Plagiobothrys greenei is a species of flowering plant in the borage family known by the common name Greene's popcornflower. It is native to Oregon and northern California, where it grows in moist woodland and grassland habitat. It is an annual herb with a spreading or erect stem growing 10 to 40 centimeters long. The leaves along the stem are 1 to 5 centimeters long and the herbage is coated in rough hairs. The inflorescence is a series of tiny flowers with white five-lobed corollas no more than 3 millimeters wide. The fruit is a minute nutlet with a surface covered in long prickles.

Plagiobothrys humistratus is a species of flowering plant in the borage family known by the common names dwarf popcornflower or low popcornflower. It is endemic to the Central Valley of California, where it grows in grassland habitats, including vernal pools and other wetland areas. Plagiobothrys humistratus is an annual herb growing prostrate, with stems extending up to 40 centimeters in length. The leaves along the stem are 3 to 8 centimeters long and coated in rough hairs. The inflorescence is a series of tiny white flowers accompanied by bracts. Each five-lobed flower is 1 or 2 millimeters in length. The fruit is a narrow oblong nutlet under 3 millimeters in length, often coated in minute bristles. Plagiobothrys humistratus is an annual herb growing prostrate, with stems extending up to 40 centimeters in length. The leaves along the stem are 3 to 8 centimeters long and coated in rough hairs. The inflorescence is a series of tiny white flowers accompanied by bracts. Each five-lobed flower is 1 or 2 millimeters in length. The fruit is a narrow oblong nutlet under 3 millimeters in length, often coated in minute bristles.

Plagiobothrys leptocladus is a species of flowering plant in the borage family known by the common names finebranched popcornflower and alkali plagiobothrys. It is native to western North America from Alaska to the Dakotas to northern Mexico, where it can be found in varied types of wet habitat, including inundated alkali flats and vernal pools. It is an annual herb growing mostly decumbent with stems 10 to 30 centimeters long. It is hairless to roughly hairy in texture. The leaves along the stem reach 10 centimeters in length near the base. The inflorescence is a series of tiny white flowers each 1 or 2 millimeters wide. Each is surrounded by a calyx of bent, ribbed sepals. The fruit is a lance-shaped nutlet.

Plagiobothrys mollis is a species of flowering plant in the borage family known by the common name soft popcornflower. It is native to Oregon, Nevada, and the Sierra Nevada of California, where it grows in scrub and grassy habitat, especially in moist and wet areas. It is a perennial herb producing small, decumbent stems running along the ground and rooting at nodes. It is very hairy in texture, the hairs soft and long. The leaves on the stem may be arranged alternately or oppositely. The inflorescence is a series of tiny white flowers up to 1 centimeter wide. It is a perennial herb producing small, decumbent stems running along the ground and rooting at nodes. It is very hairy in texture, the hairs soft and long. The leaves on the stem may be arranged alternately or oppositely. The inflorescence is a series of tiny white flowers up to 1 centimeter wide. Varieties: There are two varieties of this plant. Most incidences are var. mollis. The other variety, var. vestitus, is known only from the type specimen collected in the 19th century near Petaluma, California. It has not been seen since, and is presumed extinct.

