Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Algal factsheet: Planothidium (Achnanthidiaceae)


Diagnostic features

Small pennate diatoms, with differing valves (only one has a raphe; genus is monoraphid).  Boat-shaped in valve view, curved in girdle view. Striae radiating from the central area. Rapheless valve has an area lacking striae on one side, known as a "hood" or "horse-shoe" (cf. Achnanthidium). Chloroplasts golden brown.

Typical habitats

The specimens photographed were from a lowland river

Classification

Kingdom Chromista
Phylum Ochrophyta
Subphylum Chrysophyta
Class Bacillariophyceae
Order Achnanthales
Family Achnanthidiaceae
Common name Diatoms