FLORA OF ICELAND elements: Trisetum spicatum, Spike Trisetum

-->This species is also known as Narrow False Oat and Three-flowered Oat as well as Trisetum triflorum (see notes on species/names).

Trisetum spicatum; the Spike Trisetum is probably the only grass species on Iceland with dense hairy culms. The inflorescence is a spike-like panicle. The culms and panicles either appear purple or yellow/brown green. It grows in tussocks without stolons or otherwise creeping stems. It is about 40cm tall. The ligules are small (1-2mm) and are often fringed.

The Spike Trisetum can be found all over Iceland. It prefers gravel soils, dry grasslands and rocky grounds.

Notes on species and names: Trisetum spicatum is a complicated species to be found in a large part of the northern hemisphere. When referred to T. spicatum (s.lat. meaning in a broad sense) all variations are regarded as subtaxa of this one species. Specialists, though disagree on how to define it. On Iceland two distinct populations are found, being T. spicatum (s.str. = in the strict sense) and T. triflorum. As far as I understand the latter is not regarded by the majority of taxonomists as a seperate species and is included within T. spicatum. Icelandic taxonomists regard them as two different species. The genetic differences are well understood: T. triflorum (English name: Three-flowered False Oat) is a hexaploid where T. spicatum s.str (English name: Narrow False Oat) is a tetraploid. The morphological differences are: T. spicatum s.str. has puple colored glumes which are glabrous but for some hairs on the keel. The spikelets have two flowers. T. spicatum have hairy green or only marginal puple-fringed glumes and spikelets with three flowers. However, I have once found a plant with very purple glumes that are very hairy. This fits neither. Conclusion this is a matter for specialists!

The Spike Trisetum is a member of the grass family (Poaceae, also known as Gramineae). The Icelandic name of the the Narrow False Oat (T. spicatum s.str.) is Lógresi. The Icelandic name of the the Three-flowered False Oat (T. triflorum) is Móalógresi.

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A brief introduction to Iceland plants
Text & Photographs by Dick Vuijk - unless stated otherwise


a tuft
top of culm with panicle
focus on spikelets
focus on culm (ligules)
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a tuft

top of culm with panicle

focus on spikelets

focus on culm (ligules)

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