Poa kelloggii is a species of grass known by the common name Kellogg's bluegrass. It is endemic to the North and Central Coasts of California, where it grows in coastal forests, including redwood forests. It is a perennial grass producing single stems or loose clumps of several stems up to 85 centimeters tall. The inflorescence is a series of branches along the stem which spread out and then droop as the fruit matures. The flattened spikelets occur at the tips of the thin branches.

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 2 to 3 feet 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.

Poa macrantha is a species of grass known by the common names seashore bluegrass and large-flowered sand dune bluegrass. It is native to the west coast of North America from Alaska to northern California, where it grows in sand dunes and other beach habitat. Poa macrantha is a perennial grass growing in loose clumps with stems up to 60 centimeters in maximum height. The grass grows from a network of very long, stout rhizomes and stolons which may be up to 4 meters in length, anchoring the grass in its shifting sandy substrate. The inflorescence is a dense series of clustered spikelets which are flattened and longer than wide. The plant is dioecious with male and female individuals bearing different types of flowers; the two flower types are similar in appearance.

Poa napensis is a rare species of grass known by the common name Napa bluegrass. It is endemic to Napa County, California, where it is known from only two occurrences near Calistoga. It grows in moist, mineral-rich soil around hot springs. The rare grass only occurs on private, unprotected land and depends on water from the hot springs; changes to the local water regime or any other aspects of its specific habitat type would affect the plant. This grass was federally listed as an endangered species in 1997, along with another rare local hot spring endemic, the Calistoga popcornflower (Plagiobothrys strictus). This is a perennial grass forming dense clumps of somewhat waxy stems up to about a meter in maximum height. The inflorescence is an open array of thin branches bearing rough-haired, flattened, lance-shaped spikelets. The spikelets may be greenish to purple in color.

Poa secunda (variously known by the common names of Sandberg bluegrass, alkali bluegrass, big bluegrass, Canby's bluegrass, Nevada bluegrass, one-sided bluegrass, Pacific bluegrass, pine blugrass, slender bluegrass, wild bluegrass, and curly bluegrass. ) is a widespread species of grass native to North and South America. It is highly resistant to drought conditions, and provides excellent fodder; and has also been used in controlling soil erosion, and as revegetator, often after forest fires. Cultivars include 'Canbar', 'Service', 'Sherman', and 'Supernova'. Historically, indigenous Americans, such as the Gosiute of Utah, have used P. secunda for food. It was originally described botanically in 1830 by Jan Svatopluk Presl, from a holotype collected from Chile by Thaddäus Haenke in 1790.

Rush Blue Grass (Poa secunda ssp. juncifolia) is a common native grass that grows in northern, southern and central California. It tends to grow at elevations from 2600-10000 feet.

One-sided Bluegrass (Poa secunda ssp. secunda) is a common native grass that grows in northern, southern and central California. It tends to grow at elevations from 0-12500 feet.

California dissanthelium or Catalina grass (Poa thomasii) is a rare species of grass. It was originally discovered on Santa Catalina, an island off California's coast in 1847 by U.S. botanist and naturalist William Gambel. It was later identified on Guadalupe Island (off Baja California Peninsula), and on San Clemente Island and Catalina Island (both off southern California).

Poa unilateralis is a species of grass known by the common names San Francisco bluegrass, ocean-bluff bluegrass, and sea-bluff bluegrass. It is native to west coast of the United States from Washington to central California, where it grows in coastal habitats such as bluffs and beaches in sandy saline soils. It is a perennial grass forming dense clumps of stems up to 40 centimeters tall. The herbage may be waxy in texture. The leaves may be thin and early-withering or somewhat fleshy and persistent. The inflorescence is a dense cluster of short branches bearing small, hairy-edged spikelets.

Wheeler's Bluegrass (Poa wheeleri) is a common native grass that grows in northern, southern and central California. It tends to grow in open places with rich soils, at elevations from 4500-12500 feet.