Plagiobothrys nothofulvus is a species of flowering plant in the boraginaceae family known by the common names rusty popcornflower and foothill snowdrops. It is native to western North America from Washington, and California, to northern Mexico. It is a spring wildflower in grassy meadows, woodlands, coastal sage scrub, and wetland-riparian habitats. Plagiobothrys nothofulvus is native to parts of the Pacific Northwest. It ranges from northern California and into southern Washington. Populations have been reported as far south as Baja California, Mexico and north to the Columbia River Gorge. Habitat. Grassy meadows, especially those along the coast, are the most common habitat for Plagiobothrys nothofulvus. It can also be found in woodlands, coastal sage scrub, and wetland-riparian habitats and are often associated with serpentine or plutonic soils. Other species that commonly grow in similar grassland habitats and are often associated with Plagiobothrys nothofulvus include Aster chilensis, Lotus angustissimus, Plantago lanceolata, Galium parisiense, Brodiaea terrestris, and other native herbs. Etymology. The scientific name of the rusty popcorn flower, Plagiobothrys nothofulvus, describes some of its key characteristics. Plagiobothrys refers to a sideways pit formed by the position of the nutlet attachment scar. Lagiobothrys nothofulvus is food for many different animals. Deer, ground squirrels, and insects often forage on the plant. Turtles will also feed on the flowers in riparian zones. Black seed-harvesting ants will eat the seeds of popcorn flowers. Species of beetles will use the flower as a breeding platform. Butterflies, moths, and bees drink its nectar as they pollinate the flowers. Ctenuchid moths are frequently found on the flowers, the importance of their interactions is currently unknown. Reproduction. The flowers of Plagiobothrys nothofulvus generally bloomfrom February - April. Plagiobothrys nothofulvus is a federally listed endangered species in Oregon. The major threat to Plagiobothry nothofulvus is habitat loss by the transformation of its historical range to agricultural land. The loss of seasonal wetlands by habitat degradation and changing climate as well as the introduction of invasive species also pose large threats to the rusty popcorn flower. Efforts to restore the population include establishing protected populations, saving seeds, providing education to land owners, and restoring natural habitats.

Plagiobothrys stipitatus is a species of flowering plant in the borage family known by the common name stalked popcornflower and stipitate forget-me-not. It is native to Oregon and most of California, where it grows in vernal pools and similar wet habitat types. It is an annual herb producing a narrow, hollow, erect stem up to half a meter tall. It is coated in rough hairs. The pointed, hairy leaves along the stem are up to 11 centimeters long. The inflorescence is a series of five-lobed white flowers 2 millimeters to over one centimeter wide. The fruit is a narrow, ribbed nutlet.

Plagiobothrys tenellus is a species of flowering plant in the borage family known by the common names Pacific popcornflower and slender popcornflower. It is native to western North America from British Columbia to Mexico, where it is a common member of the flora in several types of habitat. Plagiobothrys tenellus is an annual herb producing several erect stems up to about 30 centimeters tall. It is very hairy in texture, the hairs long and white. The leaves are located in a basal rosette around the stem and there are a few smaller ones along the stem itself. The inflorescence is a coiling branch bearing many small five-lobed white flowers. Each flower is 1 to 3 millimeters wide. The fruit is a tiny cross-shaped nutlet covered in bumps and grooves. Plagiobothrys tenellus is an annual herb producing several erect stems up to about 30 centimeters tall. It is very hairy in texture, the hairs long and white. The leaves are located in a basal rosette around the stem and there are a few smaller ones along the stem itself. The inflorescence is a coiling branch bearing many small five-lobed white flowers. Each flower is 1 to 3 millimeters wide. The fruit is a tiny cross-shaped nutlet covered in bumps and grooves.

Plantago elongata is a species of plantain known by the common names prairie plantain and slender plantain. It is native to much of western North America, from British Columbia to California and as far east as Minnesota. It grows in wet habitat, such as vernal pools and wet meadows, including areas with saline and alkali soils, such as beaches. Plantago elongata is a petite annual herb producing a few narrow linear or threadlike basal leaves up to 10 centimeters long. The stemlike inflorescences grow erect to a maximum height around 18 centimeters. Atop the peduncle of the inflorescence is a spike of several tiny flowers each with a rounded or oval calyx of sepals covered with thick, fleshy green bracts.

Plantago eriopoda is a species of plantain known by the common name redwool plantain. It is native to much of western and central North America from Alaska to the southwestern United States to the Great Lakes region, where it can be found in moist and wet habitat types, sometimes in alkaline soils. It is a perennial herb producing a clump of lance-shaped to narrow oval leaves up to 25 centimeters long. The leaves may have slightly toothed edges and often have a coating of woolly red hairs near their bases. The stemlike inflorescences grow erect to a maximum height near half a meter. Atop the peduncle of the inflorescence is a dense cylindrical spike of many tiny flowers. Each flower has a whitish corolla with four lobes each about a millimeter long accompanied by sepals covered with small bracts.

