Pentachaeta alsinoides, the tiny pygmydaisy, is a species of flowering plant in the aster family endemic to California. It is an annual, low, slender, diffuse, somewhat villous; leaves filiform or nearly so; disk flowers reddish, ray flowers inconspicuous.

Pentachaeta aurea is a species of flowering plant in the aster family known by the common names golden-rayed pentachaeta, golden chaetopappa, and golden leastdaisy. It is native to southern California, where it grows in the San Gabriel and San Bernardino Mountains and the Peninsular Ranges, and northern Baja California. It is an annual herb with a hairy stem reaching a maximum height near 36 centimeters from a slender taproot. The narrow linear leaves are up to 5 centimeters long but only a few millimeters wide and may be very hairy. The inflorescence is a solitary flower head, with up to 22 heads per plant. The flower head bears many yellow, brownish, or whitish ray florets 3 to 12 millimeters long, and has a center of many five-lobed yellow to reddish disc florets. The fruit is an achene tipped with a pappus of bristles.

Pentachaeta bellidiflora (white-rayed pentachaeta or Whiteray pygmydaisy) is a Californian wildflower in the genus Pentachaeta of the (Asteraceae) family. It is included in both the state and federal lists of endangered species. It is endemic to the San Francisco Bay Area of California, United States, and occurs only at altitudes less than 620 metres (2,034 ft). P. bellidiflora is found chiefly on rocky, grassy areas. The conservation status of this species was, as of 1999, characterized by a declining population, with a severely diminished and fragmented range. The specific bellidiflora refers to the similarity of the flowers with those of common daisies (Bellis). White-rayed pentachaeta is found in serpentine grassland as well as valley and foothill grassland. It is currently known only to survive in serpentine bunchgrass communities and native prairies in two small areas of San Mateo County, including populations in Edgewood County Park and on San Francisco Water District lands at serpentine outcrops on the eastern slopes of Crystal Springs Reservoir, in the vicinity of State Route 92. It was formerly known to occur from Marin to Santa Cruz counties. One study declares only one population remains.

Pentachaeta exilis is a species of flowering plant in the aster family known by the common name meager pygmydaisy. It is endemic to California, where it is known from the North Coast Ranges to the southern Central Valley, San Joaquin Valley, and Sierra Nevada foothills. It is a member of grassland and woodland plant communities. Pentachaeta exilis is an annual herb with a hairy stem no more than about 6 centimeters tall. The narrow linear leaves are up to 3 centimeters long but only about a millimeter wide. The inflorescence is a solitary flower head, with up to 23 heads per plant. The two subspecies of the plant have different types of heads. Most incidences of the plant are ssp. exilis, which has long reddish disc florets in its head but only rudimentary ray florets. The rare subspecies aeolica, which is known from just a few occurrences in the Central Coast Ranges, generally produces some white ray florets around a center of yellow disc florets. Pentachaeta exilis is an annual herb with a hairy stem no more than about 6 centimeters tall. The narrow linear leaves are up to 3 centimeters long but only about a millimeter wide. The inflorescence is a solitary flower head, with up to 23 heads per plant. The two subspecies of the plant have different types of heads. Most incidences of the plant are ssp. exilis, which has long reddish disc florets in its head but only rudimentary ray florets. The rare subspecies aeolica, which is known from just a few occurrences in the Central Coast Ranges, generally produces some white ray florets around a center of yellow disc florets.

Pentachaeta lyonii, the Lyon's pentachaeta or Lyon's pygmydaisy, is an annual plant in the aster family. It is endemic to southern California, where it is now known only from a few areas on the heavily developed coastline of Los Angeles and Ventura Counties. This is a federally listed endangered species. At one point in time there were 43 populations of P. lyonii distributed among the Santa Monica Mountains, Simi Valley, Palos Verdes Peninsula and Catalina Island. In a 2006 search only 21 Pentacheata populations could be located, with occurrences on the Palos Verdes Peninsula and Santa Catalina Island having long been deemed extirpated. The most recent area suspected of extirpation is Stunt Ranch where no flowering individuals have been seen since 1990, after an 8 year population decline.