Podistera nevadensis is an uncommon species of flowering plant in the carrot family known by the common names Sierra podistera and Nevada podistera. Podistera nevadensis is a perennial herb forming a dense cushion in rock crevices, spreading up to half a meter wide and only a few centimeters tall. It grows from a taproot and it has no real stem, forming a mat of leaves. The fleshy pale green leaves are no more than a centimeter long. Each is divided into tiny, pointed leaflets. The leaves are coated in short, rough, whitish hairs. Podistera nevadensis is endemic to California, where it is known only from the highest peaks of the Sierra Nevada, the White and Inyo Mountains, and the San Bernardino Mountains. It is a plant of alpine climates above the tree line, growing in gravel and talus.

Pogogyne abramsii is a rare species of flowering plant in the mint family known by the common name San Diego mesa mint. It is endemic to San Diego County, California, where it is known only from a few sites at vernal pools in and around San Diego and its suburbs. Much of its range is located on the grounds of Marine Corps Air Station Miramar. The plant has been federally listed as an endangered species since 1978. Pogogyne abramsii is a small, aromatic, densely hairy annual herb producing erect stems topped with tiny but showy inflorescences. The inflorescence contains purple-tinged green bracts and densely hairy sepals surrounding lipped, bell-shaped flowers each about a centimeter long. The flower is pinkish-purple with a purple-spotted white throat. It has a strong mint scent. The plant is pollinated by several species of bee, including honey bees (Apis mellifera), Exomalopsis nitens and E. torticornis, and the bee fly Bombylius facialis.

Pogogyne clareana is a rare species of flowering plant in the mint family known by the common name Santa Lucia mint. It is endemic to Monterey, California, where it is known only from about fifty occurrences all located within the bounds of Fort Hunter Liggett, a US Army training facility. The local habitat is made up of chaparral and oak woodland with occasional vernal pools and summer-dry creek beds. This is a small, aromatic annual herb producing slender, erect stems 15 to 25 centimeters tall. Stems are topped with small but showy inflorescences containing hairy sepals and lipped, funnel-shaped flowers in shades of pinkish-purple with purple-spotted white throats. They have a strong mint scent. The plants flower for about two weeks in June, and each produces a single seed.

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 floribunda is a species of flowering plant in the mint family known by the common names profuseflower mesamint and profuse-flowered pogogyne. It is native to the Modoc Plateau and surrounding basin habitat in the northeastern corner of California. It is known from six occurrences in adjacent Oregon and one in Idaho. It can be found in vernal pools, ephemeral creeks, and other summer-dry water bodies on the plateau. This is an aromatic annual herb producing a mostly erect, branching stem which is lined nearly from base to top with inflorescence. The lipped, tubular flowers are about half a centimeter long and white in color. Most have purple spots or red speckles, while a few are pure white or solid pale purple. Each is surrounded by a calyx of pointed sepals which are coated in long white hairs. This plant, once thought to be a variety of the more common Pogogyne zizyphoroides, was elevated to species level in 1992.

Pogogyne nudiuscula is a rare species of flowering plant in the mint family known by the common name Otay mesa mint. It is native to southern San Diego County, California, where it is known only from Otay Mesa near the border with Baja California. It was identified on land south of the Mexican border, but these occurrences have probably been extirpated. It is now known from seven vernal pool complexes just north of the border, and it is a federally listed endangered species of the United States. This annual herb produces an erect stem reaching 30 centimeters in maximum height. Its herbage is strongly aromatic and coated very thinly with stiff hairs, or lacking hairs. The inflorescence is an interrupted series of flower clusters. The flowers are just over a centimeter long, bell-shaped with narrow throats, and bright purple in color, usually with some white on the lower lip.

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.

Pogogyne zizyphoroides (orth. var. P. ziziphoroides) is a species of flowering plant in the mint family known by the common names Sacramento mesamint and Sacramento beardstyle. It is native to central and northern California and southwestern Oregon. It grows in vernal pools and similar habitats, including in the Central Valley and California Coast Ranges. Pogogyne zizyphoroides is an aromatic annual herb growing erect, its sturdy stem topped with a rounded, headlike inflorescence or interrupted series of two or more clusters. Some flowers also emerge at the leaf axils. The tubular, lipped flower is under a centimeter long and purple in color, sometimes with white in the throat. Each flower is surrounded by long, hairy green sepals.

