Poa bulbosa

Tracheophyta MagnoliopsidaPoaceaePoaPoa bulbosa

Ecology

A tufted bulbous-based perennial herb of open grassland and barish sandy or rocky places near the sea; mainly on sand dunes and stabilised shingle, but also on bare chalk and limestone. Some populations are wholly or partially proliferous. Lowland.

Status

Native

World Distribution

Eurosiberian Southern-temperate element; widely naturalised outside its native range.

Broad Habitats

Supralittoral sediment (strandlines, shingle, coastal dunes)

Light (Ellenberg): 8

Moisture (Ellenberg): 3

Reaction (Ellenberg): 5

Nitrogen (Ellenberg): 2

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 4.6

July Mean Temperature (Celsius): 16.4

Annual Precipitation (mm): 741

Height (cm): 35

Perennation - primary

Perennial

Life Form - primary

Hemicryptophyte

Woodiness

Herbaceous

Clonality - primary

Tussock-forming graminoid, may slowly spread

Clonality - secondary

Detaching ramets on inflorescence

Count of 10km squares in Great Britain: 72

Count of 10km squares in Ireland: 0

Count of 10km squares in the Channel Isles: 6

Atlas Change Index: 0.63

JNCC Designations

NBNSYS0000002546

Scarce Atlas Account

Scarce Atlas Account: 

Poa bulbosa L.

Bulbous meadow-grass

Status: scarce

 

This maritime grass is found in a range of habitats, typically on infertile sandy soils but also on shingle and chalk and in crevices in bare limestone. It usually grows in open sparse grassland and even occurs on bare sand in dune systems. Typical associates in these habitats include Aira praecox, Plantago coronopus, Rumex acetosella, Trifolium striatum and the mosses Hypnum cupressiforme and Polytrichum piliferum. It is confined to the lowlands.

It is a perennial plant forming small swollen bulb-like bases to the stem that remain after the rest of the plant dies. P. bulbosa flowers very early in the spring (March-May) and the above-ground parts wither soon after flowering. The ‘bulbs’ often lie on the surface and can be dispersed by wind over tens of metres. They re-grow in autumn. A proportion of plants are viviparous (all plants in some populations such as those in South Wales), the flowers being replaced by tiny plantlets which are capable of rooting and becoming established as individual plants.

Its distribution is apparently stable, although this species is possibly overlooked in some places and new populations are discovered from time to time in regions where the plant has not been recorded in the past. It is difficult to know whether recently discovered plants, such as those in Surrey (Leslie 1987) and Berkshire, are hitherto-overlooked native populations, are the result of a natural extension of range, or are accidental introductions. 

It is a widespread species in Europe, found in the Mediterranean area and the west coast north to southern Scandinavia and the Baltic. It also grows in temperate Asia and North Africa.

 

A. J. Gray

Atlas text references

Atlas (380b)
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Meusel H, Jäger E, Weinert E
1965.  Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.