Why not try to answer this question before reading on!
By “plants” Dr M means green plants (containing chlorophyll) and this includes vascular plants (flowering plants, conifers, ferns, horsetails and clubmosses), bryophytes (mosses, liverworts and hornworts) and green algae. NB The Plant Kingdom does NOT include the fungi and lichens.
Dr M focuses on vascular plants here and will deal with bryophytes and algae in later posts.
We can divide vascular plants into natives (those which arrived in the UK without intervention by man), archaeophytes (those naturalised prior to AD 1500), neophytes (those naturalised since AD 1500), and casuals (non-native and not naturalised).
The numbers of species in these groups vary according to whether microspecies are included; the numbers given in the New Atlas of the British & Irish Flora (2002) are:
How do these numbers compare with your own answer?
How many do you know? How many do you want to know?! It’s never too late to learn more botany! Dr M will be posting his eXtreme botany manifesto shortly, this is all about how you can take your botanical skills to the next level, watch this space, don’t ever leave drmgoeswild.com!
In addition to the above numbers, the Asteraceae contains some genera with many microspecies (species based on minute differences often apomictic (asexually reproducing) species):
354 native Hieracium (Hawkweed) microspecies.
137 native Taraxacum (Dandelion) microspecies.
More than 400 Rubus (Bramble) microspecies.
And in the Ranunculaceae an unknown number of microspecies in the Ranunculus auricomus (Goldilocks Buttercup) complex.
The checklist of British vascular plants is maintained by the Botanical Society of the British Isles
BSBI makes the checklist available to the National Biodiversity Network Species Dictionary
The JNCC proves summary information on plant species