Polanisia dodecandra is a species of flowering plant in the caper family] known by the common name redwhisker clammyweed, or simply clammyweed, although there are other Polanisia species called 'clammyweed'. It is an annual plant that is found in many types of habitat throughout much of Canada and the United States. It can be found elsewhere as an introduced species. The species scientific name derives from the fact that the plant has many stamens of unequal lengths.

Polemonium californicum is a species of flowering plant in the phlox family known by the common names moving polemonium, low Jacob's ladder, and California Jacob's ladder. It is native to the northwestern United States, where it grows in shady and moist habitat, such as mountain woodlands. It is a hairy, hairy rhizomatous perennial herb forming clumps of several decumbent to erect stems 30 to 50 centimeters in maximum height. The leaves are up to 20 centimeters long and are compound, made up of several pairs of oval to lance-shaped leaflets. The leaflet at the tip of the leaf is often fused to the pair behind it. The flower cluster is a crowded cluster of bell-shaped flowers each up to 1.5 centimeters wide. The flower is blue or purple with a yellow center and a whitish tubular throat. The fruit is a capsule.

Polemonium carneum is a plant native to the northwestern United States west of the Cascade Range in Washington south to the San Francisco Bay Area in California. Common names include royal Jacob's ladder, great polemonium, and salmon polemonium. It grows in the lowlands and in prairies to moderate elevations in the mountains, and inhabits woody thickets, open and moist forests, prairie edges, and roadsides. This is a rhizomatous perennial herb producing one or more stems decumbent in form or erect to a maximum height near one meter. The leaves are compound with up to 21 leaflets each. The sticky-haired leaflets are somewhat lance-shaped and up to 4 centimeters long. The flower cluster is an open, spreading cluster of 3 to 7 flowers each borne on a thin peduncle. The flower is widely bell-shaped with a five-lobed corolla that may spread to nearly 3 centimeters wide. The flower corolla may be any shade of pale pink, salmon pink, yellow, or pale lavender to medium purple.

Polemonium chartaceum is a rare species of flowering plant in the phlox family known by the common names Mason's Jacob's-ladder and Mason's sky pilot. It is native to California, where it has a disjunct distribution. It occurs in the Klamath Mountains as well as the ranges east of the Sierra Nevada, including the White Mountains, where its distribution extends just into Nevada. It is a plant of high elevations, growing in exposed, rocky mountain slope habitat such as talus and alpine fellfields. This is a perennial herb producing a small clump of a few erect stems reaching 20 centimeters in maximum height. Leaves clustered around the base of the stems are cylindrical bunches of many small, glandular leaflets. Each leaflet is deeply divided into lobes, making it appear like several leaflets growing together. The inflorescence is a headlike cluster of several flowers atop the short, stout stem. Each flower has a tubular calyx of densely hairy sepals and a five-lobed corolla in shades of pale blue with a whitish or yellowish throat.

Polemonium eximium is a species of flowering plant in the genus which includes the Jacob's Ladders. Its common name is skypilot. It is endemic to the Sierra Nevada in California where it grows in the talus of the high mountain slopes. It occurs at elevations between 3000 and 4200 meters where few other plants grow. This perennial herb forms clumps of erect stems approaching 40 centimeters in maximum height. Surrounding the stems are nearly cylindrical leaves each made up of many leaflets, the leaflets subdivided into lobes. The herbage is hairy and hairy in texture. The showy flower cluster is a headlike cluster of several flowers. Each flower has a tubular calyx of hairy sepals and a funnel-shaped corolla in shades of pale to bright or deep blue with a whitish throat. The flowers are at full bloom for approximately one day in the very short period of appropriate flowering conditions. The plant has a strong scent reminiscent of urine which attracts pollinators to its short-lived flowers.

