Combretum glaucocarpum (Combretum glaucocarpum)

Description

Glaucocarpum is a monotypic plant genus containing the single species Glaucocarpum suffrutescens, a rare species of flowering plant in the mustard family known by the common names Uinta Basin waxfruit, waxfruit mustard, toad-flax cress, and shrubby reed-mustard. It is endemic to Utah in the United States, where it is known only from Duchesne and Uintah Counties. It is threatened by habitat degradation and destruction. It is federally listed as an endangered species of the United States. This is a perennial herb with multiple erect stems growing 10 to 35 centimeters tall from a woody base. The leaves are lance-shaped or somewhat oval in shape with smooth or slightly toothed edges, the blades measuring up to 2.5 centimeters in length. The inflorescence is a raceme of mustardlike flowers. Each flower has yellow-green sepals and four yellow petals each measuring about a centimeter long. The fruit is a curved silique 1 or 2 centimeters long. The plant is pollinated by several species of bees, likely including Dialictus perdifficilis, D. sedi, Evylaeus pulveris, Andrena walleye, A. prunorum and Halictus rubicundus. This mustard grows in the Uinta Basin on the Green River Formation, a geologic formation, in an area around the border between Duchesne and Uintah Counties in Utah. The substrate is a shallow layer of dry, fine clay and white calcareous shale. The area is a desert shrub or pinyon-juniper woodland plant community. The area is sparsely vegetated, but other plants in the habitat may include Barneby's catseye (Cryptantha barnebyi). There are seven populations of the plant located in three main areas. Five of the seven populations contain 250 or fewer plants. This plant is threatened by hydrocarbon exploration and the mining of oil shale and tar sands. All the populations of the plant are located on land which has been leased for oil and gas exploration. Its habitat is located over a large deposit of oil shale which may be a target for extraction. When the plant was added to the Endangered Species List, parts of populations had been destroyed during energy development activities. The populations are already somewhat isolated due to habitat fragmentation, which is increased by roads running through the area. Dust from the roads and from energy activity may negatively affect the plant in several ways. Some of the processes that affect the habitat and the plant also affect the plant's pollinators, such as bees. Other threats include off-road vehicle use, grazing, and the mining of surface rock for use as building stone.