Utricularia intermedia Hayne, U. ochroleuca R.W. Hartm., U. stygia Thor and U. bremii Heer ex Kölliker (Lentibulariaceae, Lamiales) are the four rarest and critically endangered European Utricularia (bladderwort) species from the generic section Utricularia. They are aquatic, submerged or amphibious carnivorous plants with suction traps which grow in very shallow, standing dystrophic (humic) waters such as pools in peat bogs and fens (also pools after peat or fen extraction), shores of peaty lakes and fishponds; U. bremii also grows in pools in old shallow sand-pits. These Utricularia species with boreal circumpolar distribution (except for U. bremii) are still commonly growing in northern parts of Europe (Scandinavia, Karelia) but their recent distribution in Central Europe is scarce to very rare following a marked population decline over the last 120 years. All species have very thin linear shoots with short narrow to filamentous leaves bearing carnivorous traps (bladders, utricles) 1−5 mm large. The first three species form distinctly dimorphic shoots differentiated into pale carnivorous ones bearing most or all traps, and green photosynthetic shoots with only a few (or without) traps, while the last species usually forms non-differentiated (monomorphic) or slightly differentiated shoots. The plants exhibit a marked physiological polarity along their linear shoots with rapid apical shoot growth. Their very high relative growth rate is in harmony with the record-high net photosynthetic rate of their photosynthetic shoots. Flowering of these species is common under favourable conditions and is stimulated by high temperatures but only U. intermedia sets seeds; the other species are sterile due to pollen malformation. Some molecular-taxonomic studies indicate that U. ochroleuca and U. stygia might be hybrids between U. intermedia and U. minor. All species propagate mainly vegetatively by regular branching and reach high relative growth rates under favourable conditions. All species form spherical dormant winter buds (turions). Suction traps actively form negative pressures of ca. -0.22 to -0.25 bar. The traps are physiologically very active organs with intensive metabolism: as a result of the presence of abundant glands inside the traps, which secrete digestive enzymes and absorb nutrients from captured prey carcasses (quadrifid glands) or take part in pumping water out of the traps and producing negative pressure (bifid glands), their aerobic respiration rate is ca. 2–3 times higher (per unit biomass) than that of leaves. Although oxygen concentrations inside reset traps are (almost) zero, traps are inhabited by many microscopic organisms (bacteria, euglens, algae, ciliates, rotifers, fungi). These commensal communities create a functional food web and in traps with captured macroscopic prey, they act as digestive mutualists and facilite prey digestion. Traps secrete a great amount of organic substances (sugars, organic acids, aminoacids) to support these commensals (‘gardening’). Yet the nutritional role of commensals in prey-free traps is still unclear. Quadrifid glands can also serve in the reliable determination of three species. Ecological requirements of U. intermedia, U. ochroleuca and U. stygia are very similar and include very shallow dystrophic waters (0−30 cm deep) with highly variable levels of dystrophy, common mild water level fluctuations, oligo-mesotrophic to slighly eutrophic waters, optimal pH values from 5.5 to 7.0 but always high free-CO₂ concentrations of 0.8–1.5 mM. Limited data indicate that U. bremii is partly a stenotopic species preferring only slightly acidic to neutral (pH 6–7), very soft to slightly hard, oligo-mesotrophic waters. Yet it can grow well both in strongly dystrophic and clear waters, in peat bogs as well as sand-pits over peaty soil and clayish sand. Long-term, very low water levels in combination with habitat eutrophication, whatever the reason, leading to peat bog and fen infilling, are the most common and unfavourable ecological threads at the most sites of the four rare Utricularia species. However, ecological consequences of high-water level at the sites can be ambiguous for the populations: it reduces the strongly competitive cyperoid and graminoid species but can speed up site eutrophication. All four species are considered (critically) threatened in European countries and are usually under official species protection or their sites are protected. Regeneration of infilled fens or peat bogs and creation of shallow fen pools and canals in these mires, combined with (re)-introductions of these species have shown to be a very successful and efficient measure to protect the natural populations for many decades. Old shallow sand-pit pools have become outstanding substitution habitats for the protection of U. bremii.