Polemonium micranthum is a species of flowering plant in the phlox family known by the common names annual polemonium or annual Jacob's-ladder. It is native to western North America from British Columbia to North Dakota to California as well as disjunct in the Andes of southern Argentina and Chile. It can be found in many types of shrubby habitat, such as sagebrush scrub and foothill woodlands. It is an annual herb with a branching or unbranched stem taking a matted, spreading, or upright form. The slender stems are up to about 30 centimeters long and the herbage is coated in short, soft hairs and stalked glands. The leaves are located along the stem, each divided into several small leaflets. The solitary flowers have small white or pale blue lobed corollas tucked within cuplike calyces of hairy, pointed sepals.

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.

Polemonium pulcherrimum is a species of flowering plant in the phlox family known by several common names, including beautiful Jacob's-ladder, showy Jacob's-ladder, and skunk-leaved polemonium. It is native to western North America from Alaska and Yukon to Arizona and New Mexico, where it can be found in many types of mountain habitat, including alpine talus at high elevations. It is a common and widespread wildflower in several regions. It is a perennial herb producing a clump of several erect stem approaching a maximum height of 30 centimeters. The leaves are mostly basal, with smaller ones arranged along the stem. The leaves are made up of several pairs of lance-shaped to oval or round leaflets. The herbage is lightly hairy, densely hairy, sticky, and strongly scented, the odor reminiscent of skunk. The showy flower cluster is a dense elongated or headlike cluster of bell-shaped flowers each just under a centimeter wide. The flower is deep to bright or pale blue to nearly white with a yellow throat.

Poliomintha incana is a species of flowering plant in the mint family which is known as frosted mint. It is native to dry and desert areas of the southwestern United States and northern Mexico. It is a strongly aromatic shrub with dark green foliage covered in small white hairs. Scattered about the foliage are fuzzy, tubular flowers in shades of light purple and blue with tiny purple spots. Frosted mint is eaten fresh or dried or used as a flavoring by Native American groups, particularly the Tewa and Hopi.

Polycarpon tetraphyllum ssp. depressum is a species of flowering plant in the pink family known by the common name California manyseed. It is native to southern California and Baja California, where it grows in sandy habitat such as coastal bluffs and disturbed habitat types such as fields and roadsides. It is a small annual herb producing a spreading, branching stem just a few centimeters long that lies prostrate on the ground. A few pairs of oppositely arranged leaves line the stems, each oval in shape narrowing to a petiole and measuring about a centimeter long. The inflorescence is a cluster of rounded flowers with minute petals tucked inside a calyx of pointed sepals.

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 austiniae, common name Mrs. Austin's knotweed, is a plant species in the buckwheat family. It is native to western Canada and the western United States, from Alberta and British Columbia south as far as California, Nevada, and Wyoming. Polygonum austiniae is an branching herb up to 20 cm (7. 9 in) tall.

Polygonum bidwelliae is an uncommon species of flowering plant in the knotweed family known by the common name Bidwell's knotweed. The plant was named for American suffragist Annie Bidwell, who at one time lived in the Bidwell Mansion in Chico, California. She is the person who collected the type specimen in Northern California. Polygonum bidwelliae is endemic to California, where it is known from the northern Sacramento Valley and adjacent slopes of the southernmost Cascade Range in Butte, Shasta, and Tehama Counties. It grows in chaparral, woodland, and grassland habitat on volcanic soils. Polygonum bidwelliae is an annual herb producing an erect green, wiry, angled stem reaching 20 centimeters (8 inches) in height. The narrow, pointed leaves are oppositely arranged along the stem, mainly on the upper parts of stem branches. The leaves have relatively large stipules which form ochrea that sheath the stem, sometimes hiding the leaf bases. The sharp-pointed stipules are membranous and silvery white. Bright pink flowers occur in upper leaf axils.

