Acer glabrum

Acer glabrum is important for browse of wild and domestic animals, and also provides important shade cover along streams.

Photo Credit: © Walter Siegmund via Wikimedia Commons.

Acer glabrum

Common Name: Rocky Mountain maple

Other Common Names: California mountain maple, Douglas maple, dwarf maple, New Mexico maple, Sierra maple

Plant Functional Group: Deciduous broadleaf

Class > Order > Family: Magnoliopsida > Sapindales > Sapindaceae

What does the species look like?

Rocky Mountain maple is a deciduous, multi-stemmed shrub growing 5 to 6.5 feet or small tree growing 20 to 30 feet tall. Male and female flowers can occur on the same plant or on different plants, and are wind- and animal-pollinated.

Rocky Mountain maple grows on moist, well-drained to dry soils in full to partly sunny sites.

Where is the species found?

States & Provinces

AB, AK, AZ, BC, CA, CO, ID, MT, NE, NM, NV, OR, SD, UT, WA, WY

Special Considerations for Observing

If drought seems to be the cause of leaf color or fall for a plant, please make a comment about it for that observation.

This species has separate male and female flowers. If you know whether the flowers you are observing are male or female (or both), please make a comment about it for that observation.

Note that individuals of this species with only male flowers will not produce fruit.

Which phenophases should I observe?

	Do you see...?
Leaves	Breaking leaf buds One or more breaking leaf buds are visible on the plant. A leaf bud is considered "breaking" once a green leaf tip is visible at the end of the bud, but before the first leaf from the bud has unfolded to expose the leaf base at its point of attachment to the leaf stalk (petiole) or stem. More... How many buds are breaking? Less than 3 3 to 10 11 to 100 101 to 1,000 1,001 to 10,000 More than 10,000
	Leaves One or more live, unfolded leaves are visible on the plant. A leaf is considered "unfolded" once its entire length has emerged from a breaking bud, stem node or growing stem tip, so that the leaf base is visible at its point of attachment to the leaf stalk (petiole) or stem. Do not include fully dried or dead leaves. More... What percentage of the potential canopy space is full with leaves? Ignore dead branches in your estimate of potential canopy space. Less than 5% 5-24% 25-49% 50-74% 75-94% 95% or more
	Increasing leaf size A majority of leaves on the plant have not yet reached their full size and are still growing larger. Do not include new leaves that continue to emerge at the ends of elongating stems throughout the growing season. More... What percentage of full size are most leaves? Less than 25% 25-49% 50-74% 75-94% 95% or more
	Colored leaves One or more leaves show some of their typical late-season color, or yellow or brown due to drought or other stresses. Do not include small spots of color due to minor leaf damage, or dieback on branches that have broken. Do not include fully dried or dead leaves that remain on the plant. More... What percentage of the potential canopy space is full with non-green leaf color? Ignore dead branches in your estimate of potential canopy space. Less than 5% 5-24% 25-49% 50-74% 75-94% 95% or more
	Falling leaves One or more leaves with typical late-season color, or yellow or brown due to other stresses, are falling or have recently fallen from the plant. Do not include fully dried or dead leaves that remain on the plant for many days before falling. More...
Flowers	Flowers or flower buds One or more fresh open or unopened flowers or flower buds are visible on the plant. Include flower buds or inflorescences that are swelling or expanding, but do not include those that are tightly closed and not actively growing (dormant). Also do not include wilted or dried flowers. More... How many flowers and flower buds are present? For species in which individual flowers are clustered in flower heads, spikes or catkins (inflorescences), simply estimate the number of flower heads, spikes or catkins and not the number of individual flowers. Less than 3 3 to 10 11 to 100 101 to 1,000 1,001 to 10,000 More than 10,000
	Open flowers One or more open, fresh flowers are visible on the plant. Flowers are considered "open" when the reproductive parts (male stamens or female pistils) are visible between or within unfolded or open flower parts (petals, floral tubes or sepals). Do not include wilted or dried flowers. More... What percentage of all fresh flowers (buds plus unopened plus open) on the plant are open? For species in which individual flowers are clustered in flower heads, spikes or catkins (inflorescences), estimate the percentage of all individual flowers that are open. Less than 5% 5-24% 25-49% 50-74% 75-94% 95% or more
	Pollen release One or more flowers on the plant release visible pollen grains when gently shaken or blown into your palm or onto a dark surface. More... How much pollen is released? Little: Only a few grains are released. Some: Many grains are released. Lots: A layer of pollen covers your palm, or a cloud of pollen can be seen in the air when the wind blows
Fruits	Fruits One or more fruits are visible on the plant. For Acer glabrum, the fruit is two joined seeds in a "V" shape, each seed having a wing, that changes from green to tan or light brown and drops from the plant. More... How many fruits are present? Less than 3 3 to 10 11 to 100 101 to 1,000 1,001 to 10,000 More than 10,000
	Ripe fruits One or more ripe fruits are visible on the plant. For Acer glabrum, a fruit is considered ripe when it has turned tan or light brown and readily drops from the plant when touched. More... What percentage of all fruits (unripe plus ripe) on the plant are ripe? Less than 5% 5-24% 25-49% 50-74% 75-94% 95% or more
	Recent fruit or seed drop One or more mature fruits or seeds have dropped or been removed from the plant since your last visit. Do not include obviously immature fruits that have dropped before ripening, such as in a heavy rain or wind, or empty fruits that had long ago dropped all of their seeds but remained on the plant. More... How many mature fruits have dropped seeds or have completely dropped or been removed from the plant since your last visit? Less than 3 3 to 10 11 to 100 101 to 1,000 1,001 to 10,000 More than 10,000

What do these phenophases look like?

There is currently no photoguide available for this species. If you'd like help us create one, use the guidance document and species template provided here. Then send it via email to education@usanpn.org when it is complete.

ITIS information for Rocky Mountain maple (ITIS TSN: 28742 )

USDA PLANTS profile for Rocky Mountain maple (USDA Symbol: ACGL )

Acer glabrum

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