Goose Tongue (Plantago maritima var. juncoides) is a native perennial herb that grows in central and northern California. It tends to grow in wet places, at elevations from - feet.

Plantago subnuda is a species of plantain known by the common name tall coastal plantain. It is native to western North America from the west coast of the United States to west-central Mexico, where it grows in wet and moist habitat types, often in coastal areas, such as marshland. It is a perennial herb producing few oval leaves around a thick caudex. The broad smooth-edged or slightly toothed leaves may be up to 40 centimeters long. The stemlike flower clusters grow erect to a maximum height near half a meter. Atop the peduncle of the flower cluster is a dense cylindrical spike of many tiny flowers. Each flower has a corolla of ephemeral petals about 3 millimeters long.

Sierra Bog Orchid (Platanthera dilatata var. leucostachys) is a native perennial herb that grows in northern, southern and central California. It tends to grow at elevations from 0-11000 feet.

Platanthera sparsiflora is a species of orchid known by the common name sparse-flowered bog orchid. It is native to the forests and meadows of the western United States (Colorado and New Mexico west to California, plus Washington and Oregon), and also south to Baja California. Platanthera sparsiflora can be found in wet habitats. It produces a slender, erect flowering stem up to about half a meter tall. The longest leaves near the base of the stem are up to 15 centimeters long by 3 wide. The inflorescence has widely spaced twisted green flowers with petals up to a centimeter in length.

Platanthera tescamnis, the intermountain bog orchid, is a species of orchid described in 2006. The plant is well-known but had been misidentified. It is native to the Great Basin and Colorado Plateau of the western United States (Colorado, Utah, Arizona, Nevada, California), where it grows in warmer, drier habitat than most related orchids. Platanthera tescamnis produces a slender, erect flowering stem which may exceed one meter (3. 3 feet) tall. There are several leaves around the base of the stem, lance-shaped to oval and measuring up to 29 centimeters long by 5 wide. The inflorescence is a dense spike of many small yellow-green flowers.

Platanus wrightii, the Arizona sycamore, is a sycamore tree native to Arizona and New Mexico with its range extending south into the Mexican states of Sonora, Chihuahua, and Sinaloa. The tree is a large deciduous tree, growing up to 70 ft. The Arizona sycamore is a tree of central Arizona's transition zone in the Mogollon Rim-White Mountains. The range extends into southwest New Mexico and parts of Sonora, Chihuahua, and Sinaloa in Mexico. In Arizona the range extends south towards northern Sonora. The range in southeast Arizona is a northeasterly part of the Sonoran Desert, and is at the northern region of the Sierra Madre Occidental cordillera. Arizona sycamore is prevalent in riparian areas of the Madrean Sky Islands, mountain sky islands in southeast Arizona, extreme southwest, Bootheel region of New Mexico, northeastern Sonora, and extreme northwest Chihuahua). The species is more prevalent west of the Madrean Sky Islands region, still in the central and northeast Sonoran Desert, an area around the Organ Pipe Cactus National Monument at the Arizona-Sonora border, with the species range extending in Sonora in the Occidentals, or its western foothills. Scattered reports have been made farther east in the Sierra Madre Occidental.

Pleuropogon californicus is a species of grass known by the common name annual semaphoregrass. It is endemic to northern California, where it grows in moist woodland and forest habitat, including redwood forests and nearby wetlands. Pleuropogon californicus is an annual or perennial bunch grass growing decumbent or erect in clumps of stems up to nearly 1 metre (3. 3 ft) in maximum height. Pleuropogon californicus is an annual or perennial bunch grass growing decumbent or erect in clumps of stems up to nearly 1 metre (3. 3 ft) in maximum height. The inflorescence bears widely spaced narrowly cylindrical spikelets which hang sideways off the stem, resembling semaphore signals. Each spikelet may be up to 5 centimeters long and may contain 20 flowers.