Goldback Fern (Pentagramma rebmanii) is a common native fern that grows in northern, southern and central California. It tends to grow in slopes and rocky places, at elevations from 0-7500 feet.

Goldenback Fern (Pentagramma triangularis) is a common native fern that grows in Northern, Southern and Central California, primarily in the Desert Mountains and Modoc Plateau regions. It tends to grow in slopes and rocky places, at elevations from 0-7500 feet.

Peraphyllum is a monotypic genus of flowering plants in the rose family containing the single species Peraphyllum ramosissimum, commonly known as wild crab apple. It is a shrub which may reach 3 meters in height and bears small pomes about a centimeter wide. Peraphyllum is most closely related to Amelanchier, Malacomeles, Crataegus, and Mespilus Squaw apple grows in California, Oregon, Idaho, Utah, Colorado, and New Mexico usually in pine and juniper woodlands. In California it can be found in the High Cascades, High Sierra Nevada, and Great Basin. Translated from the Greek, the genus Peraphyllum means "very leafy" and the species name ramosissimum means "many branches".

Pericome caudata is species of flowering plant in the aster family known by the common name mountain tail-leaf. It is native to the southwestern United States as far east as Colorado, Oklahoma, and Texas, as well as northern Mexico, where it grows in rocky habitat, often in hills and mountains, and sometimes in disturbed areas. It is a large, branching, leafy perennial herb or subshrub approaching 2 meters in maximum height. It is glandular, resinous, sparsely hairy, and aromatic. The leaves are somewhat triangular, sometimes with a few large teeth or sharp lobes, the blade measuring up to 12 centimeters long and borne on a petiole. The leaf size and shape is variable across the species' range. The inflorescence is a cluster of many flower heads each under a centimeter wide and filled with golden yellow disc florets. The Navajo used this plant for a variety of medicinal and ceremonial purposes.

Perideridia bacigalupii is an uncommon species of flowering plant in the carrot family known by the common names Mother Lode yampah and Bacigalupi's perideridia. It is endemic to California, where it is known only from the northern and central Sierra Nevada foothills. It is a member of the flora in chaparral and pine woodlands. It is a perennial herb which may exceed 1. 5 meters in maximum height, its slender, erect stem growing from tubers. Leaves near the base of the plant have blades up to 40 centimeters long which are divided into many narrow subdivided lobes. Leaves higher on the plant are smaller and less divided. The inflorescence is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits about half a centimeter long.

Perideridia bolanderi is a species of flowering plant in the carrot family known by the common name Bolander's yampah. It is native to the western United States, where it grows in many types of habitat. It is a perennial herb which may approach one meter in maximum height, its slender, erect stem growing from tubers measuring up to 7 centimeters long. Leaves near the base of the plant have blades up to 20 centimeters long which are divided into many subdivided lobes of various sizes and shapes; the terminal segments are usually lined with teeth. Leaves higher on the plant are smaller and less divided. The flower cluster is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits about half a centimeter long. The Atsugewi and Miwok of California used the tuberous roots of this plant for food.

Perideridia californica is a species of flowering plant in the carrot family known by the common name California yampah. It is endemic to California, where it is known from the Central Coast Ranges and a section of the Sierra Nevada foothills. It grows in moist soils, often near streams. It is a perennial herb which may approach 1.5 meters in maximum height, its slender, erect stem growing from cylindrical tubers measuring up to 12 centimeters long. Leaves near the base of the plant have blades up to 40 centimeters long which are divided into many flat, narrow, subdivided lobes. Leaves higher on the plant are smaller and less divided. The flower cluster is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits under a centimeter long.

