Yellow-flowered Crocuses

[davidbr]

Are these yellow-flowered crocuses, photographed in Gloucestershire on February 20th, Golden Crocus (Crocus chrysanthus), or the garden hybrid Crocus x stellaris? Or, for that matter, something else?

I've put at least three different names to them so far and I'm still no closer to finding a conclusive way to tell the difference between C. chrysanthus & C. x stellaris. Hopefully, someone can help out!

[KeenTeen17]

If you look in the Gallery, Tiggrx has uploaded photos of golden crocus and there are the purple tinges to the underside.

[Tiggrx]

Okay here are a couple of pictures to compare
C. chrysanthus


C. x stellaris


Sorry these make it look a bit simple but in fact C. chrysanthus is very variable and comes in a range of colours and patterns (even more when it hybridises with C. biflorus) and can be plain yellow.
However note:
1. flower shapes - C. chrysanthus has a more gourd shaped flower, note the distinct point about 1/3 way up the flower where the tepal starts curving outwards. C. x stellaris has a more typical crocus-shaped flower.
2. flower tube - in C. chrysanthus this is speckled with dark dots while in C. x stellaris you have distinct stripes.
3. flower size - C. x stellaris is noticeably larger than C. chrysanthus. Not that this is much help if you are not looking at both
4. the corm - this is the most distinctive bit, but would mean digging the plant up (please don't). C. chrysanthus has the corm-covering non-fibrous and splitting into rings at the base. In C. x stellaris it is fibrous.

In conclusion I think that your plants are C. x stellaris