Rhipocephalus phoenix — Pinecone Stem Plant
The uncommon pinecone of the reef.
What You Get
Rhipocephalus phoenix, commonly called the Pinecone Stem Plant, is a calcareous macroalga that grows as a tapered, pinecone-shaped sphere rising from the sand. Each plant is built from tightly arranged, calcified fronds that give it the look of a miniature conifer or Christmas tree.
In the wild, Rhipocephalus species such as phoenix, brevifolius, and longifolius occur on reef flats and sandy bottoms from roughly 3 to 100 feet deep.
At the base is a bulb-like holdfast with fine rhizoids that anchor it deeply into sand or fine rubble. In the right conditions, mature specimens can reach about 6 inches tall and 2 to 3 inches in diameter, becoming a standout focal point in deep sand beds (3 inches+) and macro displays. This species is collected with its bulb and a bit of substrate. In the aquarium, this species shows a moderate growth rate once established.
Why It Is Algaesome
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A true collector’s stem plant: Far less common than many other calcareous macros, Pinecone Stem Plant offers a sculptural form that feels more like a tiny underwater bonsai than typical seaweed.
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Pinecone meets reef flat: Native to sandy reef flats and seagrass beds in the Atlantic and Caribbean, it brings the look of natural “reef ornaments” into your aquascape.
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Deep sand specialist: Thrives in tanks with a deep sand bed of 3 inches or more, where its bulb and rhizoids can properly anchor and expand over time.
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Calcareous and reef friendly: Like other calcified stem plants, it prefers systems with strong calcium and alkalinity, making it a natural fit for reef aquariums.
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Not on the menu: Generally not palatable to most herbivorous fish and invertebrates, so it often persists where softer macros would be grazed down.
Sizing & Availability
Each Pinecone Stem Plant is shipped as a single, rooted individual, usually 2 to 4 inches in height. Shape, fullness, and degree of taper vary naturally; some plants appear more pinecone-like, while others resemble miniature trees.
Traits
Color Olive to bright green
Ease Easy with deep sand bed
Classification Calcareous green macroalgae (stem plant)
Nutrient Uptake Fair
Availability Occasional, conditions dependent
Use Display stem plant; deep sand beds
Lighting Moderate to high
Flow Moderate
A Note from the Collectors:
Every macroalga we offer is hand collected, acclimated, and observed by our team before shipping. While we carefully try to remove other algae, sponges, and tiny hitchhikers, it is possible that a few goodies from the reef may tag along. It is a natural part of receiving genuine wild collected specimens.
Many species may arrive paler or whitish in color. This is completely normal. Macroalgae shift their pigments inward during transport to protect from light and stress; color returns within a few days under good aquarium lighting and flow.
We ship via 2 Day service on Mondays and Tuesdays only to ensure specimens arrive healthy. You will receive a notification with tracking information as soon as your order ships.