Polygonum bolanderi is an uncommon California species of flowering plant in the buckwheat family known by the common name Bolander's knotweed. Polygonum bolanderi is endemic to northern California, where it is known from the northern Coast Ranges, the southern Cascades, and the northern Sierra Nevada (from Humboldt County and Shasta, south as far as Sonoma county and Tuolumne County). It can be found in open, rocky habitats. Polygonum bolanderi is a small shrub producing numerous very thin twiglike branches up to about half a meter (20 inches) long from a tough, tangled base. The slender branches are lined with small, narrow, pointed leaves which are alternately arranged and mostly found clustered toward the tips of the twigs. The leaves have narrow, fringed stipules with sharp points. Flowers occur in upper leaf axils during summer and fall. They are whitish or pink with dark midveins on each corolla lobe.

Polygonum californicum is a species of flowering plant in the buckwheat family known by the common name California knotweed. It is native to the west coast of the United States from Washington, Oregon, and northern and central California in the Coast Ranges and Sierra Nevada foothills as far south as Napa and Tulare Counties. It can be found in many types of open habitats. Polygonum californicum is an annual herb producing a slender, angled stem which grows erect to a maximum height near 40 centimeters. The narrow, pointed leaves are mostly located on upper branches of the stem. The leaves have fringed, bristle-tipped stipules attached to their bases. Solitary white or pink flowers occur in upper leaf axils. Polygonum californicum is an annual herb producing a slender, angled stem which grows erect to a maximum height near 40 centimeters. The narrow, pointed leaves are mostly located on upper branches of the stem. The leaves have fringed, bristle-tipped stipules attached to their bases. Solitary white or pink flowers occur in upper leaf axils.

Polygonum douglasii is a species of flowering plant in the knotweed family known by the common name Douglas's knotweed. It is native to much of northern and western North America, where it can be found in many types of habitat, including disturbed areas. It has been found in Canada from British Columbia north to Yukon and east as far as Québec, and in the United States as far south as California, New Mexico, Iowa, and New York. Polygonum douglasii is known as a species complex, as there are many subspecies that may be better treated as species in their own right.

Polygonum hickmanii is a rare species of flowering plant in the buckwheat family known by the common names Scotts Valley polygonum and Hickman's knotweed. It is endemic to Santa Cruz County, California, where it is known from only two sites in the Scotts Valley. It grows on coastal prairie on mudstone and sandstone substrates, in an area known for its spring wildflowers. The small plant was first noted in 1990 and described as a new species in 1995. The plant is a federally listed endangered species. Polygonum hickmanii is a small annual plant forming compact patches on the ground, its stem growing no more than about 5 centimeters (2 inches) tall. It is lined with linear leaves especially near the tips of the branches, and has a cylindrical, shreddy ochrea. Solitary flowers occur in the leaf axils. They are only 2 or 3 millimeters long and white or pink-tinged in color. The eight tiny stamens are tipped with orange-pink anthers.

Polygonum majus is a North American species of flowering plant in the buckwheat family known by the common name Wiry knotweed. It grows in the western United States and western Canada, from British Columbia south as far as the Sierra Nevada of northwestern Inyo County in California, east as far as Montana. Polygonum majus is an herb up to 60 cm (2 feet) tall. Stems are thin and wiry. Flowers are white or pink

Polygonum marinense is a rare North American species of flowering plants in the buckwheat family known by the common name Marin knotweed. It is endemic to California, where it is known from just a few locations north and east of San Francisco Bay. The taxonomy of the plant is uncertain. It has been suggested that the species may be native to the Mediterranean, and that the California specimens may actually be introduced. If, however, it is a true Bay Area endemic, the plant is rare and threatened by habitat destruction and disturbance. It is a resident of salt marsh and other wet coastal habitat.