Pleuropogon hooverianus is a rare species of grass known by the common name North Coast semaphoregrass. It is endemic to northern California, where it is known from Mendocino, Marin, and Sonoma Counties. It grows in moist marshy areas and shady forests. It is a erect perennial grass growing to a maximum height between one and 1.6 meters. The flower cluster bears widely spaced narrowly cylindrical spikelets which hang sideways off the stem, resembling semaphore signals. Each spikelet may be up to 4.5 centimeters long and may contain up to 16 flowers.

Pluchea odorata is a species of flowering plant in the aster family, Asteraceae, that is native to the United States, Mexico, Central America, the Caribbean, and northern South America. Common names include Sweetscent, Salt Marsh Fleabane, and Shrubby Camphorweed. It inhabits wetlands and other coastal habitats and moist inland areas, often in saline substrates. It is an introduced species and a noxious weed in Hawaii. It is an annual or perennial herb growing erect to a maximum height over one meter. It is hairy, coated in rough trichomes (hairs), and strongly aromatic. The toothed oval leaves are up to 12 centimeter (4.7 inches) long and alternately arranged on the stiff stems. The flower cluster is a large cluster of many flower heads. Each head is less than 1 centimeter (0.39 inches) long and filled with bright pinkish-purple or magenta flowers. The fruit is a tiny achene tipped with a bristly pappus.

Pluchea sericea, commonly called Arrowweed, is a rhizomatous evergreen shrub of riparian areas in the lower Sonoran Desert and surrounding areas. It is common in the lower Colorado River valley of California, Nevada and Arizona, as far east as Texas, and in northern Mexico where it often forms dense impenetrable thickets. It was once used medicinally by Native Americans as an antidiarrheal and eyewash. Other traditional uses include thatching, arrowmaking and food, especially the edible root.

Poa leptocoma is a species of grass known by the common names marsh bluegrass and western bog bluegrass. It is native to western North America from Alaska to New Mexico, where it grows in subalpine and alpine climates and the Arctic. It is also known from the Kamchatka Peninsula. Poa leptocoma grows in moist habitats, including meadows and land next to lakes, ponds, and streams. It is a perennial grass growing in loose clumps with stems up to 70 to 100 centimeters in maximum height. The inflorescence is a series of branches bearing spikelets, the branches growing appressed to the stem and then spreading out and drooping from the stem as the spikelets mature. The spikelets are green to blue to dark purple in color. Poa leptocoma grows in moist habitats, including meadows and land next to lakes, ponds, and streams. It is a perennial grass growing in loose clumps with stems up to 70 to 100 centimeters in maximum height. The inflorescence is a series of branches bearing spikelets, the branches growing appressed to the stem and then spreading out and drooping from the stem as the spikelets mature. The spikelets are green to blue to dark purple in color.

Pogogyne douglasii is a species of flowering plant in the mint family known by the common name Douglas' mesa mint. It is endemic to central California, where it grows in vernal pools and similar grassland habitat in the coastal and inland mountain ranges and the Central Valley. This is an aromatic annual herb producing a sturdy, erect stem up to about 40 centimeters in maximum height. The flower cluster is a headlike cluster, each flower accompanied by long, pointed sepals lined densely with long, straight, white hairs. Each lipped tubular flower is 1 to 2 centimeters in length and mostly pinkish-purple with a white throat spotted with purple and sometimes yellow.

Douglas' Mesamint (Pogogyne douglasii ssp. parviflora) is a native annual herb that grows in central and northern California.

Pogogyne serpylloides is a species of flowering plant in the mint family known by the common names thymeleaf mesamint and thymeleaf beardstyle. It is endemic to central California, where it grows in grassy habitat in coastal and inland mountain ranges and foothills. It is a petite aromatic annual herb growing decumbent or upright, often reaching no more than a centimeter in height even when erect in form, sometimes larger. The slender stem is sometimes branched. The inflorescence is a series of rounded, headlike clusters, with occasional single flowers emerging at leaf axils. The tiny tubular flower is 2 to 5 millimeters long and has a lobed, lipped mouth. It is lavender in color, sometimes with faint white markings in the mouth.

