Friday, 10 August 2012

Confusing Yellow Compositae....

Do you know your Leontodon from your Hypochoeris? Or your Taraxacum from your Crepis?

Our glorious yellow wild flowers are synonymous with summer and ooze sunshine even on the most drizzly of British summer days. But look at those yellow flowers in any grass field and you are looking at more than just dandelions (Taraxacum agg.)! The chances are that there are also cat's ears (Hypochaeris radicata), hawk's-beards (Crepis spp.), hawkbits (Scorzoneroides autumnalis, Leontodon saxatalis and L. hispidus), and possibly nipplewort (Lapsana communis) or mouse-ear hawkweed (Pilosella officinarium).

Take a look at the rosette of leaves at the base of a single proud yellow flower. Are they very hairy and is the stem of the flower branched and leafless? It's probably a cat's ear. The flowers of hawkbits (Scorzoneroides autumnalis, Leontodon spp.) can look very similar to cat's ear's. Rather unhelpfully, they also tend to both grow in the same place. To distinguish them you'll need to look carefully at the basal rosette of leaves. Are they nearly hairless? And the flower stalks are branched and leafless? Then it is probably an Autumn hawkbit (Scorzoneroides autumnalis – which also, confusingly, flowers well before Autumn – in fact we found it flowering in a pavement crack back in May). Or are the leaves very hairy and hairs forked on the tip (fold the leaf and inspect the hairs against the light)? Is the flower stalk unbranched? The plant is probably a rough hawkbit (Leontodon hispidus) or lesser hawkbit (L. saxatilis).

Who would have believed these are 4 different species of yellow composites: Crepis capillaris (left), Scorzoneroides autumnalis (bottom), Leontodon saxatilis (middle), Taraxacum agg. (top)

On the other hand, is the stem branched and slender, with small leaves along the stalk it's probably a hawk's-beard (and more than likely to be Crepis capillaris – smooth hawk's-beard).
Of course, we'd be generous with the truth if we said that this was an exhaustive list of the flowers you might find growing in a field that are yellow and dandelion-like. But these are the common ones and the chances are they're in a field near you.

These yellow Composites (named after the Daisy family of flowering plants) are a challenging group of flowers to distinguish, but if you're still keen, then pay a visit to an (unmown!) urban cemetery, parkland or road verge, and have a look at the flowers. There's no need to even identify the species...just observe and appreciate the diversity in one small patch of urban grassland. Or even in a crack in a pavement...

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