Ulnaria (Synedra)
Ulnaria spp. · Phytoplankton
Under the microscope · Photo: CC0
Also called Synedra, Needle diatom, Ulnaria ulna
How to identify Ulnaria (Synedra)
- Under the microscope: long, thin needle shaped diatoms, single or attached in fan shaped clusters
- Golden brown plastids along the length of the cell
- Fine crosswise lines on the glass shell
- In the water: part of the brown film on plants and rocks; can tint water brown in spring
Similar species
Fragilaria cells join side by side into ribbons; Nitzschia acicularis is a thinner needle with a raphe slit along the edge.
Profile
| Season | Spring and fall peaks, present much of the year. |
|---|---|
| Starts | About 40 to 60 F |
| Light | Moderate light |
| Depth | Open water and attached at the edges |
| How it spreads or reproduces | Cell division |
| Habitat | Ponds, lakes, reservoirs, canals and streams, both floating and attached to plants and rocks. |
Why it matters in a lake
Most freshwater Synedra are now called Ulnaria, but many labs still report Synedra. Harmless; heavy growth can clog irrigation screens.
Where it is found
- Idaho: Common
- Oregon: Common
- Wyoming: Common
Classification
| Kingdom | Chromista |
|---|---|
| Phylum | Bacillariophyta |
| Class | Bacillariophyceae |
| Order | Licmophorales |
| Family | Ulnariaceae |
| Scientific name | Ulnaria spp. |
Fragilaria
Cyclotella
Asterionella
Navicula
Aulacoseira
Nitzschia
Stephanodiscus
Tabellaria
Melosira
GomphonemaNeed a hand?
Want to know what is in your water?
Lab counts of the algae in your lake show what is growing, how much and whether a bloom is coming.
Idaho / Wyoming (208) 501-4531Oregon (541) 280-0596