Polemonium occidentale is a species of flowering plant in the phlox family known by the common name western Jacob's-ladder. There are two subspecies. The common ssp. occidentale is native to western North America from British Columbia to Colorado to California, where it can be found in moist areas of many habitat types, including meadows and woodlands. There is also a rare subspecies, ssp. lacustre, which is known only from a total of three counties in Minnesota and Wisconsin, and is found only in white cedar swamp habitat there. This is a rhizomatous perennial herb producing an erect stem up to one meter tall. The leaves are located along the stem, each divided into many small lance-shaped leaflets. The flower cluster is an open, elongated array of several bell-shaped, five-lobed flowers each up to 1.5 centimeters long. The flower corolla is blue to bright purple with a white throat.

Polyctenium fremontii, the desert combleaf, is named both in English and Greek for its deeply lobed leaves, which almost appear to be pinnately compound. It takes the other portion of its scientific name from John C. Frémont. It is a small and compact plant native to the western United States. Leaves have forked hairs, and the distal end of the leaf often has a single hair at the very tip. It is a member of the broccoli family, and the white flowers therefore have four petals in the shape of a cross. The flowers appear in clusters at the ends of the stems. This plant is rather uncommon, but is among the first plants of sagebrush country in the inland western U. S. to bloom in spring. It is found on the banks of seasonal streams and similar places.

Polygonum minimum is a species of flowering plant in the knotweed family known by the common name broadleaf knotweed. It is native to much of western North America where it can be found in mountainous regions. It grows in the subalpine and alpine climates of high mountain ranges from Alaska to Arizona and New Mexico. Polygonum minimum is an annual herb producing slender, stiff, zigzag-angled reddish stems up to 30 centimeters (1 foot) long, growing prostrate or erect. The leaves are lance-shaped to widely oval or nearly round and are located all along the stems but most crowded near the tips. Inflorescences occur in the leaf axils, each bearing one or more five-lobed white flowers. Polygonum minimum is an annual herb producing slender, stiff, zigzag-angled reddish stems up to 30 centimeters (1 foot) long, growing prostrate or erect. The leaves are lance-shaped to widely oval or nearly round and are located all along the stems but most crowded near the tips. Inflorescences occur in the leaf axils, each bearing one or more five-lobed white flowers.

Polygonum parryi is a species of flowering plant in the knotweed family known by the common names Parry's knotweed and prickly knotweed. It is native to the western United States from Washington to California, where it grows in several types of moist, open habitat in mountainous and coastal areas. Polygonum parryi is a small annual herb forming mats or cushions of short, angled stems growing erect up to 7 or 8 centimeters (2. 8-3. 2 inches) in height. The greenish brown stems are lined densely and evenly with linear, spine-tipped leaves. The lowest leaves are longest, reaching up to 2 centimeters (0. 8 inches) long, while leaves near the branch tips are small and scale-like. Each leaf has a thin, wide stipule which forms a fringed, fibrous ochrea around the base of the leaf. White flowers less than 2 millimeters (0. 08 inches) wide occur in the leaf axils. Polygonum parryi is a small annual herb forming mats or cushions of short, angled stems growing erect up to 7 or 8 centimeters (2. 8-3. 2 inches) in height. The greenish brown stems are lined densely and evenly with linear, spine-tipped leaves. The lowest leaves are longest, reaching up to 2 centimeters (0. 8 inches) long, while leaves near the branch tips are small and scale-like. Each leaf has a thin, wide stipule which forms a fringed, fibrous ochrea around the base of the leaf. White flowers less than 2 millimeters (0. 08 inches) wide occur in the leaf axils.

Populus angustifolia is a species of poplar tree known by the common names Narrowleaf Cottonwood and Willow-leaved Poplar. This tree is native to the Great Basin in the United States where it is most often found by streams and creeks at some elevation. The tree is slim in profile, with yellow-green lance-shaped leaves-(lance-shaped), with scalloped margins. The catkins are fluffy and white. The buds are sticky and gummy and were enjoyed as a sort of chewing gum by local Native American peoples, including the Apache and Navajo.

