Flora of Montana

Boechera fecunda (syn. Arabis fecunda) is a species of flowering plant in the mustard family known by the common names Mt. Sapphire rockcress and Sapphire rockcress. It is endemic to Montana in the United States, where there are twenty known occurrences in three counties.

Castilleja kerryana is a species of flowering plant in the family Orobanchaceae. It is commonly known as Kerry's Indian paintbrush or Kerry's paintbrush. It was formally described in 2013 and so far it is known only from a small population in the state of Montana, in the Northwestern United States. The first collection of this plant was tentatively identified as a specimen of Castilleja crista-galli, and it is also similar to C. fraterna and C. pulchella. It differs from the latter two in its color and in the shape of its stem and flower corolla.

Physaria humilis, the St. Marys Peak bladderpod or Bitterroot bladderpod, is a species within the family Brassicaceae that is endemic to the Bitterroot Mountains of Montana.

Cirsium longistylum, the long-style thistle, is a North American species of plants in the tribe Cardueae within the family Asteraceae. The species is found only in the central part of the State of Montana in the United States, in the portions of the Rocky Mountains called the Big Belt, Castle, Elkhorn, and Little Belt ranges. Cirsium longistylum is a biennial or perennial herb up to 150 cm (60 inches or 5 feet) tall, with a large taproot. Leaves are up to 30 cm (26 inches) long with thin, green on the upper side but gray to white on the underside because of numerous woolly hairs; spines along

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.

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

Eritrichium howardii, or Howard's alpine forget-me-not, is a rare flowering plant found in the Rocky Mountains area, most notably in Wyoming and Montana. It is a light blue to purplish five-petaled flower with a yellow ring in the middle.

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.

Shoshonea is a monotypic genus of flowering plants belonging to the parsley family. Its native range is Western Central USA.

Erigeron allocotus is a species of flowering plant in the family Asteraceae known by the common name Bighorn fleabane. It has been found only in the Bighorn Mountains of north-central Wyoming and southern Montana. Erigeron allocotus is a short, branching shrub rarely more than 18 cm (7 inches) tall. Leaves are 3-lobed. The inflorescence generally consists of 2 or 3 flower heads per stem, each head with sometimes as many as 40 small yellow disc florets and surrounded by a ring of up to 40 white or blue ray florets.

Artemisia porteri is a species of flowering plant in the aster family known by the common names Porter's sagebrush, Porter's wormwood, and Porter mugwort. It is endemic to Wyoming in the United States, where it is known from Fremont, Johnson and Natrona Counties. This plant is a perennial herb or small subshrub, growing in clumps or mats up to 14 centimeters tall. There are several woolly stems with silvery lobed leaves. Bell-shaped woolly flower heads contain small yellowish disc florets. This plant grows in the badlands of central Wyoming. It can be found on substrates of mudstone and

Erigeron parryi is a species of flowering plant in the family Asteraceae known by the common name Parry's fleabane. It is native to the Rocky Mountains of southern Montana and northern Wyoming. Erigeron parryi is a small perennial herb rarely more than 15 centimeters (6 inches) tall, producing a woody taproot. The leaves are covered with wool. The plant generally produces only 1 flower head per stem, though occasionally 2 or 3. Each head has 20–40, pink, or blue ray florets surrounding numerous yellow disc florets. The plant grows on rocky limestone slopes, frequently alongside sagebrush.

Castilleja puberula, commonly alpine paintbrush or short-flowered paintbrush, is a plant species in the broomrape family that grows exclusively in high elevation habitats. Before 2014 it was thought to only grow in Colorado in mountains near the Great Divide, but an additional population was located on a mountain in southwest Montana.

Castilleja nivea, the snow paintbrush or snowy paintbrush, is a rare species of alpine plant from northern Wyoming and southern Montana.

Erigeron flabellifolius is a rare North American species of flowering plants in the family Asteraceae known by the common names fan-leaf fleabane . Erigeron flabellifolius is native to the mountains in the vicinity of Yellowstone National Park and Grand Teton National Park in Montana and Wyoming. It grows at high elevations on cliffs, rockslides, and alpine meadows. Erigeron flabellifolius is a tiny perennial herb rarely more than 8 centimeters (3.2 inches) in height. Most of the leaves are clustered around the base of the stems. They are fan-shaped, narrowed at the base, triangular or

Erigeron evermannii is a North American species of flowering plants in the family Asteraceae known by the common name Evermann's fleabane. Erigeron evermannii is native to the western United States. It is native to central Idaho and has also been found in western Montana. It grows at high elevations in the mountains, on steep slopes, talus outcrops, and ridges, sometime alongside whitebark pine. Erigeron evermannii is a very short perennial herb rarely more than 10 centimeters (4 inches) in height, sprouting from the roots and hence forming a sizable clump of many shoots crowded together.

