User:Kaywhyy/Utricularia intermedia

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Utricularia intermedia, the flatleaf bladderwort or intermediate bladderwort is a small, perennial, carnivorous plant and is a member of one of three genera in the family Lentibulariaceae. The species is considered aquatic or semi-terrestrial and is found in still, shallow waters such as pools in peat bogs and fens or shores of lakes and ponds. It can reach up to 40cm tall, producing both photosynthetic shoots on which it bears most of its narrow, linear, imbricate leaves, and carnivorous shoots where the bladders/traps are found. Bright yellow flowers are produced from July to August, while subterranean bladders are found year-round. Since the species lacks roots, it is typically found free-floating below the water's surface, or attached to bottom sediments. U. intermedia is a circumboreal species, found mainly in northern parts of North America, Asia and Europe, with the exception of Iceland.

Description
Adult organisms can reach 30-40cm in deeper water but only 5-10cm long on dry soils. They have aquatic, leafy stolons and subterranean leafless stolons with bladders/traps. The species uses these bladders on underwater leaves to trap and digest a range of small insects, crustaceans or single-celled Paramecium. As perennial plants, they form turions at the end of the growing season which act as dormant storage organs to protect fragile parts of the plant from freezing and decay during the winter.

Stems
The stems of U. intermedia are dimorphic, or heterogeneous, as they grow both photosynthetic shoots and carnivorous shoots on which it bears its suction traps. Photosynthetic shoots of adult organisms grow mainly horizontally and can reach 6-24cm in length, while the carnivorous shoots typically grow to 5-12cm long in a downwards oblique position towards sediment. They can be further distinguished as the carnivorous shoots are a pale white to green color and bare most or all of the traps while the photosynthetic shoots are a green to dark red color, firmer, and bare few if any traps. New carnivorous shoots rise on both photosynthetic and carnivorous shoots while photosynthetic shoots can only rise directly from turions or as branches from carnivorous shoots.

Leaves
Leaves are numerous, 3-20mm long and polymorphic, differing depending on which stem they are found. Terrestrial photosynthetic leaves are narrowly linear, flattened, leathery, and overlap each other like shingles (imbricate). Leaf segments contain 4-12 small teeth, each of which has 1-2 small bristles on each side of the leaf margin. Leaves on submerged aquatic shoots are longer, narrower, thinner and more acute compared to their terrestrial counterparts. Leaf morphology also varies greatly based on ecological habitat and depend greatly on their respective shoot growth. Leaves found on below-ground carnivorous shoots lack chlorophyll, are filamentous, poorly branched and highly reduced.

Flowers
The inflorescence of U. intermedia is racemes of 3-5 bright yellow zygomorphic (bilateral) flowers. Flowering occurs from July to August when conditions are favorable and is further stimulated by high temperatures. The pedicles are 3-15mm long, about 4 times the length of their 1.5-4.0mm long bracts. Calyx lobes are 2.5-3.5mm long and 2.0-3.0mm wide. The corolla is irregular with a short tube. Lower lip is broad, slightly lobed and elevated at the base to block the throat of the tube. It is 5.5-18mm long and 7-20mm wide. The upper corolla lip is about half as long as the lower at 4-9mm long.

Pollen
Pollen grains of U.intermedia are radially symmetric and sub-oblate, meaning its polar axis is 5-25% shorter than its equatorial diameter. The polar regions differ slightly in size as one side is slightly wider.

Bladders
Bladders are small, hollow sacs used to trap and digest small organisms as a source of nutrients for the plant. The bladders of U. intermedia contain a sealed valve at one end which bear 4 hairs. When the hairs are touched by their prey, the valve opens up and the rush of water into the hollow cavity drags the small invertebrates inside. The quadrifid glands within the traps work to secrete digestive enzymes and absorb nutrients from prey. Additionally, bifid glands play a role in pumping water out of the traps by creating negative pressure. As such, they are very physiologically active organs with an intensive metabolism and an aerobic respiration rate 2-3 times higher (per unit biomass) than the leaves.

Distribution
U. intermedia is found most commonly in circumboreal regions of North America, and more rarely in Europe and Asia. In North America, it has been reported to be scattered through the west coast around British Columbia and considerably rarer in Oregon and Washington. Its distribution also extends to the east coast in Pennsylvania and New Jersey and well as Newfoundland and Labrador in Canada. Less common in Europe, the plants rarity is likely due to anthropogenic changes to reservoirs and watercourses that make their survival difficult. The species has been noted in the Ukrainian Carpathians and in other Central European sites in Poland, Czech Republic and Germany. In South Asia, it has been found in the Tian-Shan Mountains in Kyrgyzstan, the watershed of the Jinsha Jiang River in China and spread through Hokkaido and Honshu in Japan.

Ecology
U. intermedia shares similar habitats as other Utricularia species and is therefore often found growing together with species such as U. ochroleuca and U. stygia. It is also often found growing in habitats along with Sphagnum and sedges such as Carex rostrata and Carex elata. However, U. intermedia prefers more shaded microhabitats, which often differ from the surrounding habitat, suggesting it has a narrow optimal habitat range.