Red crust alga
Hildenbrandia rivularis · Algae
Where it grows · Photo: Héctor Ibáñez Cantero / CC BY
Also called Hildenbrandia, Red algae, Red rock crust
How to identify Red crust alga
- Thin red or brick red crust on rocks, looks like paint
- Cannot be lifted or scraped off as strands
- Smooth surface
- Usually on shaded rocks in clear streams
Similar species
Iron deposits can be red but are powdery and rub off; lichens are dry and above the waterline.
Growth profile
| Season | Present year round as a long lived crust. |
|---|---|
| Starts | Cool water |
| Light | Low light; shade tolerant |
| Depth | Crust on submerged rocks |
| How it spreads or reproduces | Fragments and spread by water to new rocks |
| Habitat | Cool, clear streams and springs, on shaded stones. |
Why it matters in a lake
A harmless long lived crust. Indicates clean, stable water.
Where it is found
- Idaho: Rare
- Oregon: Rare
- Wyoming: Rare
Classification
| Kingdom | Plantae |
|---|---|
| Phylum | Rhodophyta |
| Class | Florideophyceae |
| Order | Hildenbrandiales |
| Family | Hildenbrandiaceae |
| Scientific name | Hildenbrandia rivularis |
Didymo
Frog spawn alga
Hydrurus
Lemanea
Compsopogon
SpirogyraNeed a hand?
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