Hesperostellaria is a genus of flowering plants in the family Caryophyllaceae. It contains a single species, Hesperostellaria americana, a perennial native to subalpine areas of Alberta and Montana. The species was first described as Stellaria dichotoma var. americana in 1894, and later renamed Stellaria americana. In 2023 it was placed in the new monotypic genus Hesperostellaria as Hesperostellaria americana.

Grindelia howellii, or Howell's gumweed, is a North American species of flowering plants in the family Asteraceae. It is native to the northwestern United States, in the States of Idaho and Montana. Grindelia howellii grows in open, sunny sites on rocky slopes and in alluvial deposits. It is a perennial herb sometimes as much as 150 cm (5 feet) tall. The plant usually produces numerous flower heads in crowded, flat-topped arrays. Each head has 18-25 ray flowers, surrounding a large number of tiny disc flowers.

Carex plectocarpa is a sedge that is native to north western parts of the United States.

Hesperostellaria is a genus of flowering plants in the family Caryophyllaceae. It contains a single species, Hesperostellaria americana, a perennial native to subalpine areas of Alberta and Montana. The species was first described as Stellaria dichotoma var. americana in 1894, and later renamed Stellaria americana. In 2023 it was placed in the new monotypic genus Hesperostellaria as Hesperostellaria americana.

Allium columbianum, the Columbian onion, is a species of onion native to eastern Washington (Pend Oreille, Spokane, Lincoln and Whitman Counties), northern Idaho (Idaho, Clearwater, Latah and Kootenai Counties), and the Bitterroot Mountains of western Montana (Ravalli and Sanders Counties). It is a perennial herb that grows on shallow, wet soils at elevations of 300–1100 m. Allium columbianum produces egg-shaped bulbs up to 15 mm long. Flowers are up to 10 mm across, pink to light purple with green midrib; anthers and pollen blue to gray. Flowers bloom May to July.

Astragalus molybdenus is a species of flowering plant in the legume family known by the common names Leadville milkvetch and molybdenum milkvetch. It is endemic to Colorado in the United States. If the separate species Astragalus shultziorum and Astragalus lackschewitzii are included in A. molybdenum the range expands into Wyoming and Montana.

Mentzelia pumila, (dwarf mentzelia, desert blazing star, blazing star, bullet stickleaf, golden blazing star, yellow mentzelia, evening star, moonflower, Wyoming stickleaf, etc.) is a biennial wildflower found in the western United States and northwestern Mexico from Montana and North Dakota, south to Sonora and Chihuahua. It is a blazingstar and a member of the genus Mentzelia, the stickleafs; member species are also called "evening stars", but some stickleafs close at sunset, as does M. pumila. Leaves of Mentzelia pumila are long, very narrow, and serrated-pinnate-like; also medium to light

Kelseya is a monotypic genus of flowering plants belonging to the family Rosaceae. The only species is Kelseya uniflora. It is commonly called the oneflower kelseya, spiraea or alpine laurel. The genus was named in honor of Francis Duncan Kelsey, a Montana resident botanist, who discovered the plant in 1888 at the "Gate of the Mountains" near Townsend.

Eriogonum visheri is a species of wild buckwheat known by the common names Dakota wild buckwheat and Visher's buckwheat. It is native to the Great Plains in the United States, where it is known from North Dakota, South Dakota, and Montana. This plant is an annual herb with erect stems growing up to 10 centimeters tall. It is described as "skeletal" or "skeleton-like" in appearance. Leaves around the base of the plant are up to 2.5 centimeters long by 2.5 wide, and leaves higher on the stem are similar but smaller. The stems branch into an inflorescence studded with clusters of small yellowish

Coptis occidentalis, the Idaho goldthread, is a species of flowering plant native to western North America. It is a member of the buttercup family. This plant has also been known under the binomial Chrysocoptis occidentalis and the common name western goldthread. The Idaho goldthread is a spring flowering plant, usually found in moist coniferous forests.

Penstemon cyaneus is a species of flowering plant in the plantain family known by the common names blue penstemon and dark blue penstemon. It is native to the western United States, where it is widespread in Idaho and also found in parts of Montana and Wyoming.

Erythronium idahoense, commonly known as Idaho fawn lily, is a white-flowered plant in the Lily family native to the northwestern United States (Washington, Idaho, and Montana). Its habitats include grasslands and forest openings. This taxon was listed as Erythronium grandiflorum subsp. candidum in Flora of North America.

Astragalus barrii is a species of flowering plant in the legume family known by the common name Barr's milkvetch. It is native to the United States, where it is a "regional endemic", occurring in parts of southwestern South Dakota, northeastern Wyoming, southeastern Montana, and Nebraska. This mat-forming perennial herb grows only about 4 inches in height. The leaves are each made up of three lance-shaped leaflets. The herbage is coated in white hairs which are dolabriform, or shaped like the head of an ax. The inflorescence contains iridescent pinkish purple flowers with petals up to 1.7