Perideridia gairdneri is a species of flowering plant in the carrot family known by the common names common yampah and Gardner's yampah. It is native to western North America from southwestern Canada to California to New Mexico, where it grows in many types of habitat. It is a perennial herb which may approach 1.5 meters in maximum height, its slender, erect stem growing from cylindrical tubers measuring up to 8 centimeters long. Leaves near the base of the plant have blades up to 35 centimeters long which are divided into many narrow, subdivided lobes. Leaves higher on the plant are smaller and less divided. The flower cluster is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, rounded fruits each a few millimeters long. This was an important food plant, even a staple food, for many Native American groups, including the Blackfoot, Paiute, and Cheyenne. The tuberous roots could be eaten like potatoes, roasted, steamed, eaten fresh or dried, made into mush or pinole, used as flour and flavoring, and were also used medicinally. Montana Plant Life

Perideridia howellii is a species of flowering plant in the carrot family known by the common name Howell's yampah. It is native to the mountains of Oregon and northern California, where it grows in moist soils, often near streams and rivers. It is a perennial herb which may exceed 1. 5 metres in maximum height, its slender, erect stem growing from a cluster of many narrow fibrous roots measuring up to 15 centimetres long. Leaves near the base of the plant have lance-shaped blades up to half a metre long which are divided into many leaflets made up of toothed, oval segments. Leaves higher on the plant are similar, but generally smaller. The inflorescence is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits each about half a centimetre long.

Perideridia kelloggii is a species of flowering plant in the carrot family known by the common name Kellogg's yampah. It is endemic to California, where it is known from the north and central coasts, the San Francisco Bay Area, and the Sierra Nevada foothills. It grows in grassland habitat, sometimes on serpentine soils. It is a perennial herb which may reach 1.5 meters in maximum height, its slender, erect stem growing from a cluster of long, narrow, fibrous roots each up to 15 centimeters long. Leaves near the base of the plant have blades up to 45 centimeters wide which are divided into many leaflets subdivided into narrow, elongated lobes. The flower cluster is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits each about half a centimeter long.

Perideridia lemmonii is a species of flowering plant in the carrot family known by the common names Lemmon's yampah and tuni. It is native to the western United States, where it is known from southeastern Oregon, western Nevada, and the mountains of eastern California. It grows in meadows, forests, and other habitat. It is a perennial herb approaching one meter in maximum height, its slender, erect stem growing from usually a single small tuber about 1. 5 centimeters long. Leaves near the base of the plant have blades up to 30 centimeters long divided into one or two pairs of leaflets, each of which may be subdivided. The inflorescence is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, round or oblong-shaped fruits each under half a centimeter long.

Perideridia oregana is a species of flowering plant in the carrot family known by the common name Oregon yampah. It is native to Oregon and California in the western United States, where it grows in woodland and other habitat. This plant is quite variable in appearance. In general, it is a perennial herb 10 to 90 centimeters tall, its green to waxy-grayish erect stem growing from a cluster of small tubers. Leaves near the base of the plant have blades 3 to 30 centimeters long divided into a variable number of leaflets, which may be subdivided into smaller segments. The flower cluster is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, oblong-shaped fruits 3 to 6 millimeters long.

Perideridia parishii is a species of flowering plant in the carrot family known by the common name Parish's yampah. It is native to mountainous regions of the southwestern United States, where it grows in forests and other habitat. It is a perennial herb growing up to 90 centimeters tall, its slender green stem growing from a small tuber. Leaves near the base of the plant have blades 10 to 20 centimeters long divided into pairs of leaflets, which may be subdivided or lobed. The inflorescence is a compound umbel of many spherical clusters of small white flowers. These yield ribbed, round or oblong-shaped fruits each about half a centimeter long.

Perityle emoryi is a species of flowering plant in the Asteraceae (Sunflower) family known by the common name Emory's Rockdaisy. It is native to the southwestern United States and northern Mexico, where it is a common wildflower of the deserts and can also be found in coastal regions. It grows in many types of habitat, it tolerates disturbance, and it can become somewhat weedy. The plant is also known from Chile and Peru and it is an introduced species in parts of Hawaii. Its distribution is apparently expanding. This polyploid plant is quite variable genetically and in appearance. It is an annual herb growing 2 to 60 centimeters tall, its stem small, delicate, and simple, or thick, branching, and sprawling. It is usually hairy in texture. The alternately arranged leaves have blades of various shapes which are toothed or divided into lobes and borne on petioles. The flower head is a typical composite "flower", hemispherical to bell-shaped and generally no more than a centimeter wide. The head has a center of many golden disc florets and a fringe of 8 to 12 white ray florets each just a few millimeters long. The fruit is an achene, usually with a pappus at the tip.

