Fumaria is usually considered a difficult genus as far as identification is concerned. It is mainly due to the small size of the characters that are useful for the identification and for the fact that often both flowers and fruits are needed.
On the basis of the observations of fumitories from North America, it seems that a revision is needed in order to clarify:
- the taxa that are present in North America
- their actual distribution
I would be happy to try to help those iNat users that would like to get more insight into the identification of fumitories.
Here it is a brief list of characters tat are needed for the identification of fumitories.
- corolla color, shape and length
- upper petal shape
- sepals shape and size (length and width)
- dry fruit shape and size (length and width)
- pedicel shape (stright, spreading or reflexed) and length at frutification
- bract length and bract/pedicel ratio
- flowers number for each inflorescence
- peduncle/inflorescence ratio
- leaflets shape
characters 1, 3, 4, 5 and 6 should be measured and photographed with a linen tester or a stereomicroscope and a sheet of millimeter paper
fruits shape (surface smooth or rugose; overall shape) should be evaluated when fruits are dry. To do this, just put an infructescence in a paper bag or let it dry with some kitchen paper inside a book.
This post represents an example of how a Fumaria should be photographed for its identification:
Among those fumitories found in North America F. capreolata (reflexed fruiting pedicels, sepals broader than corolla, fruits almost smooth) is the one that poses less problems for its identification. On the other hand, some pink-flowered fumitories are, somehow, more difficult to identify and many of them may be misidentied as F. officinalis.