Fremont Cottonwood (Populus fremontii ssp. fremontii) is a native tree that grows in northern, southern and central California. It tends to grow in alluvial bottomplands and streamsides, at elevations from 0-6500 feet.

Populus tremuloides is a deciduous tree native to cooler areas of North America. The species is referred to as Quaking Aspen, Trembling Aspen, and Quakies, names deriving from its leaves which flutter in even a slight breeze. The tree can become tall, up to 25 meters, but is more often half that height, with smooth pale bark scarred with black. The glossy green leaves, dull beneath, become golden to yellow, rarely red, in Autumn. The species rarely flowers, often propagating through its roots to form large clonal groves. The quaking or trembling of the leaves is due to its flattened petioles. The specific epithet, tremuloides, is given for this trembling characteristic. Other species of Populus have petioles flattened partially along their length, while the Quaking Aspen's are flattened from side to side along the entire length of the petiole. This quaking of the leaves produces a soft sound that many consider a hallmark of the Quaking Aspen. It can be found in many parts of North America. In California it is most common in the Sierras and other high elevation mountains. Nurseries usually sell only male plants because female plants can produce large amounts of cottony seeds. Unless you have acreage, use caution in planting this tree because it will send out suckers long distances to quickly form a dense grove that will fill in any moist area. There are usually few understory plants in Quaking Aspen groves.

Black Cottonwood (Populus balsamifera ssp. trichocarpa) is a native tree that grows in northern, southern and central California. It is fast growing and moderately long-lived. It grows in an upright form to a height of 100 feet, with active growth during the spring and summer. Flowers are yellow and bloom in the mid spring. Leaves are medium green and deciduous. It tends to grow in alluvial bottomplands and streamsides, at elevations from 0-9000 feet. Tough and easy to grow as long as it is in sun, near a water sources and has very good drainage. Black Cottonwood is a great choice to help build a natural irrigation system - its long shallow roots will reach out to the water source and pull underground water molecules through your garden. It needs moist soil until mature, and then becomes moderately drought tolerant.

Porterella is a monotypic genus of flowering plants in the bellflower family containing the single species Porterella carnosula, which is known by the common name fleshy porterella, or simply porterella. It is native to the western United States from California to Wyoming, where it grows in moist spots, such as ponds or wet grasslands, sometimes just at the edge of the water or partially submerged. It is an annual herb producing an erect stem to a maximum height around 30 centimeters. The leaves along the stem are oval or triangular, those growing beneath the surface of the water more triangular in shape. They measure up to 1. 5 centimeters long by half a centimeter wide. The inflorescence bears showy flowers which are quite similar in appearance to those of some species in sister genus Downingia. Each has a narrow tubular throat opening into a wide corolla with two narrow pointed upper lobes and three wider, rounded lower lobes each with a small tooth. The upper lobes are deep blue, and the lower lobes are a similar shade with an area of white and bright yellow near the throat. The stamens are fused into a single unit tipped with tiny toothlike anthers.

Potamogeton alpinus is a species of perennial aquatic plant known by the common names alpine pondweed and red pondweed. It is widespread in the northern hemisphere in both rivers and lakes with good water quality. Red pondweed is native to much of the Northern Hemisphere, including Asia (Afghanistan, China (Heilongjiang), India (Assam), Japan, Kazakhstan, Korea, Myanmar, Pakistan, Russia, Uzbekistan), Europe (Austria, Belgium, Britain, Denmark, Estonia, France including Corsica, Germany, Ireland, Iceland, Latvia, Lithuania, Netherlands, Norway, Poland, Spain (Pyrenees), Sweden, Switzerland), Greenland, Canada, and the northern United States, especially the Rockies. Potamogeton alpinus generally grows in neutral to mildly acid (but not very base-poor) water bodies such as lakes, slow-moving rivers and streams, and ponds. P. alpinus needs a deep fine substrate such as sand, silt or peat to root in and appears to avoid exposed situations. It is, mainly restricted to fairly nutrient-poor waters.

