Note there are many fumitories which are variable and hard to distinguish. Key features include size of flower (> or < 9mm); size and shape of sepals; whether lower petal is parallel-sided; and shape/surface of fruit and whether fruit stalk curves.
Fls <9mm
F. officinalis
F. densiflora
F. parviflora
Also
F. Vaillantii
Common Fumitory
Dense-flowered Fumitory
Fine-lvd Fumitory
Fls >9mm
F. capreolata
F. muralis
F. bastardii
bastardii vs muralis
White Ramping-fumitory
Common Ramping-fumitory
Tall Ramping-fumitory
Tall vs Common
F. occidentalis
F. purpurea
Purple vs. Western
Western Ramping-fumitory
Purple Ramping-fumitory
Purple vs. Western