Swamp Knotweed (Polygonum amphibium) is a common native perennial herb in the Polygonaceae (Buckwheat) family that grows throughout California in almost every county. It is a wetland plant that is moderately fast growing and moderately long-lived. It grows in a rounded form to a height of 0.1 foot, with active growth during the summer. Flowers are yellow and bloom in the late spring. Leaves are medium green and deciduous. It tends to grow in shallow lakes and streams, at elevations from 0-10000 feet.

Water Pepper (Polygonum hydropiperoides) is a native perennial herb that grows in northern, southern and central California. It is slow growing and moderately long-lived. It grows in a flat form to a height of feet, with active growth during the summer. Flowers are green and bloom in the at unpredictable times of the year. Leaves are dark green and deciduous. It tends to grow in wet streambanks, at elevations from 0-4900 feet.

Persicaria lapathifolia (syn. Polygonum lapathifolium), known as pale persicaria, is a plant of the family Polygonaceae. It is closely related to Redshank and as such is considered a weed in Britain and Europe. Other common names for the plant include pale smartweed, curlytop knotweed, and willow weed. It is a species complex made up of a great many varying forms, sometimes considered Varieties: The environment also has a strong influence on the morphology of an individual plant. Persicaria lapathifolia is found in many parts of both the Old World and New World. Many varietal and sub-specific names have been coined, as the plant is morphologically variable. The species is found growing on the sea shore and in disturbed ground such as arable land, gardens, waste ground, rubbish tips and road verges. Persicaria lapathifolia is an annual herb with erect reddish stems with swollen joints, growing to a height of 20 to 80 cm (8 to 31 in). The leaves are alternate with short stalks, often densely hairy underneath. The leaf blades often have a dark-coloured blotch in the centre and are lanceolate or narrowly elliptical and have entire margins. Each leaf base has stipules which are fused into a stem-enclosing sheath that is loose and fringed with few if any hairs at the upper end. The inflorescence is a dense spike, often nodding. The perianth of each tiny pink flower consists of four or five lobes, fused near the base. There are six stamens, two partially fused carpels and two styles. The fruit is a rounded, flattened nut. This plant flowers from July to September in northern temperate regions. Distribution and habitat. Persicaria lapathifolia is found in many parts of both the Old World and New World. Many varietal and sub-specific names have been coined, as the plant is morphologically variable. The species is found growing on the sea shore and in disturbed ground such as arable land, gardens, waste ground, rubbish tips and road verges.

Water Smartweed (Polygonum punctatum) is a common native perennial herb that grows in northern, southern and central California. It is moderately fast growing and short-lived. It grows in an upright form to a height of 3.2 feet, with active growth during the summer. Flowers are white and striking, and bloom in the summer. Leaves are medium green and deciduous. It tends to grow in shallow water and shores, at elevations from 0-4900 feet.

Petalonyx linearis is a species of flowering plant in the family Loasaceae known by the common name narrowleaf sandpaper plant. It is native to the deserts of eastern California, western Arizona and northwestern Mexico, where it grows in scrub and other habitat. It is a rounded clumpy subshrub made up of many rough-haired, erect stems up to a meter tall. The cylindrical stems are lined evenly with linear to widely lance-shaped leaves 1 to 2. 5 centimeters long. The inflorescence at the end of each stem is a raceme of many small five-petalled white flowers surrounded by rounded or oval bracts with pointed, lobed, or notched tips.