Potamogeton amplifolius, commonly known as largeleaf pondweed or broad-leaved pondweed, is an aquatic plant of North America. It grows in water bodies such as lakes, ponds, and rivers, often in deep water. This perennial plant grows from rhizomes and produces a very slender, cylindrical, sometimes spotted stem up to a meter or so long. The leaves take two forms. Submersed leaves are up to 20 centimeters long by 7 wide and may be folded along their midribs. The submersed leaves have more veins than do those of other pondweed species, up to 49. Floating leaves are up to 10 centimeters long by 5 wide, leathery in texture, and borne on long petioles. The inflorescence is a spike of many flowers rising above the water surface on a thick peduncle.

Potamogeton berchtoldii, common name small pondweed is an aquatic plant. Potamogeton berchtoldii is native to Europe (including Britain, Ireland, continental Europe, Scandinavia), the Middle East, North America (Canada, USA), Asia (Bhutan, China, Japan, Kazakhstan, Korea, Tajikistan, Turkmenistan, Russia, Uzbekistan), Asia Minor and the Middle East (Iraq, Iran, Turkey). Ecology and Potamogeton berchtoldii has a wide ecological tolerance, growing in lakes, ponds, ditches, slow-flowing streams and rivers, temporary pools and sometimes appearing in artificial habitats such as cattle troughs. It is a good colonist and may quickly exploit new habitat. The production of large numbers of both turions and seed likely allows it to quickly exploit new or disturbed habitat, but in stable environments it is likely to be outcompeted by more robust plants. In Britain, small pondweed is common and widespread. It is probably under-recorded due to its relatively small size and confusion with P. pusillus. Although it does not occur in very acid environments, small pondweed is otherwise tolerant of a wide range of water chemistry and seems able to survive in eutrophic conditions. However, it is less tolerant of high nutrient levels than the related and very similar P. pusillus. It is the only British fine-leaved pondweed likely to be encountered in oligotrophic lakes, where it generally grows in deeper water with Isoetes and Nitella spp. Small pondweed is not in cultivation, though it is likely to spontaneously colonise new ponds, probably via waterfowl. It is unlikely to persist for long in this environment, however, unless competing plants are regularly cleared. Its small stature and noninvasive habit make it suitable for growing in a pond or aquarium.

Potamogeton diversifolius is a species of aquatic plant known by the common names waterthread pondweed and diverse-leaved pondweed. It is native to most of the United States, as well as sections of southwestern Canada and northern Mexico, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams. This is a perennial herb producing a very narrow, compressed stem branching to a maximum length around 35 centimeters. It has thin, pointed linear leaves a few centimeters long spirally arranged about the thin stem. The inflorescence is a small spike of flowers emerging from the water surface. Inflorescences also grow on submersed sections of the stem; these are smaller and spherical.

Potamogeton foliosus is a species of aquatic plant known by the common name leafy pondweed. It is native to nearly all of North America and parts of Central America, where it grows in water bodies such as ponds, lakes, ditches, and slow-moving streams. It has been reported from every state in the United States except Hawaii as well as from every Canadian province and territory except Newfoundland and Nunavut. Potamogeton foliosus is a perennial herb growing from a dense, mat-forming rhizome that anchors in wet substrate. It produces a thin, compressed, multibranched stem growing to a maximum length around 75 centimeters. The delicate, hairlike leaves are up to 10 centimeters long. They are pale green to olive green or reddish in color. The inflorescence is a small cluster or spike of flowers arising from the water on a short peduncle. Turions are sometimes present.

