Cowslip  (Primula veris)

Calcareous: containing free calcium carbonate, chalky.
Perennial: plants that live for at least three seasons; after an initial period they produce flowers once a year.
Rides: often the footpaths and access tracks which run through and divide blocks of trees in woodland. Many rides contain a mixture of rich flora and structure, and provide different habitat conditions for a range of wildlife.
Subspecies: a different race of a species, which is geographically separated from other populations of that species.

1. National Biodiversity Network Species Dictionary (Feb 2003):
   http://www.nhm.ac.uk/nbn
   
2. Clapham, A.R., Tutin, T.G. & Moore, D.M. (1987) Flora of the British Isles. 3rd Edition. Cambridge University Press, Cambridge.
   
3. Preston, C.D., Pearman, D.A. & Dines, T.D. (2002) The New Atlas of the British and Irish Flora. Oxford University Press, Oxford.
   
4. Mabey, R. (1996) Flora Britannica. Sinclair-Stevenson, London.
   
5. Press, B. & Gibbons, B (1993) Photographic field guide to wild flowers of Britain and Europe. New Holland Publishers (UK) Ltd, London.
   
6. A Modern Herbal (Feb 2003):
   http://www.botanical.com/botanical/mgmh/c/cowsl112.html
   
7. Plantlife Common Plants Survey (Feb 2003):
   http://www.plantlife.org.uk/html/commun_survey_intro.htm