Pilosocereus royenii

Royen's tree cactus helps to stabilize poor soils within its native distribution.
Photo Credit: © Pedro Acevedo-Rodriguez, USDA-NRCS PLANTS Database. Courtesy of Smithsonian Institution, Dept. of Systematic Biology, Botany.
Pilosocereus royenii
Common Name: Royen's tree cactus
Plant Functional Group: Cactus
Class > Order > Family: Magnoliopsida > Caryophyllales > Cactaceae
What does the species look like?

Royen's tree cactus is an erect, columnar, branched, perennial, succulent tree, growing to 20 feet tall. Its showy, whitish-green to purple-red flowers have both male and female parts and occur along the succulent stems.

Royen's tree cactus is barely frost tolerant, with growing tips easily damaged. It prefers full sun to bright shade on dry sites, and does well on poor, rocky soils. It is drought, wind, and salt tolerant.
Where is the species found?
States & Provinces
PR, VI
Which phenophases should I observe?
Do you see...?
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.
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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
  • More than 1,000
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.
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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
Fruits Fruits
One or more fruits are visible on the plant. For Pilosocereus royenii, the fruit is a large, pulpy berry that changes from green to red and splits open to expose the seeds. Do not include fruits that have already dropped all of their seeds.
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How many fruits are present?

  • Less than 3
  • 3 to 10
  • 11 to 100
  • 101 to 1,000
  • More than 1,000
Ripe fruits
One or more ripe fruits are visible on the plant. For Pilosocereus royenii, a fruit is considered ripe when it has turned red and has split open to expose the seeds. Do not include fruits that have already dropped all of their seeds.
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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.
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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
  • More than 1,000
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.

USDA PLANTS profile for Royen's tree cactus (USDA Symbol: PIRO6 )