Flora of Idaho

Carex aboriginum is a species of sedge endemic to Idaho in the western United States, known as Indian Valley sedge. It was not observed in the wild between 1910, when it was first described, and 1999. Until its rediscovery, C. aboriginum was considered the only plant native to Idaho to have become extinct, and it remains one of the state's rarest and most endangered plant species.

Allium aaseae, the Southern Idaho onion or Aase's onion, is a plant species endemic to southwestern Idaho. It has been reported from 6 counties: Elmore, Ada, Boise, Gem, Payette and Washington. The plant is named for American botanist Hannah Caroline Aase (1883-1980), at one time professor at Washington State University in Pullman. Allium aaseae grows on sandy and gravelly sites at elevations of 800–1100 m. It has egg-shaped bulbs up to 2 cm in diameter, and pink or white bell-shaped flowers up to 10 mm long.

Astragalus aquilonius, the Lemhi milkvetch,is a milkvetch species belonging to the Fabaceae family. It is native to Idaho.

Cardamine constancei is a rare, narrow-ranged species of perennial rhizomatous forb known by the common name Constance's bittercress. It is endemic to select tributaries of the Clearwater and Coeur d'Alene Rivers in Idaho.

Lewisia sacajaweana is a species of flowering plant in the family Montiaceae known by the common name Sacajawea's bitterroot. It is endemic to Idaho, where it is known from approximately two dozen sites, with about 75 percent of them in Boise National Forest. It is usually found at elevations ranging from 5,000 feet (1,500 m) to 9,500 feet (2,900 m) above sea level and produces white flowers shortly after snowmelt. The species is named in honor of Sacagawea, Native American guide to the Lewis and Clark Expedition. It is part of a genus named for Meriwether Lewis of the same expedition.

Lepidium papilliferum is a rare species of flowering plant in the mustard family known by the common names Idaho pepperweed and slickspot peppergrass. It is endemic to Idaho in the United States, where it is mostly limited to a specific habitat type in the southwestern part of the state. It was federally listed as a threatened species in 2009. This is an herb growing just a few centimeters to over 20 centimeters tall, and known to approach 40 centimeters. The leaves are divided into many subdivided lobes, the largest blades measuring 4 centimeters in length. The inflorescence is a raceme of

Cymopterus davisii is a species of flowering plant in the carrot family known by the common name Davis's springparsley. This small, flat, taprooted perennial is endemic to Idaho in the United States, where it occurs in the Albion Mountains. The plant is found in the Albion Division of the Minidoka Ranger District of Sawtooth National Forest. It reaches approximately 7 in (18 cm) in height with a short stem that is sheathed by fibrous leaf bases. Numerous leaves form a whorl around yellow-flowered umbels. Davis's springparsley was first collected by Ray J. Davis in 1939, who was a botany

Castilleja christii is a rare species of flowering plant in the family Orobanchaceae known by the common name Christ's Indian paintbrush. It is endemic to Idaho in the United States, where there is a single population on Mount Harrison in the Albion Mountains in the Minidoka Ranger District of Sawtooth National Forest. It is one of Idaho's rarest plants. This plant was named for John Henry Christ (1896–1973), who first collected it. It is a perennial herb with a cluster of several erect stems 15 to 30 centimetres (5.9 to 11.8 inches) tall. The lance-shaped leaves are a few centimeters long

Dasynotus is a monotypic genus of flowering plants belonging to the family Boraginaceae, it only contains one known species, Dasynotus daubenmirei I.M.Johnst.. Its native range is north-western USA and it is only found in Idaho. The genus and species were circumscribed by Ivan Murray Johnston in J. Arnold Arbor. vol.29 on page 233 in 1948. It has the common name of 'Daubenmire's Dasynotus'. The Latin specific epithet of daubenmirei is in honour of Rexford F. Daubenmire (1909—1995), an American ecologist that went to the University of Minnesota, where he was taught by William Skinner Cooper

Erigeron salmonensis is a rare North American species of flowering plant in the family Asteraceae known by the common name Salmon River fleabane. It has been found only in the Salmon River Canyon in central Idaho. Erigeron salmonensis grows on ledges and cracks in north-facing cliffs. It is a perennial herb that can reach up to 35 cm (14 inches) tall, forming a woody underground caudex. The inflorescence generally contains only 1 to 3 flower heads per stem. Each head contains 11 to 15 white ray florets surrounding many yellow disc florets.

Chaenactis evermannii is a North American species of flowering plants in the aster family known by the common name Evermann's pincushion. It is found only at high altitudes in the mountains in the central part of the US State of Idaho.

Hartmaniella oxyphylla, the robust starwort or Robinson's starwort, is a rare species of plant endemic to the north-western United States, where it is known only from Kootenai and Shoshone Counties, Idaho. It grows along stream-banks in conifer forests at elevations of 800–900 m.

Camassia cusickii, common name Cusick's camas or Cusick's quamash, is a species of plant in the family Asparagaceae (subfamily Agavoideae). It is native to parts of North America. C. cusickii originally appeared in horticultural journals in the late 1800s.

Astragalus scaphoides, the bitterroot milkvetch, is a flowering plant in the family Fabaceae, the third-largest plant family in the world. It is found only in a small area of southwest Montana and adjacent parts of Idaho and as far west as Prineville, Oregon. It grows on shallow, south-facing slopes, in semi-arid sage scrub. Astragalus scaphoides is a perennial herbaceous plant with pinnate leaves. The pale yellow flowers open in May and are visited by several species of bumblebees and solitary bees, including those from the genera Osmia and Anthophora. Plants can be found near Lemhi Pass on

Allium simillimum, the simil onion, or dwarf onion, is a plant species native to Idaho and Montana (Gallatin and Ravalli Counties). It grows on sandy soils at high elevations in the mountains, 1800–3400 m. Allium simillimum produces egg-shaped bulbs up to 1.7 cm long. Flowering stalks are rarely more than 5 cm tall. Flowers are bell-shaped, up to 10 mm across; tepals white with green or pink midribs; anthers purple; pollen white or gray.

