1946 Planting guide for the best evergreens, shrubs, plants, trees, vines, fruits - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Richards' Gardens, 1946)

1954 handbook of alpines and rock garden plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Mayfair Nurseries, 1954)

1997 IUCN red list of threatened plants (1997)

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Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 1996)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 1996)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2000)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2000)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2000)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2001)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2001)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2002)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2005)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2010)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2010)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2013)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2015)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2016)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2017)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2022)

Aquilegia - Colorado Native Plant Society. (Colorado Native Plant Society, 2022)

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Bulletin - Colorado Agricultural Experiment Station (Colorado State University Experiment Station, 1905)

Bulletin - National Museum of Canada. (National Museum of Canada, 1949)

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Checklist of vascular plants of the Southern Rocky Mountain Region - Snow, Neil Wilton (2009)

Contributions from the New York Botanical Garden - New York Botanical Garden (The Garden, 1912)

Contributions from the New York Botanical Garden - New York Botanical Garden (The Garden, 1912)

Contributions from the New York Botanical Garden - New York Botanical Garden (The Garden, 1912)

Contributions from the New York Botanical Garden - New York Botanical Garden (The Garden, 1918)

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Flora of Colorado - Rydberg, Per Axel, 1860 -1931 (Experiment Station, 1906)

Flora of Colorado - Rydberg, Per Axel, 1860 -1931 (Experiment Station, 1906)

Flora of Colorado - Rydberg, Per Axel, 1860 -1931 (Experiment Station, 1906)

Flora of Colorado - Rydberg, Per Axel, 1860 -1931 (Experiment Station, 1906)

Flora of the Black Hills of South Dakota - Rydberg, Per Axel, 1860 -1931 (Govt. Print. Off, 1896)

Flora of the Black Hills of South Dakota - Rydberg, Per Axel, 1860 -1931 (Govt. Print. Off, 1896)

Flora of the Rocky Mountains and adjacent plains : Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, North Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (Rydberg, 1917)

Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (The author, 1917)

Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (The author, 1917)

Flora of the Rocky Mountains and adjacent plains : Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, North Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (Rydberg, 1917)

Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, North Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (The author, 1922)

Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (The author, 1917)

Flora of the Rocky Mountains and adjacent plains, Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (The author, 1917)

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The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1955)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1955)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1958)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1963)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1963)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1978)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1980)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1983)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1985)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1985)

The Green thumb - Denver Botanic Gardens. (Colorado Forestry and Horticulture Association, 1989)

Green thumb news - Denver Botanic Gardens. (Educational Dept., Denver Botanic Gardens, Inc.], 1983)

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Green thumb newsletter - Denver Botanic Gardens. (Denver Botanic Gardens, 1975)

Green thumb newsletter - Denver Botanic Gardens. (Denver Botanic Gardens, 1975)

Hardy native and imported alpines and perennials : retail catalog 1934 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Wm. Borsch & Son, Inc, 1934)

Hardy perennials, trees, evergreens, shrubs, roses - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1947)

Hardy perennials, trees, evergreens, shrubs, roses - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1936)

Hardy perennials, trees, evergreens, shrubs, roses - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1944)

Hardy perennials, trees, evergreens, shrubs, roses - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1936)

Hardy perennials, trees, evergreens, shrubs, roses - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1945)

Hardy perennials, trees, evergreens, shrubs, roses - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1936)

Journal of the New York Botanical Garden - New York Botanical Garden (Published for the Garden by the New Era Printing Co, 1937)

Key to the Rocky Mountain flora. Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and parts of Nebraska, South Dakota, North Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (1919)

Key to the Rocky Mountain flora. Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and parts of Nebraska, South Dakota, North Dakota, and British Columbia - Rydberg, Per Axel, 1860 -1931 (1919)

Leaflets - Brooklyn Botanic Garden. (1936)

Life zone investigations in Wyoming - United States. Bureau of Biological Survey. (Government Printing Office, 1917)

Madroño; a West American journal of botany - California Botanical Society. (California Botanical Society, 1998)

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Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1990)

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Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1990)

Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1990)

Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1996)

Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1996)

Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1998)

Mountain, plain and garden : the magazine of Denver Botanic Gardens - Denver Botanic Gardens. (The Gardens, 1998)

New manual of botany of the central Rocky Mountains, vascular plants - Coulter, John Merle, 1851 -1928 (American Book Co, 1909)

New manual of botany of the central Rocky mountains (vascular plants) - Coulter, John Merle, 1851 -1928 (American Book Company, 1909)

New manual of botany of the central Rocky Mountains, vascular plants - Coulter, John Merle, 1851 -1928 (American Book Co, 1909)

New manual of botany of the central Rocky mountains (vascular plants) - Coulter, John Merle, 1851 -1928 (American book company, 1909)

New manual of botany of the central Rocky mountains (vascular plants) - Coulter, John Merle, 1851 -1928 (American Book Company, 1909)

New manual of botany of the central Rocky mountains (vascular plants) - Coulter, John Merle, 1851 -1928 (American book company, 1909)

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North American fauna - U.S. Fish; Wildlife Service (Fish and Wildlife Service; for sale by the Supt. of Docs., U. S. Govt. Print. Off, 1918)

Park and cemetery and landscape gardening - Haight, R. J. (Rufus J.) (R.J. Haight, 1913)

Phytogeographic survey of North America. A consideration of the phytogeography of the North American continent, including Mexico, Central America and the West Indies, together with the evolution of North American plant distribution - Harshberger, John W. (John William), 1869 -1929 (W. Engelmann, 1911)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1997)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1997)

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Rhodora - Robinson, Benjamin Lincoln, 1864 -1935 (New England Botanical Club [etc.], 1920)

Rhodora - Robinson, Benjamin Lincoln, 1864 -1935 (New England Botanical Club [etc.], 1920)

Rock garden alpines, and other Colorado native plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1933)

Rock garden alpines, and other Colorado native plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1933)

Rock garden alpines, and other Colorado native plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1933)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1941)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1936)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1936)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1937)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1938)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1937)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1941)

Rocky Mountain rarities from Colorado - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1938)

Rocky Mountain rarities from Colorado : plants and seeds - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1945)

Rocky Mountain rarities from Colorado : plants and seeds - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Upton Gardens, 1945)

Some common Colorado wild flowers - Roberts, Harold D. (Denver Museum of Natural History, 1953)

Synoptical flora of North America - Gray, Asa, 1810 -1888 (American Book Company, 1895)

University studies of the University of Nebraska - University of Nebraska (Lincoln campus) (1904)

University studies of the University of Nebraska - University of Nebraska (Lincoln campus) (1904)