Fennel similar spices – anise, star anise, and coriander. In 2014, India produced 60% of the world total of fennel, with China and Bulgaria as leading secondary producers (table). Many species in the family Apiaceae or Umbelliferae are superficially similar to fennel, and some, such as poison hemlock, are toxic, so it is unwise, and potentially extremely dangerous, to use any part of any of these plants as an herb or vegetable unless it can be positively identified as being edible. Dill, coriander, and caraway are similar-looking herbs, but shorter-growing than fennel, reaching only . Dill has thread-like, feathery leaves and
Flavour (particle physics) violated by weak interactions. Therefore, such flavour quantum numbers are not of great use. A separate quantum number for each generation is more useful: electronic lepton number (+1 for electrons and electron neutrinos), muonic lepton number (+1 for muons and muon neutrinos), and tauonic lepton number (+1 for tau leptons and tau neutrinos). However, even these numbers are not absolutely conserved, as neutrinos of different generations can mix; that is, a neutrino of one flavour can transform into another flavour. The strength of such mixings is specified by a matrix called the Pontecorvo–Maki–Nakagawa–Sakata matrix (PMNS matrix). All quarks carry a