Astragalus mulfordiae is a species of flowering plant in the legume family known by the common name Mulford's milkvetch. It was so named after its discoverer Anna Isabel Mulford. It is native to the Snake River Plain in Idaho and Oregon in the United States. This perennial herb grows up to 25 or 30 centimeters tall with slender stems. The green or yellow-green leaves have several pairs of leaflets that vary in shape, the largest ones about 1.1 centimeters long. The inflorescence is a raceme of up to 20 flowers with white or cream-colored petals which may be striped or tinged purple. The fruit

Lewisia kelloggii is a species of flowering plant in the family Montiaceae known by the common name Kellogg's lewisia. It is endemic to the Sierra Nevada of California, where it is known from several sites high in the mountains. It grows in rocky mountain habitat in granite and slate substrates. This is a perennial herb growing from a thick, short taproot and caudex unit. It produces a basal rosette of many thick, leathery, spoon-shaped leaves up to 9 centimeters (3.5 in) long. The inflorescence bears several flowers, each on a very short stalk. The flower has 5 to 13 shiny white or pinkish

Allium madidum, common name mountain swamp onion, is a plant species native to the west-central Idaho (Valley, Adams, and Washington Counties), southern Washington (Walla Walla County) and eastern Oregon. It grows in wet meadows at elevations of 1100–2000 m. Allium madidum produces 1-3 bulbs with as many as 30 smaller bulbils attached. The full-size bulbs are round to egg-shaped, up to 1.6 cm long. Flowers are bell-shaped, up to 10 mm across; tepals white with green or pink midveins; pollen yellow. Flowers bloom May to July.

Primula alcalina, the alkali or bluedome primrose, is a species of primrose found in central-east Idaho and Montana.

Lomatium salmoniflorum (salmonflower biscuitroot) is a perennial herb native to the northwest United States. In February and March one to nineteen umbels bloom, each with up to 300 flowers. Each flower is either strictly staminate or hermaphroditic. It has glabrous leaves that are deeply dissected into narrow blades.

Frasera fastigiata (syn. Swertia fastigiata) is a species of flowering plant in the gentian family known by the common name clustered green gentian. It is native to the northwestern United States, where it grows in meadows, grasslands, woodlands, and forest openings. It is a perennial herb that grows 5 ft (1.5 m) tall. The basal leaves have oval or spoon-shaped blades up to 30 centimeters long by 10 wide. Leaves higher on the stem may be smaller and narrower. Some of the leaves have white margins. The inflorescence is a dense panicle atop the stem, sometimes interrupted into a series of

Chionophila tweedyi, or Tweedy's snowlover, is a perennial herb in the plantain family. It is native to Idaho and Montana in the western United States.

Calochortus nitidus, the broadfruit mariposa lily, is a North American species of flowering plants in the lily family native to the northwestern United States. Calochortus nitidus is found primarily in northern Idaho and southeastern Washington, but isolated populations have been reported from Jackson County in southwestern Oregon.

× Amelasorbus is a flowering plant in the family Rosaceae. A naturally occurring hybrid, it is the result of a cross between two distinct tree genera, Amelanchier and Sorbus, and shows phenotypic similarities to both parents. This type of intergeneric hybrid is quite rare, and is indicated by a multiplication symbol before the name. The name Amelasorbus is an example of a portmanteau word, a combination of the two parents' names.

Micranthes bryophora is a species of flowering plant known by the common name bud saxifrage. It is native to the western United States, where its two varieties are geographically separated. The more common var. bryophora is endemic to the mountains of California, and the rare var. tobiasiae is known only from the Payette National Forest of western Idaho. This plant is a perennial herb producing a basal rosette of fleshy, hairy, lance-shaped leaves up to 4 centimeters long. The inflorescence arises on a peduncle up to 25 centimeters tall with widely spaced flowers, each at the tip of a

Hackelia cronquistii is a species of flowering plant in the borage family known by the common name Cronquist's stickseed. This species was formerly treated as a variety of Hackelia patens, until elevated to its own species status in 1972.

Symphyotrichum jessicae (formerly Aster jessicae) is a species of flowering plant in the family Asteraceae endemic to Idaho and Washington states in the United States. Commonly known as Jessica's aster, it is a perennial, herbaceous plant that may reach 40 to 150 centimeters (1+1⁄4 to 5 feet) tall. Its flowers have violet ray florets and yellow disk florets. It is of conservation concern and known only from the Palouse River and Clearwater River drainages of eastern Washington and northwestern Idaho.

Rubus bartonianus, or Barton's raspberry, is an uncommon North American species of flowering plant in the rose family.

Pyrrocoma liatriformis is a species of flowering plant in the family Asteraceae. Its common names include Palouse goldenweed and smallhead goldenweed. It is native to the northwestern United States, where it is endemic to the Palouse prairie, growing in grassland dominated by blue bunchgrass. It is a perennial herb growing from a taproot, producing one to three stems up to 70 centimeters (28 inches) in length. The stems are erect and hairy. Leaves near the base of the plant are larger and rounder than the leaves connected to the stem, which are lanceolate and hairy. Basal leaves measure

Chaenactis cusickii is a North American species of flowering plants in the aster family known by the common name Morning brides or Cusick's pincushion. It has been found only in southeastern Oregon and southwestern Idaho.