Potamogeton gramineus is a species of aquatic plant known by the common name various-leaved pondweed, variableleaf pondweed, grass-leaved pondweed or grassy pondweed, native to the northern hemisphere where it grows in shallow, clean water. Potamogeton gramineus is native to much of the Northern Hemisphere, with a Holarctic distribution. It occurs in northern Europe (Britain, Ireland, Iceland, Scandinavia, Germany, Switzerland, France, Poland, Russia, the Baltic States), Greenland, North America (USA except for the southeast, Canada). There are outlying populations in southern Europe (Iberia, Corsica, Italy), Caucasus, Pyrenees and western USA. This is an aquatic perennial growing from a creeping rhizome that anchors in wet substrate. It produces thin, cylindrical, heavily branching stems usually less than a metre in length.

Potamogeton illinoensis, commonly known as Illinois pondweed or shining pondweed, is an aquatic plant. It provides food and cover for aquatic animals. It is generally not weedy in its native range, but it is a troublesome noxious weed in Viedma, Río Negro, Argentina, where it is an introduced species.

Potamogeton natans L. (Broad-leaved Pondweed, Floating Pondweed, Floating-leaf pondweed) is an aquatic species in the genus Potamogeton native to quiet or slow-flowing freshwater habitats throughout the Holarctic Kingdom. It produces both floating and submersed leaves on the same plant. The floating leaves are ovate to oblong-ovate and almost always heart-shaped at the base. They are dark green, leathery, opaque, with translucent longitudinal veins. They are 5 to 10 centimeter long, pointed at the tips, and rounded at the base.

Potamogeton nodosus is a species of aquatic plant known by the common names longleaf pondweed and Loddon pondweed. It is native to Eurasia and the Americas, where it is widespread and can be found in water bodies such as ponds, lakes, ditches, and streams. This is a perennial herb producing a thin, branching stem easily exceeding a meter in maximum length. The leaves are linear to widely lance-shaped and up to 15 centimeters long by 4 wide. Both floating leaves and submerged leaves are borne on long petioles, a distinguishing characteristic. The inflorescence is a spike of many small flowers arising from the water on a peduncle.

Potamogeton pusillus is a species of aquatic plant known by the common names small pondweed, lesser pondweed or least pondweed. It occurs in standing and slow-flowing freshwater habitats throughout the Northern Hemisphere. Lesser pondweed is widely distributed globally, occurring across most of Europe (including Scandinavia) and North America. It is reported from scattered locations in Central and Southeast Asia and is widespread in China. It is also widespread in South America and Africa. Ecology and Lesser pondweed grows in standing or slow-flowing water bodies such as ponds, lakes, ditches, slow-moving streams, and river backwaters. It is a lowland plant and requires calcareous water, with a marked preference for high nutrient levels, and may form extensive beds in favourable situations, growing with other nutrient-tolerant species such as Myriophyllum spicatum and Zannichellia palustris. It is tolerant of turbid water and is a good colonist, often exploiting temporary or disturbed habitats such as livestock drinking ponds, canals and ditches. In lakes it is very tolerant of eutrophication and the resulting competition from phytoplankton and periphyton, and is often one of the last submerged plants to disappear.

Potamogeton richardsonii is a species of aquatic plant known by the common name Richardson's pondweed. It is native to much of northern North America, including all of Canada and the northern and western United States. It grows in water bodies such as ponds, lakes, ditches, and streams. This perennial herb grows a narrow, mostly unbranched stem from a mat of rhizomes in the substrate. It reaches about a meter in maximum length. The leaves are up to 13 centimeters long and about 3 wide with crinkly pointed or rounded tips. The inflorescence is a spike of flowers arising from the water surface on a peduncle.

Argentina anserina, also known as common silverweed, silverweed cinquefoil or just "silverweed", is a flowering perennial plant in the rose family Rosaceae. It is native throughout the temperate Northern Hemisphere, often on river shores and in grassy habitats such as meadows and road-sides. The plant was formerly classified in the genus Potentilla but was reclassified into the resurrected genus Argentina by research in the 1990s. It is a species aggregate which has frequently been divided into multiple species. Silverweed is most often found in sandy or gravelly soils, where it may spread rapidly by its prolific rooting stolons. It typically occurs in inland habitats, unlike A. egedii, which is a salt-tolerant coastal salt marsh plant.