Petalonyx nitidus is a species of flowering plant in the family Loasaceae known by the common name shinyleaf sandpaper plant. It is native to the deserts and desert mountains of the southwestern United States, where it grows in scrub, woodland, and other habitat. It is a clumpy subshrub made up of many rough-haired, erect or spreading stems growing 15 to 45 centimeters long. The leaves are oval, pointed, usually toothed or serrated, and up to 4 centimeters long. The inflorescence at the end of the stem is a crowded raceme of many flowers. The flower appears tubular, its white petals fused near the spreading tips but open lower, the long stamens extending well beyond the corolla, and unusual in that they emerge from outside the corolla.

Petalonyx thurberi is a species of flowering plant in the family Loasaceae known by the common name Thurber's sandpaper plant. It is native to the deserts of the southwestern United States and northwestern Mexico, where it grows in sandy and scrubby habitat. It is a rounded or spreading, clumpy subshrub made up of many rough-haired stems approaching one meter in maximum height. The stems are lined with clasping leaves varying in shape from lance-shaped to triangular to oval and sometimes toothed. The flower cluster at the end of the stem is a small, crowded raceme of several flowers. The white flower appears tubular, its petals fused near the spreading tips but open lower, the stamens emerging from between them in such a way that they appear to originate outside the corolla. There are two subspecies, with the rarer, ssp. gilmanii (Death Valley sandpaper plant), limited to the deserts in and around Death Valley.

Petasites frigidus (Arctic Butterbur or Arctic Sweet Coltsfoot; syn. P. speciosa) is a species of Petasites native to Arctic to cool temperate regions of the Northern Hemisphere in northern Europe, northern Asia and northern North America. It is a herbaceous perennial plant producing flowering stems in early spring, and large leaves through the summer. The upright flowering stems are 10-20 centimeter tall, and bear only 5-12 flower clusters, yellowish-white to pink in colour. The leaves are rounded, 15-20 centimeter broad, with a deeply cleft base and shallowly lobed margin, and rise directly from the underground rootstock. The underside of the leaves is covered with matted, woolly, fuzz. It grows in moist shaded ground, preferring stream banks and seeping ground of cut-banks.

Arctic Sweet Coltsfoot (Petasites frigidus var. palmatus) is a native perennial herb that grows in central and northern California. It tends to grow in wet places, at elevations from 0-1300 feet.

Peteria thompsoniae is a species of flowering plant in the legume family known by the common names spine-noded milkvetch and Thompson's peteria. It is native to the western United States, where it grows in salt desert shrublands in soils of volcanic ash origin, and in alluvial fans. It is a spiny perennial herb growing from a taproot and rhizome system, its stem growing 20 to 60 centimeters tall. The leaves are made up of several pairs of oval leaflets. The inflorescence, a spikelike raceme at the top of the stem, produces white or pinkish pealike flowers up to 2. 5 centimeters long, its base encapsulated in a tubular calyx of glandular sepals. The fruit is a leathery, slightly inflated legume pod up to 6 centimeters long.

Petradoria is a genus of North American subshrubs in the aster tribe within the daisy family. The only known species is Petradoria pumila, known by the common name rock goldenrod. It is native to the western United States (California, Arizona, Nevada, Utah, New Mexico, Colorado, Wyoming, Idaho). It is quite common in some regions, carpeting areas in yellow blooms.

Petrophyton caespitosum (orth. var. Petrophytum caespitosum) is a species of flowering plant in the rose family known by the common name mat rock spiraea. It is native to the western United States where it grows in mountainous areas from the Sierra Nevada to the Rocky Mountains. It grows among rocks in forested and woodland habitat. This is a very low matted shrub growing in carpets up to 80 centimeters wide, creeping over rocks. The plant often grows on vertical surfaces and hangs by its roots, which cling to cracks in rock. The stems are thick and very short, covered densely in rosettes of oval leaves. It produces many flower clusters which are spikelike clusters of flowers arising on erect peduncles up to 10 centimeters tall. Each flower cluster is packed with flowers, each with five tiny white petals, many whiskery stamens, and usually 5 hairy pistils. The flower parts dry and may fall away, leaving a cluster of developing fruits, follicles containing the seeds.