狸中间海恩，U. ochroleuca RW Hartm，U. stygia雷神和U. bremii希尔前Kölliker（狸藻科，唇形目）是四个最稀有和濒危的欧洲狸从通用部分（狸）种狸。它们是带有吸阱的水生，淹没或两栖食肉性植物，生长在非常浅的站立的营养不良（腐殖质）水域中，例如泥炭沼泽和中的水池（泥炭或提取后的水池），petty湖和鱼塘的海岸；布雷米（U. bremii）也生长在旧的浅沙坑中的水池中。这些乌拉圭利亚具有北半球极极分布的物种（除了U. bremii）在欧洲北部（斯堪的纳维亚半岛，卡累利阿）仍普遍生长，但由于过去120年来人口显着减少，它们最近在中欧的分布非常稀少。所有的物种都有非常细的线状芽，短而窄到丝状的叶子，长有1-5毫米的肉食性陷阱（膀胱，小囊）。前三个物种形成明显的双态芽，分化为带有大多数或所有陷阱的浅色肉食芽，以及只有几个（或不带）陷阱的绿色光合芽，而最后一个物种通常形成未分化的（单态）或轻度分化的芽。这些植物沿其线性枝条显示出明显的生理极性，并具有快速的顶芽生长。它们很高的相对生长速率与光合作用新芽的创纪录的净光合速率相一致。这些种类的花在有利条件下很常见，并且受高温刺激，但仅U. intermedia设置种子；由于花粉畸形，其他种类是不育的。一些分子分类学研究表明，U。ochroleuca和U. stygia可能是U. intermedia和U. minor的杂种。。所有物种主要通过规则分支无营养地繁殖，并在有利条件下达到较高的相对生长速率。所有种类都形成球形的休眠冬芽（假穗）。吸气阱会主动形成约负压。-0.22至-0.25 bar。诱捕器是具有很高代谢的生理上非常活跃的器官：由于诱捕器内部存在大量腺体，这些腺体会分泌消化酶并从捕获的pre体（四头腺）中吸收营养，或参与将水从诱捕器中抽出。产生负压（双腺体），其有氧呼吸速率约为 （每单位生物量）比叶片高2-3倍。尽管重置诱捕器内的氧气浓度（几乎）为零，但诱捕器被许多微观生物（细菌，藻类，藻类，纤毛虫，轮虫，菌类）。这些共同的社区创造了一个功能性的食物网，并在捕获了宏观猎物的陷阱中，充当了消化共生主义者并促进了猎物的消化。陷阱会分泌大量有机物质（糖，有机酸，氨基酸）来支持这些奖励（“园艺”）。然而，尚不清楚在无捕食陷阱中，营养成分的营养作用。四股腺也可以可靠地测定三种。的生态要求 然而，尚不清楚在无捕食陷阱中，营养成分的营养作用。四股腺也可以可靠地测定三种。的生态要求 然而，尚不清楚在无捕食陷阱中，营养成分的营养作用。四股腺也可以可靠地测定三种。的生态要求U.中间，U. ochroleuca和U. stygia非常相似，并且与营养不良的高度可变的水平，共同温和水位波动，寡中营养到性能稍微水域富营养化，最适pH包括很浅水域营养不良（0-30厘米深）值从5.5到7.0，但始终保持0.8-1.5 mM的高游离CO ₂浓度。有限的数据表明U. bremii是部分狭窄的物种，只偏酸性至中性（pH 6-7），极软至偏硬的中营养营养水。然而，它在营养不良和清澈的水域，泥炭沼泽以及在豌豆土和黏土中的沙坑中都能生长良好。从长期来看，与栖息地水体富营养化，无论是什么原因，导致泥炭沼泽和沼泽充填组合非常低的水位，是在四个罕见的大多数网站最常见的和不利的生态主题狸种类。但是，这些地点的高水位给人们带来的生态后果可能是模棱两可的：它减少了竞争激烈的类固形和类粒动物的种类，但可以加速富营养化。在欧洲国家，这四种物种都被认为（受到了严重威胁），通常受到官方物种保护，或者其所在地受到保护。在这些泥潭中，填充的ed或泥炭沼泽的再生以及浅池和运河的形成，再加上对这些物种的（重新）引入，已被证明是保护自然种群数十年的非常成功和有效的措施。旧的浅沙坑池已成为保护U. bremii的重要替代栖息地。