Hypochaeris glabra
Ecology
An annual of open summer-parched grasslands and heathy pastures, on usually acidic, nutrient-poor, sandy or gravelly soils; also occurring in dune grassland and on sandy shingle. It was formerly widespread as a weed of arable fields, and as a wool-shoddy alien. Lowland.
Status
Trends
H. glabra is declining in semi-natural habitats, even though there have been many new records since it was mapped by Stewart et al. (1994). It has been lost from some squares as a result of agricultural improvement or loss of grazing. It can easily be overlooked, however, particularly as the flowers close in the afternoon.
World Distribution
European Southern-temperate element; widely naturalised outside its native range.
Broad Habitats
Light (Ellenberg): 8
Moisture (Ellenberg): 4
Reaction (Ellenberg): 4
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4
July Mean Temperature (Celsius): 15.9
Annual Precipitation (mm): 754
Height (cm): 20
Perennation - primary
Life Form - primary
Woodiness
Clonality - primary
Count of 10km squares in Great Britain: 270
Count of 10km squares in Ireland: 5
Count of 10km squares in the Channel Isles: 14
Atlas Change Index: -1.01
JNCC Designations
Scarce Atlas Account
Hypochaeris glabra L.
Smooth cat's-ear
Status: scarce
This plant grows on disturbed, usually nutrient-poor, light soils in acidic sandy, heathy and gravelly places. H. glabra prefers a sunny, warm and exposed situation, and is relatively intolerant of competition, for instance, in open communities on sand dunes, with Jasione montana and occasionally Corynephorus canescens. It often occurs in resown pastures, providing they are not fertilised or irrigated, with Agrostis spp., Potentilla argentea, Radiola linoides, Trifolium spp. and Vicia lathyroides. It was formerly found as a component of open arable communities with Scleranthus annuus and Teesdalia nudicaulis. It also colonises bare ground, along with other pioneer annuals such as Aphanes arvensis, Filago minima, Rumex acetosella and Senecio sylvaticus (Sinker et al. 1985).
H. glabra is a self-compatible annual herb, pollinated by bees. It produces fruit of two forms, which geminates after autumn rains have begun (Fone 1989).
There is no doubt that the range and frequency of H. glabra have been considerably reduced. It used to be more frequent as a weed of sandy arable land and also occurred as a shoddy weed (Silverside 1990). However, it is often overlooked because of its small size, and because it does not open its flowers until 9 a.m. and they shut again by 1 or 2 p.m. (Curtis 1777). Conversely, small forms of H. radicata are often optimistically recorded as H. glabra. The two occasionally hybridise (Stace 1975).
It is found in Europe, northwards to southern Scandinavia, and in North Africa and the Middle East. It is widely naturalised elsewhere.
D. A. Pearman
Atlas text references
Atlas (294a) .
1988. The Irish Red Data Book. 1. Vascular Plants. .
1989. Competition in mixtures of the annual Hypochoeris glabra and perennial H. radicata. Journal of Ecology. 77:484-494. .
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols. .
1992. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 3. 2 vols.