Peucephyllum is a monotypic genus of flowering plants containing the single species Peucephyllum schottii. Its common names include pygmy cedar, Schott's pygmy cedar, desert fir, and desert pine. It is not a cedar, fir, or pine, but a member of the aster family, Asteraceae. It is a leafy evergreen shrub with glandular, resinous foliage. It flowers in yellow flower heads which have only disc florets. The fruits are woody, bristly seeds with a pappus. This plant is native to the deserts of Arizona, California, Nevada, and Utah in the United States and Baja California and Sonora in northern Mexico. The species form is similar to that of the common creosote bush (Larrea tridentata): small, greenish, and hemispherical with similar yellow flowers in the spring.

Phacelia adenophora is a species of phacelia known by the common name hairy yellow phacelia. It is native to the northwestern United States where it can be found in Oregon, northeastern California, and northwestern Nevada. It grows in mountain and plateau habitat. This is an annual herb producing decumbent, creeping, spreading, or upright branched stems up to 40 centimeters long. The leaves are oblong in shape and deeply lobed, measuring up to 3 centimeters long. The flower cluster is a one-sided cyme of many bell-shaped flowers each under a centimeter long. Unlike many phacelias, which bloom in shades of blue and purple, this species has yellow to golden flowers. The fruit is a fuzzy, oblong capsule a few millimeters in length containing up to 14 seeds.

Phacelia affinis is a species of flowering plant in the borage family, Boraginaceae, known by the common names limestone phacelia and purple-bell scorpionweed. It is native to the southwestern United States and Baja California and Sonora in Mexico. It can be found in scrub, woodland, forest, and other habitat. It is an annual herb growing erect to a maximum height near 30 centimeters, its stem branching or not. The leaves are oblong in shape and are generally either deeply lobed or divided into several lobed leaflets. In texture the plant is slightly hairy and glandular. The inflorescence is a one-sided curving or coiling cyme of many bell-shaped flowers each just a few millimeters long. The flower is pale lavender or white with a yellowish tubular throat. The fruit is a capsule about half a centimeter long containing up to 30 seeds.

Phacelia anelsonii is a species of phacelia known by the common name Aven Nelson's phacelia. It is native to the Southwestern United States, where it is known from scattered occurrences in southwestern Utah, southern Nevada, and eastern California. It can be found in scrub and woodland habitat. It is named after the botanist Aven Nelson. It is an annual herb growing erect to a maximum height near 50 centimeters, its stem usually unbranched. It is coated in dark glandular hairs. The leaves are up to 8 centimeters long, the blades oblong in shape and divided into scalloped lobes or teeth. The inflorescence is a one-sided curving or coiling cyme of many bell-shaped flowers each about half a centimeter long. The flower is pale lavender to white. The fruit is a hairy, glandular capsule 2 or 3 millimeters long.

Phacelia argentea is a rare species of phacelia known by the common names sand dune phacelia and silvery phacelia. It is native to the coastline of southwestern Oregon and far northwestern California, where it was counted at a total of 33 sites in 1995. It is the only phacelia species endemic to coastal sand dune habitat, an ecosystem which is altered and declining in the area. This is a hairy, fleshy perennial herb growing prostrate or upright to a maximum length near 45 centimeters. The leaves are thick and coated in long, straight, silvery hairs. They are roughly oval, pointed or rounded at the tips, and up to 12 centimeters long. The inflorescence is an array of one-sided coiling cymes of many bell-shaped flowers each about half a centimeter long. The flower is white or cream with whiskery protruding stamens.

Phacelia austromontana is a species of phacelia known by the common name Southern Sierra phacelia. It is native to the southwestern United States, where it can be found in the Transverse Ranges and Sierra Nevada of California east to Utah. It grows in open mountainous habitat. It is an annual herb growing prostrate or upright, its multibranched stem reaching up to about 27 centimeters long. It is glandular and coated in soft and coarse hairs. The lance-shaped to oval pointed leaves are 1 to 3 centimeters long and have few or no lobes. The hairy, glandular inflorescence is a one-sided curving or coiling cyme of many bell-shaped flowers. Each flower is lavender or light blue and no more than 6 millimeters long.