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 paronychia is a species of flowering plant in the knotweed family known by the common names dune knotweed, black knotweed, and beach knotweed. It is native to the coastline of western North America from British Columbia to California, where it grows in sandy coastal habitat such as beaches, dunes, and scrub. Polygonum paronychia is a small prostrate or upright shrub producing multibranched brown stems up to a meter (40 inches) long. The stems may root at nodes that come in contact with moist substrate. The leaves are alternately arranged on the stems but are mostly located bunched around the tips of the stem branches. The leaves are linear to lance-shaped with rolled edges and bristly midribs on the undersides. Each leaf has a large stipule which forms a wide, membranous ochrea. The ochrea is up to 2 centimeters (0. 8 inches) long and is persistent, fraying into fibrous, silvery shreds that remain on the plant through the seasons. Flowers occur in the leaf axils. Each is up to a centimeter (0. 4 inches) wide with five narrow white or pinkish corolla lobes. Polygonum paronychia is a small prostrate or upright shrub producing multibranched brown stems up to a meter (40 inches) long. The stems may root at nodes that come in contact with moist substrate. The leaves are alternately arranged on the stems but are mostly located bunched around the tips of the stem branches. The leaves are linear to lance-shaped with rolled edges and bristly midribs on the undersides. Each leaf has a large stipule which forms a wide, membranous ochrea. The ochrea is up to 2 centimeters (0. 8 inches) long and is persistent, fraying into fibrous, silvery shreds that remain on the plant through the seasons. Flowers occur in the leaf axils. Each is up to a centimeter (0. 4 inches) wide with five narrow white or pinkish corolla lobes.

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.

Polygonum polygaloides is a North American species of flowering plants in the buckwheat family known by the common names milkwort knotweed and polygala knotweed. It is native to much of western North America, where it can be found in many types of moist habitat. It is a variable species, usually divided into a number of subspecies. Polygonum polygaloides is an annual herb producing slender, wiry green stems 1 to 30 centimeters (0. 4-12 inches) in length. The linear or lance-shaped leaves are alternately arranged uniformly along the stem, the ones near the tips of stem branches highly reduced. The leaves have membranous stipules which fuse to form silvery ochrea at the leaf bases. The flowers are mainly located in clusters around the stem tips. They are white, pink, or red, and most remain closed. Subspecies. Some sources accept the following as subspecies of Polygonum polygaloides, while others regard all but subsp. polygaloides as belonging to a distinct species, P. kelloggii. Polygonum polygaloides subsp. confertiflorum (Nutt. ex Piper) J. C. Hickman - from British Columbia east to Saskatchewan and south as far as New MexicoPolygonum polygaloides subsp. esotericum (L. C. Wheeler) J. C. Hickman - California, OregonPolygonum polygaloides subsp. kelloggii (Greene) J. C. Hickman - from British Columbia to ArizonaPolygonum polygaloides subsp. polygaloides - Washington, Oregon, Idaho, Alberta, Montana, Wyoming

Polygonum ramosissimum is a North American species of herbaceous annual plants in the buckwheat family, widespread across much of Canada and the United States, where it is commonly called bushy knotweed. Polygonum ramosissimum has erect stems growing 30 to 100 cm (12 to 39. 5 in) (sometimes to 200 cm or 80 inches) tall, with yellowish-green to blue-green foliage. The stems are freely branched with closed flowers produced in groups of (1) 2 to 3(5) flowers in the upper ocreae of racemes that are up to 15 cm (6 in) long, the inflorescences are spike-like. The greenish-yellow, rarely pink or white marked flowers, are on pedicels that are longer than the calyx. The calyx is around 3 mm (0. 12 in) long and 5-parted with the outer three sepals longer than the inner sepals. The seeds are produced in fruits called achenes, which are egg-shaped, dark brown and around 3 mm (0. 12 in) long. The achenes also have a smooth shiny surface. The late season achenes are larger, from 4 to 15 mm long. Polygonum ramosissimum has erect stems growing 30 to 100 cm (12 to 39. 5 in) (sometimes to 200 cm or 80 inches) tall, with yellowish-green to blue-green foliage. The stems are freely branched with closed flowers produced in groups of (1) 2 to 3(5) flowers in the upper ocreae of racemes that are up to 15 cm (6 in) long, the inflorescences are spike-like. The greenish-yellow, rarely pink or white marked flowers, are on pedicels that are longer than the calyx. The calyx is around 3 mm (0. 12 in) long and 5-parted with the outer three sepals longer than the inner sepals.