains. In Texas and Oklahoma, Post Oak and Blackjack Oak are major components of the Cross Timbers - a dense forest of small trees forming the transition zone from forest to prairie grassland.

Post Oak Summer Leaf Post Oak Fall Leaf Its distinctive leathery leaves typically have five lobes, with the terminal three squarish lobes resembling a cross. The upper leaf surface is dark, shiny green in summer, while the lower surface is paler and covered with stellate (star-shaped) hairs. In the fall, leaves turn to a golden or bronze color.

Post Oak Bark Post Oak Acorns The bark is similar to White Oak but not as flaky in older trees. The light to dark brown acorns are less than 1 in. length, with a cap covering about 1/3 of the nut.

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Princess Tree (Paulownia tomentosa)

Princess Tree Princess Tree (Royal Paulownia, Empress Tree), a native plant of China, was introduced into the U.S. in the mid 1800's. It is found on Arboretum property but is more commonly seen along roadsides and disturbed sites throughout our region. Although still planted as an ornamental tree and used for reclamation of mine sites, it has become naturalized in many parts of the eastern U.S, and is considered an invasive species in many states, including Tennessee where it is listed as a severe threat by the Tennessee Exotic Pest Plant Council.

Princess Tree Flowers Princess Tree Leaf

Although considered a member of the Figwort family (Scrophulariaceae) by many taxonomists, Princess Tree has recently been assigned to its own family, the Paulowniaceae. It produces upright clusters of pink to lavender flowers up to 2 in. long. The large leaves (5 to 26 inches long) are oval to heart-shaped and densely hairy (tomentose) beneath. In the fall, thousands of seeds are dispersed from the dry, brown capsules. Princess Tree reproduces by seeds and root sprouts and grows very rapidly (up to 15 ft. a year). Once established it is difficult to eliminate. The wood is in high demand in Asia for a wide variety of uses such as carvings, musical instruments, jewelry boxes, veneer, furniture, water pails, and spoons. In the 1970's and 1980's, the demand for this high value wood resulted in extensive commercial planting of Princess Tree in the US and other countries for export to Japan.

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University of Tennessee - Forest Resources AgResearch and Education Center
901 South Illinois Avenue, Oak Ridge, Tennessee 37830 · Telephone: 865-483-3571 · Email: UTforest@utk.edu